Generation, reactions, and kinetics of sterically congested triplet diphenylcarbenes. Effects of bromine groups

A series of polybrominated diphenylcarbenes are generated by irradiation of the corresponding precursor diazomethanes, and their reactivities are investigated by means of low temperature spectroscopies and laser flash photolysis. While the replacement of a 4-bromine group with a methyl group resulted in a sharp decrease in the lifetime introduction of a tert-butyl group resulted in an increase in the lifetime.