Aryl-imido niobium complexes with chloro-silyl and aryl-η-amidosilyl cyclopentadienyl ligands: X-ray structure of the constrained-geometry compound [Nb(η5-C5H4SiMe2-η1-NAr)(NAr)Cl](Ar=2,6-Me2C6H3)

Abstract

Reactions of the magnesium imides [Mg(NAr)(THF)]6 (Ar = 2,6-Me2C6H3, 1a; Ph, 1b) with [NbCpClCl4] (CpCl = η5-C5H4(SiMe2Cl)) afforded the imido complexes [NbCpClCl2(NAr)] (Ar = 2,6-Me2C6H3, 2a; Ph, 2b) in good yield. Compound 2a reacted with excess LiNH(2,6-Me2C6H3) to give the silyl-η-amido complex [Nb(η5-C5H4SiMe2-η1-NAr)Cl(NAr)] (Ar = 2,6-Me2C6H3, 3a). Hydrolysis of the Si–Cl bond of compounds 2a and 2b yielded the dinuclear complexes [{NbCl2(NAr)}2{(η5-C5H4SiMe2)2(μ-O)}] (Ar = 2,6-Me2C6H3, 4a; Ph, 4b), respectively. All of the new compounds reported were characterized by NMR spectroscopy and the molecular structure of 3a was determined by X-ray diffraction methods.