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A NOVEL SUBSTITUENT EFFECT ON 31 P NMR CHEMICAL SHIFTS IN THE ARYL DIPHENYLPHOSPHINATE SERIES

1985; Taylor & Francis; Volume: 24; Issue: 3 Linguagem: Inglês

10.1080/03086648508074244

0308-664X

Shmaryahu Hoz, Edward J. Dunn, Erwin Buncel, R. A. B. Bannard, J. G. Purdon,

Phosphorus compounds and reactions

Abstract Abstract The 31P NMR chemical shifts of a series of meta- and para-substituted phenyl diphenylphosphinates, Ph2P(O)OC6H4-X. have been determined. The δ 31P values exhibit an increasing downfield trend as the electron-withdrawing properties of the substituent X become greater and a reasonable correlation between δ 31P and Hammett–Taft substituent constants is obtained. This trend is opposite to that exhibited in several families of compounds of the type ArP(O)Y2, where δ 31P values show an increasing upfield trend as the electron-withdrawing ability of the substituent in Ar is increased. The results are explained by proposing varying degrees of d-orbital occupancy in the phosphorus–oxygen bonds (P–OAr and P˭O) in the series of compounds as a factor influencing 31P chemical shifts.