Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The combination of a cobalt-dioxolene core that exhibits valence tautomerism (VT) with pyridine-3,5-dicarboxylic acid functionalized with chains bearing two, four, or six oxyethylene units led to new complexes ConEGEspy (n = 2, 4, and 6). These complexes commonly form violet crystals of the low-spin (ls)-[Co-III(nEGEspy)(2)(3,6-DTBSQ)(3,6-DTBCat)] (ls-[Co-III], 3,6-DTBSQ = 3,6-di-tert-butyl semiquinonato, 3,6-DTBCat = 3,6-di-tert-butyl catecholato). Interestingly, violet crystals of Co2EGEspy in the ls-[Co-III] transitioned into a green liquid, accompanied by an almost complete VT shift (94 %) to the high-spin (hs)-[Co-II(nEGEspy)(2)(3,6-DTBSQ)(2)] (hs-[Co-II]) upon melting. In contrast, violet crystals of Co4EGEspy and Co6EGEspy in the ls-[Co-III] exhibited partial VT (33 %) and only a 9.3 % VT shift after melting, respectively. These data demonstrate the tunability of the synchronicity of the molecular VT and macroscopic solid-liquid transitions by optimizing the tethered chains, thus establishing a new strategy for coupling bistable molecules with the macroscopic world.

DOI： 10.1002/chem.202103090

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Exploring new types of photochemical reactions is of great interest in the field of synthetic chemistry. Although excited-state hydrogen detachment (ESHD) represents a promising prospective template for additive-free photochemical reactions, applications of ESHD in a synthetic context remains scarce. Herein, we demonstrate the expansion of this photochemical reaction toward oligomerization, disulfidation, and regioselective C(sp2)-H carboxylation of aromatic alcohols, thiols, and amines. In the absence of any radical initiators in tetrahydrofuran upon irradiation with UV light (λ = 280 or 300 nm) under an atmosphere of N2 or CO2, thiols and catechol afforded disulfides and oligomers, respectively, as main products. Especially, the photochemical disulfidation proceeded highly selectively with the NMR and quantum yields of up to 69 and 0.46%, respectively. In stark contrast, the photolysis of phenylenediamines and aminophenols results in photocarboxylation in the presence of CO2 (1 atm). p-Aminophenol was quantitatively carboxylated by photolysis for 17 h with a quantum yield of 0.45%. Furthermore, the photocarboxylation of phenylenediamines and aminophenols proceeds in a highly selective fashion on the aromatic C(sp2)-H bond next to a functional group, which is directed by the site-selective ESHD of the functional groups for the formation of aminyl and hydroxyl radicals.

DOI： 10.1021/acs.joc.0c02456

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We previously reported that a tris-(o-phenylenediamine) iron(ii) complex promotes photochemical H2 generation and C-H carboxylation of o-phenylenediamine without any additives under N2 and CO2 atmospheres, respectively, in tetrahydrofuran at room temperature. Herein, the key mechanistic process, namely, excited-state hydrogen detachment from the o-phenylendiamine moiety, is demonstrated under an N2 atmosphere.

DOI： 10.1039/d0cc06219g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Zeolites are usually synthesized by hydrothermal reactions using monomeric or polymeric Al- and Si-containing precursors, whereas simple and direct routes for the rational synthesis of zeolites remain elusive. In this work, we demonstrate the synthesis of the two zeolites L (LTL type) and W (MER type) from a single molecular precursor (MP), (PyH)[Al{Ph2Si(OSiPh2O)(2)}(2)] (AlSi6 ; PyH = pyridinium cation), under hydrothermal conditions using KOH as the only additive. Under acidic conditions, the heptanuclear structure of AlSi6 is hydrolyzed without cleavage of the Si-Ph bonds, while the hydrothermal reaction under basic conditions allows the crystallization of zeolites under concomitant Si-Ph cleavage. X-ray diffraction and scanning electron microscopy studies revealed that zeolite L, which exhibits a cylindrical morphology, was produced selectively by hydrothermal treatment of AlSi6 at 160-200 degrees C in the presence of KOH (3 eq.). In contrast, increasing the amount of KOH (from 6 to 12 eq.) resulted in the formation of zeolite W with a twin-ball morphology. The specific surface area and Si/Al ratios of the synthesized zeolites L and W are comparable to those previously reported. These experimental results suggest promising potential of structurally and compositionally well-defined MPs, including even those with organic functional groups, for the construction of zeolites.

DOI： 10.1039/d0ce00546k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VCH Verlag  

The global demand for energy and the concerns over climate issues renders the development of alternative renewable energy sources such as hydrogen (H2) important. A high-spin (hs) FeII complex with o-phenylenediamine (opda) ligands, [FeII(opda)3]2+ (hs-[6R]2+), was reported showing photochemical H2 evolution. In addition, a low-spin (ls) [FeII(bqdi)3]2+ (bqdi: o-benzoquinodiimine) (ls-[0R]2+) formation by O2 oxidation of hs-[6R]2+, accompanied by ligand-based six-proton and six-electron transfer, revealed the potential of the complex with redox-active ligands as a novel multiple-proton and -electron storage material, albeit that the mechanism has not yet been understood. This paper reports that the oxidized ls-[0R][PF6]2 can be reduced by hydrazine giving ls-[FeII(opda)(bqdi)2][PF6]2 (ls-[2R][PF6]2) and ls-[FeII(opda)2(bqdi)][PF6]2 (ls-[4R][PF6]2) with localized ligand-based proton-coupled mixed-valence (LPMV) states. The first isolation and characterization of the key intermediates with LPMV states offer unprecedented molecular insights into the design of photoresponsive molecule-based hydrogen-storage materials.

DOI： 10.1002/chem.202001873

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/chem.201900172

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1038/s41598-018-33060-3

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Other Link： http://www.nature.com/articles/s41598-018-33060-3

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VCH Verlag  

Methylation of the molybdenum sulfide cluster unit [Mo6S8(PEt3)6] (1) with CH3OTf resulted in the formation of mono- and dimethylated cluster units, [Mo6S8–x(SCH3)x(PEt3)6]OTf·yCH2Cl2 {[2]OTf·0.5CH2Cl2 (x = 1, y = 0.5) and [3]OTf·CH2Cl2 (x = 2, y = 1)}. Structural and electrochemical investigations revealed that the methylation of the µ3-S ligand(s) induced a characteristic structural distortion of the [Mo6S8] cluster core and enhanced its ability to accept multiple electrons.

DOI： 10.1002/ejic.201800587

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DOI： 10.1002/chem.201706006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

The reaction of N,N'-bis(diisopropylphosphoniumacetyl)-o-phenylenediamide dibromide (H4L center dot 2Br) with Ni-II[ClO4]center dot 6H(2)O in the presence of Et3N resulted in the formation of N, N'-bis(diisopropylphosphinoacetyl)-o-phenylenediamidate nickel(II) ([Ni-II(L)]). The single-crystal X-ray diffraction analysis of [Ni-II(L)] revealed that each pair of N and P atoms in L2- coordinates in a tetradentate fashion to afford a distorted square-planar Ni-II amide complex. On the other hand, N, N'-bis(diisopropylphosphinoacetyl)- o-phenylenediamide copper(I) bromide ([Cu-I(H2L)Br]) was isolated by the reaction of H4L center dot 2Br with [Cu-I(MeCN)(4)][PF6] in the presence of Et3N. The structural analysis revealed that the two P atoms in H2L coordinate in a bidentate fashion to afford a trigonal-planar Cu-I complex, in which the amide moieties remain in free form. Complex [Ni-II(L)] showed reversible deprotonation processes on the amidate ligand (L2-), whereas the protonated state of the N atoms of the amide ligand (H2L) in [Cu-I(H2L)Br] was maintained, even in the presence of excess Et3N, suggesting substantial stability for the protonated state.

DOI： 10.1002/ejic.201700433

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The design of redox-active metal-organic frameworks and coordination networks (CNs), which exhibit metaland/or ligand-centered redox activity, has recently received increased attention. In this study, the redox-active metalloligand (RML) [Me4N](3)fac-[CrIII(mp)(3)] (1) (mp= 2-mercaptophenolato) was synthesized and characterized by single-crystal X-ray diffraction analysis, and its reversible ligand-centered one-electron oxidation was examined by cyclic voltammetry and spectroelectrochemical measurements. Since complex 1 contains O/S coordination sites in three directions, complexation with K+ ions led to the formation of the two-dimensional honeycomb sheet-structured [K(3)fac{ Cr-III(mp)(3)}(H2O)(6)] n (2.6H(2)O), which is the first example of a redox-active CN constructed from a RML with o-disubstituted benzene ligands. Herein, we unambiguously demonstrate the ligand-centered redox activity of the RML within the CN 2.6H(2)O in the solid state.

DOI： 10.1002/chem.201701613

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The coordinative interactions of o-phenylenediamine and alkali or alkaline earth metals like Li+, Na+, Mg2+, or Ca2+, were investigated by X-ray structural analyses and IR, UV-vis, and (HNMR)-H-1 spectroscopies. These studies revealed that the coordinative interactions of o-phenylenediamine with metal ions through amino groups depend on the ratio of the charge and the ionic radius of the metal ions both in the solid state and in THF solution.

DOI： 10.1246/cl.160997

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Dehydrogenation of anhydrous methanol is of great importance, given its ubiquity as an intermediate for the production of a large number of industrial chemicals. Since dehydrogenation of methanol is an endothermic reaction, heterogeneous or homogeneous precious-metal-based catalysts and high temperatures are usually required for this reaction to proceed. Here we report the photochemical dehydrogenation of anhydrous methanol at room temperature catalysed by o-aminophenol (apH(2)), o-aminophenolate (apH(-)) and the non-precious metal complex trans-[Fe-II(apH)(2)(MeOH)(2)]. Under excitation at 289 +/- 10 nm and in the absence of additional photosensitizers, these photocatalysts generate hydrogen and formaldehyde from anhydrous methanol with external quantum yields of 2.9 +/- 0.15%, 3.7 +/- 0.19% and 4.8 +/- 0.24%, respectively, which are the highest values reported so far to the best of our knowledge. Mechanistic investigations reveal that the photo-induced formation of hydrogen radicals triggers the reaction.

DOI： 10.1038/ncomms12333

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-Blackwell  

DOI： 10.1002/chem.201503247

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Chemical one-electron oxidation of [Pt-II(3,5-DTBCat)(DTBbpy)] (1) (3,5-DTBCat = 3,5-di-tert-butyl catecholato, DTBbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) afforded the corresponding paramagnetic complex, [Pt-II(3,5-DTBSQ)(DTBbpy)]+PF6- (1(PF6)), as a result of ligand-centred oxidation. While complex 1 is relatively stable in common organic solvents, the present study demonstrates that cationic [1](+) is subject to an unprecedented solvent-induced disproportionation in highly polar solvents such as DMSO and DMF, which results in the formation of 1 and a free benzoquinone.

DOI： 10.1039/c6dt00487c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Chemical Society of Japan  

DOI： 10.1246/bcsj.20140208

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Language：Japanese   Publisher：Japanese Liquid Crystal Society  

Redox-active liquid crystals that have both liquid crystalline and redox properties are expected to give new and attractive electronic devises controlled by electrochemical methods at ambient conditions. We have reported the design and properties of Pt(II) metallomegens possessing redox-active catecholato or benzenedithiolato and long alkyl chain-substituted bipyridine ligands. Especially, metallomesogen possessing 3,5-t-butylcatecholato shows direct electrochemical redox responses and electrochemically -induced transformation between columnar liquid crystal and isotropic ionic liquid phases. In this work, the effects of coordinating atoms, the position of substituents, temperature, and electrolytes on electrochemical property of metallomesogens will be presented.

DOI： 10.11538/ekitou.2015.0__PB26

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.inorgchem.5b00578

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

<p>The redox behavior of redox-active metalloligand (RML), [Cr^III(F₄Cat)₃]³⁻ (F₄Cat: perfluorocatecholato), responsible for interaction with guest metal ions in solution are systematically demonstrated.</p>

DOI： 10.1039/c5dt01963j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/ic5021302

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The reaction of tetraethyl [2,3-dihydroxy-1,4-phenylenebis-(methylene)]bisphosphonate (Et4LH2) with [PtCl2(DTBbPY)] (DTBbpy: 4,4'-di-tert-butyl-2,2'-bipyridine) afforded [Pt(Me4L)-(DTBbpY)] (1), [Pt(Bn4L-)(DTBbPY)] (2), Na-2[Pt(Me2L)-(DTBbpy)] (3), and [Pt(H4L)(DTBbpy)] (4) with tetramethyl-, tetrabenzyl-, half-protected, and fully-deprotected groups under different reaction conditions. The introduction of phosphonatomethyl groups at the 3,6-position of a redox-active catecholato unit led to slight shifts in charge-transfer bands and catecholato-centered redox processes in solution. The presence of deprotonated anchors in 3 resulted in the immobilization of the complex onto an indium-doped tin oxide electrode, demonstrating a well-defined redox response from the tethered complex.

DOI： 10.1246/cl.140235

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A new porous coordination polymer (PCP), formulated as {[La-2(III)(mu(3)-OH)(CH3COO)(2)(H2O)][Cu-I(dmdcbpy)(2)]center dot 9H(2)O} (La2Cu center dot 9H(2)O; H(2)dmdcbpy: 6,6'-dimethyl-5,5'-dicarboxy-2,2'bipyridine), was synthesized and characterized by X-ray diffraction and vapor-adsorption isotherms. The porous framework of La2Cu consists of a 3-D coordination network of the Cu(I)-metalloligand and the tetranuclear La-4 cluster {La-4(mu(3)-OH)(2)(CH3COO)(4)(H2O)(2)}. La2Cu exhibits reversible guest adsorption desorption for various vapors, with reversible structural transformations.

DOI： 10.1246/cl.140249

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A heterodinuclear complex, syn-[PtCu(mu-pyt)(2)(bpy)(2)](2+) (syn-[PtCu]; Hpyt = pyridine-2-thiol, bpy = 2,2 '-bipyridine), was synthesized by stepwise complexation. Three different crystal structures of the hexafluorophosphate salts with solvent molecules as guests at the axial sites of the Cu(II) ions, i.e. syn-[PtCu-G] (G = acetonitrile, acetone, and methanol), were determined by X-ray analyses. In the solid-state, these complexes adopt dimer-of-dimer motifs characteristic of the syn isomers of dinuclear complexes with two pyt bridging ligands arranged in a head-to-head configuration. These dinuclear complexes have a short Pt. Cu distance (2.75-2.81 angstrom) and slightly different intermolecular Pt...Pt distances (3.43-3.51 angstrom), which affect the colour of the solid complexes. All the syn-[PtCu-G] systems absorbed/desorbed vapour molecules; however, they exhibit different chromic changes because of the unique structural hysteresis of the desorbed form, i. e. syn-[PtCu], according to powder X-ray diffraction measurements. In addition, guest exchange occurred in the syn-[PtM-G] complexes upon exposure to the vapour of different solvents.

DOI： 10.1039/c4dt00316k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Halide-bridged rhombic dicopper(I) complexes, [Cu-2(mu-X)(2)(DMSO)(2)(PPh3)(2)] (X = I-, Br-; DMSO = dimethyl sulfoxide; PPh3 = triphenylphosphine), were synthesized, the iodide complex of which exhibited interesting photochromic luminescence driven by photoirradiation and by exposure to DMSO vapor in the solid state. Single-crystal Xray diffraction measurements revealed that the iodo and bromo complexes (abbreviated Cu2I2-[O,O] and Cu2Br2-[O,O]) were isomorphous, and that the two DMSO ligands were coordinated to the Cu(I) ion via the O atom in both complexes. Both complexes exhibited bright blue phosphorescence at room temperature (lambda(em) = 435 nm, Phi(em) = 0.19 and 0.14 for Cu2I2[O,O] and Cu2Br2-[O,O], respectively) with a relatively long emission lifetime (tau(em) similar to 200 mu s at 77 K) derived from the mixed halide-to-ligand and metal-to-ligand charge transfer ((XLCT)-X-3 and (MLCT)-M-3) excited state. Under UV irradiation, the blue phosphorescence of Cu2Br2-[O,O] disappeared uneventfully and no new emission band appeared, whereas the blue phosphorescence of Cu2I2-[O,O] rapidly disappeared with simultaneous appearance of a new green emission band (lambda(em) = 500 nm). On further irradiation, the green emission of the iodide complex gradually changed to bright yellowish-green (lambda(em) = 540 nm); however, this change could be completely suppressed by lowering the temperature to 263 K or in the presence of saturated DMSO vapor. The initial blue phosphorescence of Cu2I2-[O,O] was recovered by exposure to DMSO vapor at 90 degrees C for a few hours. IR spectroscopy and theoretical calculations suggest that the DMSO ligand underwent linkage isomerization from O-coordination to S-coordination, and both the occurrence of linkage isomerization and the removal of DMSO result in contraction of the rhombic Cu2O4-O-2 core to make the Cu.-Cu interaction more effective. In the contracted core, the triplet cluster-centered ((CC)-C-3) emissive state is easily generated by thermal excitation of the (XLCT)-X-3 and (MLCT)-M-3 mixed transition state, resulting in the green to yellowish-green emission. In contrast, the Cu"Cu distance in Cu2Br2-[O,O] is considerably longer than that of Cu2I2[O,O], which destabilizes the (CC)-C-3 emissive state, resulting in the nonemissive character.

DOI： 10.1021/ic402104q

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：RSC  

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The combination of o-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris(o-phenylenediamine) iron(II) complex, [FeII(opda)3](ClO4)2 (1), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV-vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H+/e- donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H+/e- pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H2 production/storage materials. © 2013 American Chemical Society.

DOI： 10.1021/ja4025116

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The presence of lone pairs on the Pt and S atoms of [Pt(Bdt)(DTBbpy)] (1) (Bdt = 1,2-benzenedithiolato and DTBbpy = 4,4'-di-tert-butyl-2,2'-bipyridine) and [Pt (Bdt) (C13bpy)] (2) (C13bpy = 4,4'-ditridecyl-2,2'-bipyridine) led to selective dative bond formation with Cd(II). Complexes 1 and 2 show no binding interaction with Zn(II), while they bind selectively with Cd(II) to give a twisted trinuclear complex, [Cd{Pt(Bdt)(DTBbpy)}(2)(ClO4)(H2O)](ClO4) (3), and a shuttlecock-shaped tetranuclear complex, [Cd{Pt(Bdt)(C13bpy)}(3)(H2O)](ClO4)(2)center dot CH2Cl2 (4), respectively, depending upon the alkyl groups substituted on the 2,2'-bipyridine. The two platinum moieties in 3 are connected to the seven-coordinated Cd atom through Pt -&gt; Cd (2.7331(7) and 2.7936(7) angstrom) and S -&gt; Cd (2.690(3), 2.940(3), and 3.067(3) angstrom) dative bonds, while the three moieties in 4 are connected to the tetrahedral Cd atom only by S -&gt; Cd (2.552(4) angstrom) dative bonds. These structural variations found in 3 and 4 are caused not only by steric hindrance of the t-Bu groups but also by the microsegregation effect derived from the tridecyl chains. The three platinum moieties in 4 align so as to form a parallel orientation of their dipole moments, in contrast to the twisted arrangement found in 3. The dative bonds formed in 3 and 4 are commonly stable in the solid state and in less coordinative solvents such as dichloromethane, while dissociation behavior of platinum moieties with Cd(II) was observed in more coordinative THF. UV-vis and NMR spectroscopy unsealed the characteristic association/dissociation properties depending on the coordination abilities of solvents. Finally, the present study revealed that the formation of dative bonds between the platinum moieties with Cd(II) plays important roles not only in stabilizing the ground states, which leads to blue shifts in both absorption and emission energies, but also in electronic interactions between the moieties, which are revealed by electrochemical studies.

DOI： 10.1021/ic302352k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Heterodinuclear complexes, syn-[MPt(mu-pyt)(2)(bpy)(2)](n+) (syn-[MPt], M = Pd2+, Au3+, Hpyt = pyridine-2-thiol, bpy = 2,2'-bipyridine), were synthesized as a selective geometrical isomer by stepwise complexation. X-ray analyses of the hexafluorophosphate salts of these complexes proved their dinuclear structures with short M...Pt distances (2.9084(4) angstrom for syn-[PdPt] and 2.9071(4) angstrom for syn-[AuPt]), similar to the homodinuclear complex (2.9292(2) angstrom for syn-[PtPt]). In the syn-[PdPt] crystal, two dinuclear motifs are arranged closely in a head-to-head manner with a short Pt...Pt distance (3.3757(3) angstrom), forming a dimer-of-dimer structure as in the case of syn-[PtPt], whereas the corresponding crystal of syn-[AuPt] has a discrete arrangement of the dinuclear motifs. By the isomerisation of syn-[PdPt], anti-[PdPt] with equivalent environments of the Pd2+ and Pt2+ ions was also obtained successfully. Syn-[PdPt](PF6)(2) exhibits vapochromic behaviour based on the absorption/desorption of CH3CN vapour, similar to that observed for syn-[PtPt](PF6)(2). The reversible structural transformations induced by the uptake and release of CH3CN molecules were investigated by powder and single-crystal X-ray diffraction studies. These revealed that the vapochromic behaviour was based on the interconversion between two phases, the dimer-of-dimer structure with a short Pt. Pt distance and a p-p stacked arrangement with no Pt. Pt intermolecular interaction. The introduction of the heterometal ions enabled control of the colour region: orange. red for syn-[PdPt] vs. light red. dark red for syn-[PtPt], reflecting the weaker metal-metal interaction between Pd2+ and Pt2+ ions in the dinuclear motif. In addition, these complexes were found to exhibit mechanochromic behaviour based on a crystal-to-amorphous transformation upon grinding, and the reconstruction of the crystal structures by vapour sorption.

DOI： 10.1039/c3dt33100h

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VCH  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We synthesized a novel Pt(II)-diimine complex with a typical ambidentate thiocyanato ligand, [Pt(thiocyanato)(2)(H(2)dcbpy)] (1; H(2)dcbpy =4,4'-dicarboxy-2,2'-bipyridine), and found that the complex 1 exhibits unique linkage isomerizations with drastic color and luminescence changes driven by exposure to volatile organic chemical (VOC) vapors in the solid state. Reaction between [PtCl2(H(2)dcbpy)] and KSCN in aqueous solution at 0 degrees C enabled successful isolation of an isomer with the S-coordinated thiocyanato ligand, [Pt(SCN)(2)(H(2)dcbpy)] (1SS center dot H2O), as a nonluminescent orange solid. Interestingly, 1SS center dot H2O was isomerized completely to one isomer with the N-coordinated isothiocyanato ligand, [Pt(NCS)(2)(H(2)dcbpy)] (1NN center dot 3DMF) by exposure to DMF vapor, and this isomerization was accompanied by significant color and luminescence changes from nonluminescent orange to luminescent red. IR spectroscopy and thermogravimetric analysis revealed that adsorption of the DMF vapor and transformation of the hydrogen-bonded structure both played important roles in this vapor-induced linkage isomerization. Another isomer containing both S- and N-coordinated thiocyanato ligands, [Pt(SCN)(NCS)(H(2)dcbpy)] (1SN), was obtained as a nonluminescent yellow solid simply by exposure of 1SS center dot H2O to acetone vapor at room temperature, and about 80% of 1SS center dot H2O was found to be converted to 1SN. In the solution state, each isomer changed gradually to an isomeric mixture, but pure 1SS was regenerated by UV light irradiation (lambda(irr) = 300 nm) of an MeOH solution of the mixture. In the crystal structure of 1SN, the complex molecules were hydrogen-bonded to each other through the carboxyl groups of the H(2)dcbpy ligand and the N site of the thiocyanato ligand, whereas the 1NN molecules in the 1NN.4DMF crystal were hydrogen-bonded to the solvated DMF molecules. Competition of the hydrogen-bonding ability among the carboxyl groups of the H(2)dcbpy ligand, N and S atoms of the thiocyanato ligand, and the vapor molecule was found to be one of the most important factors controlling linkage isomerization behavior in the solid state. This unique linkage isomerization controlled by vapor can provide an outstanding vapochromic system as well as a new molecular switching function driven by vapor molecules.

DOI： 10.1021/ic202734f

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The redox-active fac-[Mo-V(mp)(3)](-) (mp: o-mercaptophenolato) bearing asymmetric O- and S-cation binding sites can bind with several kinds of metal ions such as Na+, Mn-II, Fe-II, Co-II, Ni-II, and Cu-I. The fac-[Mo-V(mp)(3)](-) metalloligand coordinates to Na+ to form the contact ion pair {Na+(THF)(3)[fac-Mo-V(mp)(3)]} (1), while a separated ion pair, n-Bu4N[fac-Mo-V(mp)(3)] (2), is obtained by exchanging Na+ with n-Bu4N+. In the presence of asymmetric binding-sites, the metalloligand reacts with (MnCl2)-Cl-II center dot 4H(2)O, (FeCl2)-Cl-II center dot 4H(2)O, (CoCl2)-Cl-II center dot 6H(2)O, and (NiCl2)-Cl-II center dot 6H(2)O to afford UV-vis-NIR spectra, indicating binding of these guest metal cations. Especially, for the cases of the MnII and CoII products, trinuclear complexes, {M(H2O)(MeOH)-[ fac-Mo-V(mp)(3)](2)}center dot 1.5CH(2)Cl(2) (3.1.5CH(2)Cl(2) (M = Mn-II), 4.1.5CH(2)Cl(2) (M = Co-II)), are successfully isolated and structurally characterized where the M are selectively bound to the hard O-binding sites of the fac-[Mo-V(mp)(3)](-). On the other hand, a coordination polymer, {Cu-I(CH3CN)[mer-MoV(mp)(3)]}(n) (5), is obtained by the reaction of fac-[Mo-V(mp)(3)]-with [Cu-I(CH3CN)(4)]ClO4. In sharp contrast to the cases of 1, 3.1.5CH(2)Cl(2), and 4.1.5CH(2)Cl(2), the Cu-I in 5 are selectively bound to the soft S-binding sites, where each CuI is shared by two [MoV(mp) 3]-with bidentate or monodentate coordination modes. The second notable feature of 5 is found in the geometric change of the [MoV(mp) 3]-, where the original fac-form of 1 is isomerized to the mer-[Mo-V(mp)(3)](-) in 5, which was structurally and spectroscopically characterized for the first time. Such isomerization demonstrates the structural flexibility of the [Mo-V(mp)(3)](-). Spectroscopic studies strongly indicate that the association/dissociation between the guest metal ions and metalloligand can be modulated by solvent polarity. Furthermore, it was also found that such association/dissociation features are significantly influenced by coexisting anions such as ClO4- or B(C6F5)(4)(-). This suggests that coordination bonds between the guest metal ions and metalloligand are not too static, but are sufficiently moderate to be responsive to external environments. Moreover, electrochemical data of 1 and 3.1.5CH(2)Cl(2) demonstrated that guest metal ion binding led to enhance electron-accepting properties of the metalloligand. Our results illustrate the use of a redox-active chalcogenolato complex with a simple mononuclear structure as a multifunctional metalloligand that is responsive to chemical and electrochemical stimuli.

DOI： 10.1039/c2dt30178d

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Reactions of a Pt(II)-diimine-based metalloligand Na-2[Pt(CN)(2)(4,4'-dcbpy)] (4,4'-H(2)dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) with alkaline-earth metal salts Mg(NO3)(2)center dot 6H(2)O, CaCl2, SrCl2 center dot 6H(2)O, and BaBr2 center dot 2H(2)O in aqueous solution gave luminescent complexes formulated as [Mg(H2O)(5)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 4H(2)O (MgPt-4 center dot 9H(2)O), {[Ca(H2O)(3)][Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (CaPt-4 center dot 6H(2)O), {[Sr(H2O)(2)][Pt(CN)(2)(4,4'-dcbpy)]center dot H2O}(infinity) (SrPt-4 center dot 3H(2)O), and {[Ba(H2O)(2)][ Pt(CN)(2)(4,4'-dcbpy)]center dot 3H(2)O}(infinity) (BaPt-4 center dot 5H(2)O), respectively. The crystal structures of all MPt-4 complexes were determined by X-ray crystallography. In these structures, the alkaline-earth metal ions are commonly coordinated to the carboxyl groups of the [Pt(CN)(2)(4,4'-dcbpy)](2-) metalloligand. In the case of MgPt-4 center dot 9H(2)O, the Mg(II) ion is bound by five water molecules and one oxygen atom of a carboxyl group to form a neutral complex molecule [Mg(H2O) 5][Pt(CN)(2)(4,4'-dcbpy)]. In contrast, the alkaline-earth metal ion and metalloligand form two-dimensional (CaPt-4 center dot 6H(2)O) and three-dimensional (SrPt-4 center dot 3H(2)O and BaPt-4 center dot 5H(2)O) coordination networks, respectively. All fully hydrated complexes exhibited a strong phosphorescence from the triplet pi-pi* transition state. Luminescence spectroscopy revealed that MgPt-4 center dot 9H(2)O exhibited interesting multichromic (i.e., thermo-, mechano-, and vapochromic) luminescence, whereas CaPt-4 center dot 6H(2)O showed only thermochromic luminescence. The other two complexes did not exhibit any chromic behaviour. Combination analysis of powder X-ray diffraction, thermogravimetry, and IR spectroscopy suggests that the dimensionality of the coordination network contributes considerably to both the structural flexibility and luminescence properties; that is, the low-dimensional flexible coordination network formed in MPt-4 complexes with smaller alkaline-earth metal ions enables a structural rearrangement induced by thermal and mechanical stimuli and vapour adsorption, resulting in the observed multichromic behaviour.

DOI： 10.1039/c1dt11155h

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Dinuclear complexes [{Pt(trpy)}(2)(L)](PF6)(2) (trpy = 2,2': 6',2 ''-terpyridine, L = 2-octylthio-1,3,5-triazine4,6- dithiolate ion (1), L = 2-octadecylthio-1,3,5-triazine-4,6-dithiolate ion (2), L = 2-di-n-butylamino1,3,5- triazine-4,6-dithiolate ion (3)) and a trinuclear complex [{Pt(trpy)}(3)(L)](PF6)(3) (L = 1,3,5-triazine2,4,6- trithiolate ion (4)) have been synthesized and characterized. The single crystal X-ray analysis revealed that the two {Pt(trpy)}(2+) fragments in 1 and 3 adopt a syn-configuration. The Pt...Pt distances are around 4.3 angstrom, suggesting no intramolecular Pt...Pt interactions. Complexes 1-4 in acetonitrile show broad absorption bands at around 470 nm, assigned to mainly the ligand-to-ligand charge transfer ((LLCT)-L-1) from triazine thiolates to trpy based on the comparison to the related complexes and the density functional theory (DFT) calculations. The red luminescence of 1-4 in acetonitrile is attributable to emission predominantly from (LLCT)-L-3. Cyclic voltammograms of 1-3 exhibit four redox couples from -2.0 V to 0 V vs. Ag/AgCl. The two consecutive processes at around -0.70 V are assigned to the sequential reduction of two trpy ligands. This assignment was further supported by the observation of the anion radical of trpy in spectroelectrochemical experiments. The splitting of the redox potentials of two trpy ligands evidences the moderate electronic coupling interactions mediated by the triazine dithiolate bridges. Complex 2 formed a transparent red gel in CH3CN, whereas 4 produced a gel-like solid in the mixtures of CH3CN and other solvents. The interactions dominating the aggregative behaviours have been discussed based on the results of electronic absorption and emission spectroscopy.

DOI： 10.1039/c2dt30997a

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A new copper(II)-hydrazone complex, [Cu(paph)Cl(CH3-OH)] (Hpaph: 2-pyridinecarboxaldehyde 2-pyridylhydrazone) (1) has been synthesized and characterized by single-crystal X-ray diffraction and UV-vis spectroscopy. This complex shows distinctive color changes by the protonation/deprotonation and exhibits interesting ON OFF switching of solvatochromic behavior on the basis of the protonation/deprotonation of the hydrazone moiety.

DOI： 10.1246/cl.2011.1335

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We describe the novel synthesis of a bis(hydrazone)iron(B) complex in protonated [Fe(Hpbph)(2)]Cl-2 (1) and deprotonated [Fe(pbph)(2)] (2) forms and several hydrogen-bonded proton-transfer (HBPT) assemblies having different dimensionalities of hydrogen-bonded network structures, [Fe(Hpbph)2] (CA)center dot 2CH(3)OH (3), [Fe(Hpbph)(2)](HCA)(2)center dot 2THF (4), and [Fe(Hpbph)(2)](CA)(H(2)CA)(2)center dot 2CH(3)CN (5) (Hpbph = 2-(diphenylphosphino)benzaldehyde-2-pyridylhydrazone), consisting of a deprotonated Fe(II)-hydrazone complex (2) as a proton acceptor (A) and chloranilic acid (H2CA) as a proton donor (D). The deprotonated complex 2 exhibited two-step reversible protonation reactions to form the double-protonated form 1, and the acid-dissociation constants were determined to be 7.6 and 10.3 in methanol solution. Utilizing this proton-accepting ability of 2, we succeeded in synthesizing HBPT assemblies 3, 4, and 5 from the reactions in CH3OH, THF, and CH3CN, respectively, with the same D/A ratio of H(2)CA/[Fe(pbph)(2)] = 10:1. These assemblies were found to have one-dimensional (1-D), two-dimensional (2-D), and three-dimensional (3-D) hydrogen-bonded networks with D/A ratios of 1:1, 2:1, and 3:1 for 3, 4, and 5, respectively. In 3, a 1-D hydrogen-bonded chain composed of the alternate arrangement of [Fe(Hpbph)(2)](2+) and CA(2-), {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot CA(2-)center dot center dot center dot}(infinity), was surrounded by solvated methanol molecules to form isolated 1-D hydrogen-bonded chains. In the HBPT assembly 4, a 2-D hydrogen-bonded sheet was formed from two types of hydrogen-bonded chains, {center dot center dot center dot[Fe(Hpbph)(2)](2+)center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity) and {center dot center dot center dot HCA(-)center dot center dot center dot HCA(-)center dot center dot center dot}(infinity), and solvated THF molecules did not form any hydrogen bonds. In 5, two orthogonal hydrogen-bonded chains constructed from the neutral chloranilic acid molecules, {center dot center dot center dot CA2(-)center dot center dot center dot 2(H(2)CA)center dot center dot center dot}(infinity), were formed in addition to the 1-D hydrogen-bonded chain similar to that in 3, resulting in the formation of a rigid 3-D hydrogen-bonded network structure. By controlling the dimensionality of the hydrogen bond network, we found that the 2-D HBPT assembly 4 is sufficiently flexible to exhibit interesting vapochromic behavior in response to various organic vapors.

DOI： 10.1021/ic2008396

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Liquid crystalline (LC) platinum(II) complexes with 1,2-thiophenolato and 1,2-benzendithiolato have been newly synthesized and investigated by spectroscopy together with the catecholato analogue. The variations in coordinating atoms (O or S or O/S mixed) lead to significant modulation in electrochemical properties in solution and absorption and emission properties of the complexes both in solution media and in the condensed phases. The asymmetric, polar mesogens/chromophores consisting of Pt(II), redox-active ligands, and alkyl-substituted bipyridine commonly play important roles not only in stabilizing the columnar LC phases, but also in fluctuations of the ground state energies. A key finding of the present work is the chromic properties of LC complexes induced by the interplay of self-association of the mesogens/chromophores and their fluctuating properties.

DOI： 10.1021/ic102123n

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

DOI： 10.1021/ic102070c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We synthesized new porous coordination polymers (PCPs) {Ln(III)[Co(III)(dcbpy)(3)]center dot nH(2)O} (Ln = Nd(3+), Gd(3+); H(2)dcbpy = 4,4&apos;-dicarboxy-2,2&apos;-bipyridine) and characterized them by X-ray diffraction and vapor-adsorption measurements. These three Ln-Co-based PCPs have similar rock-salt types and highly symmetrical porous structure and show a reversible structural collapse regeneration accompanied by water-vapor desorption adsorption. Similar structural regeneration was also observed for the Gd-Co PCP upon exposure to MeOH and CH(3)CN vapors, whereas the remaining two PCPs barely responded to organic vapors.

DOI： 10.1021/ic102361d

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A series of cyclometalated dinuclear platinum(II) complexes bridged by pyridine-2-thiolate (pyt) ions, [Pt-2(L)(2)-(pyt)(2)] (HL = 2-(p-tolyl)pyridine (Hptpy), 2-(2-thienyl)pyridine (Hthpy), or benzo[h]quinoline (Hbzqn)), as well as their two-electron-oxidized dinuclear platinum(III) complexes, [Pt2Cl2(L)(2)(pyt)(2)], have been synthesized and characterized. The structures and luminescence properties have been investigated by comparing them with those of the corresponding 2-phenylpyridinato (ppy) complex. All divalent complexes have similar dinuclear frameworks, with short Pt center dot center dot center dot Pt distances (ca. 2.85 angstrom), and exhibit similar intense luminescence from the triplet metal metal-to-ligand charge-transfer ((MMLCT)-M-3) state in glassy solutions. However, they provide different luminescence features reflecting their dynamic behaviors in fluid solutions and their intermolecular interactions in the solid state. [Pt-2(bzqn)(2)(pyt)(2)] containing fused aromatic rings exhibits the most sensitive features to the environment, i.e., it shows the most red-shifted luminescence spectrum in the solid state due to the intermolecular pi-pi interaction. However, in fluid solution, it provides very weak luminescence based on a rapid nonradiative deactivation mainly caused by the fluctuation of the intramolecular pi-pi repulsion between the ligands. [Pt-2(Ptpy)(2)(pyt)(2)], on the other hand, is the most stable luminophore, which always exhibits intense luminescence with an almost constant emission maximum independent of its temperature and state.

DOI： 10.1246/bcsj.20100304

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We synthesized a thiosemicarbazone-functionalized flavin (Fl-(H) TSC: 2-[2-(3,4-dihydro-7,8-dimethyl-2,4-dioxobenzo[g]pteridin-10(2H)-yl)ethylidene]-hydrazinecarbothioamide) and its Pt(II) complex [Pt(Fl-TSC)(2)], and characterized it using X-ray diffraction, UV-visible absorption and luminescence spectroscopy. X-ray structural analysis for [Pt(Fl-TSC)(2)] revealed that the structure of the isoalloxazine part was almost the same as that in lumiflavin (7,8,10-trimethylisoalloxazine), and the thiosemicarbazone moiety acted as a bidentate ligand to form a PtS2N2 planar conformation. UV-visible absorption and luminescence spectra of these compounds were very similar to those of riboflavin, but the emission intensity and the lifetime decreased considerably. Theoretical calculations suggested that the charge-separated state (Fl(center dot-)-TSC center dot+) contributed to the faster quenching from the (1)pi-pi* emission state.

DOI： 10.1039/c0dt01139h

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Four new bimetallic coordination polymers (CPs), {M[Pt(CN)(2)(5,5&apos;-dcbpy)]center dot 4H(2)O}(n) (M = Mg(2+), Ca(2+), Sr(2+), Ba(2+); 5,5&apos;-H(2)dcbpy = 5,5&apos;-dicarboxy-2,2&apos;-bipyridine) were synthesized using four alkaline-earth metal ions and a Pt(II)-diimine metalloligand [Pt(CN)(2)(5,5&apos;-H(2)dcbpy)]. All four CPs are isomorphous with the Zn complex, {Zn[Pt(CN)(2)(5,5&apos;-dcbpy)]center dot 4H(2)O}(n), which exhibits effective metallophilic interactions between Pt(II) ions. These CPs exhibited colourful thermochromic behaviour and solid-state solvatochromic-like behaviours when suspended in various solvents. Thermogravimetric analysis and vapour-adsorption measurements revealed that the CPs can reversibly adsorb water and MeOH vapours. The emission energy of the triplet metal-metal-to-ligand charge-transfer ((3)MMLCT) state varied markedly upon guest adsorption/desorption. The chromic and vapour-adsorption properties of these CPs depend strongly on the cross-linking M(2+) ions.

DOI： 10.1039/c1dt10518c

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A new series of substituted hydrazone complexes, [Cu(Hpbph)I] (1), [Cu(Hpbph)PPh3]PF6 (2-PF6), [NiCl-(Hpbph)]Cl (3-Cl), [PtCl(Hpbph)]ClO4 (4-ClO4), and [PtCl(pbph)] (4b) (Hpbph = 2-(diphenylphosphino)benzaldehyde 2-pyridylhydrazone) have been synthesized and characterized. X-ray crystallography revealed that the copper(1) complexes adopt pseudo-tetrahedral geometry, while the nickel(II) and platinum(II) complexes provide square-planar forms. All the complexes exhibit distinct color changes on the basis of the deprotonation/protonation on the ligand although their acid/base behaviors are largely different. The acidity constants (pK(a)) in methanol were determined to be 11.4 (1), 12.5 (2), 7.7 (3), and 6.7 (4). The results indicate that the dissociation of the proton on the ligand strongly depends on the ligand deformation controlled by the coordination geometry of the complexes and ancillary ligands also somewhat affect the acidity.

DOI： 10.1246/bcsj.20100065

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Functionalization of a cobalt/dioxolene complex with branched, asymmetric alkyl chains promotes non-cooperative and cooperative valence tautomerisms synchronized with thermodynamically favoured crystal-to-melt and kinetically generated glass-to-melt phase transitions, respectively, depending on the degree of crystallinity.

DOI： 10.1039/c001568g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Mineral oil microdroplets containing the model antioxidant N,N-didodecyl-N&apos;,N&apos;-dietliyl-phenylene-diamine (DDPD) are immobilized into a 100 x 100 pore-array (ca. 10 mu m individual pore diameter, 100 mu m pitch) in a boron-doped diamond electrode surface. The robust diamond surface allows pore filling, cleaning, and reuse without damage to the electrode surface. The electrode is immersed into aqueous electrolyte media, and voltammetric responses 1 or the oxidation of DDPD are obtained. In order to further improve the current responses, 20 wt% of carbon nanofibers are co-deposited with the oil into the pore array. Voltammetric signals are consistent with the oxidation of DDPD and the associated transfer of perchlorate anions (in aqueous 0.1 M NaClO(4)) or the transfer of protons (in aqueous 0.1 M HClO(4)). From the magnitude of the current response, the DDPD content in the mineral oil can be determined down to less than 1 wt% levels. Perhaps surprisingly, the reversible (or midpoint) potential for the DDPD oxidation in mineral oil (when immersed in 0.1 NaClO(4)) is shown to be concentration-dependent and to shift to more positive potential values for more dilute DDPD in mineral oil solutions. An extraction mechanism and the formation of a separate organic product phase are proposed to explain this behavior.

DOI： 10.1002/elan.200904590

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Coordination Chemistry  

The present contribution reviews the synthesis and properties of complexes including redox-active dioxolene ligands as well as its analogues, diiminosemiquinonato, and dithiolene ligands. This review first summarizes the structural and electronic features of new molecular complexes as a building block for constructing electronically labile molecular assemblies. Ligand-based mixed valence (LBMV) state has been realized both in mononuclear chromium and pentanuclear cobalt complexes. Second topic will be on the construction of molecular assemblies integrated by intermolecular stacking or charge-transfer interactions, clusterization, and ligand-unsupported M-M bonds. The formation of a thin film which acts as an active layer of a field-effect transistor will also be described. Final attention is drawn to the use of the redox-active complexes for the construction of stimuli-responsive molecular assemblies. The review will demonstrate recent developments of molecular assemblies that show macroscopic phase transition or phase transformation triggered by intramolecular electron transfer or redox reaction in solid, liquid, and liquid crystals.

DOI： 10.4019/bjscc.53.24

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Other Link： https://jlc.jst.go.jp/DN/JALC/00337206410?from=CiNii

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

This paper describes a molecular valence tautomeric (VT) bistability synchronized with polymorphic crystal-melt phase transitions of a newly designed VT complex, [Co(C9Espy)(2)(3,6-DTBQ)(2)] (CoC9Espy, C9Espy = dinonyl-pyridine-3,5-dicarboxylate and 3,6-DTBQ = 3,6-di-tert-butyl-semiquinonate (3,6-DTBSQ) or catecholate (3,6-DTBCat)). Two polymorphic crystals which are the thermodynamically stable phase (K1) and the kinetically stable phase (K2), commonly containing a [low spin-Co(III)(C9Espy)(2)(3,6-DTBSQ)(3,6-DTBCat)] (ls-[Co(III)]) tautomer with a low-spin Co(III) atom and mixed-valence ligands. These polymorphic crystals show a molecular VT interconversion that is synchronized with crystal-to-melt phase transitions at different temperatures, 368.2 and 362.6 K for the ls-[Co(III)]subset of K1 and the ls-[Co(III)]subset of K2 phases, respectively. Interestingly, the ls-[Co(III)]subset of K2 obtained from a melt of a [high spin-Co(II)(C9Espy)(2)(3,6-DTBSQ)(2)] (hs-[Co(II)]) tautomer with a high-spin Co(II) atom with two 3,6-DTBSQ exhibits a double-melting phenomenon that includes, in part, the thermodynamically unfavorable hs-[Co(II)]-to-ls-[Co(III)] VT interconversion. Eventually, three types of VT interconversions synchronized with macroscopic crystal-melt phase transitions appear either in equilibrium or nonequilibrium conditions: (1) the thermodynamically stable ls-[Co(III)]subset of K1 to the hs-[Co(II)]subset of melt, (2) the metastable ls-[Co(III)]subset of K2 to the hs-[Co(II)]subset of melt, and (3) the relaxing process of the metastable hs-[Co(II)]subset of melt to the thermodynamically stable ls-[Co(III)]subset of K1. A new strategy for simultaneous control of molecular states and macroscopic phases using thermodynamically and kinetically formed polymorphic crystalline phases is presented.

DOI： 10.1021/cm900543r

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

A zinc complex of biladienone forms a dimer in toluene and dichloromethane. Binding of two molecules of amino alcohols and diamines to the dimer occurs cooperatively, with the first binding constant being two orders OF three orders of magnitude smaller than the second binding constant. Simple amines such as butylamine did not show Such cooperative binding. We suggest the mechanism of cooperative binding, where the amino or hydroxyl group in amino alcohols or diamines prevents the dinner dissociation to result in the less tight binding for the first guest, while the binding of the second ligand caused dimer dissociation to release strain in the intermediate complex. (c) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.tetlet.2008.11.057

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A novel alkyl chain-functionalized manganese complex with dioxolene ligands shows a bimodal three-membered valence tautomerism, one of which synchronizes with a cooperative solid-melt phase transition and the other occurs in the melt noncooperatively.

DOI： 10.1039/b901939a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Dynamic properties of a diruthenium complex with ligand-unsupported Ru-Ru triple bonds, Na(2)[Ru(2)(3,6-DTBCat)(4)] (1), were studied using variable-temperature (1)H NMR. Structural freedom derived from the ligand-unsupported structure leads to torsional motion about the Ru-Ru bonds in THF and in DMF. The observed solvent dependency corresponds to the electrostatic interactions between the diruthenium complex and Na(+) counter cations, which are sensitive to the polarity of solvents. In addition, a new diruthenium complex, [{Na(THF)(2)(H(2)O))[Na(THF)(0.5)(H(2)O)}{Ru(2)(3,6-DTBCat)(2)(H(4)Cat)(2)}] (2-2.5THIF center dot 2H(2)O), with a ligand-unsupported Ru-Ru bond surrounded by two different kinds of catecholate derivatives, has been synthesized and crystallographically characterized. The complex, which was characterized by single-crystal structural analysis, will provide an opportunity to investigate not only static molecular structures but also dynamic physicochemical properties in comparison with analogues containing four identical catecholate derivatives. (c) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.molstruc.2008.05.027

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VCH  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Here, we show a synchronic bistability of valence tautomeric (VT) molecular interconversion and a macroscopic crystal-melt phase transition in long alkoxy-functionalized cobalt-dioxolene complexes. Studies have been carried out for a novel series of complexes, [Co(CnOPY)(2)(3,6-DTBQ)(2)] (3,5-dialkoxy(CnH2 On+1-; n = 9, 12, and 17)pyridine (CnOpy) and 3,6-di-tert-butyl semiquinonate or catecholate ligands (3,6-DTBQ)). All complexes show the molecular VT interconversion with thermal hysteresis attributed to the synchronous crystal-melt phase transition. Thermodynamic analysis has revealed that the molecular VT interconversion is restricted over 50 K and crystal-melt phase transition is accelerated about 50 K by the synchronicity. The synchronicity is attributed to enthalpic and entropic effects of the alkoxy chains in the crystalline phase of the one tautomer and the melt phase of the other, respectively. Our results show efficient chemical and thermodynamic strategies to combine molecule-based and macroscopic bistabilities.

DOI： 10.1021/ja711268u

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We demonstrate a strategy that appears particularly well suited for the design of redox-active liquid crystals and also constitutes the first demonstration of cyclic voltammetric responses of a metallomesogen in the columnar liquid crystalline phase.

DOI： 10.1039/b709103f

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Chemical oxidation of [Ru-2(6+)(3,6-DTBCat)(4)](2-) affords [n-Bu4N][Ru-2(3,6-DTBDiox)(4)]center dot acetone (2 center dot acetone). The oxidized species was characterized by X-ray crystallographic analysis and EPR, and the delocalization of the unpaired electron over the entire molecule was indicated. This example showed that the utilization of redox-active ligands into a Ru-2 complex expanded the degree of freedom in the electronic structure. DFT calculations support this view, and the spin population was estimated to be approximately 18% and 82% for the Ru-2 core and the four dioxolene ligands, respectively.

DOI： 10.1021/ic052180p

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Three novel trinuclear cobalt(II) compounds of pyridazine, [CO3(mu-OH)(2)(P-pdz)(4)(pdz)(2)(NO3)(2)(H2O)(2)]-(NO3)(2)(.)(THF)(.)2(MeOH) (1), [Co-3 (mu-OH)(2)(mu-pdz)(4)(pdz)(4) (NO3)(2)] (.) [Co-3 (mu-OH)(2)(P-pdz)(4)(MeOH)(4)(NO3)(2)](.)(NO3)(4) (2), and [Co-3(P-pdz)(4)(mu-NCS)(2)(pdz)(2)(NCS)(4)](.)2MeOH (3) (pdz = pyridazine), have been synthesized and characterized. The structures of all three compounds consist of centrosymmetric trimer building blocks bridged by the two nitrogen atoms of the pyridazine ligands and the second small bridging anions (hydroxide in I and 2, and end-on thiocyanate in 3). The two-atom bridging modes of the pyridazine ligand in 1 and 2 are unusual: each bridging pyridazine ligand affords two nitrogen donors to two metal ions with different bond lengths. This results in two kinds of spin states for the cobalt(II) atoms in 1. Magnetic measurements show a typical antiferromagnetic interaction between the high-spin metals in 3, but an unusual magnetic coupling through two high- and one low-spin cobalt atoms within the trimer in 1. An irregular spin states structure is also observed in 1 at low temperature. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).

DOI： 10.1002/ejic.200500741

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A novel series of valence tautomeric (VT) complexes, [Co(Cnbpy)(3,5-DTBQ)(2)] (Cnbpy = 4,4'-dialkyl-2,2'-bipyridine (alkyl = (CnH2n+1) where n = 0 (CoCObpy), 1 (CoC1bpy), 5 (CoC5bp), 9 (CoC9bpy) and 13 (CoC13bpy); 3,5-DTBQ = 315-di-tert-butylsemiquinonate or catecholate), including two previously reported complexes (CoCObpy and CoC1bpy), were systematically prepared and their properties examined. Introduction of alkyl groups into VT chromophores leads to unexpected variations in the VT process, depending on the lengths of the alkyl chains. An even more interesting observation is that significant polytypic phase transitions with crystallographic symmetry changes accompanying the abrupt VT conversion are induced for the first time in CoC9bpy and CoC13bpy.

DOI： 10.1039/b513807h

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Language：Japanese   Publisher：THE JAPANESE LIQUID CRYSTAL SOCIETY  

A first example of redox-active metallomesogen with catechol was designed using the branched alkyl chains. A hexagonal columnar ordered phase (Colho) is fairly stable over 161 degeeC from 31 degreeC. The direct electrochemical study on the Colho phase illustrates that the redox process occurred at a three-phase junction of the Colho, the electrode, and the electrolyte solution.

DOI： 10.11538/ekitou.2006.0.97.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

To explore the relationships between the structures of ligands and their complexes, we have synthesized and characterized a series of metal complexes with two structurally related ligands, 9-acridinecarboxylic acid (HL1) and 4-quinolinecarboxylate acid (HL2), [Cu-2(mu(2)-OMe)2(L-1)2(H2O)(0.69)](n) 1, [Cu-2(L-1)(4)(CH3OH)(2)] 2, [Cu-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 3, [Mn-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 4, [Co-3(L-1)(6)(CH3OH)(6)]center dot 3H(2)O 5, [Cu(L-2)(2)], 6, [Mn(L-2)(2)(H2O)](n) 7, and [Co(L-2)(2)(H2O)](n) 8. 1 is a three-dimensional (3D) polymer with an interpenetrating NbO type network showing one-dimensional (1 D) channels, whereas 2 and 3 take bi- and trinuclear structures, respectively, because of the differences in basicity of the reaction systems in preparing the three complexes. 4 and 5 have trinuclear structures similar to that of 3. In 1-5, ligand L-1 performs different coordination modes with NO-bridging in 1 and O,O'-bridging in 2-5, and the metal ions also show different coordination geometries: square planar in 1, square pyramidal in 2, and octahedral in 3-5. 6 has a two-dimensional structure containing (4,4) grids in which L-2 adopts the NO-bridging mode and the Cull center takes square planar geometry. 7 and 8 are isostructural complexes showing 1 D chain structures, with L-2 adopting the O,O-bridging mode. In addition, the intermolecular O-H center dot center dot center dot N hydrogen bonds and pi-pi stacking interactions further extend the complexes (except 1 and 6), forming 3D structures. The magnetic properties of 2-7 have been investigated and discussed in detail.

DOI： 10.1021/ic050886d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Isomers of [Ru-2(III,III)(3,5-DTBCat)(4)](2-) (3,5-DTBCat(2-) = 3,5 -di-tert-butylcatecholate) were successfully characterized. It is found that the isomerization from the kinetically stable cis,cis form to the thermodynamically stable trans,trans form is caused not only by heating but also by the cation exchange from Na+ to n-BU4N+, revealing that the isomerization is regulated by the specific cation-anion interactions.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

DOI： 10.1021/ja052663s

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The reactions of isonicotinic acid analogues, 4-quinolinecarboxylic acid (HL1) and 9-acridinecarboxylic acid (HL2) with M(NO3)(2) (M = Zn-II and Cd-II) in the presence of Et3N in MeOH (or EtOH) led to the formation of four new complexes, [Zn(L-1)(2)(H2O)](infinity) (1), [Zn(L-2)(2)(MeOH)(2)](3)center dot(H2O)(1.5) (2) and [Cd(L-2)(2)(MeOH)(2)](3)center dot(H2O)(1.5) (3) and [Cd(L-2)(2)(EtOH)(2)](3)center dot(H2O)(0.5) (4). Single crystal X-ray diffraction analyses revealed that the Zn-II and Cd-II complexes of the same ligand (L-1 or L-2) are isostructural, with 1 taking a 1D chain structure, with 2-4 being trinuclear complexes. In such complexes, the carboxylate groups adopt a bidentate syn, syn-bridging coordination fashion to bridge adjacent metal centers. The N donors do not take part in the coordination, but form O-H center dot center dot center dot N hydrogen bonds with the coordinated water or MeOH (or EtOH), leading to the formation of 3D frameworks. The effects of pi-pi stacking and the structural differences between these complexes and those with isonicotinic acid were also discussed.

DOI： 10.1039/b506721a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The molecular structures and physicochemical properties of diruthenium complexes with ligand-unsupported Ru-Ru bonds, generally formulated as [A(2){Ru-2(DTBCat)(4)}] (DTB = 3,5- or 3,64-tert-butyl; Cat(2) = catecholate), were studied in detail by changing the countercations. First, the binding structures of the cations in a family of [{A(DME)n}(2){Ru-2(3,5-DTBCat)(4)}] (n = 2 for A(+) = Li+ and Na+ and n = 1 for A(+) = K+ and Rb+) were systematically examined to reveal the effects of the cations on the molecular structures and electrochemical properties. Second, the complex (n-Bu4N)(2)[Ru-2(3,6-DTBCat)(4))]with a cation-free structure was synthesized using tetra-n-buyammonium cations. The complex clearly demonstrates first that the ligand-unsupported Ru-Ru bonds are essentially stabilized by the dianionic nature of the catecholate derivatives without any other bridging or supporting species. In contrast, the redox potentials and absorption spectra of the complexes can sensitively respond to the countercations depending upon the polarity of the solvents.

DOI： 10.1021/ic048250u

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A family of diruthenium complexes with ligand-unsupported Ru-Ru bonds has been systematically synthesized, and their crystal structures and physical properties have been examined. A simple, useful reaction between Ru-2(OAc)(4)Cl (OAc- = acetate) and catechol derivatives in the presence of bases afforded a variety of diruthenium complexes, generally formulated as [Na-n{Ru-2(R(4)Cat)(4)}] (n = 2 or 3; R-4 = -F-4, -Cl-4, -Br-4, -H-4, -3,5-di-t-Bu, and -3,6-di-t-Bu; Cat(2-) = catecholate). The most characteristic feature of the complexes is the formation of short ligand-unsupported Ru-Ru bonds (2.140-2.273 angstrom), These comprehensive studies were carried out to evaluate the effects of the oxidation states and the substituents governing the molecular structures and physicochemical properties. The Ru-Ru bond distances, rotational conformations, and bending structures of the complexes were successfully varied. The results presented in this manuscript clearly demonstrate that the complexes with ligand-unsupported Ru-Ru bonds can sensitively respond to redox reactions and ligand substituents on the basis of the greater degree of freedom in their molecular structures.

DOI： 10.1021/ic048251m

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

A tetrameric [Co-II(phenSQ)(2)](4) with homovalent semiquinonates reacts with o-phenylenediamines to give a ligand-based mixed-valence pentanuclear cluster [{Co-5(II)(phenSQ)(4)(phen-Cat)(3)(THF)(3)(H2O)}center dot THF], containing two differently charged ligands, whose formation is triggered by a dehydration condensation reaction between the semiquinonates and o-phenylenediamines.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Two novel isomorphous porous frameworks of Ln( III), {[Ln(2)(imidc)(2)(H2O) (3)](H2O)}(n), [Ln = Gd(III) (1) and Er(III) (2)] have been synthesized hydrothermally using multifunctional 4,5-imidazoledicarboxylic acid (imidc) as a connector; they have a zeolite-like network topology which can provide another form upon dehydration, and exhibit selective adsorption properties for H2O over N-2, CO2 and MeOH.

DOI： 10.1039/b500971e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

DOI： 10.1002/anie.200462962

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Bilindiones and biladienones carrying aryl groups at the meso positions were prepared using coupled oxidation reactions of iron tetraarylporphyrins in 20 - 63% yield.

DOI： 10.1039/b414299c

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/anie.200490079

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Novel metal-complex assemblies constructed from the flexible hinge-like ligand H(2)bhnq (H(2)bhnq= 2,2'-bi(3-hydroxy-1,4-naphthoquinone)) have been synthesized. The X-ray crystal structures of these compounds reveal that four types of architectures are accessible by variation of the metal ions. In copper(II) compounds 1-3, the chelating bhnq(2-) ions bridge copper(II) centers to form one-dimensional zigzag chains. The chains of 1-3 are arranged by hydrogen-bonding interactions and stacking interactions to produce porous structures. Cobalt(II) and zinc(II) compounds 4 and 5 form one-dimensional helical chains. In 4 and 5, the crystal packing induces spontaneous resolution of the helical chains with chiral cavities formed perpendicular to the helices. Nickel(II) compounds 6 and 7 form cyclic tetramers. The fourth architecture, a dimer (compound 8), is obtained by the reaction of zinc(II) and bhnq(2-) in MeOH. In these compounds, changes of the dihedral angles and the metal-coordination mode of the bhnq(2-) ion induce the structural versatility. The assemblies of the zigzag chains of the copper(II) compounds exhibit reversible vapochromic behavior. UV/Vis, powder X-ray diffraction, EPR, and adsorption isotherm measurements indicate that this vapochromic behavior is based on the hinge-like flexibility of the bhnq(2-) ion.

DOI： 10.1002/chem.200305640

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The magnetic properties of molecular oxygen adsorbed in the micro-porous metal-organic solids have been investigated. Adsorbed O-2 molecules form a ladder structure in the nanochannels of CPL-1. The temperature dependence of susceptibility and the high-field magnetization process indicate the nonmagnetic ground state of the adsorbed O-2 at low temperatures. (C) 2003 Elsevier B. V. All rights reserved.

DOI： 10.1016/j.jmmm.2003.11.327

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A 2D bilayered ferromagnetic coordination polymer, generated by lower-temperature hydrothermal reactions of cobalt(II) salt with the 3,4-pyridinedicarboxylate dianion, was controlled to transform into a 3D magnetic coordination network with Co-3(OH)(2) ferrimagnetic chains at a higher temperature.

DOI： 10.1039/b312058a

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE-INT SOC OPTICAL ENGINEERING  

We synthesized novel ligand-based mixed valence (LBMV) Cr-III-dioxolene complexes, [Cr(X(4)SQ)(X(4)Cat)(4,4'-di-tertbutyl-2,2'-bpy)] (SQ = semiquinone, Cat = catecohol, 2,2'-bpy = 2,2'-bipyridine; X = Cl (2a) and Br (2b)) and [Cr(X(4)SQ)(X(4)Cat)(4,4'-dinonyl-2,2'-bpy)] (X = Cl (3a) and Br (3b)), and prepared thin films for investigating their third-order nonlinear optical (NLO) properties in terms of the mixed valence states. Electronic absorption spectra of these complexes in solution and solid states showed an intervalence charge-transfer (IVCT) band from Cat(2-) to SQ(.) at the IR region, indicating of a coexistence of SQ and Cat ligands, namely, LBMV state of the complexes. These complexes were well soluble in nonpolar organic solvent, which allowed us to prepare thin films by spin coating. The obtained films showed the electronic absorption spectra similar to those in solution and were amorphous because of steric hindrance of halogen and alkyl substituents in o-dioxolene and 2,2'-bpy moieties, respectively. The chi((3)) values of the films of 3a and 3b with a thickness of 30 similar to 40 nm were determined for 1.0 x 10(-12) esu at 1.907 mum.

DOI： 10.1117/12.559114

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.200453923

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.200352024

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Syntheses and crystal structures of three new compounds {trans-[Cu(Hsal)(2)(4,4'-bipy)](DMF)}(n) (1), {cis-[Cu(Hsal)(2)(4,4'-bipy)](2H(2)O)}(n) (2), and [Cu-2(Hsal)(4)(4,4'-bipy)](n) (3) are reported. These three compounds have trans-, cis-, and dimer geometries bearing a common motif [Cu(Hsal)(2)(4,4-bipy)(n)] leading to ladder, zig-zag, and linear one-dimensional (1-D) networks, respectively. The Cu...Cu distances separated by 4,4'-bipy are different in these three compounds, which leads to an extension structure in compound 3 and a compact structure in compound 2. Conformations of 4,4'-bipy ligands in these three compounds are also different. In compound I there is stacking of the bidentate salicylate and the bridging salicylate from another molecule. There is also stacking of salicylate and 4,4'-bipy from another molecule in compound 2. (C) 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/S0020-1693(03)00254-8

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

An interesting ferromagnetic linear trinuclear copper(II) compound containing an in-situ synthesised functional ligand has been rationally obtained and crystallographically characterised, confirming a new route to magnetic polynuclear clusters. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).

DOI： 10.1002/ejic.200300197

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A new family of three-dimensional cubic-like [M(dca)(3)](-) networks ( dca = dicyanamide) templated by appropriate cations has been constructed and structurally characterized by X-ray crystallography.

DOI： 10.1039/b300760j

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Language：Japanese   Publisher：Japanese Liquid Crystal Society  

Novel mono/trinuclear palladium/platinum complexes have been synthesized and characterized by X-ray diffraction, electrochemical, and thermogravimetric analyses. All the complexes possess catecholate derivatives, which have been known to show rich redox activity. Almost complexes show multi-step thermal phase transitions, and each transition was studied by XRPD and DSC measurements. Interestingly, the complexes demonstrate redox activity based on the electronically labile nature of the catecholate derivatives. The results obtained in this study clearly suggest that the complexes would be candidates for redox-active metallomesogens.

DOI： 10.11538/ekitou.2003.0_389

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

A novel three-dimensional coordination polymer with a mixed-valence localized copper(I, II) dimeric unit, [Cu-2(4-pya) (3)](n) (4-pya = 4-pyridinecarboxylate), was hydrothermally synthesized via a simultaneous in-situa redox and hydrolysis reaction of Cu(II) and 4-cyanopyridine and crystallographically characterized to be a twofold interpenetrated three-dimensional coordination network with a cubic [Cu-16(4-pya)(12)] building unit.

DOI： 10.1039/b210914j

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC ADVANCEMENT SCIENCE  

We report the direct observation of dioxygen molecules physisorbed in the nanochannels of a microporous copper coordination polymer by the MEM (maximum entropy method)/Rietveld method, using in situ high-resolution synchrotron x-ray powder diffraction measurements. The obtained MEM electron density revealed that van der Waals dimers of physisorbed O(2) locate in the middle of nanochannels and form a one-dimensional ladder structure aligned to the host channel structure. The observed O-O stretching Raman band and magnetic susceptibilities are characteristic of the confined O(2) molecules in one-dimensional nanochannels of CPL-1 (coordination polymer 1 with pillared layer structure).

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A fascinating 3D pseudo-polyrotaxane architecture with 1D polymeric [Ag(bpp)](n) chains penetrating 2D (6,3) [Ag-2(bpp)(2)(ox)](n) sheets and a 3D coordination network constructed with 2D infinite [Ag(ppa)], beta-sheetlike layers pillared by ox ligands (bpp = 1,3-bis-(4-pyridyl)propane; ppa = N-(4-pyridinylmethyl)-4-pyridinecarboxamide; ox = oxalate) have been prepared by utilizing flexible pyridyl-type ligands and have been crystallographically characterized. Crystal data for 1: monoclinic, space group C2/c, a = 7.619(2) Angstrom, b = 19.781(4) Angstrom, c = 26.799(5) Angstrom, beta = 94.720(10)degrees, U = 4025.2(15) Angstrom(3), and Z = 4. Crystal data for 2: monoclinic, space group C2/c, a = 28.947(8) Angstrom, b = 8.617(3) Angstrom, c = 16.307(6) Angstrom, beta =121.07(l)degrees, U = 3484(2) Angstrom(3), and Z= 4.

DOI： 10.1021/ic0256922

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Language：Chinese   Publishing type：Research paper (scientific journal)   Publisher：CHINESE CHEMICAL SOCIETY  

The title complex, [Cu(Hsal) (2)(py)(2)], was synthesized by layered-solution technique and structurally characterized by single-crystal X-ray. The copper atom has a square pyramidal geometry and the coordination number is five. The molecular structure is linear one-dimensional network. There is a stacking effect between pyridine ligands of neighbouring 1-D chains and the molecular structure is extended into two-dimensional stacking network. Two salicylates in the complex have a position of crab pincers-like, in which one salicylate is unidentate and another coordinates through the carboxylate group and phenyl group unidentately.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

The treatment of CrIII(X(4)SQ)(3) (SQ = o-semiquinonate; X = Cl and Br) with acetonitrile affords trans-Cr-III(X(4)SQ)- (X(4)Cat)(CH3CN)(2) (X = Cl (1) and Br (2)). In the presence of 2,2'-bipyridine (bpy) or 3,4,7,8-tetramethyl-1,10-phenanthrene (tmphen), the reaction affords Cr-III(X(4)SQ)(X(4)Cat)(bpy)(.)nCH(3)CN (X = Cl, n = 1 (3); X = Br, n = 0.5 (4)) or Cr-III(X(4)SQ)(X(4)Cat)(tmphen) (X = Cl (5) and Br (6)), respectively. All of the complexes show a ligand-based mixed-valence (LBMV) state with SQ and Cat ligands. The LBMV state was confirmed by the presence of the interligand intervalence charge-transfer band. Spectroscopic studies in several solvent media demonstrate that the ligand dissociation included in the conversion of Cr-III(X(4)SQ)(3) to 1-6 occurs only in solvents with relatively high polarity. On the basis of these results, the effects of solvent media were examined and an equilibrium, Cr-III(X(4)SQ)(3) Cr-III(X(4)BQ)(X(4)SQ)(X(4)Cat) (BQ = o-benzoquinone), is proposed by assuming an interligand electron transfer induced by solvent polarity.

DOI： 10.1021/ic025643p

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Four porous crystalline coordination polymers with two-dimensional frameworks of a double-edged axe-shaped motif, {[Co(NCS)(2)(3-pia)(2)] . 2EtOH . 11 H(2)O}(n) (1a), {[Co(NCS)(2)- (3-pia)(2)] . 4Me(2)CO}(n) (3a), {[Co(NCS)(2)- (3-pia)(2)] . 4THF}(n) (3b) and {[Co(NCS)(2)- (3-pna)(2)](n)} (5), have been synthesized by the reaction of cobalt(ii) thiocyanate with N-(3-pyridyl)isonicotinamide (3-pia) or N-(3-pyridyl)nicotinamide (3-pna). X-ray crystallographic characterization reveals that adjacent layers are stacked such that channels are created, except in 5. The channels form a hydrogen-bonded interior for guest molecules; in practice, I a contains ethanol and water molecules as guests in the channels with hydrogen bonds, whereas 3b (3a) contains tetrahydrofuran (acetone) molecules. In la, the "double-edged axe-shaped" motifs in adjacent sheets are not located over the top of each other, while the motifs in 3b stack so perfectly as to overlap each other in an edge-to-edge fashion. This subtle change in the three-dimensional framework is associated with the template effect of the guests. Compound 5 has no guest molecules and, therefore, the amide groups in one sheet are used for hydrogen-bonding links with adjacent sheets. Removal of the guest molecules from la and 3b (3a) causes a structural conversion accompanied by a color change. Pink 1 a cannot retain its original framework and changes into a blue amorphous compound. On the other hand, the framework of pink 3b (3a) is transformed to a new crystalline framework of violet 4. Interestingly, 4 reverts to the original pink crystals of 3b (3a) when it is exposed to THF (or acetone) vapor. Spectroscopic measurements (visible, EPR, and IR) provide a clue to the crystal-to-crystal transformation; on removal of the guests, the amide groups are used to form the P sheet-type hydrogen bonding between the sheets, and thus the framework withstands significant stress on removal of guest molecules. This mechanism is attributed to the arrangement of the adjacent sheets so suited in regularity that the P sheet-type structure forms efficiently. The apohost 4 does not adsorb cyclopentane, showing a guest selectivity that, in addition to size, hydrogen-bonding capability is required for the guest molecules. The obtained compound is categorized as a member of a new generation of compounds tending towards functional porous coordination polymers.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Reactions of the Rh hydrido complex [Rh(H)(2)(PPh3)(2)(EtOH)(2)]ClO4 (1) With nitrogen ligands such as 2-(4-thiazolyl)benzimidazole (tbz). pyridazine (pdz), imidazole (im) and pyrimidine (pmd) in CH,Cl, afforded Various mononuclear Rh hydrido complexes, [Rh(H)(2)(PPh3)(2)(tbz)]CIO4 (2), [Rh(H)(2)(PPh3)(2)(pdZ)(2)]ClO(4)(.)2CH(2)Cl(2) (3). [Rh(H)Cl(PPh3)(2)(pdz)(2)](ClO4CH2Cl2)-C-. (4). [Rh(H)(2)(PPh3)(2)(im)(2)]ClO(4)(.)2CH(2)Cl(2) (5). [Rh(H)Cl(PPh3)(2)(im)(2)](ClO4CH2Cl2)-C-. (6). [Rh(H)(2)(PPh3)(2)(pmd)(2)](ClO4CH2Cl2)-C-. (7) and the Rh non-hydrido complex [RhCl2(pmd)(4)]ClO4 (8). The Rh complexes 2. 3, 5 and 6 were crystallographically characterized. The formation process was monitored by H-1 NMR and UV-Vis spectra. In all the Rh hydrido complexes, the Rh atom is coordinated by two PPh3. ligands in trans-positions and two nitrogen ligands in the cis-positions. The remaining sites Lire occupied by one or two hydride atoms to form a saturated 18-electron framework in a slightly distorted octahedral geometry. For complex 2 an appreciable inter-molecular pi interaction is observed between planes of tbz and PPh3 ligands, while an intra-molecular hydrogen bonding interaction between C-H and Cl atoms is found in complex 6. (C) 2002 Elsevier science Ltd. All rights reserved.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of|rn|Chemistry  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Reactions of Rh and Ir hydrido complexes. [Rh(H)(2)(PPh3)(2)(solv)(EtOH)]ClO4 (solv = Me2CO, 1a; EtOH, 1b) and [Ir(H)(2)(PPh3)(2)(Me2CO)(2)]BF4 (2), with various N,N'-donor bridging ligands, such as pyrazine (pyz), 4,4'-trimethylenedipyridine (tmdp) and di(4-pyridyl) disulfide (dpds), in some solvents were examined, and their reaction products were characterized by X-ray crystal structure analysis. IR, H-1 NMR and UV-vis spectra. Rh hydrido complexes, la or 1b, formed a dinuclear Rh complex, [Rh-2(PPh3)(2) {(eta(6)-C6H5PPh2}(2)] (ClO4)(2).6CH(2)Cl(2) (3.6CH(2)Cl(2)), in dichloromethane with a reductive elimination of hydrogen. The reactions of 1a or 1b with the pyz ligand in dichloromethane and tetrahydrofuran gave triangular Rh-3 complexes, [Rh-3(PPh3)(6)(pyz)(3)](ClO4)(3).CH2Cl2 (5.CH2Cl2) and [Rh-3(PPh3)(6)(pyz)(3)](ClO4)(3).EtOH (5.EtOH), respectively, in contrast to the formation of a dinuclear Rh hydrido complex, [Rh-2(H)(4)(PPh3)(4)(Me2CO)(2)(pyz)](ClO4)(2).EtOH A-EtOH). in acetone. The reactions of la or 1b with the tmdp ligand in dichloromethane and 3-methyl-2-butanone also afforded dinuclear Rh complexes, [Rh-2(PPh3)(4)(tmdp)(2)](ClO4)(2) (6) and [Rh-2(PPh3)(4)(tmdp)(2)](ClO4)(2).4MeCOCHMe(2) (6.4MeCOCHMe(2)), respectively. On the other hand, Ir hydrido complex 2 reacted with pyz and dpds ligands in dichloromethane to afford dinuclear Ir complexes, [Ir-2(H)(4)(PPh3)(4)(Me2CO)(2)(pyz)]- (BF4)(2).3CH(2)Cl(2) (7.3CH(2)Cl(2)) and [Ir-2(H)(4)(PPh3)(4)(dpds)(2)](BF4)(2).3CH(2)Cl(2).H2O (8.3CH(2)Cl(2).H2O), respectively, without any reductive elimination of hydrogen. Based on structural studies in solution and in the solid state. it was demonstrated that various Rh and Ir complexes were selectively produced depending on the choice of solvents and N,N'-donor bridging ligands.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Three novel one-diniensional coordination polymers with pyridazine (pdz), [M (pdz) Cl-2]n (M = Cu (II) (1), Fe (II) (2), Mn (II) (3)), were synthesized and characterized. All the compounds have one-dimensional zigzag chain structures. The copper ion in compound 1 has a planer coordination sphere with two bridging pdz ligands and two Cl-anions, while the metal ions in the other compounds have a distorted octahedral environment with pdz and Cl- groups both acting as bridges. The magnetic data of these compounds show antiferromagnetic interaction between the magnetic centers within the chains.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Tris(tetrahalogeno-o-semiquinonate) chromium (III) complexes, Cr-III(Cl(4)SQ)(3).4C(6)H(6) (1) and Cr-III(Br(4)SQ)(3).4C(6)H(6) (2), crystallize in an isostructural form; tetragonal, P4(1)2(1)2 with a = 13.452(2) Angstrom, c = 24.78(2) Angstrom, V = 4484(3) Angstrom(3) and a = 13.7465(7) Angstrom, c = 25.680(1) Angstrom, V = 4852.6(4) Angstrom(3) for 1 and 2, respectively. The inner coordination environments of the complex molecules are similar to that of previously reported crystal, Cr-III(Cl(4)SQ)(3).CS2.1/2C(6)H(6), while both complexes show strong pi...pi interaction between the three SQ ligands and the four solvate benzene molecules, resulting the formation of two-dimensional pi...pi stacking array. The effect of pi...pi interactions was evaluated by thermogravimetric and differential scanning calorimetric analysis where the weigh loss corresponding to the four benzene molecules was observed up to 500 K indicative of the interactions between the ligands and solvated benzene molecules.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Metal-metal bonded Ru3+(mu -OR)(2)Ru3+ and Ru3.5+(mu -OR)(2)Ru3.5+ (R = CH3 and CH3CH2) compounds with tetrachlorocatecholate (Cl(4)Cat) have been synthesized in the corresponding alcohol, MeOH and EtOH, from a nonbridged Ru2+-Ru3+ compound, Na-3[Ru-2(Cl(4)Cat)(4)(THF)]. 3H(2)O . 7THF (1). In alcohol solvents, compound 1 is continuously oxidized by oxygen to form Ru3+(mu -OR)(2)Ru3+ and Ru3.5+(mu -OR)(2)Ru3.5+ species. The presence of a characteristic countercation leads to selective isolation of either Ru3+(mu -OR)(2)Ru3+ or Ru3.5+(mu -OR)(2)Ru3.5+ as a stable adduct species. In methanol, Ph4PCl and dibenzo-18-crown-6-ether afford Ru3+(mu -OMe)(2)Ru3+ species, [A](2)[Ru-2(Cl(4)Cat)(4)(mu -OMe)(2)Na-2(MeOH)(6)] ([A](+) = Ph4P+ (2), [Na(dibenzo-18-crown-6)(H2O)(MeOH)](+) (3)), while benzo-15-crown-5-ether provides a Ru3.5+(mu -OMe)(2)Ru3.5+ species, [Na(benzo-15-crown-5)(2)][Ru-2(Cl(4)Cat)(4)(mu -OMe)(2)Na-2(MeOH)(6)] (4). The air oxidation of 1 in a MeOH/EtOH mixed solvent (1:1 v/v) containing benzo-15-crown-5-ether provides a Ru3.5+(mu -OMe)(2)Ru3.5+ species, [Na(benzo-15-crown-5)(H2O)][Ru-2(Cl(4)Cat)(2)(mu -OMe)(2)Na-2-(EtOH)(2)(H2O)(2)(MeOH)(2)](.)(benzo-15-crown-5) (5). Similarly, the oxidation of 1 in ethanol with Ph4PCl provides a Ru3.5+(mu -OEt)(2)Ru3.5+ species, (Ph4P)[Ru-2(Cl(4)Cat)(4)(mu -OEt)(2)Na-2(EtOH)(6)] (7). A selective formation of a Ru3+(mu -Oet)(2)Ru3+ species, (Ph4P)(2)[Ru-2(Cl(4)Cat)(4)(mu -OEt)(2)Na-2(EtOH)(2)(H2O2)(2)] (6), is found in the presence of pyrazine or 2,5-dimethylpyrazine. The crystal structures of these compounds, except 2 and 7, have been determined by X-ray crystallography, and all compounds have been characterized by several spectroscopic and magnetic investigations. The longer Ru-Ru bonds are found in the Ru3+(mu -OR)(2)Ru3+ species (2.606(1) and 2.628(2) Angstrom for 3 and 6, respectively) compared with those of Ru3.5+(mu -OMe)(2)Ru3.5+ species (2.5260(6) Angstrom and 2.514(2) Angstrom for 4 and 5, respectively.
These structural features and magnetic and ESR data revealed the electronic configurations of sigma (2)pi (2)delta (*2)delta (2)pi (*2) and sigma (2)pi (2)delta (*2)delta (2)pi (*1) for Ru3+(mu -OR)(2)Ru3.5+(mu -OR)(2)Ru3.5+, respectively, in which the former is diamagnetic and the latter is paramagnetic with S = 1/2 ground state. Compound 5 forms a one-dimensional chain with alternating arrangement of a Ru3.5+(mu -OMe)(2)Ru3.5+ unit and a free benzo-15-crown-5-ether molecule by intermolecular hydrogen bonds (O(H2O). . .O(crown-ether) = 2.91-3.04 Angstrom).
The cyclic voltammetry in DMF affords characteristic metal-origin voltammograms; two quasi-reversible redox waves were observed. The feature of cyclic voltammograms for the Ru3+(mu -OR)(2)Ru3+ species (2,3, and 6) and the Ru3.5+(mu -OR)(2)Ru3.5+ species (4 and 7) are similar to each other, indicating that both species are electrochemically stable. The isolation of the pyrazine-trans-coordinated species, [Ph4P][Ru(Cl(4)Cat)(2)(L)(2)] (L = pyrazine (8), 2,5-dimethylpyrazine (9)), revealed the selective isolation of 6 from pyrazine-containing solution. UV-vis spectral variation by ethanolysis for 9 demonstrated the selective conversion from the pyrazine-trans-coordinated species to the Ru3+(mu -OEt)(2)Ru3+ species without an oxidation to the Ru3.5+(mu -OEt)(2)Ru3.5+ species. This result suggests the presence of equilibrium between [Ru(Cl(4)Cat)(2)(L)(2)](-) and Ru3+(mu -OEt)(2)Ru3+ species in the synthetic condition for 6.

DOI： 10.1021/ic0010252

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A series of redox isomers of [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) , [Cr-III(X(4)SQ)(2)(X(4)Cat)](-), and [Cr-III(X(4)SQ)(3)](0) (X = Cl and Sr, SQ = semiquinonate, and Cat = catecholate) have been synthesized and characterized as charge-transfer (CT) compounds with metallocenium cations: ((CoCP2)-C-III)(2)[Cr-III(Cl(4)SQ)(Cl(4)Cat)(2)] (1), ((CoCp2)-Cp-III)(2)[Cr-III(Br(4)SQ)(Br(4)Cat)(2)] (2), ((FeCp2)-Cp-III) [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)].C6H6 (4), ((FeCp2)-Cp-III) [Cr-III(Br(4)SQ)(2)(Br(4)Cat)]. CS2 (5), and ((FeCp2)-Cp-III)[Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)][Cr-III(Cl(4)SQ)(3)] (6). First, the oxidation states of the chromium complexes are strongly dependent on the redox potentials of the metallocenes used. The (CoCp2)-Cp-II, exhibiting stronger reduction power than (FeCp2)-Cp-II, is useful for two-electron reduction of the [Cr-III(X(4)SQ)(3)](0), affording [Cr-III(X4SQ) (X(4)Cat)(2)](2-) (1 and 2), which are first isolated and crystallographically characterized in the solid state. In contrast the reaction with (FeCp2)-Cp-II affords only [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) (4 and 5). Second, solvents influence crystal structures of these compounds. The solvent set of C6H6/CS2 gives 1:1:C6H6 compound 4 with unique charged anions, [Cr-III(C(4)SQ)(2)(Cl(4)Cat)](-), while the other set, n-C6H12/CS2, affords 1:2 compound 6 including the two redox isomers, [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-) and [Cr-III(Cl(4)SQ)(3)](0). The [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) anions in 1 and 2 show no significant interconnection between them (discrete type), while the [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) anions in 4-6 show one- dimensional column-type structures with the aid of intermolecular stacking interactions of the ligand moieties. The anions in 4 show additional stacking interaction with the [(FeCp2)-Cp-III](+) to form one-dimensional ...[D][A][S][D][A]...(D = [(FeCp2)-Cp-III](+), A = [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-), and S = C6H6) type mixed-stack arrangements similar to that of previously reported ((CoCp2)-Cp-III)[Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)].C6H6 (3) Compound 6 forms a two-dimensional sheet structure where the two redox isomers, [Cr-III(Cl(4)SQ)(2)(Cl(4)Cat)](-) and [Cr-III(Cl(4)SQ)(3)](0), are included. The sheet is regarded as a mixed-valence molecular assembly.
Two types of the anions, [Cr-III(X(4)SQ)(X(4)Cat)(2)](2-) (1 and 2) and [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) (4-6), exhibiting an intramolecular mixed-valence state, show intramolecular intervalence CT transition (IVCT) from the Cat to the SQ at near 5800 and 4300 cm(-1), respectively, both in the solution and in the solid states. The intermolecular mixed- valence state of 6 was characterized by absorption spectroscopy, electric conductivity, and SQUID magnetometry. Interestingly, this mixed-valence state of the chromium module is dependent on the redox active nature of the coordinated ligands.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GORDON BREACH SCI PUBL LTD  

The crystal structure of the title complex was first determined, showing a dimeric copper form with the four carboxylate groups. The Cu ... Cu distance is short, associated with the hydrogen bond link of the apically coordinated water molecules with the nearest neighbor vanillic hydroxyl group. The hydrogen bond links afford an infinite 3-D network.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The reaction of tris-tetrahalogeno-o-benzosemiquinonate chromium(III) complexes, [Cr-III(X(4)SQ)(3)] (X=Cl 1a or Br 1b), with bis(cyclopentadienyl) cobalt [(CoCp2)-Cp-II], tetramethyltetraselenafulvalene (TMTSF) and tetrakis(methylsulfanyl)tetrathiafulvalene (TMT-TTF) afforded four charge-transfer compounds, [(CoCp2)-Cp-III][Cr-III(X(4)SQ)(2)(X(4)Cat)] (X=Cl 2a or Br 2b), [TMT-TTF][Cr-III(Br(4)SQ)(2)(Br(4)Cat)] 3b and [TMTSF][Cr-III(Br(4)SQ)(2)(Br(4)Cat)] 4b, where Cat is catecholate. The paramagnetic [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) complexes are commonly formed by cocrystallization with a diamagnetic [(CoCp2)-Cp-III](+) cation for 2a . C6H6 and 2b, and paramagnetic TMT-TTF.+ and TMTSF.+ cations for 3b . C6H5CH3 and 4b . 2CH(2)Cl(2), respectively. The one-electron reduced complexes, [Cr-III(X(4)SQ)(2)(X(4)Cat)](-), with two semiquinonate and one catecholate ligands were isolated and crystallographically characterized. The crystal structures of 2a . C6H6 and 3b . C6H5CH3 consist of alternating stacks of cations and anionic complexes, which form one-dimensional column structures. On the other hand, the anionic complexes in 4b . 2CH(2)Cl(2) form a hexagonal honeycomb network, whose cavities are occupied by the dimerized cation molecules. The temperature dependence of the magnetic susceptibilities reveals that all the [Cr-III(X(4)SQ)(2)(X(4)Cat)](-) complexes are in a ground state of S=1/2, which results from the intramolecular antiferromagnetic interaction between Cr-III(d(3)) and two semiquinonates. In addition, 3b and 4b have a contribution of the paramagnetic TMT-TTF.+ (3b) and TMTSF.+ (4b) cations. In all compounds weak intermolecular magnetic interactions were recognized from the decrease of the chi(m)T values at low temperature.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP  

A complex (TMTSF)[Cr(Cl(4)SQ)(2)(Cl(4)Cat)](1). 0.5CH(2)Cl(2) (SQ = semiquinonate; Cat = cate-cholate, TMTSF = tetramethyltetraselenafulvalene) has been synthesized and characterized. 1 . 0.5CH(2)Cl(2) crystallizes in the monoclinic, space group P2(1)/n with a = 12.472(3) A, b = 17.451(4) Angstrom, c = 18.815(5) Angstrom, beta = 101.80(2)degrees and V=4008(1) Angstrom(3). 1 . 0.5CH(2)Cl(2) contains a paramagnetic TMTSF+ cation and an unprecedented anion [Cr(Cl(4)SQ)(2)(ClCat)](-) as a result of one-electron redox reaction between TMTSF and Cr(Cl(4)SQ)(3). Structure of 1 . 0.5CH(2)Cl(2) consists of dimerized TMTSF+ cation, (TMTSF+)(2) and one dimensionally stacked [Cr(Cl(4)SQ)(2)(Cl(4)Cat)(-) anions. 1 behaves as a semiconductor, and its magnetic susceptibility obeys a Curie-Weiss law in the region of 150-300 K.

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