Nonclassical complex of dichlorosilylene with CO: direct spectroscopic detection

A complex between SiCl2 and CO of the 1:1 composition with coordination of the silylene to the C atom of carbon monoxide is detected in Ar matrices using FTIR spectroscopy. A positive shift of the nu(CO) band of the complex relative to the corresponding band of free CO and a theoretical analysis of the nature of the complex indicate that it is a nonclassical carbonyl complex. It is the first experimentally detected nonclassical carbonyl complex of any silylenes. The main direction of photoinduced transformations of the complex is its decomposition into the starting reactants. The potential energy surface of the SiCl2 + CO system was explored theoretically. It is shown that further thermal transformations of the primary complex are energetically unfavorable.