Synthesis, Structure, and Reactivity of SomeN-Phosphorylphosphoranimines

Abstract

A large series of new N-phosphorylphosphoranimines that bear potentially reactive functional groups on both phosphorus centers were prepared by silicon-nitrogen bond cleavage reactions of N-silylphosphoranimines. Thus, treatment of the N-silylphosphoranimines, Me(3)SiN=P(Me)(R)X (R = Me, Ph; X = OCH(2)CF(3) and R = Me, X = OPh), with phosphoryl chlorides, RP(=O)Cl(2) (R' = Cl, Me, Ph), readily afforded the corresponding N-phosphoryl derivatives, R'P(=O)(Cl)-N=P(Me)(R)X, in high yields. Subsequent reaction with 1 or 2 equiv of the silylamine, Me(3)SiNMe(2), resulted in ligand exchange at the phosphoryl (P=O) group to give the P-dimethylamino analogues, R'P(=O)(NMe(2))N=P(Me)(R)X (R' = Cl, NMe(2), Me, Ph; R = Me, Ph; X = OCH(2)CF(3), OPh). These new N-phosphorylphosphoranimines (and one thiophosphoryl analogue) were obtained as thermally stable, distillable liquids and were characterized by NMR ((1)H, (13)C, and (31)P) spectroscopy and elemental analysis. One member of the series, Cl(2)P(=O)N=P(Me)(Ph)OCH(2)CF(3) (4), was also studied by single-crystal X-ray diffraction which revealed that the formal P(O)-N single bond [1.55(1) A] is shorter than the formal N=PR(2)X double bond [1.60(1) A]. Such structural features are compared to those of similar compounds and discussed in relationship to the unexpected thermolysis pathways observed for these N-phosphorylphosphoranimines, none of which produced poly(phosphazenes).

N-versus O-silylation in cis-[(tBuHN)OP(μ-NtBu)2PO(NHtBu)] and [Me2Si(μ-NtBu)2PO(NHPh)]. Solid-state structures of their silylation products, of co-crystalline cis-[(tBuHN)OP(μ-NtBu)2PO(NHtBu)], and of {[Me2Si(μ-NtBu)2PO(N(SiMe3)Ph)]VCl3}

“…Inorganic and organometallic chemists employ this group both, as a ligand in its own right [4] and as a mild and clean transfer reagent for ligands, because it reacts with certain element chlorides under the elimination of volatile chlorotrimethylsilane [5]. In this latter role the trimethylsilyl group has also proven invaluable for the synthesis of inorganic polymers, such as in the generation of polyphosphazenes from trimethylsilyl-substituted amino-, and iminophosphines [6][7][8][9][10].…”