SYNTHESIS AND STRUCTURE OF THE CATIONIC TERT-BUTOXIDE COMPLEXES Y3(OR)7CL(THF)3+, Y2(OR)4CL(THF)4+, AND Y(OR)CL(THF)5+ - REPRESENTATIVES OF A NEW CLASS OF YTTRIUM ALKOXIDES

Y3(OR)7C12(THF)2 (1) (R = CMe3) reacts with AgBPh4 to form a mixture of [Y3(μ3-OR)(μ3-C1)(μ-OR)3-(OR)3(THF)3][BPh4] (2) and [Y2(μ-Cl)(μ-OR)2(OR)2(THF)4][BPh4] (3). At 0 °C the reaction favors 2, which can be isolated by crystallization from toluene at -37 °C. 2 forms crystals in space group Pī (Ci1; No. 2) with a = 14.131 (3) Å, b = 15.035 (3) Å, c = 18.712 (5) Å, α = 85.01 (2)°, β = 85.02 (2)°, γ = 81.75 (2)°, V= 3908 (2) Å3, and Dcalcd = 1.23 g cm-3 for Z = 2. Least-squares refinement of the model based on 4692 reflections converged to a final RF = 9.1%. The three yttrium atoms in 2 form an equilateral triangle with doubly bridging alkoxide groups along the edges and triply bridging alkoxide and chloride ligands above and below the plane of metals. The three terminal alkoxide groups are all on the ju3-alkoxide side of the plane. At room temperature, the reaction of 1 with AgBPh4 favors 3, whichcan be isolated in 74% yield by reaction of the product mixture with NaBPh4. 3 crystallizes from THF/toluene/hexane at -37 °C in space group P42/n with a = 18.424 (5) Å, c =17.738 (9) Å, V = 6021 (4) Å3, and Dcalcd = 1.23 g cm-3 for Z = 4. Least-squares refinement of the model based on 1099 reflections converged to a finalRF = 9.9%. In 3, two Y(OR)(THF)2 units are connected by two alkoxide bridges and one chloride bridge to form a distorted face-shared bioctahedron. The six ligands around each yttrium atom are arranged such that the terminal alkoxide ligand is trans to the bridging chloride ion. 1 reacts with NaBPh4 to form [Y(OR)(Cl)-(THF)5] [BPh4] (4), which can beprepared in higher yield (85%) from the reaction of YC13 with NaOR and NaBPh4. 4 crystallizes from THF/hexane at -37 °C in space group P21/n with a = 13.675 (3) Å, b= 12.418 3) Å, c = 32.803 (8) Å, β = 90.43 (2)°, V = 5570 (2) Å3, and Dalci = 1.22 g cm-3 for Z = 4. Least-squares refinement of the model based on 6073 reflections converged to a final RF = 8.1%. The OR and Cl ligands in 4 are located at the axial positions of a pentagonal bipyramid. The five THF ligands occupy the equatorial sites. 1 can be regenerated from 2 and 3 by reaction with NaCl. © 1990, American Chemical Society. All rights reserved.