Theoretical Studies of Three-Membered Ring Compounds Y(2)H(4)X (Y = C, Si; X = CH(2), NH, O, SiH(2), PH, S).

摘要

The heats of formation of the three-membered ring compounds Y2 H4X (Y = C, Si; X = CH2, NH, O, SiH2, Ph, S) and the thermodynamics of the insertion reactions X + YH =YH2 yields (c)-Y2H4X are predicted by using MP2/6-31G(d) energies at the 6-31G(d) geometries. Bent bond lengths are calculated by tracing the path of maximum electron density connecting two nuclei with the 6-31 G (2d) basis set at the 6-31 G (d) structures. The short Si-Si internuclear distances in Si2H4X (X = CH2, NH, O, PH,S) apparently are the result of severe bond bending rather than significant Pi character in the Si-Si bonds. Reprints. (AW)