LASER-INDUCED FLUORESCENCE-SPECTRUM OF THE CYANOCYCLOPENTADIENYL RADICAL - A BAND SYSTEM LONG ATTRIBUTED TO TRIPLET PHENYLNITRENE

The UV electronic spectrum long attributed to the triplet phenylnitrene intermediate has been reexamined. A variety of evidence strongly indicates that the true carrier of this spectrum is not phenylnitrene, but the cyanocyclopentadienyl radical. This evidence is based upon the spin and rotational structure of the band, its ground-state vibrational frequency characteristic of a C=N triple bond, and several experiments involving different chemical precursors. A discussion of the photochemistry of phenylnitrene and related molecules reinterprets and reconciles much of the considerable existing body of work in both the gas and condensed phases.