Pt_2M_2异金属四核原子簇化合物成键规律探讨

Exploration on Bonding Regularity for Mixed-metal Four-nuclear Clusters Pt_2M_2

对十二个Pt_2M_2四核异金属簇化合物进行了鼻子化学DV－Xα方法的计算与讨论，探讨了这些原子簇的成键规律．它们大致可分为三类：Pt与回族金同形成的四该簇，Pt尽量保持自己原有的公电行；Pt与VB族金属形成的原子簇，VB族元素是电荷的主要提供者；Pt与IB族金属形成的原子簇，体系主要由配体PPh_3提供电荷．并提出，簇合时，三笨基膦配体起电子调节作用，环戊烯基配体起推电子作用．从能带分析，VB族或IB族金属介入原子簇，使Pt的5d能带上升或下降。

12 nied-metal, four-nuclear clusters Pt2M2 have been calculated and discussed using DV-X. method of quantum cheAnstry. We studied their bonding reguJarity and found out that they may be classilied 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 ndes with rm group metal, rm metal make ma jor contribution of charges; in the third clusters, in which Pt and Cu, Ag, or Au present qulte 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 rm or l B metal atom interjects into the platinum c1uster. In this case, adsorption ability on the surface of nied metal will change remarkbly clearly.