Synthesis and characteriaztion of novel zirconium(iv) derivatives containing the bis-amido ligand SiMe2(NRR?)2

The silicon compounds SiMe2(NRR')(2) [NRR' = NMe2 (1), NEt2 (2), NC4H8 (3), NHEt (4), (NHPr)-Pr-i (5), (NHBu)-Bu-t (6), NMeBu (7)] have been synthesised via aminolysis of the dichloro species SiMe2Cl2 and their ligating ability has been investigated towards zirconium(IV). The dimer zirconium compound {Zr[((NPr)-Pr-i)(2)SiMe2](2)}(2) (8) has been synthesised by reacting ZrCl4 with the lithium salt Li-2[((NPr)-Pr-i)(2)SiMe2] and its molecular structure has been determined in the solid state by X-ray diffraction analysis. The reaction of ZrCl4 with SiMe2(NRR')(2) yields the Lewis adducts ZrCl4[(NRR')(2)SiMe2] [NRR' = NMe2 (10), NC4H8 (11), NHEt (12), (NHPr)-Pr-i (13), (NHBu)-Bu-t (14), NMeBu (15)]. On the other hand, the mixed amido derivative Zr(NMe2)(3)(NHMe)[((NBu)-Bu-t) SiMe2((NHBu)-Bu-t)] (9) has been obtained from the reaction of Zr(NMe2)(4) with SiMe2((NHBu)-Bu-t)(2). The solution molecular structure and dynamics of the zirconium derivatives have been elucidated by 1D and 2D multinuclear NMR spectroscopy.