Abstract: Examination of the spectra of a series of tolyl-and benzylphosphonium salts, phosphonates, and phosphine oxides shows the existence of two types of long-range 31P- 1H spin-spin couplings. Four-bond allylic couplings (1-2.5 Hz) are observed in both series of compounds; the magnitude of 4 J~~ depends upon the position of attachment (sp2 or sp3 carbon) of phosphorus to the allylic triad. Both five-and seven-bond homoallylic couplings ...
