ETHYLENE, SILENE, AND DISILENE COORDINATE BONDS WITH PLATINUM(0) AND PLATINUM(II) - AN ABINITIO MO/MP4 AND SD-CI STUDY

[PtCl3L]- and Pt(PH3)2L (L = C2H4, SiH2CH2, or Si2H4) are investigated with ab initio MO/MP4 and SD-CI methods. Binding energies of these complexes increase in the order ethylene < silene < disilene in both Pt(0) and Pt(II) complexes, and their coordinate bonds are stronger in Pt(II) complexes than in Pt(0) complexes. The disilene coordinate bond of Pt(PH3)2(Si2H4) can be described as a three-centered metallocyclopropane type interaction, while the ethylene coordinate bond of [PtCl3(C2H4)]- and Pt(PH3)2(C2H4) exhibits the character of C = C double-bond coordination. Electron correlation has little effect on geometries of these complexes but has a significant influence on binding energies.