Deprotonation of a hydrophosphorane and synthesis of the Ni(II) metallophosphorane [NiCl{P(OC6H4N(CH3))2}(P(CH3)3)2

Abstract

The hydrophosphorane [HP(OC6H4N(CH3))2] has been deprotonated using lithium tetramethylpiperidide to produce Li[P(OC6H4N(CH3))2] (1). Compound 1 reacts further with NiCl2(PMe3)2 to form the Ni(II) phosphoranide complex [NiCl{P(OC6H4N(CH3))2}(P(CH3)3)2] (2). The crystal structures of both 1 and 2 were determined. The structure of 1 is dimeric with bridging lithium cations and also features one THF solvent molecule coordinated to each lithium cation; the geometry about the lithium atom is tetrahedral. The structure of 2 displays tetrahedral distortion from an idealized square-planar geometry. Both 1 and 2 characterized by 1H and 31P NMR, with 13C NMR for 2 also. DFT calculations (B3LYP/6-311++G(2df,2p)) were also done on 2; both the NMR and DFT studies indicate π-donation from the metal to the pentacoordinate phosphorus.