Laser flash photolysis of 2-diazo-1,3-diphenyl-1,3-propanedione: An unusual long-lived triplet as a reaction intermediate
Laser flash photolysis of 2-diazo-1,3-diphenyl-1,3-propanedione (DBD) is presumed to involve a short-lived carbene, followed by Wolff rearrangement to a long-lived ketene. We have detected ketene ylides following photolysis of DBD in the presence of amines but not with pyridine. The triplet state of DBD lives several microseconds, an unusual observation for a diazo compound; however, the triplet is not a ketene precursor, which must result from excited singlet state fragmentation of DBD.
Ortica
F
Department of Chemistry, University of Ottawa, Ottawa, Canada K1N 6N5, and Shipley Company, Inc., R&D, Marlborough, Massachusetts 01752-3092, USA.
Pohlers
G
Scaiano
JC
Cameron
JF
Zampini
A