LAUSR

Abstract We report the synthesis and structure of a series of tantalum(V) complexes having the trimethylsilylimide moiety and using as ancillary support the pincer ligand PNP (PNP− = N[2-PiPr2-4-methylphenyl]2). Via transmetallation of Li(PNP) with Cl3(py)2Ta N{SiMe3} (py = pyridine), the precursor complex (PNP)Ta N{SiMe3}Cl2 (1) could be prepared in 94% isolated yield. Attempts to promote FSiMe3 elimination when 1 was treated with FSnMe3 resulted in mixtures from which the salt-like product [{(PNP)Ta N{SiMe3}}2(μ2-F)3][Me3 ClSn(μ2-X)SnClMe3] (2) (X− = F or Cl) was structurally identified. However, conducting the reaction with NaOAr (Ar = 2,6-iPr2C6H3) resulted in clean formation to (PNP)Ta N{SiMe3}(OAr)Cl (3) in 79% isolated yield, and when 3 was mixed with FSnMe3, the fluoride-imide complex (PNP)Ta N{SiMe3}(OAr)F (4) and ClSnMe3 were formed cleanly. Attempts to promote FSiMe3 elimination in 4 thermally and photochemically did not yield the desired nitride (PNP)Ta N(OAr). Complexes 1–4 were characterized by single-crystal X-ray diffraction studies and in the case of complexes 1, 3 and 4 a variety of multinuclear NMR studies are presented and discussed.