Study on Oxamidato-Bridged Binuclear Copper（Ⅱ）Complex Cu₂（oxen）（SCN）₂ with ah initio Calculation

The investigation of the ets-trans conformations and the singlet and triplet electronic configurations of the oxamidato-bridged binuclear copper（Ⅱ） complex Cu₂ （oxen） （SCN）₂ H₂oxen=N, N’-bis（2-aminoethyl） oxamide was camed out with ah initio calculation by means of Gaussian 94W package and taking LanL2DZ basis set. The stability of the binuclear unit, the energies of the molecular orbitals, the population regularity of the atomic net charges and the characteristic of the electronic structure, etc., were described and discussed. It has been indicated from the calctilations that the triplet electronic configuration of the complex with oxamidate in trans-conformation, i. e., trans-Cu₂L（T） is more stable in four possible conformations and configurations of the complex. It may be explained that the centric symmetry of the comPlex is advantageous to the averaging populations of the electron cloud and then leads to the molecular orbital energies of trans-Cu₂L lower than the corresponding orbital energies of cis-Cu₂L. The results also show that the bridging effect of oxamidate does not change mainly the spin populations of Cu atoms, but it plays an important role in transfering spin electron. The calculation results are agreeing with the experimental regularlies