Linear trimeric, dimeric, and monomeric titanium(III) aryloxides

Abstract

Reactions of trans-Ti(TMEDA)2Cl2 (TMEDA = N,A,N,N'-tetramethylethylenediamine) with 2 equiv of RONa IR = Ph, 3,5-(t-Bu)2C6H3] formed the paramagnetic light-green linear trimeric Ti(III) derivative Ti3(PhO)9-(TMEDA)2 (1) and the pink dimeric complex [Ti(RO)Cl(TMEDA)]2(mu-OR)2[R = 3,5-(t-Bu)2C6H3](2),respectively. Complex 1 could also be conveniently synthesized from TiCl3(THF)3 and PhONa in the presence of TMEDA. Conversely, complex 2 could be obtained from TiCl3(THF)3 only when the reaction was carried out in toluene, since bright-yellow crystals of the mononuclear anionic complexes [Ti(RO)2(TMEDA)Cl2] [M'] [M' = Na(TMEDA)2+ (3a), 1/2(TMEDA)H+ (3b)] were isolated when the reaction was performed in THF. Reaction of Ti[N(SiMe3)2]3 with 3 equiv of 2,6-Me2C6H3OH in toluene led to the formation of the first dinuclear homoleptic complex [Ti(RO)3)2 [R = 2,6-Me2C6H3 (4)], which was isolated as green-blue crystals. A similar reaction with the more bulky 2,6-(i-Pr)2C6H3OH led to the formation of the neutral homoleptic Ti(IV) species Ti[OC6H3-2,6-(i-Pr)2]4 (6). Conversely, the anionic homoleptic complex {Ti[OC6H3-2,6-(i-Pr)2]4}{Li(TMEDA)2}.toluene (7) was obtained by reacting the corresponding lithium phenoxide with TiCl3(THF)3. The structures of 1, 3b, and 4 were determined by X-ray analysis. Crystal data are as follows. 1: monoclinic, C2/c, a = 14.758 (5) angstrom, b = 21.920 (2) angstrom, c = 11.855 (1) angstrom, beta = 102.339 (4)-degrees, V = 6274 (7) angstrom3, Z = 4, R = 0 058 (R(w) = 0.024) for 417 parameters and 2425 significant reflections out of 4648. 3b: triclinic, P1Bar, a = 12.877 (2) angstrom, b = 16.850 (3) angstrom, c = 12.605 (2) angstrom, alpha = 106.65 (1)-degrees, beta = 100.65 (1)-degrees, gamma = 68.63 (1)-degrees, V = 2430.4 (7) angstrom3, Z = 2, R = 0.080 (R(w) = 0.081) for 435 parameters and 4685 significant reflections out of 7234. 4: triclinic, P1Bar, a = 11.372 (3) angstrom, b = 11.458 (3) angstrom, c = 10.859 (4) angstrom, alpha = 117.04 (2)-degrees, beta = 115.29 (3)-degrees, gamma = 93.56 (4)-degrees, V = 1080.1 (9) angstrom3, Z = 2, R = 0.036 (R(w) = 0.051) for 362 parameters and 3297 significant reflections out of 4020.