An ab initio study on structures and isomerization of magnesium chlorosilylenoid H2SiClMgCl

The structures and isomerization of magnesium chlorosilylenoid H2SiClMgCl were investigated by ab initio molecular orbital theory for the first time. Four equilibrium structures and three isomeric transition states were located and fully optimized at the G3MP2B3 level. For more accurate structural analysis, the B3LYP/cc-pVTZ and QCISD/6-311+G* calculations were performed, respectively. Based on the B3LYP/6-31G(d) optimized geometries, 29Si chemical shifts and harmonic frequencies of various structures were obtained. Isomerization paths for isomers were confirmed by the intrinsic reaction coordinate (IRC) calculations. Tetrahedral, three-membered ring and p-complex structures are suggested to be experimentally detectable ones. σ-Complex structure has the highest energy and will not exist. The solvent effects were considered by means of the polarizable continuum model (PCM) using THF as a solvent.