Singlet and triplet states in the reactions of nitrenium ions

Nitrenium ions (R-N-R+) are reactive intermediates which are isoelectronic with carbenes. Like the more familiar carbenes, nitrenium ions have low-ene rgy singlet and triplet states. Recent experiments have been directed at un derstanding how singlet and triplet nitrenium ions differ in their chemical reactivity. Singlet nitrenium ions typically react rapidly with nucleophil es whereas the triplet nitrenium ions tend to abstract H atoms. Several spe cific cases are discussed including the parent system, NH2+, and several ar ylnitrenium ions. Copyright (C) 1999 John Wiley & Sons, Ltd.