Theoretical studies on the structures and isoemrization of silylenoid H_2SiNaCl

摘要

The structures and isomerization of siJyJenoid H2SiNaCl were studied by ab initio molecular orbital theory at RHF/6-31G(d; and MP2/6-311G(d,p) levels. Three equilibrium structures and two isomeric transition states were located. Based on the MP2/6. 311 G( d,p ) calculations, harmonic frequencies of various isomers were obtained and further single-point calculations werf performed at the QCISD(T)/6-311G(d) and MP2/6-311 +G(3df,2p) levels, respectively. G2(MP2) theory was used for ~alcula. tions on energies. Isomerization paths for isomers were investigated by intrinsic reaction coordinate (IRC) calculations at MP2i 6-311G(d,p) level. Changes (AH and ~G) of thermodynamic functions, equilibrium constant K(T), A factor and reaction rate constant k of the isomerization reaction among isomers of H2SiNaCl were calculated and then thermodynamic and kinetic properties were analyzed. The stability, reactivity. and existence of various equilibrium structures were also discussed in this paper.