Synthesis, structure, and reactivity of Group 4 metallocene tellurolates. X-ray crystal structures of Cp2Zr[TeSi(SiMe3)3]2, Cp'2Ti[TeSi(SiMe3)3]2, Cp2Zr(.eta.2-COMe)[TeSi(SiMe3)3], and Cp2Ti[TeSi(SiMe3)3]PMe3

Abstract

Treatment of Cp 2 MCl 2 (Cp=η 5 -C 5 H 5 ; M=Ti, Zr, Hf) with 2 equiv of (THF) 2 LiTei(SiMe 3 ) 3 produces the bis-tellurolates Cp 2 M[TeSi(SiMe 3 ) 3 ] 2 (M=Ti (1), Zr (2), Hf (3)) in high yields. For titanium, the Cp'(Cp'= η 5 -C 5 H 4 Me) derivative (4) was also prepared. The X-ray structures of 2 and 4 were determined and are presented for comparison. Tellurolysis of Cp 2 ZrMe 2 with 1 equiv of HTeSi(SiMe 3 ) 3 gave Cp 2 Zr(Me) [TeSi(SiMe 3 ) 3 ] (5); treatment with a second equiv of tellurol produced 2, again in high yield. Addition of CO to the methyl tellurolate 5 formed the acyl derivative Cp 2 Zr(η 2 -COMe) [TeSi(SiMe 3 ) 3 ] (6).Treatment of Cp 2 MCl 2 with the alkyltellurolate reagent (THF) 3 -LiTeC(SiMe 3 ) 3 leads to unstable complexes, Cp 2 M[TeC(SiMe 3 ) 3 ] 2 (M= Ti(7), Zr(8), which extrude elemental tellurium between -60 and 20°C to form alkylmetallocene complexes Cp 2 M[C(SiMe 3 ) 3 ] 2 (M=Ti(9), Zr(10); the latter species are unstable at room temperature and subsequently decompose givung the alkane HC(SiMe 3 ) 3 and unidentified metal products