Formation of manganese(II) porphyrin derivatives from manganese(III) derivatives by ionizing radiation

Abstract

Exposure of manganese(III) porphyrin solutions to ⁶⁰Co γ-rays at 77 K gave the manganese(II) derivatives, with g_⊥(apparent)≈ 6, A(⁵⁵Mn)≈ 77 G and |D| 0.3 cm^–1. The spectra are very similar to those for Mn^II derivatives prepared chemically. Weak features in the g= 2 region for these complexes were obscured by features from a symmetrical Mn^II derivative of unknown origin. These features grew in intensity on melting and re-freezing.

These results suggest that low-temperature irradiation coupled with e.s.r. spectroscopy may be a suitable technique for detecting Mn^III derivatives in biological systems.