Aryl- and Alkylnitrenium Ions: Singlet-Triplet Gaps via Ab Initio and Semi-Empirical Methods

Falvey, D. E.; Cramer, C. J.
Tetrahedron Lett. 1992, 33, 1705.

The accuracy of semi-empirically predicted singlet-triplet energy gaps for substituted nitrenium ions is examined by comparison to correlated (CISD), ab initio calculations. Unrealistically low singlet energies are delivered by both the AM1 and MNDO method.