PHOTOGENERATED ARYLNITRENIUM IONS - REACTIONS OF N-TERT-BUTYL-(2-ACETYL-4-SUBSTITUTED)PHENYL NITRENIUM IONS WITH ALCOHOLS AND WATER STUDIEDBY LASER FLASH-PHOTOLYSIS

Photolysis of N-tert-butyl-3-methylanthranilium ion as well as its 5-h alo and methyl derivatives produces transient nitrenium ions via an el ectrocyclic ring-opening process. This is confirmed by identification of the stable products and transient absorption experiments. Laser fla sh photolysis of the substituted anthranilium ions gives short-lived ( 80-200 ns) species which absorb in the UV and visible region of the sp ectrum. These transient species react with nucleophiles such as alcoho ls and water with rate constants ranging from 10(6)-10(9) M(-1) s(-1). Reactivity of the nucleophiles follows the trend MeOH > EtOH > i-PrOH similar to H2O > t-BuOH. This is the same trend that has been observe d by others for diarylcarbenium ions and styrene cation radical cation s and provides further confirmation for the assignment of the spectra to the singlet state arylnitrenium ions.