Abstract: Laser flash photolysis of 1-phenyldiazoethane in heptane releases 1- phenylethylidene which can be intercepted with pyridine to form an ylide (Amx= 475 nm). Oxygen trapping experiments indicate that relaxation of singlet 1-phenylethylidene to the ground triplet state is rapid relative to pyridine trapping. Analysis of the data reveals that the (singlet/triplet) carbene equilibrium constant K= 2 X and AGsT (298 K)= 2.3 kcal/mol at ...
