Synthesis and Characterization of Phenylnitroxide-Substituted Zinc(II) Porphyrins.

The syntheses and fluid-solution EPR spectra of nitroxide-substituted porphyrins 1-3 are described. The phenylnitroxide is attached to the meso-position of three porphyrins: (a) directly through a single bond (1); (b) through an ethenyl group (2); and (c) through an ethynyl group (3). The spin distribution in each of the three radicals is discussed and compared to model compounds 4-9. It is suggested that delocalization increases in the order 2, 1, 3.