N.m.r. spectra of α-tetraphosphorus trisulphide isothiocyanates: extreme broadening of phosphorus-31 absorptions by nitrogen-14 and large phosphorus–nitrogen coupling constants
Abstract
The collapse of the PB parts of the 31P n.m.r. spectra of α-P4S3(14NCS)2(1a), α-P4S3(14NCS)I (2a), and α-P4S3(14NCS)Cl (3a) at room temperature is due to 14N relaxation effects rather than to chemical exchange, as shown by analysis of the spectra of the corresponding 15N isotopomers (1b), (2b), and (3b), which show very large 1JPN coupling constants.