The synthesis of dichlorodiazirine and the generation of dichlorocarbene: spectroscopy and structure of dichlorocarbene ylides

Reaction of 2,4-dinitrophenoxychlorodiazirine (13) with chloride ions affords dichlorodiazirine (4). Photolysis of 4 generates dichlorocarbene. In laser flash photolysis (LFP) experiments, CCl2 forms chromophoric ylides or oxides with pyridine, 2-picoline, thioanisole, and oxygen. Spectroscopic and computational studies of the ylides are reported. The UV spectrum of CCl2 in solution, however, is not observed. It appears possible that CCl2 is rapidly captured by oxygen to afford a chromophoric dichlorocarbene carbonyl oxide. We present a theoretical analysis of this process.