Search

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...

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.

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.

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.

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.

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.

Tripodal tetradentate ligands (H2L1: N,N-bis(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine, H2L2: N-(3,5-di-t-butyl-2-hydroxybenzyl)-N-(2-hydroxybenzyl)-N′,N′-dimethylethylenediamine, H2L3: N,N-bis(3,5-di-t-butyl-2-hydroxybenzyl)-N′,N′-dimethylethylenediamine, H2L4: N,N-bis(2-hydroxy-3-methoxybenzyl)-N′,N′-dimethylethylenediamine, H2L5: N-(3,5-di-t-butyl-2-hydroxybenzyl)-N-(2-hydroxy-3-methoxybenzyl)-N′,N′-dimethylethylenediamine) made it possible to prepare sterically controlled polynuclear manganese complexes. In the presence of carboxylate ligands, in contrast to the L3 ligand which gave mononuclear MnIII complexes, the other ligands afforded mixed-valence trinuclear complexes with an MnIII–MnII–MnIII arrangement. In methanol, the general formula of the products is [Mn3(L)2(carboxylato)2(OCH3)2]. While preparations in acetonitrile generated [Mn3(L1)2(ba)4] (ba = benzoate(1−)) and [Mn3(L2)2(ba)2(OH)2]. The structure of [Mn3(L1)2(ba)4] was determined by X-ray analysis. The three manganese cores are arra...

The dinuclear rhenium(IV) complexes with the C3S4Se-ligand [1,3-dithiole-2-selone-4,5- dithiolate(2-)], [PPh4]2- (1) and [NEt4]2[Re2(C3S4Se)5] (2), were prepared. Complex 2 was oxidized by a reaction with [Fe(C5H5)2][PF6] or [TTF]3[BF4]2 (TTF·+ = the tetrathiafulvalenium radical cation) and by the current-controlled electrolysis to yield [NEt4]x[Re2(C3S4Se)5] (x = 0.15 and 0.5) and [TTF][Re2(C3S4Se)5]. The compounds exhibit electrical conductivities of 3.3 x 10-3 - 9.3 x 10-4 S cm-1 for compact pellets at room temperature. Electrochemical and spectroscopic properties of the complexes are discussed on the basis of cyclic voltammetry and ESR, XPS and IR spectra as well as the magnetic susceptibility of the TTF salt.

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.

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

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.

A series of di- and trinuclear copper(II) complexes containing N,N,N′,N′-tetramethylethylenediamine(tmen), N,N-diethylethylenediamine(deen), 2,2′-bipyridyl(bpy) or 1,10-phenanthroline(phen) and azide, thiocyanate or cyanate ions have been prepared and characterized by their magnetic susceptibilities, infrared, electronic, and ESR spectra, and electric conductances. Magnetic susceptibility data for the dimeric complex [Cu2(tmen)2(N3)2] (ClO4)2 shows the presence of a ferromagnetic interaction (Weiss constant θ=+30 K) above 150 K, whereas the two copper(II) ions are apparently non-coupled below 150 K. On the other hand, the dimeric complex [Cu2(bpy)2(N3)2] (ClO4)2 shows the presence of a large antiferromagnetic exchange interaction (μeff

Cobalt(II), nickel(II), and copper(II) complexes with 2-furancarbaldehyde oxime have been prepared and characterized mainly on the basis of electronic spectra and magnetic data. The cobalt(II) and nickel(II) complexes of the formula MX2(oxime)4 (X=Cl, Br) have been isolated. They are all six-coordinated, the oxime being coordinated as a unidentate through the nitrogen atom. Copper(II) forms complexes of the formula CuX2(oxime)2 (X=Cl, Br). Possible structures for these complexes are discussed.

Polyacrylates containing tetraphenylporphinatocobalt(II) (TPP-Co(II)) and chloro(tetraphenylporphinato)iron(III) (TPP-Fe(III)Cl) as side chains were prepared. Their physicochemical properties were investigated by UV-visible spectroscopy, ESR spectroscopy, and magnetic susceptibility (χM) measurement. In comparison of the visible spectra of polymers with those of the corresponding monomers, hypochromism of the Soret band and some of Q bands was observed in both polymers. In the measurements of ESR spectra, hyperfine splitting constants and anisotropic g-values of TPP-Co(II) or -Fe(III)Cl moieties bound to the polymers were somewhat different from those of TPP-Co(II) and -Fe(III)Cl, respectively. These differences in spectroscopic behavior suggest that there are some interactions between porphinatometal ion moieties in the polymers. The values of χM for the polymers containing TPP-Co(II) were found to obey the Curie–Weiss law with θ=190 K, which was explained in terms not only of spin-orbit interaction of t...

The magnetic properties of polymers containing tetraphenylporphin-Cu(II) (TPP-Cu(II)) or tetraphenylporphin-Ag(II) (TPP-Ag(II)) in the side chains were studied by the magnetic susceptibility (χM) measurement (4—300 K) and ESR spectroscopy. The values of χM for the polymer containing TPP-Cu(II) were found to obey the Curie–Weiss law, and a magnetic moment showed the occurrence of a weak antiferromagnetic interaction between Cu(II) ions. The values of χM for the polymer containing TPP-Ag(II) did not obey any simple equation such as the Curie–Weiss law or Bleaney–Bowers equation and simulation of temperature dependence of χM showed the presence of strongly interacting sites. This strong interaction may possibly arise from a hyperexchange interaction through C = O groups situated among the Ag(II) ions. An ESR study also supported the presence of this interaction between the side groups in a polymer chain.

The influence of electron exchange on the physical properties of polymers containing nitroxyl radical in their side chains has been studied by ESR, magnetic susceptibility measurement and cyclic voltammetry. ESR study shows that the electron exchange interaction between free radicals bound to a polymer chain is more effective than that between the corresponding monomeric radicals. Magnetic susceptibility (XM) was measured at temperatures between 4K and 273 K. The values of XM for the polymers obey the Curie-Weise Law (XM=c/(T−θ)), where magnetic moments obtained from XM show the presence of antiferromagnetic interaction between the nitroxyls of a polymer chain, although the interaction is not large enough to bring about long range ordering in the spin orientation of the nitroxyls. In the corresponding monomers, no antiferromagnetic interaction was observed. Cyclic voltammetry in DMF shows that the electrode process in polymer system is a reversible multiple-electron transfer reaction, where the number of the transfer (np) is 60% of the total free radicals per molecule. A comparison of the shape of the voltammetric response curve in the polymers with that in the corresponding monomers suggests that the interaction between nitroxyl radicals in the polymer is too weak to be reflected in electrochemical behavior.

High- and low-spin Fe(III) complexes with the titled ligands, [Fe(Sal23,3,3-tet)](NO3) (S=5/2) (1) and [Fe(Sal23,2,3-tet)](NO3) (S=1/2) (2), have been synthesized. X-ray analyses for 1 and 2 show that, in each complex, the metal environment is pseudo octahedral with the two O atoms being trans. Difference of one CH2 group in the methylene chain of the ligand causes a copmlete change in the spin state without changing coordination gemetries. In methanol, 2 is essentially low spin with μeff=1.95 BM(263.5 K), whereas 1 exhibits the behavior for the spin equilibrium [μeff=3.00(244.5 K)–4.04(305.5 K) BM]. The equilibrium constant of 1, K = [low-spin]/[high-spin]=2.6±0.9 at 25 °C and ΔH = −11.8±2.5 kJ mol−1 were obtained from detailed analyses of the temerature dependent electronic spectra.

On the basis of the generally accepted view that copper ions take part in the occurrence of inflammation, hydroxamic acids and acid hydrazides derived from various substituted cinnamic acids and hydrocinnamic acids, which were expected to chelate with copper ions, were synthesized and evaluated for anti-inflammatory activity by the carrageenin-induced rat paw edema assay and for analgesic activity by the phenylquinone writhing method in mice. Some of the synthesized compounds exhibited both activities, and 3-(3, 4-dimethoxyphenyl)propiohydroxamic acid and its Zn complex were more active than aspirin. The Cu (II) complexes of hydroxamic acid derivatives were synthesized and were assumed to have polymeric structures from the results of elemental analysis, molecular weight measurement and determination of magnetic susceptibility.

Reaction of copper(I) thiocyanate with imino oximes 3-[[2-(alkylamino)ethyl]imino]-2-butanone oximes or 3-[[2-(dialkylamino)ethyl]imino]-2-butanone oximes, (abbreviated as Hdox-enRR′), gave a series of copper(II) complexes which consist of binuclear complexes [Cu2(dox-enRR′)2(NCS)2] with a thiocyanate anion coordinated to the copper(II) ion. The magnetic susceptibilities over the temperature range 77–320 K show a strong antiferromagnetic spin coupling through the N–O bridge for these complexes. The magnetic behavior can be explained by using the Bleaney–Bowers equation.

Two types of imino oxime copper(II) complexes were obtained by the reactions of copper(I) halides CuX (X=Br, I) with imino oximes (3-[2-[(alkylamino)ethyl]imino]-2-butanone oximes or 3-[2-[(dialkylamino)ethyl]imino]-2-butanone oximes, abbreviated as Hdox-enRR′). One type contains the binuclear complexes [Cu2(dox-enRR′)2]2+ and uncoordinated halide anions. The magnetic susceptibilities measured over the temperature range 77–320 K show a strong antiferromagnetic spin coupling interaction through the N–O bridge in these complexes. The magnetic behavior can be explained by using the Bleaney–Bowers equation. It is assumed that the complexes of the other type consist of copper(I) and copper(II) in 2:1 ratio without spin-coupling interaction between the copper ions. The plot of the reciprocal magnetic susceptibilities versus temperatures is linear.

Synthesis and Physicochemical Properties of Polyacrylates and Polymethacrylates with Tetraphenylporphinatocopper(II) and -vanadyl(II)

Schiff bases (3, 4) were obtained by condensation of D-threo-2-amino-1-(4-nitrophenyl)-1, 3-propanediol (2) with salicylaldehyde and acetylacetone. Copper (II) chelates (5 and 6) were synthesized from 3 and 4, respectively, and their chemical structures were determined by elemental analysis, molecular weight measurement, and infrared and nuclear magnetic resonance spectroscopies. From the temperature dependence of their magnetic susceptibilities, 5, 6 and the phenylcarbamate (7) derived from 5 were inferred to be tetramers having cubane-type structures. The phenylcarbamate (9) derived from 6 was presumed to have a dimeric structure.

The structure of the title compound has been determined by an X-ray method. The dinuclear complex is composed of two Cu(dien) units which are bridged by pyrazolate and Br− anions. The geometry around each copper(II) may be described as a square pyramid. The antiferromagnetic interaction within the dinuclear complex has been observed (J=−14 cm−1, H=−2JS1·S2).

Comparaison de la susceptibilite magnetique du polymere (obtenu par polymerisation dans le THF a 0°C du diphenyl-1,5 (p-methacryloyloxymethylphenyl)-3 verdazyl), en presence de butyllithium avec celle du monomere