Observation of the two triplet state conformations of alkyl phenylglyoxylates.
Step-scan time-resolved FT-IR spectra of alkyl phenylglyoxylates in hexane with a 4 cm(-1) spectral resolution reveal splitting of the transient absorption signal near 1650 cm(-1) into two closely located peaks with different lifetimes on the nanosecond time scale. This signal had been previously assigned to the triplet state of the starting material that gives rise to the alpha-hydroxyphenylketene. In the current article, evidence is presented to assign these two peaks to different triplet state conformers only one of which undergoes fast Norrish Type II photoelimination. This assignment was made on the basis of chemical reactivity, steric effects, and kinetic data.
Merzlikine
Alexei G
AG
Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
Voskresensky
Sergey V
SV
Danilov
Eugene O
EO
Fedorov
Andrei V
AV
Rodgers
Michael A J
MA
Neckers
Douglas C
DC