Inorganic Chemistry, Vol.33, No.17, 3784-3787, 1994
Sterically Enforced Linearity in a Bridging Telluride Ligand - X-Ray Structure of ((CH3)2Si((T-C4H9)C5H3)2Sc(PMe3))2(Mu-Te)Center-Dot-C6H6
Insertion of elemental tellurium into the scandium-carbon bond of {meso-(CH3)2Si[(t-C4H9)C5H3]2}Sc(CH2SiMe3) (DpScR) occurs readily at 50-degrees-C in hexane solution to produce the scandocene tellurolate DpScTeR (1) in 78% isolated yield. Alternatively, when TePBu3 is employed as a tellurium transfer agent, 1 is produced rapidly in high yield (100% by NMR) at room temperature. Heating tellurolate 1 leads to expulsion of TeR2 and production of the dimeric A-telluride DpSc-Te-ScDp (2), which was separately synthesized by the reaction of [DpScH]2 with 0.5 equiv of TePBu3 (74% yield). Telluride 2 was further characterized as the benzene solvate of its bis(trimethylphosphine) adduct DpSc(PMe3)-Te-Sc(PMe3)Dp (3), the subject of an X-ray diffraction analysis (triclinic space group P1BAR, a = 10.6755(6) angstrom, b = 11.8654(6) angstrom, c = 23.8264(14) angstrom, alpha = 92.415(4)-degrees, beta = 102.808(5)-degrees, gamma = 106.513(4)-degrees, V = 2803.7(3) angstrom3, Z = 2, R = 0.029, R(w) = 0.036 for 7994 reflections with I > 3sigma(I)). The asymmetric unit is comprised of two "half-molecules with the Te atom in each case lying on an inversion center; the Sc-Te-Sc coordination is as a consequence precisely linear, and the mean Sc-Te bond distance is 2.875(5) angstrom.
Keywords:MAIN-GROUP ELEMENTS;MULTIPLE BONDS;TRANSITION-METALS;CRYSTAL-STRUCTURES;COMPLEXES;ELIMINATION;CONVERSION;CHEMISTRY;ZIRCONIUM;EXAMPLE