Transition-metal Complexes of E_2R_2 Species(E=Si or Ge)Including an E(ident to)E Triple Bond.A Theoretical Study

摘要

Transition-metal complexes of E_2R_2(E=Si or Ge;R=H)are theoretically investigated with DFT,MP2 ~ MP4(SDQ),and CCSD(T)methods.In free molecule of Si_2H_2,there are many isomers;HE(ident to)EH 1 including a triple bond,H-moved form,Si=SiH2 2,two H-bridged form 3,and one H-bridged form 4.Species 3 is the most stable.When Pt(PMe_3)_2 is used as a metal moiety,the complex of 2 is the most stable,that of 1 is the next,and that of 4 is the least stable.When RhCl(PMe_3)_2 is employed as a metal moiety,the complex of 2 is the most stable and that of 3 is the next,while that of 1 is the least stable.When Cp_2Zr species is used as a metal moiety,the complex of 2 is the most stable,that of 1 is the next,and that of 3 is the least stable.The relative stabilities of Ge analogues are different.These relative stabilities are interpreted in terms of the energy levels of the occupied d orbital of the metal species and the pi * orbital of E_2H_2.