Phosphorus–nitrogen–phosphorus spin coupling in the nuclear magnetic resonance spectra of some cyclodiphosph(III)azanes

Abstract

The magnitude and sign of the coupling constant ²J(PNP) has been obtained from the n.m.r. spectra of a series of cyclodiphosphazanes, [graphics omited]Bu^t(X = Y = F, Me,OMe, or NMe₂; X = Cl, Y = F, OMe, or NMe₂; X = F, Y = NM_e), [graphics ommited] (X = OMe or NMe₂), and Bu^t [graphics omited] +AIC1^4– by single- and double-resonance methods. More positive PNP couplings are found in those derivatives where X and Y are of relatively high electron-withdrawing power, although chlorine-containing compounds have more positive couplings than analogous fluorine-containing compounds. When X = Y = OMe or NMe₂, geometrical isomers have PNP couplings of opposite sign.