Phosphorus–nitrogen compounds. Part 51. Carbon-13 and phosphorus-31 nuclear magnetic resonance properties of phenylphosphonothioic di(monoalkylamides). Determination of aromatic substituent constants by 13C nuclear magnetic resonance spectroscopy

Abstract

Carbon-13 and phosphorus-31 n.m.r. spectra have been obtained for a series of phenyl-phosphonothioic di(monoalkylamides), PhP(S)(NHR)₂(R = H, Me, Et, Prⁿ, Prⁱ, cyclopropyl, Buⁿ, Buⁱ, Bu^s, Bu^t, neopentyl, cyclopentyl, cyclohexyl, or CH₂Ph). Inductive and resonance substituent coefficients have been evaluated using the dual-substituent parameter method from the relative shieldings of the meta- and para-carbon nuclei in the phenyl ring. An attempt is also made to correlate data arising from different n.m.r. measurements to chemical behaviour, and to explore the relationship between carbon-13 and phosphorus-31 n.m.r. chemical shift data for the above group of compounds.