Product sensitization in the photochemical generation of carbenes from sulfonium ylides

Abstract

Photolysis of thiophene ylides provides a route to certain carbenes with adjustable photophysical parameters, in that the absorption spectrum of the precursor and the initial spin population of the carbene can be varied. However, the accumulated thiophene from extensive photolysis can act as a triplet sensitizer leading to triplet carbene. It is demonstrated that dibenzothiophene has this property and 2,5-dichlorothiophene does not.