A phosphorus-31 nuclear magnetic resonance spectroscopic study of complexes of zinc with some phosphine oxides, sulfides, and selenides

Abstract

Zn(SbF6)2 in liquid SO2 has been shown to act as an acceptor towards a variety of phosphine oxides, sulfides, and selenides, forming complexes which have been characterized in solution using 31P nmr. Slow-exchange 31P nmr spectra are reported for the complexes ZnLn2+ (n = 6, L2 = Ph2P(O)CH2P(O)Ph2 or L3 = (Ph2P(O)(CH2)2)2P(O)Ph; n = 4, L2 = Ph2P(E)CH2P(E)Ph2 (E = O, S, or Se) or bidentate (Ph2P(E)CH2)3CMe (E = S or Se), or L = (C6H11)3PE (E = O, S, or Se) or R3PE (E = S or Se, R = Ph or o-C6H4Me); n = 3, L3 = (Ph2P(E)(CH2)2)2P(E)Ph (E = S or Se) or L = R3PE (E = S or Se, R = C6H11, Ph, or o-C6H4Me); n = 2, L = R3PE (E = S or Se, R = o-C6H4Me or, perhaps, C6H11); n = 1 (possibly), L = (o-C6H4Me)3PS), and partial spectra for [Zn(SeP(C6H11)3)x(SP(C6H11)3)n−x]2+ (n = 3 or 4). No evidence was found for the mixed oxide-chalcogenide species [Zn(EP(C6H11)3)x(OP(C6H11)3)4−x]2+. In most cases the 31P nmr spectra are very similar to those reported earlier for the corresponding cadmium complexes. However, in most instances where comparison could be made it was found that the rate of intermolecular ligand exchange was less for the zinc complexes than for their cadmium counterparts. (Complexes with (Ph2P(O)(CH2)2)2P(O)Ph and Ph2P(O)(CH2)2P(O)Ph2 arc exceptional in being more labile for zinc than cadmium.)