YTTRIUM AND LANTHANUM SILYLOXIDE COMPLEXES

Reaction of [M{N(SiMe3)2}3] (M = Y, La) with 3 equiv of Ph3SiOH in toluene gave high yields of [M(OSiPh3)3]n. The homoleptic tris-((triphenylsilyl)oxy)yttrium and -lanthanum complexes could be converted nearly quantitatively to monomeric Lewis base adducts, [M(OSiPh3)3L(n)].xL (M = Y, La, L = THF, n = 3, x = 1; L = pyridine, n = 3, x = 0; L = OP((n)Bu)3, n = 2, x = 0) by the addition of tetrahydrofuran, pyridine, or 2 equiv of OP((n)Bu)3, respectively. The silanol complex [{Y(OSiMe2(t)Bu)2(HOSiMe2(t)Bu)}{Y(OSiMe2(t)Bu)2}(mu-OsiMe2(t)Bu)2], was isolated from the reaction of [Y{N(SiMe3)2}3] and 3.5 equiv of HOSiMe2(t)Bu. This complex could be converted in high yields to [Y(OSiMe2(t)Bu)3(THF)3] upon exposure to excess tetrahydrofuran. Hydrogen-1 NMR studies on [M(OSiPh3)3(THF)3].THF (M = Y, La) and [Y(OSiMe2(t)Bu)3(THF)3] demonstrated that these complexes are kinetically labile on the NMR time scale with respect to exchange with free, added ligand. Low-temperature NMR studies implicated a dissociative mechanism for this process. Phosphorous-31 NMR studies in [Y(OSiPh3)3{OP((n)Bu)3}2] demonstrated that this complex participates in an exchange reaction between free and coordinated phosphine oxide via an associative mechanism. Anionic tetrakis((triphenylsilyl)oxy)yttrium complexes, [K(eta-2-DME)3(eta-1-DME)][Y(OSiPh3)4(eta-2-DME)] (11) and [K(18-crown-6)][Y(OSiPh3)4] (12), were formed by reaction of [Y(OSiPh3)3]n with 1 equiv of the corresponding potassium silyloxide reagent in dimethoxyethane or toluene, respectively. Single-crystal X-ray data are available for five compounds. [Y(OSiPh3)3(THF)3].THF (3) has a (i) facial arrangement of the three -OSiPh3 ligands and (ii) nearly linear Y-O-Si angles [crystal data: monoclinic space group P2(1), a = 14.530 (7) angstrom, b = 16.407 (8) angstrom, c = 14.534 (8) angstrom, beta = 114.32 (2)-degrees, V = 3157.21 angstrom 3, Z = 2, with final residuals R = 0.0841, and R(w) = 0.0790]. [La(OSiPh3)3(THF)3].THF (4) is isomorphous with 3 [crystal data: monoclinic space group P2(1), a = 14.830 (4) angstrom, b = 16.291 (4) angstrom, c = 14.667 (4) angstrom, beta = 115.45 (1)-degrees, V = 3199.32 angstrom 3, Z = 2, with final residuals R = 0.0464 and R(w) = 0.0448]. [Y(OSiPh3)3{OP(n-Bu)3}2] (7) exhibits (i) trigonal-bipyramidal coordination geometry at Y with axial OP((n)Bu)3 groups, and (ii) Y-O-Si angles range from 158 to 175-degrees [Crystal data: space group P1BAR, a = 13.555 (1) angstrom, b = 24.035 (3) angstrom, c = 12.780 (1) angstrom, alpha = 100.87 (0)-degrees, beta = 114.51(0)-degrees, gamma = 86.05 (0)-degrees, V = 3720.22 angstrom 3, Z = 2, with final residuals R = 0.0626 and R(w) = 0.0607]. [{Y(OSiMe2(t)Bu)2(HOSiMe2(t)Bu)}{Y(OSiMe2(t)Bu)2}(mu-OSiMe2(t)Bu)2] (9) is a (i) dinuclear complex featuring a trigonal-bipyramidal Y center linked to a tetrahedral Y center via two bridging -OSiMe2(t)Bu ligands, with (ii) an HOSiMe2(t)Bu ligand in an axial position and (iii) no hydrogen-bonding networks [crystal data: monoclinic space group P2(1)/c, a = 17.486 (3) angstrom, b = 14.983 (3) angstrom, c = 24.286 (5) angstrom, beta = 97.94 (1)-degrees, V = 6301.56 angstrom 3, Z = 4, with Final residuals R = 0.1112 and R(w) = 0.1081]. [K(eta-2-DME)3(eta-1-DME)][Y(OSiPh3)4(eta-2-DME)] (11) contains (i) a discrete K-centered cation/Y-centered anion, (ii) a seven-coordinate K cation with three chelating DME ligands and one monodentate DME ligand, and (iii) a distorted octahedral Y-centered anion [crystal data: space group P2(1)/n, a = 14.545 (3) angstrom, b = 29.865 (6) angstrom, c = 21.726 (4) angstrom, beta = 107.61 (1)-degrees, V = 8995.69 angstrom 3, Z = 4, with final residuals R = 0.0654 and R(w) = 0.0616].