THEORETICAL-STUDIES ON THE STRUCTURES AND REACTIVITY OF SILYLENOIDS .3. THE STRUCTURES AND ISOMERIZATION OF SILYLENOID H2SINAF

The potential energy surface of the singlet silylenoid H2SiNaF has bee n examined by ab initio calculations. The 3-21G and 6-31G+ basis sets were used for full geometry optimizations. Four equilibrium structures and three isomeric transition states were located. The calculations h ave shown that the structures with three-membered ring and p-complex f orm are the most stable, and that there are two basic structures in wh ich silylenoid, H2SiNaF, exists and takes part in chemical reactions. The classical tetrahedral and sigma-complex forms are also local minim a, but should rearrange easily to the three-membered ring structure wi th minimal activation.