CIDNP FROM PHOTOGENERATED GEMINATE RADICAL-ION PAIRS HIDDEN IN TRIPLET-STATE PRODUCTS

Radical ion pairs generated by photoinduced electron transfer from N,N -dimethyl-1-naphthylamine to benzonitrile in acetonitrile solutions un dergo reverse electron transfer to the singlet ground state and to the donor excited triplet state of the parent compounds. Both pathways le ad to chemically induced nuclear polarization, but on a short time sca le the triplet contribution is hidden in the triplet donor molecules. This leads to unusual CIDNP phases and time dependencies which are unr avelled by FT NMR measurements and auxiliary optical studies.