The photoinitiated dimerization of 2-quinolinecarbonitrile (1) in HCl-acidified 2- propanol/water (41) has been studied at 77 and 331 K at 250,300 and 350 nm in unsensitized and benzophenone and biphenyl-sensitized reactiona One principal product, a dimer lactam (5), is formed at all wavelengths through a triplet state of 1. ESR spectra taken in ethanol at 77 K show a signal for ethyl radical which is formed by a biphotonic process ...
