RELATIVE SIGNS OF THE (31)P-(1)H AND (31)P-C-(1)H NMR COUPLINE CONSTANTS

Abstract : The possibility that terms other than Fermi contact interaction make significant contributions to nuclear spin-spin coupling with heavy nuclei has stimulated considerable interest in the nmr spectra of compounds containing heteroatoms. In particular, relative signs and magnitudes of J sub XCH and J sub XCCH have been reported for ethyl derivatives of several heavy isotopes of spin 1/2. Inorder to understand better the factors responsible for spin couping with a representative heavy nucleus, we have analyzed the spectra of (CH3)3P, (CH3)2PH and (CH3)PH2 and have obtained relative signs and magnitudes of J sub PH and J sub PCH.