ESR SPECTROSCOPIC INVESTIGATION OF SOME 4-SUBSTITUTED 1,3,2-DITHIAZOLYL AND 2,3,1-DITHIAZOLYL RADICALS

Further information has been obtained on the electronic structure of 1,3,2-dithiazol-2-yl radicals. The structure has been well characterized previously except for positions 4 and 5 in the CSNSC ring. We have obtained solution and powder ESR spectra of radicals substituted with C-13 in both positions and of radicals substituted with nitrogen or phosphorus in the 4-position. It is probably the first time that a compound has been prepared containing the CSNSP ring. Two especially interesting facts emerged from the ESR spectra of these 1,3,2-dithiazolyl radicals: the C-13-substituted radical has a considerable amount of p spin density in the plane of the ring and the phosphorus-substituted radical has a very low unpaired spin density at the phosphorus atom. It is known that 1,3,2,4-dithiadiazolyl radicals isomerize readily by photolysis to the symmetrical 2,3,1,4-dithiadiazolyl radicals; we attempted the same reaction with ButCSNSP and a new radical was produced that we have been unable to identify.