ELECTRONIC CONFIGURATIONS OF TRANSITION METAL SANDWICH COMPLEXES

In this paper the electronic configurations of n+1-decker transition metal sandwich com-plexes have been generally discussed by means of the structural rule of transition metalheterocarborans and the numbers of their valence bonding orbitals have been obtained as fol-lows: VBO = 6n + 3-6n + 5,which are not dependent on the properties of transition metal atoms and coordination rings.Then the results of EHMO quantum chemistry calculations of the model skeletons and cor-responding analyses on electronic configurations of actual molecules for double-, triple- andtetra-decker sandwich complexes have been discussed to verify the above formula.     

THERMAL DECOMPOSITION OF METAL COMPLEXES. MIXED COMPLEXES OF DIVALENT TRANSITION METALS WITH α-NITROKETONES

Abstract

The thermal behaviour of mixed complexes containing transition metals, α-nitroketones and pyridine or ethanol was investigated by thermogravimetric analysis (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The values of the activation energies and the enthalpies for the dissociation processes have been calculated in high vacuum and isothermal conditions. Comments are made on the obtained heats and correlations with structural characteristics are looked for.     

STUDIES OF THE HOMOLOGATION OF METHANE ONSUPPORTED TRANSITION METAL CATALYSTS

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SYNTHESIS OF CHIRAL MIXED-LICAND COMPLEXES AND THEIR USE IN ASYMMETRIC SYNTHESIS OF CHRYSANTHEMIC ACID

Several chiral mixed-ligand complexes have been synthesized and theirefficiency as catalysts for the asymmetric synthesis of chrysanthemic acid tested.     

CHARACTERIZATION OF SOME SCHIFF BASES OF HETEROCYCLIC COMPOUNDS AND THEIR TRANSITION METAL COMPLEXES

Some new Schiff bases were synthesized by the condensation ofequimolar quantities of salicylaldehyde and 2-amino-5-phenylazo-pyridine orits derivatives in dry benzene(1):Metal complexes of the type ML_2and M'L_3where M=Cu~(2+),Co~(2+),Ni~(2+),Mn~(2+)Pd~(2+),M'=Fe~(3+)and L=different newly synthesizedmonobasic Schiff bases were prepared in absolute ethanolic medium(2)andcharacterized by elementary analysis,conductance measurements,infraredspectra,electronic spectra,magnetic moments studies.     

A STUDY ON MULTIPLE METAL TO METAL BONDS IN TRANSITION METAL COMPLEXES

<正> We report here the calculation on electronic structures of model compounds of dimetal tetracarboxylate M2(O2CH)4 (M=V, Cr, Mo) by means of a DPS8 computer CNDO program. On the basis of molecular orbital components and contour maps of wave functions the character of the multiple metal to metal bonds are analysed and discussed.     

STABILITY OF TETRANUCLEAR EARLY TRANSITION —METAL CLUSTERS

<正> The bonding capacities of tetranuclear early transition-metal clusters have been estimated based on the extended Huckel calculations.Using the Walsh diagram which shows orbital levels during the variation in geometry,a method has been established to determine their stability which is described with three factors:the symmetry and geometrical size,the distribution of ligands,and the number of cluster core electrons(CCEs).The stabilities of many cluster compounds can be successfully explained.     

THE SYNTHESIS AND CHARACTERIZATION OF ANSYMMETRIC PENTAAZADENTATE PORPHYRIN-LIKE METAL COMPLEXES

This paper presents the synthesis and structural characterization of asymmetrictripyrrane-containing macrocycle.This macrocycle could be oxidized to the methinebridged,22 π-electron aromatic macrocyclic complexes containing cadmium(Ⅱ),samarium(Ⅲ),europium(Ⅲ)and gadolinium(Ⅲ)by treating with corresponding metal chloride inthe presence of air Their structures were characterized by spectral methods.     

STUOIES ON TRANSITION METAL COMPLEXES OF SCHIFF BASE—OXYGEN—CARRYING PROPERTIES OF THREE COBALT（Ⅱ） COMPLEXES OF N－SALICYLIDENEAMINO ACIDS

ＳＴＵＯＩＥＳＯＮＴＲＡＮＳＩＴＩＯＮＭＥＴＡＬＣＯＭＰＬＥＸＥＳＯＦＳＣＨＩＦＦＢＡＳＥ—ＯＸＹＧＥＮ—ＣＡＲＲＹＩＮＧＰＲＯＰＥＲＴＩＥＳＯＦＴＨＲＥＥＣＯＢＡＬＴ（Ⅱ）ＣＯＭＰＬＥＸＥＳＯＦＮ－ＳＡＬＩＣＹＬＩＤＥＮＥＡＭＩＮＯＡＣＩＤＳＸｉａ...     

PRELIMINARY STUDIES ON THE SYNTHESIS AND CHARACTERIZATION OF OXY-AND THIO-DIACETIC ACID HYDRAZITION AND THEIR FIRST-ROW TRANSITION METAL COMPLEXES

It has been made certain that thio-and oxy-diacetic acid hydrazidesare potential anticancer compounds.However,their ability to formcomplexes with transition metals and the properties of the complexes thusformed have not been studied.Employing a new potential anticancer ligand1,2-bis(thioacetic acid hydrazide)ethane prepared in our lab,along withligands oxydiacetic hydrazide and 1,2-bis(oxyacetic acid hydrazide)ethane,a series of 11 new first-row transition metal(M=Zn~(2+),Cu~(2+),Co~(2+),Ni~(2+))complexes with each of the above three ligands have been synthesizedand characterized by means of elemental analyses,IR,TG and X-raypowder diffraction.     

SYNTHESIS AND CHARACTERIZATION OF COMPLEXES OF TRANSITION METAL WITH PBDETA, A NEW POLYDENTATE LIGAND

The synthesis and characterization are reported for a series of bi- and trinuclear complexes of the first transition metal ions with PBDETA, the newly syn thesized polydentate ligand. The electron transition energy in binuclear compound is stronger than that in trinuclear. There is a weak antiferromagnetic exchange interaction in tricopper and trimanganese.     

STUDIES OF THE MOBILITY OF SURFACE CARBON FORMED BY THE DECOMPOSITION OF METHANE ON SUPPORTED TRANSITION METAL CATALYSTS

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PREPARATION OF DI－GRIGNARD REAGENTS MEDIATED BY THE TRANSITION METAL CHLORIDES

ＰＲＥＰＡＲＡＴＩＯＮＯＦＤＩ－ＧＲＩＧＮＡＲＤＲＥＡＧＥＮＴＳＭＥＤＩＡＴＥＤＢＹＴＨＥＴＲＡＮＳＩＴＩＯＮＭＥＴＡＬＣＨＬＯＲＩＤＥＳＰＲＥＰＡＲＡＴＩＯＮＯＦＤＩ－ＧＲＩＧＮＡＲＤＲＥＡＧＥＮＴＳＭＥＤＩＡＴＥＤＢＹＴＨＥＴＲＡＮＳＩＴＩＯＮＭ...     

SYNTHESIS AND SPECTRA STUDIES OF TRANSITION METAL COMPLEXES DERIVED FROM 2， 4－DINITROPHENYL HYDRAZINE

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THE INFRARED SPECTRA (4000 - 50 cm−1) OF COMPLEXES OF QUINOLINE N-OXIDE AND ITS PERDEUTERATED ANALOGUE WITH METAL(II) PERCHLORATES OF THE FIRST TRANSITION SERIES

Abstract

Infrared assignments (4000 - 50 cm^?1) are presented for the complexes [M(quinO)_n](ClO₄)₂(quinO = quinoline N-oxide; n = 6 for Mn, Co, Ni; n = 5 for Zn, and n = 4 for Cu) and their perdeuterated analogues. The spectra are consistent with octahedral structures for the 6-coordinate complexes, a trigonal bipyramidal structure for the Zn(II) complex and a square planar structure for the Cu(II) complex, with some distortion from idealised symmetry evident for each complex. In the Mn(II) complex, strong coupling occurs between the vM-O of lowest frequency and the ligand vibration, xN-O (mode 45). In the Cu(II) complex, the single vCu-O is strongly coupled with the ring torsion (mode 28).     

SYNTHESIS,CHARACTERIZATION AND BIOLOGICAL ACTIVITY OF TRANSITION METAL COMPLEXES WITH 5-HYDROXY-7, 4''''-DIMETHOXYFLAVONE

Complexes of Cu~Ⅱ, Ni~Ⅱ, Co~Ⅱ, Zn~Ⅱ, Fe~Ⅲ, Cr~Ⅲ, Cd~Ⅱ and Mn~Ⅱ with the natural product 5-hydroxy-7,4′-dimethoxyflavone(1) have been prepared and their probable structures were proposed on the basis of elemental analyses, thermal analyses and IR and UV spectral data. The ligand and all the complexes were tested in vitro for their antibacterial activity.     

THE MULTIPLE CENTRIC d-pπBONDS AND ITS EFFECT ON THE ELECTRONIC STRUCTURES OF SOME TRANSITION METAL CLUSTERS

<正> 1. THE THEORETICAL CALCULATION AND EXPERIMENTAL MEASUPEMNT FOR THE MULTIPLE CENTRIC d-pπ BONDING. It was shown from the data of bond lengths and IR spectra of the M-Lb,or t bonds in the c(?)ters(b denotes bridge;t terminal) that there is certain bonding interaction (about 0.3 bond order ) in addition to σ single bond between metal M and ligand Lb,or t. By systematic EHMO and DV-X calculations of a series of the cluster with 2-6 metal atoms (Tab.l), the following new information has been obtained.     

CHIRAL COMPLEXES BY DIRECT SYNTHESIS OF A BIOMOLECULE AND METAL POWDERS. CRYSTAL STRUCTURES OF THE DICHLORO[(−)-SPARTEINE-N,N′]M(II) COMPLEXES (M = Cu,Zn)

Abstract

Direct synthesis of chiral complexes dichloro[(?)-sparteine-N,N′]copper(II) 2 and dichloro[(?)-sparteine-N,N′]zinc(II) 3 derived from a biomolecule-namely the natural base (?)-sparteine- and elemental metals (Cu and Zn) in a CCl₄/DMSO solvent system (DMSO = dimethylsulfoxide) is reported. The complexes were partly characterized by spectroscopic methods and their structures were fully confirmed by single-crystal x-ray analysis. A comparison between the new crystal structures of 2 and 3 and that of the free ligand (?)-sparteine displayed only slight differences on the ligand framework.