ESR studies of some iminoxyl radicals containing 13C, sulphur and phosphorus substituents

Some new aryliminoxyl radicals with a 13-C, a 31-P or a sulphur atom bonded to the azomethine carbon have been generated and studied by ESR spectroscopy. The influence of substitution on the relative stabilities of the syn and anti isomeric forms of these radicals are discussed. It is shown that a relation exists between the phosphorus splittings in these iminoxyls and the a(31-P) of similarly substituited phosphonyl ant thiophosphonyl radicals.