E.S.R. and ENDOR studies of X-irradiated 4-phenyl-3-thiosemicarbazide single crystals

Abstract

A radical identified as C₆H₅NHCSṄNH₂ has been studied with E.S.R. and ENDOR spectroscopy in X-irradiated 4-phenyl-3-thiosemicarbazide single crystals. The ENDOR measurements reveal interactions between the unpaired electron and two hydrogen nuclei with the principal values

These interactions are of NH α-type and arise from the amino hydrogens. The E.S.R. indicates additional interaction between the unpaired electron and three nitrogen nuclei. These interactions are all axially symmetric about the direction of intermediate hydrogen coupling and have principal values estimated to be

From these results and those from the hydrogen interactions, the nitrogen interaction labelled N2 is assigned to the amino nitrogen.