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A paddlewheel-type dirhodium-based, photoactive, porous metal-organic framework, [Rh2(ZnTCPP)(H2O)7.5] ([1]; ZnTCPP = zinc tetra(4-carboxyphenyl)porphyrin), was prepared and characterized via synchrotron X-ray analyses (X-ray powder diffraction, extended X-ray absorption fine structure, and X-ray absorption near-edge structure), elemental analysis, infrared spectroscopy, and N2 gas adsorption isotherm analysis. Spectroscopic study revealed a drastic decrease in the emission intensity of [1] compared with [ZnTCPP], although features present in the absorption spectra of the two complexes were almost the same. This indicated that [1] underwent the photo-induced intramolecular charge transfer and/or energy transfer from the ZnTCPP moiety to dirhodium moiety.

We report the synthesis of a novel porphyrin-based metal carboxylate framework, [Cu2(ZnBBCPPP)(H2O)2]·6DMF·11H2O (BBCPPP-Cu2), with a large void volume, by using a two-dimensionally expanded building block: {bis[3,5-bis(4-carboxyphenyl)phenyl]porphyrinato}zinc (ZnBBCPPP). Single-crystal X-ray analysis of BBCPPP-Cu2 revealed a three-dimensional network. The void volume per unit cell of BBCPPP-Cu2 is 76.8%, which is considerably larger than that of previously reported porphyrin-based MOFs.

Two novel heterobimetallic coordination polymers, [Cd{Pt(nic)4}]n・5nH2O (Cd–Pt-1) and [Zn{Pt(nic)4}(H2O)4]n・nH2O (Zn–Pt-1) (nicH = nicotinic acid), were synthesized by a one-pot slow-evaporation reaction system in water. Single crystal X-ray analysis revealed that Cd–Pt-1 and Zn–Pt-1 are two-dimensional sheet frameworks with open pores and one-dimensional chain polymers, respectively. However, crystal structure of Cd–Pt-1 is not robust in air. Therefore, BET surface area (pore volume) of Cd–Pt-1 calculated by N2 gas adsorption measurement is very low and the value is 22.5 m2 g− 1 (0.00813 cm3 g− 1).

We prepared single crystals of basic copper formate Cu(2)(OH)(3)HCO(2) (1) by hydrolysis of formate anions in an aqueous solution of copper formate. X-ray structure analysis showed that this material has a two-dimensional triangular lattice network with S = 1/2. The temperature dependence of magnetic susceptibility revealed antiferromagnetic ordering at 5.4 K. A spin-flop transition was observed at about 20 kOe at 2 K, thereby indicating metamagnetic-like behavior. The saturation magnetization was almost one-half of the theoretical value at 2 K under 70 kOe. The magnetic behaviors of 1 were also discussed with regard to its crystal structure. The preparation method presented herein is convenient and available for single crystal growth of metal hydroxide derivatives with various anions.

We have successfully synthesized rhodium-containing MOFs with 1:1 abundance ratios of paddle-wheel units of Rh2 and Cu2/Zn2, i.e., [Rh2M2(1,4-bdc)4]·nSolvent (M = Cu: RhCu-DMF, RhCu-EtOH; M = Zn: R...

New Pd–Zn coordination polymers incorporating a PdII complex were prepared in one-pot reactions from isonicotinic acid, K2[PdCl4] and ZnII ions in water. Depending on the reaction conditions, four new types of Pd–Zn coordination polymers (one-, two- and three-dimensional networks), which consist of a PdII complex coordinated by two or four isonicotinic acids, were formed. The structures were determined by single-crystal X-ray diffraction, X-ray powder diffraction, TGA and CHN elemental analysis. Interestingly, for the N2 and H2 gas adsorption measurements at 77 K and 760 Torr, two of the new Pd–Zn coordination polymers show selective H2 gas adsorption performances. Therefore, these complexes may be potentially attractive materials for heterogeneous catalysts or for H2 gas separation for hydrogenation reactions.

In this study, we investigated the photochemical production of hydrogen from water using bio-inspired heterogeneous microporous porphyrin coordination lattices (PCLs), [Ru2(MTCPP)BF4] (M = H2 (PCL-1), Zn (PCL-2); TCPP = Tetrakis(4-carboxyphenyl)porphyrin), under visible (380 nm

We investigated the thermochromism of copper(II) anthracene-9-carboxylate experimentally and theoretically. We performed X-ray crystal structure analysis at 233 and 113 K, measured magnetic suscept...

In this study we investigated the photochemical production of hydrogen from water using three heterogeneous microporous ruthenium coordination polymers [Ru2(p-BDC)2X] n (p-BDC = 1,4-benzenedicarboxylate, X = Cl, Br and BF4) in the presence of multi-component systems. The order of catalytic performances is [Ru2(p-BDC)2Br] n >[Ru2(p-BDC)2BF4] n >[Ru2(p-BDC)2Cl] n . The most active catalyst, [Ru2(p-BDC)2Br] n , caused the evolution of 46.7 μmol hydrogen molecules with a turn-over number of 18.7 based on [Ru2(p-BDC)2Br] n under visible light irradiation for 4 h. We ascertained that the differences in catalytic activities originated from (1) the efficiency of the quenching of methyl-viologen radicals by [Ru2(p-BDC)2X] n and (2) the durability of the structure in the reaction. In order to examine the catalytic reaction mechanism, we performed theoretical calculations for neutral model structures [Ru2(HCOO)4X(H2O)] (X = Cl, Br), one-electron reduction model complexes [Ru2(HCOO)4X(H2O)]− and deduced intermediate...

The electronic structures of ground and excited states of [Rh2(CH3COO)4(H2O)2] in aqueous solution are studied using a density functional theory (DFT) with a time-dependent (TD) method. Up to now, several theoretical assignments and explanations of its excitation characters have been reported based on the absorption spectra. In this study, we reinvestigate its absorption spectrum by the TD-DFT approach with the polarisable continuum model in order to clarify the excitation characters of the complex, especially in the aqueous solution well.

The electronic configurations and the nature of chemical bonds of the classical lantern-type dinuclear rhodium(II) tetraacetato complexes [Rh2(CH3COO)4(L)2] (L = H2O, free) have been carefully inve...

The electronic structure and spectra of cupric acetate mono-hydrate were investigated by measuring magnetic susceptibility from 2–300 K, temperature dependence of electronic spectra in EPA solutions and DFT calculations. A comparison of electronic spectra at 300 K and 77 K revealed four isosbestic points indicating the coexistence of the triplet and singlet bands. Calculations showed that the Cu 3dx2 − y2 orbitals are strongly bonded with the acetate groups and that there was no obvious direct overlap of Cu–Cu δ-type orbitals in the singlet ground state. The magnetic interaction energy J was estimated using the unrestricted MO calculation and HOMO–LUMO mixing method. The UKS HOMO indicated the importance of the super-exchange interaction via the acetate group. Assignments of electronic spectra are presented for the singlet and triplet bands by the TD-DFT method. Polarization characteristics are explained for the visible and near-UV electron transfer band between the two Cu ions proposed by Yamada et al. [S. Yamada, H. Nakamura, R. Tsuchida, Bull. Chem. Soc. Jpn. 30 (1957) 303].

A pair of structural isomers was isolated at room temperature for the thermochromic nickel complex bis( N-isopropyl-5,6-benzosalicylideneiminato)nickel(II); one is a diamagnetic green form with square-planar coordination geometry (G phase), and the other is a paramagnetic brown form with a tetrahedral geometry (B phase). However, a question as to which form is thermodynamically stable was left open. To solve this problem, thermal and magnetic properties of this complex were investigated by adiabatic heat capacity calorimetry in the 6-508 K temperature range and magnetic measurements in the 2-400 K region. In addition to the two forms previously reported, two metastable crystal forms (G' and B' phases) were found. The stable phase sequence was G phase, B phase, and then liquid upon heating. The supercooled B phase gave rise to a small phase transition with nonmagnetic origin at around 50 K. By rapidly cooling the liquid, a glassy liquid state was realized below approximately 290 K. The order of thermodynamic stability at 298.15 K was revealed to be the G, B, G', and then the B' phase. The entropy, enthalpy, and Gibbs energy differences between the B and the G phases at 298.15 K were S degrees (B) - S degrees (G) = 32.8 J K (-1) mol (-1), H degrees (B) - H degrees (G) = 16.0 kJ mol (-1), and G degrees (B) - G degrees (G) = 6.25 kJ mol (-1), respectively.

The hydrogen adsorption properties and uptake capacities of three-dimensional microporous materials of lantern-type dinuclear M(BDC)(DABCO) 1/2 (M = Co II , Cull, and Zn II ; BDC = 1,4-benzenedicarboxylate, DABCO = 1,4-diazabicyclo[2.2.2]octane; Co(BDC)(DABCO) 1/2 (1), Cu(BDC)(DABCO) 1/2 (2), Zn(BDC)(DABCO) 1/2 (3)) were investigated at various temperatures of 77-333 K and pressures up to 10 MPa using a PCT automatic measuring system (Sievert-type apparatus). The results indicated that uptake to 4.11, 2.70, and 3.17wt% of hydrogen can be stored on 1, 2, and 3, respectively, at 77 K. The amounts of hydrogen are adsorbed by all complexes at around room temperature (293 K) and high-pressures are much lower (

The synthesis and crystal structure of a Dawson-type dirhenium(V)-oxido-bridged polyoxotungstate are described. The potassium salt K 14 (O{Re V (OH)(α 2 -P 2 W 17 O 61 )} 2 ]·21H 2 O (K-1) was obtained as analytically pure, homogeneous, black-purple crystals by the reaction of a monolacunary Dawson polyoxotungstate with [Re IV Cl 6 ] 2- in water, followed by crystallization from an aqueous HCl solution in the dark. Single-crystal X-ray structure analysis revealed that the dimeric dirhenium(V)-oxido-bridged structure has overall C 2h symmetry. Characterization of K-1 was also accomplished by elemental analysis, TG/DTA, and FTIR, UV/Vis absorption, ESR, and solution 31 P NMR spectroscopy. Furthermore, the black-purple compound K-1 was grafted onto a TiO 2 surface by electrostatic binding to give TiO 2 with a cationic quaternary ammonium moiety (1-grafted TiO 2 ). Elemental analysis of 1-grafted TiO 2 indicated that the seven potassium counterions of K-1 were ion-exchanged with seven cationic ammonium moieties to form {TiO 2 } 5500 [=-Si(CH2)3N(CH3)3Cl]7[=Si(CH2)3-N + {CH 3 } 3 ] 7 (K 7 (O(Re(OH)(α 2 -P 2 W 17 Ο 61 )} 2 ] 7- ) and seven molecules of KCl. The diffuse reflectance (DR) UV/Vis spectrum of 1-grafted TiO 2 exhibited two sharp bands at 496 nm and 751 nm due to the Re V →W VI intervalence charge transfer (IVCT) band and the d-d band of the rhenium(V) atom, respectively, in the visible light region, which suggested that polyoxoanion 1 was isolated on the TiO 2 surface. With 1-grafted TiO 2 , hydrogen evolution from water vapor under irradiation with visible light (>400 nm and >420 nm) was achieved.

Adsorption properties of magnetic species in nano-porous crystals were studied theoretically. The crystal [Rh 2 bza 4 pyz] n , which had been reported by Mori, Takamizawa and their co-workers in detailed, was employed in this study. As adsorbed magnetic radicals, a oxygen molecule (O 2 ; S = 1) was treated. From the results by our MO calculations, weak magnetic interactions between O 2 molecules in cavities existed. Two types of magnetic interactions (ferro- and antiferro-magnetic) made alignment of trimer spin structure. Our theoretical calculations analyzed not only position but also orientation of the adsorbed O 2 molecules. For the position, cloud of mass densities of O 2 molecules by MD simulation showed stacking styles in nano-pores statistically. Number of adsorbed gas was estimated to be 3.00 molecules/unit. For the orientation, a certain adsorbed O 2 molecule was stabilized by contribution of the two next O 2 molecules as well as four phenyl groups.

A microporous copper(II) carboxylate complex, copper(II) trans -1,4-cyclohexanedicarboxylate [Cu 2 II,II (OOCC 6 H 10 COO) 2 ]·H 2 O ( 1 ) can act as a biomimetic heterogeneous catalyst for selective oxidation of various alcohols with H 2 O 2 . A green-colored active intermediate, H 2 [Cu 2 II,II (OOCC 6 H 10 COO) 2 (O 2 )]·H 2 O ( 2 ), observed in the reaction of 1 with 20-fold excess H 2 O 2 in acetonitrile was characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance (DR) UV–vis, electron paramagnetic resonance (EPR), X-ray powder diffraction (XRPD), resonance Raman, BET surface area, pore size distribution, and nitrogen occlusion measurements. The molecular structure of 2 was determined from XRPD data and refined by the Rietveld method. The microporous structure of 2 was constructed by intermolecular bridging of μ-1,2- trans Cu–OO–Cu species between two-dimensional [Cu 2 (O 2 CC 6 H 10 CO 2 )] layers, which was the first example of microporous copper(II) peroxo complex for heterogeneous oxidation catalysis. Moreover, a microporous ruthenium(II,III) complex having porphyrin [Ru II,III 2 (H 2 TCPP)]BF 4 ( 3 ) (H 2 TCPP = 4,4′,4″,4‴-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis benzoic acid) particularly exhibited an effective catalytic performance for the heterogeneous oxidation of primary aliphatic alcohols with dioxygen and air without any additives at room temperature. The reaction pathway included the formation of an Ru–oxygen radical intermediate, which was due to the high affinity of diruthenium(II,III) sites for dioxygen.

A novel three-dimensional microporous ruthenium (II,III) polymer complex, [ Ru 2 II , III ( H 2 TCPP ) ] BF 4 (1) (H2TCPP = 4,4′,4′,4‴-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis benzoic acid) was synthesized and characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance UV–Vis, ESR, X-ray powder diffraction, BET analysis, and nitrogen and oxygen adsorption measurements. Complex 1 exhibited an effective catalytic performance for the heterogeneous oxidation of various types of alcohols, particularly primary aliphatic alcohols, with molecular oxygen and air without any additives at room temperature.

Two dinuclear nickel(II) complexes, [Ni2(L-Et)(N3)(H2O)3](NO3)2 · 2H2O (1) and [Ni2(L-Et)(μ-1,3-N3)(H2O)2](NO3)2 · 4H2O (2) containing (HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane), have been synthesized and characterized by their IR and UV–Vis spectra and magnetic susceptibilities. The crystal structures of [Ni2(L-Et)(N3)(H2O)3](NO3)2 · CH3OH (1′) and [Ni2(L-Et)(μ-1,3-N3)(H2O)2](NO3)2 · 2C2H5OH (2′) similar to 1 and 2 were determined by X-ray crystallography. In 1′, the two nickel(II) ions are bridged by only an alkoxo group of L-Et−, while an azido and an alkoxo connect two nickel(II) ions in 2′. Magnetic susceptibility measurements (2–300 K) showed a weak ferromagnetic exchange coupling between the two nickel(II) ions (2J = 10.1 cm−1) for 1. On the other hand, antiferromagnetic interactions were observed for 2 (2J = −15.8 cm−1).

Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases. This complex has opened the new field of adsorbent complex chemistry. It is recognized as the lead complex in the construction of microporous complexes. This specific system has been expanded to a systematic series of derivatives of other isomorphous transition metals, molybdenum(II), ruthenium(II, III), and rhodium(II). These complexes with open frameworks are widely recognized as very useful materials for applications to catalysis, separation at molecular level, and gas storage.

Novel microporous rhodium(II) carboxylate polymer complexes containing metalloporphyrin, Rh2[MTCPP] (M = H21, Cu2+2, Ni2+3, Pd2+4) (H2TCPP = 4,4′,4″,4′″-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis benzoic acid), were synthesized and completely characterized by elemental analysis, TG/DTA, magnetic susceptibilities, FT-IR, DR-UV–vis, XRPD, BET analysis, and nitrogen adsorption measurements. These complexes possess carboxylate bridged dinuclear rhodium(II) sites and mononuclear copper(II), nickel(II), and palladium(II) centers in the porphyrin ring that form uniform micropores of ca. 5.0 A. Furthermore, they show high surface areas and high nitrogen adsorption capacities and act as efficient heterogeneous catalysts for the hydrogenation of olefins at approximately 200 K. The unique bimetallic effects shown by metalloporphyrin and dinuclear rhodium sites in micropores were investigated by kinetic studies and hydrogen and propene adsorption–desorption measurements; the priority coordination of olefins onto metalloporphyrins and the intramolecular transfer of hydrogen from a rhodium center to a olefin molecule coordinated onto metalloporphyrin remarkably reflects the catalytic activities in hydrogenation.

A two-dimensional microporous dinuclear copper(II) trans-1,4-cyclohexanedicarboxylate, [CuII,II2(OOCC6H10COO)2] ⋅ H2O (1), can act as a heterogeneous catalyst for selective oxidations of various alcohols with hydrogen peroxide. Complex 1 catalyzed the selective oxidations of 2-propanol, cyclohexanol, benzyl alcohol, 2-octanol, and 1-octanol with >99% selectivities in a heterogeneous system. A green-colored active intermediate, H2[CuII,II2(OOCC6H10COO)2(O2)] ⋅ H2O (2), observed in the reaction of 1 with a 20-fold excess H2O2 in acetonitrile was characterized by elemental analysis, TG/DTA, magnetic susceptibility, FT-IR, diffuse reflectance UV–vis, EPR, X-ray powder diffraction (XRPD), resonance Raman spectra, BET surface area, pore size distribution, and nitrogen occlusion measurements. The molecular structure of 2 was determined from XRPD data and refined by the Rietveld method. The microporous structure of 2 was constructed by intramolecular bridging of μ-1,2-trans Cu OO Cu species between two-dimensional [Cu2(O2CC6H10CO2)] layers. The complex 2 was the first example of the microporous copper(II) peroxo complex for heterogeneous oxidation catalysis.

We successfully synthesized a novel porphyrin-based metal carboxylate framework, [Cu2(ZnBDCBPP)]·5DMF·5H2O, with expanded pore windows and interior spaces, by using a ZnBDCBPP building block. Singl...

The dinuclear and trinuclear copper(II) complexes [Cu 2 (O)(OH)(ClO 4 )(phen)(H 2 O)]ClO 4 .[Cu 2 (L)(OH)(ClO 4 ) 2 (phen)(CH 3 OH)] (1) and [Cu 3 (L) 2 (OH) 2 (H 2 O) 2 ](NO 3 ) 2 (2) (HL=2-[2-(α-pyridyl)ethyl]imino-3-butanone oxime and phen=1,10-phenanthroline) were prepared and their crystal structures have been determined by X-ray crystallography. Complex 1 is composed of [Cu 2 (L)(OH)(ClO 4 )(phen)(H 2 O)]ClO 4 (la) and [Cu 2 (L)(OH)(ClO 4 ) 2 (phen)(CH 3 OH)] (1b). In la and 1b, one oximato of L and one hydroxo group bridge two copper(II) ions. The linear trinuclear cation [Cu 3 (L) 2 (OH) 2 (H 2 O) 2 ] 2 - in 2 is centrosymmetric, and one oximato and one hydroxo group bridge the central and terminal copper(II) ions. The strong antiferromagnetic interactions within the dinuclear and trinuclear complexes 1 and 2 have been observed (2J =∼ -900 cm - 1 for 1 and 2, respectively, H = -2JS 1 .S 2 ).

The X-ray crystallographic structures of 2-(2-phenyl-5-oxo-1,3,2-oxathiagermolan-2-ylthio)acetic acid (2), its pyridinium salt (3), and the pyridinium salt of 2-(2-t-butyl-5-oxo-1,3,2-oxathiagermolan-2-ylthio)acetic acid (1), (4), together with 2-(2-phenyl-1,3,2-oxathiagermolan-2-ylthio)ethanol (5) were determined and compared with that of 1. All of compounds investigated, 2–5, have the TBP-like, pentacoordinated structure. This fact seems to indicate that the driving force of pentacoordination of this type of compounds is the existence of an oxygen atom δ to the germanium atom that readily forms a five membered ring by hypercoordination.

A series of tris[(2-methoxymethyl)phenyl]germanes with a substituent on germanium was prepared and their solid-state and solution structures were investigated by means of X-ray crystallography and NMR spectroscopy to elucidate the effect of the substituent on the hypercoordination of the germanium atom in triarylgermanes. It was shown that when the substituent is a halogen, the triarylgermanes tend to be pentacoordinated trigonal bipyramidal while the triarylgermane is tetrahedral with no coordination when the substituent is a phenyl group. The methyl derivative is a monocapped tetrahedron.

A new series of microporous materials containing infinite chains of a mononuclear metal (Cu(II), Zn(II), Ni(II))-pyridine unit bridged by dicarboxylates (copper(II) terephthalate-pyridine 1a, copper(II) terephthalate-4-phenylpyridine 1b, zinc(II) fumarate-pyridine 2a, zinc(II) terephthalate-pyridine 2b, nickel(II) fumarate-pyridine 3a, and nickel(II) terephthalate-pyridine 3b) have been prepared. These complexes, which have a regular one-dimensional structure, occlude large amounts of gases. The maximum amount of N2 gas is 0.7–10.7 mole per mole of metal(II) salt, indicating the presence of a large number of micropores. A porous structure, which is formed by stacking and self-assembly of the linear metal(II) dicarboxylates, was determined by X-ray crystallography. We have elucidated the paramagnetic properties of 1a, 1b, 3a, and 3b by magnetic measurement (SQUID), whereas 2a and 2b were found to be diamagnetic. The magnetic susceptibilities of 1a and 1b obey the Curie-Weiss law over the range of 70–300 K ...

Copper(II) trans-1,4-cyclohexanedicarboxylate (Cu(trans-1,4-OOCC6H10COO)) was synthesized, and the heat capacity was measured by adiabatic calorimetry between 13 and 300 K. A heat capacity anomaly due to the first-order phase transition was found at 160.0 K, and the enthalpy and entropy of transition were determined to be 413.4 J mol −1 and 2.66 J K −1 mol −1 , respectively. The sample was found to absorb a large amount of toluene, which were desorbed and re-absorbed reversibly. The reversibility of the absorption/desorption was confirmed by measurements of heat capacity; no phase transition was observed in the fully absorbed sample, but it reappeared in the desorbed sample. A sample that absorbed 11% toluene showed about a half size of the anomaly at 174 K in the heat capacity curve.

A hydroxo-bridged MnIIIMnIIMnIII trinuclear complex, [Mn3(L1)2(2,6-dcba)2(OH)2] (1), where H2L1 is N′,N′-bis-(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine and H2,6-dcba is 2,6-dichlorobenzoic acid, was synthesized by the reaction of Mn(ClO4)2·6H2O with H2L1, H2,6-dcba, and a base in acetonitrile. The structure of 1 was determined by X-ray crystallography: 1 crystallizes in the monoclinic space group P21/c with a = 9.616(4) A, b = 12.537(4) A, c = 23.099(4) A, β = 94.73(2)°, V = 2775(1) A3, and Z = 2. The central MnII and terminal MnIII ions are bridged by phenolato, carboxylato, and hydroxo ligands to form a linear MnIII–MnII–MnIII arrangement. The bridging structure between MnIII and MnII is similar to that of analogous alkoxo-bridged complexes, [Mn3(L)2(carboxylato)2(alkoxo)2], where L is L1 or its derivatives. Most of the alkoxo-bridged complexes [Mn3(L)2(carboxylato)2(alkoxo)2] exhibit a weak ferromagnetic interaction between MnIII and MnII, while the hydroxo-bridged complex 1 exhibits a weak antife...

The reaction of [Cr(aet) 3 ] (aet=2-aminoethanethiolate) with Ag I in water gave an S-bridged Cr III 2 Ag 3 I pentanuclear complex [Ag 3 {Cr(aet) 3 } 2 ] 3+ ([1] 3+ ). The crystal structure of [1](NO 3 ) 3 ·2H 2 O was determined by X-ray analysis, which established that two fac ( S )-[Cr(aet) 3 ] units are linked by three Ag I ions through S atoms (average Cr-S=2.387(5), Ag-S= 2.403(5) A). The three Ag I ions in [ 1 3+ were replaced by Au I ions to form the corresponding Cr 2 III Au 3 I pentanuclear complex [Au 3 {Cr(aet) 3 } 2 ] 3+ ([ 2 ] 3+ ). Treatment of [Cr( D -pen- N, O, S ) 2 ] m ( D -pen= D -penicillaminate) with Ag I in water produced an S-bridged Cr 3 III Ag 3 I hexanuclear complex [Ag 3 {Cr( D -pen- N, O, S ) 2 } 3 ] ([ 3 ]), which has a cyclic structure composed of three trans ( O )-[Cr( D -pen- N, O, S ) 2 ] m units. Variable-temperature magnetic susceptibility data indicated the weak antiferromagnetic interaction for [ 1 3+ ] ( J = m 0.84 cm m 1 ) while the very weak ferromagnetic interactio...

Embedding of bistable molecules into an organic conductor is expected to yield interesting hysteretic conductive properties. As a typical bistable species switchable under a temperature change, a spin-crossover iron(III) complex was utilized to prepare two charge-transfer salts containing an organic acceptor molecule, [Fe(acpa) 2 ](TCNQ) n (Hacpa = N -(1-acetyl-2-propylidene)-2-pyridyl-methylamine; TCNQ = 2,2'-(2,5-cyclohexadien-1,4-diylidene)-bispropanedinitrile), and their magnetic and electrical properties were studied. While magnetic behavior of dilute spin-crossover complex molecules is well described by an entropy-driven spin equilibrium between low-spin and high-spin states across an energy gap, intermolecular interactions should be taken into account and often abrupt phase transitions are found in densely-packed complex molecules like crystalline solids. In order to delineate these systems in a unified manner, a phenomenological two-state model based on a mean-field approximation was examined. It ...

New dinuclear nickel(II) complexes ([Ni2(L-Et)(CH2ClCOO)(H2O)2](ClO4)2·H2O (3), [Ni2(L-Et)(CCl3COO)(H2O)2](ClO4)2·H2O (4), [Ni2(L-Et)(CF3COO)(H2O)2](ClO4)2·3H2O (5)) and their urea complexes ([Ni2(L-Et)(RCOO)(ur)(H2O)](ClO4)2 (R = CH3 (6), C2H5 (7), CH2Cl (8), CCl3 (9), CF3 (10)) (HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane and ur = urea) have been prepared in order to model the active site urease. These complexes were characterized by IR and UV-vis spectra, and by magnetic susceptibilities. The crystal structures of the complexes [Ni2(L-Et)(CH2ClCOO)(CH3OH)2](ClO4)2 (3′) and [Ni2(L-Et)(OAc)(ur)(H2O)](ClO4)2· 2(CH3)2CO (OAc = acetate) (6′) were determined by X-ray crystallography. In the cation of 6′, the two nickel(II) ions are bridged by an alkoxo of L-Et− and an acetato, and a monodentate urea molecule is attached to a nickel(II) through its oxygen atom. Variable temperature magnetic susceptibility measurements of the urea complexes 6, 8, and 10 show an ant...

The adsorption properties in nanoporous crystals of a metal-organic framework were studied theoretically. The Zn3(BDC)3·6CH3OH (BDC=1,4-benzenedicarboxylate) crystal was mainly treated as a stable metal-organic assembled species, which was reported by O.M. Yaghi and co-workers. Its crystalline structure very much resembles several crystals that have been reported by W. Mori et al. For adsorbed molecules, N2, CO2, Ar and H2 for nonmagnetic species and O2 for magnetic radical species were treated. The following systematic procedures were carried out: (1) decision of parameters for MC simulations; (2) execute MC simulation; (3) search of configuration of O2 molecules by MM method; and (4) study of magnetic interactions by means of ab initio HF, post-HF and DFT methods. Finally, magnetic interactions between O2 pairs exist and this cooperation might run in the nanoporous cavity.

The triply (two oximato and one pyrazolato or one phthalazine) bridged dinuclear copper(II) complexes [Cu2(L1)2(pz)]ClO4 (1) and [Cu2(L1)2(phta)](ClO4)2 (2) (HL1=2-[2-(α-pyridyl)ethyl]imino-3-butanone oxime, pz=pyrazolate anion, phta=phthalazine) were synthesized and characterized; the crystal structures of 1 and 2 were determined by X-ray crystallography. Magnetic susceptibility measurements from liquid helium temperature to room temperature showed a weak antiferromagnetic exchange coupling between two copper(II) ions (2J=−17 cm−1) for l, on the other hand, a very strong antiferromagnetic interaction for 2 was observed (2J=−760 cm−1).

Linearly aligned tetranuclear Pt(II)-Cr(II)-Cr(II)-Pt(II) complexes were prepared using a tridentate pyphos ligand (pyphos = 6-diphenylphosphino-2-pyridonate). The bonding between Cr(II) and Pt(II) was discussed on the basis of magnetic measurements. A dichromium complex, [Cr2(pyphos)4] (1), was prepared by the reaction of [Cr2(OAc)4] with the sodium salt of pyphos ligand. The complex 1 has four phosphorus atoms capable of holding transition metals at both of the axial positions of the Cr2 moiety. Three tetranuclear Pt(II)-Cr(II)-Cr(II)-Pt(II) complexes, i.e., [Cr2Pt2Me4(pyphos)4] (2), [Cr2Pt2Cl4(pyphos)4] (3), and [Cr2Pt2Cl2Me2(pyphos)4] (4), have been prepared by the addition of the respective platinum species, PtIIMe2, PtIICl2, and PtIIMeCl, to the axial positions of the Cr2 moiety of 1. Magnetic measurements of 1-4 together with a crystallographic study for the complexes 1 and 2 revealed that the quadruply-bonded Cr-Cr distance was delicately altered by the nature of the Pt atoms, i.e., the kind of su...

A novel three-dimensional interpenetrated coordination polymer, [Zn{Pd(INA)4}]n (INA = isonicotinate), was synthesized and structurally characterized. This material was performed as a hydrogen prod...

The magnetic data of chromium chalcogenide cluster complexes [Cr6Se8(PEt3)6] (1), [Cr6Se8(H)(PEt3)6] (2), and [Cr6S8(H)(PEt3)6] (3) have been analyzed using the Heisenberg-Dirac-Van Vleck Hamiltonian. The analysis has shown that all of these complexes display an antiferromagnetic interaction between chromium atoms and that the coupling constants decrease in the order 2 > 3 > 1. This interaction is mediated by Cr-(μ3-E)-Cr bridges (E = Se, S) and Cr-Cr bonds. In a comparison of the two hydride clusters, the selenide 2 has a larger antiferromagnetic coupling than the sulfide 3. The shorter Cr-Cr distances in 2 (mean 2.66 A) than those in 1 (mean 2.81 A) seem to cause larger antiferromagnetic interaction through the Cr-Cr bonds.

Novel inclusion complexes between host microporous molybdenum(II) dicarboxylates (fumarate, terephthalate, trans−trans-muconate, and pyridine-2,5-dicarboxylate) and guest organic polyethers (poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG)) of various molecular weights were synthesized. The rate of complex formation depends on the shapes of the micropores and polyethers. The amount of included polyethers increased with their molecular weight, and reached a saturated amount, with the exception that molybdenum(II) pyridine-2,5-dicarboxylate did not form complexes with bulky PPG. The amount of adsorbed argon in the microporous molybdenum(II) dicarboxylates decreased with increased amounts of included polyethers. The 13C CP/MAS NMR measurement of molybdenum(II) terephthalate with PEG demonstrated that PEG chains are included in the capillaries. This is an effective method for synthesizing supramolecular complexes.

New dinucleating ligands having two metal-binding sites bridged by an imidazolate moiety, Hbdpi and HMe4bdpi (Hbdpi = 4,5-bis(di(2-pyridylmethyl)aminomethyl)imidazole, HMe4bdpi = 4,5-bis(di(6-methyl-2-pyridylmethyl)aminomethyl)imidazole), have been designed and synthesized as model ligands for copper−zinc superoxide dismutase (Cu,Zn-SOD). The corresponding mononucleating ligand, MeIm(Py)2 (MeIm(Py)2 = ((1-methyl-4-imidazolyl)methyl)bis(2-pyridylmethyl)amine), has also been synthesized for comparison. The imidazolate-bridged Cu(II)−Cu(II) homodinuclear complexes represented as [Cu2(bdpi)(CH3CN)2](ClO4)3·CH3CN·3H2O (1), [Cu2(Me4bdpi)(H2O)2](ClO4)3·4H2O (2), a Cu(II)−Zn(II) heterodinuclear complex of the type of [CuZn(bdpi)(CH3CN)2](ClO4)3·2CH3CN (3), and a Cu(II) mononuclear complex of [Cu(MeIm(Py)2(CH3CN)](ClO4)2·CH3CN (4) have been synthesized, and the structures of complexes 1−4 were determined by X-ray crystallography. The Cu(II)−Zn(II) distance of 6.197(2) A in 3 agrees well with that of native Cu,Zn-S...

Copper(II) terephthalate absorbs a large amount of gases such as N2, Ar, O2, and Xe. The maximum amounts of absorption of gases were 1.8, 1.9, 2.2, and 0.9 mole per mole of the copper(II) salt for N2, Ar, O2, and Xe, respectively, indicating that the gases were not adsorbed on the surface but occluded within the solid. Other microporous copper(II) dicarboxylates are also reviewed. The porous structure of copper(II) terephthalate, in which the gas is occluded, is deduced from the temperature dependence of magnetic susceptibilities and the linear structure of terephthalate. Microporous molybdenum(II) and ruthenium(II, III) dicarboxylates are discussed. We describe that rhodium(II) monocarboxylate bridged by pyrazine form stable micropores by self-assembly of infinite linear chain complexes.

Rhodium(II) benzoate bridged by pyrazine derivatives occlude a large amount of N2 gas, reversibly. The maximum amounts of the occluded N2 were 1.8, 1.7, 0.5, 0.1, 1.3, and 1.3 mol per one mole of rhodium(II) salt with 2-methylpyrazine, 2,3-dimethylpyrazine, quinoxaline, 1,5-naphthyrizine, and triethylenediamine, respectively, indicating the presence of a large number of micropores in these rhodium(II) carboxylates. The porous structure which is formed by the self-assembly of linear rhodium(II) benzoate-pyrazine derivatives was deduced by analogy to the structure of rhodium(II) benzoate-pyradine reported previously.

The bis-μ-dicarboxylate ruthenium (II,III) complexes, Ru (II,III)2L2Br (L=trans-O2C-CH═CH-CO2 (1), trans-trans-O2C-CH═CH-CH═CH-CO2 (2), and p-O2C-C6H4-CO2 (3)), were prepared and their gas-occlusio...