Versatility of a diamidosilylether ligand supporting yttrium complexes: Synthesis, structure and reactivity

Abstract

Yttrium alkyl complex [NONDippY(CH2SiMe3)(THF)], 1 (NONDipp = (DippNSiMe2)2O, Dipp = 2,6-iPr-C6H3) can be prepared in high yields by a σ-bond metathesis reaction between [Y(CH2SiMe3)3(THF)2] and the free bis(aminosilyl)ether. The reaction of 1 with one equivalent of PhSiH3 generates the hydride bridged yttrium dimer [μ-NONDippY(μ-H)(THF)]22, however, each diamidosilylether ligand does not chelate each yttrium centre but instead bridges to both yttrium atoms in a “flyover” fashion. This ligand rearrangement maybe reversed by the addition of a strong Lewis base to give the dimeric yttrium hydride [NONDippY(μ-H)(DMAP)]23, where each diamidosilylether ligand now chelate to each yttrium center respectively. The effect of the different diamidosilylether bonding modes on the reactivity of the yttrium complexes is examined with heterocumulenes.