CIDNP INVESTIGATIONS OF PET-INDUCED REACTIONS OF ORGANIC SUBSTRATES

CIDNP (chemically induced dynamic nuclear polarization) is an extremel y versatile tool for the investigation of reactions involving radical pairs. The application of this effect to photoreactions initiated by p hotoinduced electron transfer (PET) is discussed. Examples include ide ntification of radicals that are too short-lived to be detectable by E PR spectroscopy (e.g., of sulfur-containing amino acids), measurements of electron self-exchange reactions between organic radical cations a nd their parent compounds, discrimination between two radical pathways (in the deprotonation of aminium cations) or a radical and a nonradic al pathway (in the Paterno-Buchi reactions of donor olefins with elect ron-deficient carbonyl compounds) that lead to the same products, and tracing of skeleton rearrangements (in cycloadditions of quinones with norbornadiene or quadricyclane).