Triplet arylnitrenium ions

Srivastava, S. and Falvey, D. E., Reactions of a triplet arylnitrenium ion laser flash photolysis and product studies of N-tert-butyl(2-acetyl-4-nitrophenyl)nitrenium ion, J. Am. Chem. Soc., 117, 10186, 1995. 

Nitrenium ions (or imidonium ions in the contemporaneous nomenclature) were described in a 1964 review of nitrene chemistry by Abramovitch and Davis. A later review by Lansbury in 1970 focused primarily on vinylidine nitrenium ions. Gassmann s ° 1970 review was particularly influential in that it described the application of detailed mechanistic methods to the question of the formation of nitrenium ions as discrete intermediates. McClelland" reviewed kinetic and lifetime properties of nitrenium ions, with a particular emphasis on those studied by laser flash photolysis (LFP). The role of singlet and triplet states in the reactions of nitrenium ions was reviewed in 1999. Photochemical routes to nitrenium ions were discussed in a 2000 review. Finally, a noteworthy review of arylnitrenium ion chemistry by Novak and Rajagopal " has recently appeared. 

Figure 13.58. Evidence for a triplet ground-state arylnitrenium ion.

Experimental determination of singlet-triplet gaps. This has not been reported for any N-arylnitrenium ions, and no unambiguous examples of ions with triplet ground states have been reported. 

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