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Approximately spin-projected UMP4(2) and UCC SD(T) computations show that ferromagnetic intermolecular interactions are feasible for T-shape and rhombus conformations in parallel interplane orientations for nitroxide pairs because of no-overlap between π ∗ -type SOMOs (no kinetic exchange) and non-zero potential exchange via SOMO-SOMO through-space contact. On the other hand, antiferromagnetic kinetic exchange interactions via SOMO-SOMO overlap are predominant for rectangular conformations. The no-overlap and orientation principle proposed previously is a useful guide for the theoretical understanding of ferromagnetic exchange interactions between nitroxide groups. Implications of the calculated results are discussed in relation to the discovery of ferromagnetic interactions in the crystals of adamantane dinitroxide, TEMPO derivatives and MOTMP.

A Zn-Pd heterometallic metal-organic framework (MOF) based on 3,5-pyridine-dicarboxylic acid (H2-pydc), namely [Zn2(H2O)3{PdCl2(pydc)2}]n (Zn-Pd-2) was successfully synthesized by a slow diffusion method and characterized by single-crystal X-ray diffraction, CHN elemental analysis, FT-IR spectroscopy, thermogravimetric (TG) analysis and N2 gas adsorption measurement. The single-crystal X-ray analysis revealed that the framework morphology of Zn-Pd-2 is as same as that of [Zn2(DMF)3{PtCl2(pydc)2}]n. The Zn-Pd-2 was found to be an effective catalytic performance for the photochemical reduction of water in a well-known photo-system made up of [Ru(bpy)3Cl2] (bpy = 2,2'-bipyridine), MV(2+) (methyl-viologen) and Na2 EDTA (Disodium ethylenediaminetetraacetate); 20.2 turnover based on Zn-Pd-2 was achieved at 4 h irradiation.

The ORHF and CAS CI calculations by MNDO and PM3 parametrizations are carried out for poly-cation and -anion states of C 60 in order to elucidate bond alternations and changes of ground spin multiplicities by doping of electrons or holes. The singlet state is calculated to be more stable than the triplet state for the dianion of C 60 in accordance with a recent experiment. A three-band model is constructed of the t 1u orbitals of C 60 in order to examine the itinerant ferro- and antiferro-magnetism. Implications of the calculated results are discussed in relation to the organic ferromagnetism observed in the C 60 ·TDAE complex.

Ab initio post-Hartree-Fock calculations have been carried out for the lowest-spin (LS) and highest-spin (HS) states in several conformations of molecular oxygen dimers. The LS-HS energy gap can be embodied by effective exchange interactions (Jab) in the Heisenberg hamiltonian when the O2-O2 intermolecular distance (R) exceeds 3.2 A. The Jab-values decrease exponentially with the increase of R, in accord with experiments. For all orientations examined the effective exchange interactions are found to be antiferromagnetic. The calculated results are in good agreement with the experimental ones in the a phase of the O2 crystal, which is found to be a collinear antiferromagnet on experimental grounds. The implications of the calculated results are also discussed in relation to a theoretical possibility of Haldane systems of one-dimensional O2 arrays embedded in host molecules.

A series of alkoxo-bridged copper(II) complexes with 2-dialkylaminoethanol and 1-dialkylamino-2-propanol, [Cu2(R2NCH2CH2O)2(NCS)2] and [Cu2{R2NCH2CH(CH3)O}2(NCS)2] (R = CH3, C2H5, n-C3H7, i-C3H7), have been prepared and characterized by infrared and electronic spectroscopies, and temperature dependence of magnetic susceptibilities. The crystal structures of [Cu2{i-C3H7)2NCH2CH2O}2(NCS)2] and [Cu2{R2NCH2CH(CH3)O}2(NCS)2] (R = CH3, C2H5, n-C3H7, i-C3H7) have been determined by X-ray crystallography. The compounds are polymeric with copper atoms alternately bridged by two alkoxo oxygen atoms and two thiocyanate ions, except for [Cu2{(i-C3H7)2NCH2CH(CH3)O}2(NCS)2] which is a discrete alkoxo-bridged dinuclear molecule. The unusual magnetic properties are discussed in relation to the crystal structures.

Semi-empirical and ab initio molecular orbital (MO) calculations have been carried out for clusters of p -nitrophenyl nitronyl nitroxide ( p -NPNN) extracted from the experimental crystal structure of its γ-phase. It is found that the intraplane exchange interactions ( J ab ) are ferromagnetic, whereas the interplane one is antiferromagnetic. The antiferromagnetic transition temperature ( T N ) is estimated by a generalized Langevin-Weiss-Neel (GLWN) model combined with the calculated J ab values by the MO methods. The Neel temperature ( T N ) by the mean-field GLWN model is of the order of the experimental value, although the former is much larger than the latter because of the low dimensionality of the γ-phase. A systematic theoretical explanation is presented for the magnetic long-range orderings in the β- and γ-phase crystals of p -NPNN.

Several copper(II) and nickel(II) complexes are prepared from N,N′-disubstituted imidazole-4,5-dicar☐amides [substituent = 2-(dimethylamino)ethyl, 3-(dimethylamino)propyl, 2-pyridylmethyl, and 2-(2-pyridyl)ethyl; abbreviated as H 2 L collectively or H 2 aei, H 2 api, H 2 pmi, and H 2 pei, respectively]. Copper(II) forms two types of complexes: CuL·nH 2 O and Cu 2 LCl 2 ·nH 2 O, both of which are magnetically subnormal. The temperature-dependent magnetic susceptibilities of CuL·nH 2 O are compatible with an imidazolate bridged tetramer while those of Cu 2 LCl 2 ·nH 2 O are compatible with an imidazolate bridged dimer. Nickel(II) afforded only Ni(Hpmi)(NCS) and Ni 3 (pei) 2 (NCS) 2 ·8H 2 O. The former is a diamagnetic, square planar monomer, while the latter consisted of one octahedral and two square planar nickel(II) centres bridged by an imidazolate moiety. The latter is a rare example of complexes containing metal ions in different stereochemistries and spin states.

The red imported fire ant (Solenopsis invicta) lives up to its name - 'invicta' means 'not having been overcome' in Latin. Researchers around the world are battling to control this damaging pest.

[NBu n 4 ] 4 °W(C 3 S 5 ) 3 ] and [NBu n 4 ] 2 °Mo(C 3 S 5 ) 3 ] [C 3 S 5 2- =4,5-dimercapto-1,3-dithiole-2-thionate(2-)] were prepared. Single-crystal X-ray structure analyses revealed a distorted trigonal prismatic coordination around the metal atom for both the anion moieties. They were oxidized by [Fe(C 5 Me 5 ) 2 ][BF 4 ] to afford [Fe(C 5 Me 5 ] 2 [W(C 3 S 5 ) 3 ] and [Fe(C 5 Me 5 ) 2 ][Mo(C 3 S 5 ) 3 ], respectively

Ab initio post Hartree-Fock calculations were carried out for polyradical species formed by the through-bond couplings between organic radical groups such as triplet carbenes. Detailed numerical results indicate that the dynamic spin polarization (SP) rules proposed previously are applicable to qualitative predictions of the ground spin states of these species. On the other hand, the spin derealization (SD) mechanism is operative in the case of polyradicals linked with hetero atoms such as oxygen and nitrogen atoms. The ionized states of polycarbenes and polyenes are also investigated in relation to possibilities of organic magnetic conductors. Computational results are compatible with experimental results available.

A new binuclear nickel(II) complex having the formula [Ni2(acac)2(tmen)2ox] (acac = acetylacetonate, tmen = N,N,N′,N′-tetramethylethylenediamine, ox = oxalate) has been characterized, and its crystal structure has been determined at room temperature. This crystal was obtained in its solvated form, [Ni2(acac)2(tmen)2ox]·2TCE (where TCE = 1,1,2,2-tetrachroloethane); orthorhombic system, space group Pcab (No. 61), with a = 20.172(4), b = 17.180(5), c = 13.132(3) A, Z = 4, R = 0.044. The oxalate ligand acts as a bridging group between the two Ni(II) moieties.

Intermolecular spin alignment rules are derived on the basis of ab initio results obtained for clusters of triplet carbenes, free radicals, etc. Interrelationships between several theoretical models are also clarified. The APUHF calculations are performed for radical pairs in the β and γ-phase crystals of para-nitrophenyl nitronyl nitroxide. The magnetic transition temperatures are calculated by the use of Langevin-Weiss type mean-field theory combined with the calculated effective exchange integrals. The origins of ferromagnetic interactions in both the phases are discussed in relation to the intermolecular spin alignment rules.

The magnetic properties of a microcrystalline sample of the title free radical were measured. This magnetic behavior can be interpreted in terms of ferromagnetic interaction inside chains or sheets...

The magnetic properties of 4-methacryloyloxy- and 4-acryloyloxy-2,2,6,6-tetramethylpiperidine-l-oxyl (MOTMP and AOTMP, respectively) were studied. The magnetic susceptibility, magnetization, and molar heat capacity of MOTMP show that the crystal has one-dimensional ferromagnetic coupling, and that the coupling between the one-dimensional coupling chains was antiferromagnetic, resulting in a metamagnet below 0.16 K. On the other hand, AOTMP, where hydrogen atom is substituted for a methyl group at α-position, shows an antiferromagnetic coupling between the nitroxyl radicals.

Spin-restricted and unrestricted post-Hartree—Fock calculations were carried out for clusters of triplet methylene and nitroxide radicals. The UHF-based methods such as UMP and QCISD followed by approximate spin projection provide reasonable energy differences between the high-and low-spin states of these species. They are close to the corresponding values from spin-restricted multi-reference (MR) approaches such as CASSCF and second-order (SO) CI. Implications of SOCI and MRSDCI results are discussed in relation to the size inconsistency erros involved in ab initio calculations of weak interaction energies, such as the effective exchange integrals in Ising and Heisenberg models.

Molecular orbital calculations have been carried out for clusters of para-nitrophenyl nitronyl nitroxide ( p -NPNN) extracted from the experimental crystal structure of its β-phase. Three-dimensional effective exchange integrals ( J ab ) are found to be possitive (ferromagnetic). The ferromagnetic transition temperature is estimated by a generalized Langevin—Weiss model combined with the calculated J ab , being consistent with the observed value. A theoretical explanation is presented for the long-range ferromagnetic ordering in the p -NPNN crystal. Implications of the calculated results are also discussed in relation to a theoretical possibility of organic ferromagnetism of other substituted phenyl nitronyl nitroxides.

Vanadium(III) complexes with trdta, Na[V(trdta)].3H 2 O and K[V(trdta)].4H 2 O, were synthesized by the reaction of vanadium(III) chloride with sodium and potassium salts of trdta, respectively, where trdta denotes 1,1-diaminopropane-N,N,N',N'-tetraacetate. Crystal structure analysis of Na[V(trdta)].3H 2 O showed that the complex contains a hexadentate trdta ligand and adopts a distorted octahedral geometry.

The temperature dependence of the magnetic susceptibilities for 4-methacryloyloxy- and 4-acryloyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl (MOTMP and AOTMP, respectively) was measured. Intermolecular magnetic coupling in these radicals was changed from antiferromagnetic to ferromagnetic by substituting hydrogen at α-position with a methyl group. A magnetic phase transition for MOTMP was observed at 0.14 K in the measurement of the temperature dependence of heat capacity. The circumstantial evidences support that the ordered state is of ferromagnet.

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.

Magnetic Properties of Polymers Containing Tetraphenyl-porphinatosilver(II) as Their Side Chains

Configurational switch around the seven-coordinate manganese(II) center ligated by a cage-type N-glycoside ligand was found to depend on its counter anion by X-ray crystallographic analyses of [Mn(aldose3-tren)]X2 (2: aldose = D-mannose, X = Br; 4: aldose = L-rhamnose X = 1 2 SO 4 ), where aldose3-tren is tris(N-aldosyl-2-aminoethyl)amine.

We have found a form of copper(II) terephthalate that occluded an enormous amount of gases such as N2, Ar, O2, and Xe. Copper(II) terephthalate is the first metal complex found capable of adsorbing gases. This complex has opened a new field of adsorbent chemistry and is recognized as a leader in the construction of microporous metal complexes. In extending the route for the synthesis of microporous complexes, we obtained many new porous materials that are widely recognized as useful materials for applications in areas such as gas storage, molecular sieves, catalysis, inclusion complexes, and surface science. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 336–351; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20060

A new series of microporous materials containing infinite chains of mononuclear metal (Cu(II), Zn(II), Ni(II))-pyridine unit bridged by dicarboxylates, copper(II) terephthalate-pyridine, [CuII(OOCC6H4COO)(C5H5N)2(H2O)] · C5H5N · H2O (1), copper(II) terephthalate-4-phenylpyridine, [CuII(OOCC6H4COO)(C11H9N)2(H2O)] · (MeOH)2 (2), zinc(II) fumarate-pyridine, [ZnII(OOCC2H2COO)(C5H5N)3] · C5H5N · (H2O)0.5 (3), zinc(II) terephthalate-pyridine, [ZnII(OOCC6H4COO)(C5H5N)2(H2O)2] · (C5H5N)2 · (H2O)2 (4), nickel(II) fumarate-pyridine, [NiII(OOCC2H2COO)(C5H5N)3] · C5H5N · (H2O)2 (5), and nickel(II) terephthalate-pyridine, [NiII(OOCC6H4COO)(C5H5N)3]6 · (C5H5N)2 · (DMF)6 · (H2O)9 (6), have been prepared. A porous structure, which is formed by stacking and self-assembly of the linear metal(II) dicarboxylates, has been determined by X-ray crystallography. When released with guest solvents, these complexes, except for 5, occlude large amounts of gases such as N2 and Ar. The maximum amount of N2 gas is 0.7–10.7 mol per mole of metal(II) salt, indicating the presence of a large number of micro- and/or mesopores. The magnetic susceptibilities of 1 and 2 obey the Curie–Weiss law over the range of 70–300 K (θ=−1.4 K and θ=+5.5 K, respectively); the obtained Weiss constants (θ) indicate the existence of small antiferromagnetic interactions (1), and ferromagnetic interactions (2). The different magnetic behaviors between 1 and 2 demonstrate that hydrogen bonding between the carboxylate groups and coordinated water molecules plays an important role in determining the bridge geometries and superexchange interaction between the Cu(II) ions through the Cu–O–C–O–H–O–Cu pathways. In contrast to those of the copper(II) complexes, the magnetic susceptibilities of 5 and 6 obey the Curie law. Novel inclusion complexes between host microporous molybdenum(II) dicarboxylates (fumarate (7), terephthalate (8), trans–trans-muconate (9), and pyridine-2,5-dicarboxylate (10)) and guest organic polyethers (poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG)) of various molecular weights have been synthesized. The rate of complex formation depends on the shapes of the micropores and polyethers. The amount of included polyethers increases with their molecular weight, and reaches up to a saturated amount, with the exception that complex 10 does not form complex with bulky PPG. The amount of absorbed argon in the microporous molybdenum(II) dicarboxylates decreases with increase in the amount of include polyethers. The 13C CP/MAS NMR measurement of complex 8 with PEG has demonstrated that PEG chains are included in the capillaries. This is an effective method for synthesizing supramolecular complexes. Three dimensional microporous polymers of Rh fumarate (Rh(f)) (11), Rh terephthalate (Rh(t)) (12), and a novel porphyrin rhodium coordination polymer, [Rh2(H2TCPP)] (H2TCPP=4,4′,4″,4‴-(21H,23H-porohine-5,10,15,20-tetrayl)tetrakis benzoic acid) complexes (13) have exhibited high catalytic activities for hydrogen exchange and hydrogenation of olefins (ethylene, propene, and butene) at 200 K. The turnover frequencies of complexes 11, 12, and 13 for hydrogenation of ethylene at 194 K are much higher than those of other published Rh-containing materials. The microwave spectroscopic analyses of the deuterium isotopic distribution of formed propene-d1 during C3H6–C3D6 reaction over complexes 11 and 12 reveal that the hydrogen exchange reactions take place only inside the nanopores of complexes 11 and 12 without complete scission of C–H bond of olefin molecule. Such a novel bimolecular pathway may play an important role for development of new heterogeneous hydrogenation catalysts.

The title compound, a Pd(II)-Co(II) coordination polymer selected isonicotinic acid (H-INA), [Co(H2O)4{PdCl2(INA)2}]n, was synthesized and characterized by single-crystal X-ray analysis. The compound was crystallized in the triclinic space group, P1 and Z = 1 with cell parameter a = 5.580(4)A, b = 6.709(4)A, c = 12.846(4)A, α = 71.52(5)°, β = 79.41(7)°, γ = 83.40(8)°, V = 447.5(5)A3. The crystal structure was solved by direct methods and refined by full-matrix least-squares on F2 to final values of R1 = 0.0282 and wR2 = 0.0954 for all 1845 independent reflections.

Dinuclear copper(II) complexes, [Cu2(L1)(X)], 1—4 (X = N3−, OH−, OAc−, pyrazolate(Pz−)), [Cu2(L2)(X)], 5—8 (X = N3−, OH−, OAc−, Pz−), [Cu2(L3)(X)], 9—12 (X = N3−, OH−, OAc−, Pz−), and [Cu2(L4)(OH)], 13 have been prepared, where H3L1 is the Schiff base derived from acetylacetone and 1,3-diamino-2-propanol, H3L2 the Schiff base derived from benzoylacetone and 1,3-diamino-2-propanol, H3L3 the Schiff base derived from acetylacetone and 1,5-diamino-3-pentanol, and H3L4 the Schiff base derived from benzoylacetone and 1,5-diamino-3-pentanol. An azide ion bridges in μ-1,3-fashion for 1 (diamagnetic) and 5 with 6-5-5-6 fused-chelate-rings. On the other hand, a μ-1,1-azide bridge has been observed for 9 (coupling constant, J = −126 cm−1, H = −2JS1·S2) with a 6-6-6-6-fused-chelate ring. The relationship between the various physical properties and the structures of fused-chelate rings is discussed.

The dinuclear copper(II) complexes of HL-Et or HL-Me and a bridging ligand (X (X = N3−, NCS−, NCO−, OH−, OAc−, (CH3)3CCOO− (OPi−), o-C6H4 (CH3)COO− (OTo−), pyrazolate (Pz−), and imidazolate (Im−))) have been prepared and characterized, where HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane and HL-Me = N,N,N′,N′-tetrakis[(1-methyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane. The magnetic moments of these complexes differ depending upon their bridging groups. The electrochemistry in N,N-dimethylformamide showed that only one-electron reduction(Cu2+–Cu2+ → Cu+–Cu2+) can occur for the dinuclear complexes bridged by X = N3−, OAc−, OPi−, OTo−, Pz−, whilst the other complexes showed irreversible processes.

Heterogeneous dinuclear rhodium(II) coordination polymer, [Rh 2 (p-BDC) 2 ] n (p-BDC = 1,4-benzenedicarboxylate), which formed self-assembly infinite two-dimentional slit sheets structure was performed as hydrogen production catalyst for photochemical reduction of water under visible light irradiation in the presence of a multicomponent system containing Ru(bpy) 3 2+ , MV 2+ , and EDTA-2Na.

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.

A three-dimensional (3-D) cobalt coordination polymer Co(BDC)(DABCO)1⁄2 (BDC = 1,4-benzenedicarboxylate; DABCO = 1,4-diazabicyclo[2.2.2]octane), which has a novel lantern-type structure, was synthe...

A novel microporous rhodium(II) coordination polymer, [Rh2(H2TCPP)] (1) (H2TCPP = 4,4′,4″,4″′-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis benzoic acid) was synthesized. The complex 1 showed high porosity of the micropores of 7.3 A. The amount of nitrogen adsorbed by 1 was 2.87 mole per mole of Rh, which is about three times that of rhodium(II) fumarate and rhodium(II) terephthalate. Complex 1 also showed high turnover frequencies for the hydrogenation of ethylene and propene at ca. 200 K.

The dinuclear nickel(II) complexes [Ni2(L-Et)(μ-1,3-N3)(N3)(H2O)]·[Ni2(L-Et)(μ-1,3-N3)(N3)(CH3OH)](NO3)2·H2O, (1) and [Ni2(L-Et)(μ-1,3-N3)(N3)(H2O)]NO3·H2O, (1′) (HL-Et = N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane) bridged by one alkoxo of L-Et− and one azido were prepared and the crystal structure of 1 was determined by X-ray crystallography. Magnetic susceptibility measurements for 1′ from liquid helium temperature to room temperature showed an antiferromagnetically strong interaction (2J = −187 cm−1, H = −2JS1·S2).

Mononuclear copper(II) terephthalate-pyridine, which has a regular one-dimensional structure, occludes large amounts of gases. The maximum amount of N2 gas that can be occluded by mononuclear copper(II) terephthalate-pyridine is 1.1 mole per mole of copper(II) salt, indicating the presence of a large number of micropores. A porous structure, which is formed by hydrogen bonding and self-assembly of the linear copper(II) terephthalate-pyridine, was determined by X-ray crystallography.

The structure of a linear chain complex [Rh(II)2(O2CPh)4(pyz)]∞ was characterized by X-ray diffraction analysis. The solid indicates nitrogen adsorption on a microporous medium although the crystal does not seem to have a microporous structure. There is a high possibility that the structure changes to open the crystal packing for gas molecules.

Theoretical studies have been carried out in order to elucidate possibilities of high-Tc organic ferromagnetism, ferrimagnetic long-range order and Haldane gap, which are conceivable for stable nitroxide systems. Organic helimagnets and photo-induced ferromagnets are also discussed in relation to possibilities of new organic magnetic systems.

The cation of [Cu(L1)(OMe)(ClO4)Cu(bpy)] ClO4 (1) consists of two coppers triply bridged by an oximato, a methoxo, and a perchlorato ligand, where L1 is 3-[2-(2-pyridyl)ethyl]amino-2-butanone oxime. The geometry around each copper is distorted square-pyramidal. The cation of [Cu(L1)(OAc)2Cu(bpy)]ClO4 (2), consists of two coppers triply bridged by an oximato, an unidentate and a bidentate acetato ligand. The geometry around the coppers is intermediate between a square pyramid and a trigonal bipyramid.

Three dimensional microporous polymers of Rh fumarate or Rh terephthalate complexes exhibited high catalytic activity for hydrogen exchange and hydrogenation of olefins at 200 K. The hydrogen exchange reaction takes place only inside the nanopores of the complexes without complete scission of C–H bond of olefin molecule.

We have detected the first example of open porous metal–organic frameworks (MOFs) that functions as an activity site for the reduction of water into hydrogen molecules in the presence of Ru(bpy)32+, MV2+, and EDTA–2Na under visible light irradiation. This activity is highly efficient: the turnover number based on MOFs and the apparent quantum yield are 8.16 and 4.82%, respectively. Furthermore, this material enables the adsorption of various gases into its pores; its hydrogen uptake capacity is 1.2 wt% at 77.4 K.

Reaction of copper(II) benzoate with pyrazine (pyz) gave a compound, [Cu2(bz)4(pyz)]n (1) which has a gas-occlusion property. The X-ray structure analysis of 1·2nCH3CN shows a microporous structure formed by chains where the carboxylate dimer units are linked by pyrazine molecules.

The reaction of a tripodal tetradentate ligand (H2L = N,N-bis(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine) with Fe(ClO4)2·6H2O and a carboxylic acid in basic methanol generates an iron(III) species under aerobic conditions. Further addition of an Mn2+ cation gave a heterotrinuclear complex, [{FeIII(L)(carboxylato)(OCH3)}2MnII]. On the other hand, an additional Fe2+ cation gave a μ3-oxo homotrinuclear complex, [{FeIII(L)(carboxylato)}2OFeIII(OCH3)]. Drastic changes in the structure were induced by the addition of metal ions.

The first hydrogencarbonato-bridged dinuclear copper(II) complex [Cu2(L)(HCO3)](BF4)2·5H2O, 1 was obtained by allowing of acetone solution containing a copper(II) complex [Cu2(L)(OH)](BF4)2·6H2O, where HL is N,N,N′,N′-tetrakis[(1-methyl-2-benzimidazolyl)methyl]-2-hydroxy-1,3-diaminopropane. The crystal structure of 1 was determined by X-ray crystallography and characterized by the magnetic susceptibility and infrared and visible absorption spectrum.

In this paper, we report the synthesis, spectral and magnetic properties, and X-ray crystal structure of the unique mononuclear iron(III) complexe

The crystal structure of the paramagnetic, title complex revealed one-dimensional molecular interaction through S–S non-bonded contacts. The complex with the one-electron C3S5 ligand-centered oxidation exhibited a strong antiferromagnetic interaction in the solid state.

The gas-occlusion properties of some ruthenium(II,III) dicarboxylate derivatives are reported.

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 one 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. 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.

Monomethyl carbonato-bridged dinuclear nickel(II) complexes [Ni2(L)(OOC-O-CH3)(CH3OH)2](ClO4)2·H2O·CH3OH, 1 and [Ni2(L)(OOC-O-CH3)(H2O)2](ClO4)2·H2O, 2 were obtained in the presence of [Ni2(L)(OH)(H2O)2](ClO4)2 and N-methylurea at room temperature in air, where HL is N,N,N′,N′-tetrakis[(1-ethyl-2-benzimidazolyl)methyl]- 2-hydroxy-1,3-diaminopropane. The crystal structure of 1 was determined by X-ray crystallography and 2 was characterized by the magnetic susceptibility and visible absorption spectrum.

New bis(β-diketonato)Cr(III) and Ni(II) complexes with a chelating nitronyl nitroxide radical were synthesized and characterized. The intensification and/or large Stokes shift of the spin-forbidden components and the charge transfer transitions revealed by the resonance Raman spectra in the visible region were found, which result from the moderate exchange coupling.

Reaction of manganese(II) salts (MnX 2 ·nH 2 O, X = Cl, Br, NO 3 ) with tris[(N-aldosyl)aminoethyl]amines L n , prepared by the reaction between tris(aminoethyl)amine (tren) with aldose [D-mannose (D-man) (L 1 )] or L-rhamnose [L-rha = 6-deoxy-L-man) (L 2 )] in situ, affords red–orange crystals formulated as [(MnL n ) 2 Mn(H 2 O)]X 3 (n = 2, X = Cl 1; n = 2, X = Br 2; n = 2, X = NO 3 3; n = 1, X = Cl 4), complexes 3 and 4 are characterized by X-ray crystallography.