On the Solution Chemistry of Parent Nitrenium Ion NH2+: The Role of the Singlet and Triplet States in Its Reactions with Water, Methanol, and Hydrocarbons

Abstract

Chemical reactions of the parent nitrenium ion NH2+ were examined. The latter was generated in various solutions through photolysis of 1-amino-2,4,6-triphenylpyridinium perchlorate. It was found that the hydrocarbons, toluene and triphenylmethane, trap NH2+ through two independent pathways. There is a free radical pathway which leads to bibenzyl (in the case of toluene) or the trityl radical (in the case of triphenylmethane). There is also a hydride transfer pathway which leads to benzyltoluene (in the case of toluene) or triphenylmethanol (in the case of triphenylmethane). Results from dilution, triplet sensitization, and EPR experiments lead to the assignment of the hydride transfer pathway to the singlet state of NH2+ and the radical pathway to the triplet state of NH2+. Trapping experiments with H2O and CH3OH were also carried out, and it was shown that the singlet state of NH2+ undergoes a net insertion into the O−H bonds of these substrates.