Modification of Yttrium Silyl-Bridged Amide Alkyl Complexes through Si-H/C-H Cross-Dehydrocoupling of Silanes with a Silylamino Ligand: Synthesis, Reactivity, and Mechanism.

A new method for the modification of a silylamino ligand has been developed through mono and dual C(sp )-H/Si-H cross-dehydrocoupling with silanes. The reaction of [LY{η -(C,N)-CH Si(Me )NSiMe }] (L=bis(2,6-diisopropylphenyl)-β-diketiminato, L' (1 '); L=tris(3,5-dimethylpyrazolyl)borate, Tp (1 )) with 2 equivalents of PhSiH in toluene gave the complexes [LY{η -(C,N)-C(SiH Ph) Si(Me )NSiMe }] (L=L' (2 ); L=Tp (2 )). Moreover, 1 reacted with the secondary silanes Ph SiH and Et SiH to afford the corresponding mono C-H activation products [Tp Y{η -(C,N)-CH(SiHR )Si(Me )NSiMe }] (R=Ph (4 b); R=Et (4 c)). The equimolar reaction of 1 with PhSiH also produced the mono C-H activation product 4 a ([Tp Y{η -(C,N)-CH(SiH Ph)Si(Me )NSiMe }(thf)]). A study of their reactivity showed that4 a facilely reacted with 2 equivalents of benzothiazole by an unusual 1,1-addition of the C=N bond of the benzothiazolyl unit to the Si-H bond to give the C-H/Si-H cross-dehydrocoupling product [(Tp )Y{η -(N,N,N)-N(SiMe )SiMe CH Si(Ph)(CSC H N)(CHSC H N)}] (5). These results indicate that this modification endows the silylamino ligand with novel reactivity.