Abstract:

12 mixed-metal, four-nuclear clusters Pt2M2 have been calculated and discussed using DV-Xαmethod of quantum chemistry. We studied their bonding regularity and found out that they may be classified as three types: the first kind of clusters formed from Pt and group metal are the most stable one) and Pt atom as far as possible preserves valence electrons of itself, for the second clusters, platinum mixes with group metal, ⅥB metal make major contribution of charges; in the third clusters, in which Pt and Cu, Ag, or Au present quite low electronic valences, the charges of such systems are mainly suppied by the ligand PPh3. We have also found that the triphenyl phosphine ligand is an electronic adjuster for cluster syntheses and the cyclopentadienyl ligand pushes much charges from VIB metal towards the cluster compounds. The 5d energy bands of Pt will rise or fall if ⅥB or IB metal atom interjects into the platinum c1uster. In this case, adsorption ability on the surface of mixed metal will change remarkbly clearly.

Key words: Pt2M2, Mixed-metal cluster, DV-X&alpha, method, Charge transport, Ligand effect