THE POSITIONS OF LAMBDA(MAX) FOR SOME TRIMETHYLSILYL-SUBSTITUTED SILYLENES

Low-temperature photolysis of tris(trimethylsilyl)silane derivatives in a 3-methylpentane glass at 77 K yields hexamethyldisilane and trimethylsilyl-substituted silylenes. These silylenes exhibit broad n --> p absorptions at wavelengths typically >600 nm in the UV and have been captured by 2,3-dimethylbutadiene in cyclohexane at room temperature. Exceptions to the usual position of lambda(max) have been observed and are discussed.