ABSTRACT
This chapter describes recent contributions of photochemical methods to the study of nitrcniurn ions. This family of reactive intermediates includes any species with a positively charged, divalent nitrogen atom (RRN~ ). Because the nitrogen atom has only six valence electrons, nitrcnium ions are typically very strong clcctrophilcs and tend to be very shor1-livcd at room temperature in solution. Arylnitrcnium ions (i.e., nitrcniurn ions which ha,·c a benzene or other aromatic ring directly attached to the nitrcniurn ion center) have received the most attention due to their postulated role in DNA damage mechanisms and cancer formation. This aspect of nitrcnium ion chemistry has been reviewed elsewhere. Most of the biologically relevant reactions arc thermal rather than photochemical. Consequently. this chapter will not focus on this aspect of nitrenium ion chemistry other than to note the contributions of photochemistry to these studies.
