Structural effects on ESR hyperfine coupling constants of some dithiazolidinyl free radicals

Abstract

A series of related dithiazolidin-2yl free radicals prepared from cyclic strained alkenes and tetrasulphur dinitride, and an attempt was made to relate the nitrogen and proton hyperfine coupling constants to the radical structures. The radical made from dimethoxybenzonorbornadiene was studied by ENDOR and it was found that isotopic substitution with "N gives well resolved ENDOR spectra; the TRIPLE measurements showed that the I4N coupling constants are positive whereas all the resolved proton coupling constants are negative.

Radical Single-Molecule Junctions

“…Thioaminyl radicals (RNSR • ) − are sulfur analogues of aminyl radicals ( 6e ), are somewhat persistent in nature, and exist mainly as N–N dimers . However, bulky substituents on the nitrogen can increase stability and enable isolation. − There are other derivatives of thioaminyls, those with the structure RSNSR • ( 6f,g ) and those that are resonance-stabilized ( 6h,i ), which are persistent and isolable. − Thiazinyl radicals, which have the structure C 2 N 3 S • , are six-membered ring radicals ( 6j ). 1,2,4,6-Thiatriazinyl radicals, as well as their selenium analogues, are highly stable and form cofacial π-dimers in the solid state. − …”