Carbon-13 NMR studies of diphenyl dichalcogenides, (C6H5)2X2 (X = S, Se, Te)

The 13C NMR chemical shifts and spin-lattice relaxation times for diphenyl disulfide, diselenide and ditelluride have been measured and assigned. The shielding effects experienced by the carbon atoms re qualitatively discussed in terms of the inductive and mesomeeric properties of the dichalcogen group. The attempt to calculate the magnetic shielding tensors for the 13C nuclei in terms of the Pople theory gave unsatisfactory results.