Half-sandwich metal diselenolate complexes Cp#M(NO)(SePh)(2) (M = Mo or W; Cp# = Cp or MeCp) as ligands. Synthesis of selenolate-bridged heterobimetallic compounds

The reactions of half-sandwich diselenolate Mo and W complexes (CpM)-M-#(NO)(SePh)(2) (M = Mo; Cp-# = Cp' (1a), MeCp (1b); M = W; Cp-# = Cp' (1c)) with (Norb)Mo(CO)(4), Ni(COD)(2) and Fe(CO)(5) have been investigated. Treatment of (1a), (1b) and (1c) with (Norb)Mo(CO)(4) in PhMe gave the bimetallic complexes: Cp'Mo(NO)(mu -SePh)(2)Mo(CO)(4) (2a), MeCpMo(NO)(mu -SePh)(2)Mo(CO)(4) (2b) and Cp'W(NO)(mu -SePh)(2)Mo(CO)(4) (2c) in moderate yields. Irradiation of (1a) and (1c) in the presence of Fe(CO)(5) gave heterobimetallic complexes Cp'Mo(CO)(mu -SePh)(2)Fe(CO)(3) (3a) and Cp'W(NO)(mu -SePh)(2)Fe(CO)(3) (3c). Ni(COD)(2) reacts with two equivalents of (1a), (1b) and (1c) to give [Cp'Mo(NO)(mu -SePh)(2)](2)Ni (4a), [MeCpMo(NO)(mu -SePh)(2)](2)Ni (4b) and [Cp'W(NO)(mu -SePh)(2)](2)Ni (4c) in good yields. The new heterobimetallic complexes were characterized by i.r., H-1-n.m.r., C-13-n.m.r. and EI-MS spectroscopy.

Metal-oxo cluster-supported transition metal complexes: hydrothermal synthesis and characterization of [{M(phen)(2)}(2)(Mo8O26)] (M = Ni or Co)

Two new metal-ore supported transition metal complexes, E{M(phen)(2)}(2)(Mo8O26) (M = Ni or CO; phen = 1,10-phenanthroline) are synthesized by a hydrothermal method and characterized by X-ray crystallography, showing that the octamolybdate possesses a novel unprecedented structure and that [M(phen)(2)](2+) units are covalently bonded to the [Mo8O26](4-) cluster.

Use of lanthanide metal complexes for the hydrolysis of 3 ',5 '- and 2 ',3 ' cyclic nucleotides

Lutetium(III) and lanthanum(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP), 3',5'-cyclic deoxyadenosine monophosphate (dcAMP) and 2',3'-cyclic adenosine monophosphate (2',3'-cAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. 2',3'-cAMP is converted to 3'-AMP and 2'-AMP, the ratio of 3'-AMP to 2'-AMP produced being 1.4.

Investigation on molecular and crystal structures of metal complexes with aminopolycarboxylic acids .1. Synthesis and structure of Na-2[Fe-III(ida)(2)](2)center dot 3H(2)O

The crystal structure of the title complex salt has been determined by single-crystal X-ray structure analysis. The crystal data areas follows; Monoclinic, P2(1)/c, a=15.6480(10)Angstrom, b=16.7870(10)Angstrom, c=10.347(2)Angstrom, beta=90.790(10), V=2717.7(6)Angstrom(3), Z=3, and R=0.0333 for 4789 unique reflections. The complex anion has a pseudo-octahedral structure distorted more than the Cr-III and Co-III analogs, in which each, iminodiacetato ligand (ida(2-)) is coordinated in a facial fashion with the two N atoms in a cis configuration, resulting in an unsym-fac structure.

Lanthanide metal complexes for the hydrolysis of adenosine-5'-monophosphate and deoxyadenosine-5'-monophosphate

The hydrolysis of adenosine-5'-monophosphate and deoxyadenosine-5'-monophosphate has been studied with lanthanide(III) metal complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) by NMR and HPLC and by measuring the liberated inorganic phosphates.

Lanthanide metal complexes for the hydrolysis of ribonucleoside 3',5'-cyclic phosphate and deoxyribonucleoside 3',5'-cyclic phosphate

Ytterbium(III) and praseodymium(III) complexes of 2-carboxyethylgermanium sesquioxide (Ge-132) can hydrolyze the phosphodiester linkage of 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic deoxyadenosine monophosphate (dcAMP). Both cAMP and dcAMP are hydrolyzed with high selectivity, yielding predominantly 3'-monophosphates. The selectivity and activity for hydrolyzing cAMP and dcAMP by lanthanide metal(III) complexes and lanthanide metal ions are compared.

Kinetics of electrocatalytic ascorbic acid at ultramicroelectrode modified by Eastman-AQ polymer containing tris(2,2-'-bipyridine) osmium(III/II) complexes as electron-transfer centers

The theoretical model[17] of an ultramicroelectrode modified with a redox species film is used as the diagnostic tool to characterize the catalytic oxidation of ascorbic acid at carbon fiber ultramicrodisk electrodes coated with an Eastman-AQ-Os(bpy)(3)(2+) film. The electrocatalytic behavior of ascorbic acid at the ultramicroelectrode modified by an Eastman-AQ polymer containing tris(2,2'-bipyridine) osmium(III/II) as mediators is described. In order to determine the five characteristic currents quantitatively, the radius of the ultramicroelectrode and the concentration of ascorbic acid are varied systematically. The kinetic zone diagram has been used to study the electrocatalytic system. This system with 0.5-2.75 mM ascorbic acid belongs to SR + E case, and the concentration profiles of the catalyst in the film are given in detail. Finally, optimizing the design of catalytic system is discussed.

STUDIES ON OLEFIN-COORDINATING TRANSITION-METAL CARBENE COMPLEXES .20. SYNTHESIS OF 1,3-CYCLOHEXADIENE(DICARBONYL) [ETHOXY(ARYL)-CARBENE]IRON COMPLEXES AND THEIR PHOSPHINE ADDUCTS - CRYSTAL-STRUCTURE OF C6H8(CO)2FEC(OC2H5)C6H4CH3-O

Reaction of 1,3-cyclohexadiene(tricarbonyl)iron (1) with ortho-substituted aryllithium reagents ArLi (Ar=o-CH3C6H4, o-CH3OC6H4, o-CF3C6H4) in ether at low temperature, and subsequent alkylation of the acylmetalates formed with Et3OBF4 in aqueous solution at 0-degrees-C or in CH2Cl2 at -60-degrees-C gave the 1,3-cyclohexadiene(dicarbonyl)[ethoxy(aryl)carbene]iron complexes (eta4-C6H8)(CO)2FeC(OC2H5)Ar (3, Ar = o-CH3C6H4; 4, Ar = o-CH3OC6H4), and the isomerized product (eta3-C6H8)(CO)2FeC(OC2H5)C6H4CF3-o (5), respectively, among which the structure of 3 has been established by an X-ray diffraction study. Complex 3 is monoclinic, space group P2(1) with a = 8.118(4), b = 7.367(4), c = 14.002(6) angstrom, beta = 104.09(3)-degrees, V = 812.2(6) angstrom3, Z = 2, D(c) = 1.39 g cm-3, R = 0.056, and R(w) = 0.062 for 976 observed reflections. Complexes 3 and 5 were converted into the chelated allyliron phosphine adducts(eta3-C6H8)(CO)2(PR31)FeC(OC2H5)Ar (6, Ar = o-CH3C6H4, R1 = Ph; 7, Ar = o-CH3C6H4, R1 = OPh; 9, Ar = o-CF3C6H4, R1 = Ph), by reaction with phosphines in petroleum ether at low temperatures.

ANODIC-OXIDATION OF HYDRAZINE ON GLASSY-CARBON MODIFIED BY MACROCYCLIC TRANSITION-METAL COMPLEXES .1. COBALT PROTOPORPHYRIN DIMETHYL ESTER MODIFIED ELECTRODE

The electrocatalytic oxidation of hydrazine (N2H4) on a glassy carbon electrode (GC) modified by monolayer and polymer films of cobalt protoporphyrin dimethyl ester (CoPP) has been studied. Both the monolayer and polymer films of CoPP are very active to the anodic oxidation of N2H4. The activity of CoPP for the anodic oxidation of N2H4 is dependent on the pH of the solution, and the thickness of polymerized CoPP film. The oxidation kinetics were examined by methods of cyclic voltammetry, rotating disc electrodes and steady-state polarization measurement.

STUDIES ON THE REACTION AND STRUCTURE OF THE COMPLEXES OF ALKALINE-EARTH METAL WITH CHLOROPHOSPHONAZO-DBC

In this paper, the reaction and structure of the complexes of alkaline earth metal (Ca, Sr, Ba) with 2-(4'-chloro-2'-phosphonazo)-7-(2', 6'-dibromo-4'-chlorophenylazo 1, 8-dihydroxy-3, 6-naphthalene disulfonic acid (Chlorophosphonazo-DBC) have been studied. This ligand has eight forms under different acidity. The protonation reactions take place at [H+] > 0.36 mol.dm-3. The ligand begins dissociations at pH > 0.5. Two protons are released in the complexes formation reactions(Me2+ + 2HI half-arrow-pointing-left and half-arrow-pointing-right MeL2 + 2H+). The stability constants of the complexes of Calcium, Strontium and Barium have been determined by Yoe-Jone method, Majumder-Chakrabartty method and calculation method. The order of the stability of complexes is as follows: Sr > Ba > Ca. The structure of the complexes have also been studied by infrared spectroscopy, Laser Raman spectroscopy, NMR, and EPR. The results show that these groups of N = N, PO3H2 and OH are active groups in the complex reactions. The structure of the complexes of Strontium, Barium and Calcium with chlorophosphonazo-DBC are represented and the reaction and the complex bonds are discussed in this paper.

HE PHASE TRANSFER OF CO(II) CATALYZED BY 2,2 '-BIPYRIDINE AT THE WATER/NITROBENZENE INTERFACE

The chemical reactions coupled with the phase transfer of Co(Ⅱ) catalyzed by 2,2′ -bipyridine across the water/nitrobenzene interface have been observed by using cyclic voltammetry (CV). Coupled chemical reactions both in the organic phase or in the aqueus phase influence the CV behavior of successive complex phase transfer obviously and an irreversible phenomenon similar to that existed at the metal electrode/electrolyte solution interface was observed. For different complexes, the phase transfer mechanism...

Epoxidation of styrene with NaOCl and catalyzed by nickel(II) complexes

Epoxidation of styrene was catalyzed by some nickel(II) complexes, with NaOCl as the oxygen donor. The catalyst Ni(PA)(2). 2H(2)O has been found to be stable for the epoxidation of styrene. Some additives were introduced in the reaction to improve the "micro-environment" of the catalyst. Radical trap had little influence on styrene epoxidation. It was interesting to find that phase-transfer agent had negative influence on epoxidation in this biphase reaction. A possible mechanism of styrene epoxidation catalyzed by Ni(PA)(2). 2H(2)O has been proposed.