Ti−Sn, Zr−Sn, and Hf−Sn Heterodimetallic Complexes: Stabilizing Unsupported Group 4−Group 14 Metal−Metal Bonds

Reaction of the tripodal amido complexes [MeSi{SiMe2N(4-CH3C6H4)}3ZrCl] and [MeSi{SiMe2N(4-CH3C6H4)}3HfCl] with LiSnPh3 in toluene yielded the Zr−Sn and Hf−Sn
complexes [MeSi{SiMe2N(4-CH3C6H4)}3ZrSnPh3] (1) and [MeSi{SiMe2N(4-CH3C6H4)}3HfSnPh3] (2), while attempts to synthesize the corresponding Ti−Sn complex resulted in
the oxidative coupling of the stannate to give Ph3Sn−SnPh3 and unidentified titanium
species. More stable group 4−group 14 complexes were obtained by reaction of the triamido
stannate complex [MeSi{SiMe2N(4-CH3C6H4)}3SnLi(OEt2)] with the metallocene dichlorides
[Cp2MCl2] of all three titanium group metals, giving [MeSi{SiMe2N(4-CH3C6H4)}3SnM(η5-C5H5)2(Cl)] (M = Ti, 3; Zr, 4; Hf, 5). X-ray diffraction studies of 4 and 5 established Zr−Sn
and Hf−Sn bond lengths of 3.02313(17) and 2.9956(3) Å, respectively.