Stannylenes: An MNDO (Modified Neglect of Differential Overlap) Investigation

摘要

While the chemistry of carbon (II) compounds (carbenes) has been extensively studied, references to the organic chemistry of tin(II) compounds (stannylenes) remain sparse. While the stable tin(II) halides have been well characterized and MNDO studies of them reported, organotin(II) compounds have remained elusive and most of the early claims for their preparation have been refuted. In recent years, however, clear evidence for the preparation and reactions of stannylenes has emerged. The reactions so far reported include insertion into carbon-halogen or tin-halogen bonds, polymerization, and cheletropic cycloadditions. As in the case of divalent carbon, the reactions may take place either via free stannylenes or through stannylenoid intermediates. We have now examined several such processes, using the MNDO SCF MO model. MNDO parameters for tin have recently become available, and extensive studies of tin compounds have led to satisfactory results.