Heterospin organic molecules: nitrene-radical linkages

The cryogenic, matrix-isolated ESR and electronic spectroscopy of a set of quarter state organic phenylnitreno-radicals are described, using nitronyln itroxide, benzo-nitronylnitroxide, and verdazyl radical spin sites, and bot h meta and para a connectivities. Delocalization of the nitrene unit in the para-linked series is not extensive, judging by the computational results. The ESR spectral results show that zero-field splitting is affected much m ore by the connectivity in the systems (para versus meta) than by structura l variations within the nitreno-radical theme. (C) 2001 Elsevier Science Lt d. All rights reserved.