The coordination chemistry of the C1-symmetric bissilylmethyl ligand CHSiMe3SiMeOMe2−revisited: LiM- M Zn, Tl, Ce, Li4- or Ce2-methoxy-bridged alkyls

The following crystalline oligonuclear metal alkyls have been synthesised under mild conditions and structurally characterised: THFLiμ-Aμ-Clμ3-OMeZn23, Liμ-A2Tl24and 4′, Li4μ-A3μ3-OMe 5, μ-ALi2μ-A2μ3-OMeCeA6 and CeAμ2-OMeμ2-OSOCF3O211A CHSiMe3SiMeOMe2. Compounds 2–6were obtained from Liμ-A∞1 and ZnCl23, TlCl (4and 4′ and 5) and CeCl36, and 11was isolated from KA prepared from 1 KOBut and ceriumiii triflate CeOTf3. The principal novel features are i and ii as follows. As for i, the diversity of ligand-to-metal bonding is noteworthy, the ligand being aC,O-bridging in 3as in the known compounds 1and in Li2Mg5μ3-OMe6μ2-OMe2μ2-A42; bC,O,O′-bridging and O,O′-chelating in 4and 4′; cC,O,O′-bridging in 5; dC,O,O′-bridging and C,O-chelating in 6; and eC,O-chelating in 11. Regarding ii, it is interesting that the ligand A−is surprisingly ready to undergo fragmentation by Si–OMe cleavage and thereby present bridging methoxy ligands μ2-OMe2to a pair of Ce3ions in 11, or μ3-OMe acting as a cap for triangular arrays of three hard metal ions Mg3in 2, LiZn2in 3, Li3in 5, and Li2Ce in 6.