关键词: 化学键, 电子结构, 原子簇, 配体效应

We have chosen 14 mixed-metal, four-nuclear cluster compounds formed from IB-Ⅷ or IB elements to study their bonding regularity, liqand effect and energy change using DV-Xα method. Quantum chemical calculation show that they may be classified as three types: the first cluster core presents a triangular pyramid, there are 6 metal skeleton orbitals and is more stable one. For second cluster, its metal skeleton likes a butterfly (double bond at body and single bond at wing), IB atom preserves valence electrons of itself as far as possible and Ⅷ atom make major contribution of charges. In third cluster, the metal bond is strong between two IB atoms and is weak between IB-Ⅷ or IB-ⅥB atoms, so cluster is more unstable one. We have also found that the triphenyl phosphine liqand is a better electronic adjuster for cluster synthesis-unnecessory. Because energy of IB metal is difference with Ⅷ or ⅥB metal, energy of mixed-metal cluster changes clearly, so cluster reaction activity and catalysis selectivity change, too.

Key words: CHEMICAL BONDS, ELECTRONIC STRUCTURE