Reactions of (Me₃ECH₂)₃ZrSi(SiMe₃)₃(E = C, Si) with 2,6-Dimethylphenyl Isocyanide. Preferential Isocyanide Insertion into Zr−Silyl Bonds

Abstract

The reactions of alkyl silyl complexes (Me3ECH2)3ZrSi(SiMe3)3 [E = C (1), Si (2)] with 2,6-dimethylphenyl isocyanide (ArNC) have been investigated. The first ArNC was found to insert exclusively into the Zr−Si bond, and the second and third ArNC into the Zr−C bonds in 1 and 2. 1 and 2 react with up to 3 equiv of ArNC to give (Me3ECH2)3Zr{η2-C[Si(SiMe3)3]NAr} [E = C (3), Si (4)], (Me3ECH2)2Zr[η2-C(CH2EMe3)NAr]{η2-C[Si(SiMe3)3]NAr} [E = C (5), Si (6)], and (Me3ECH2)Zr[η2-C(CH2EMe3)NAr]2{η2-C[Si(SiMe3)3]NAr} [E = C (7), Si (8)]. The tri-insertion complexes 7 and 8 are inert to excess ArNC. The structures of 3 and 7 have been determined by X-ray crystallography. In the structure of 3, the α-hydrogen atoms on one neopentyl ligand lie in close contact (av 2.41 Å) with the metal center giving rise to Zr−C−Hα bond angles of 90 and 92°. The crystal structure of the precursor 1 has also been determined.