Synthesis and Characterization of Group 4 Amido Silyl Complexes Free of Anionic π-Ligands
作者:Zhongzhi Wu、Jonathan B. Diminnie、Ziling Xue
DOI:10.1021/ic980821t
日期:1998.11.1
A series of early-transition-metal silyl complexes free of anionic pi-ligands such as cyclopentadienyl (Cp = eta(5) C5H5) have been synthesized. These Cp-free complexes (Me2N)(3)MSi(SiMe3)(3) [M = Zr (1), Hf (2)], (Me2N)(3)-TiSiPh2But (3), (Me2N)(3)ZrSiPh2But. 0.5THF (4), (Me2N)(3)HfSiPh2But. nTHF [n = 0.5 (5a), 1 (5b)], and (Me2N)(2)[(Me3Si)(2)N]ZrSiR3 [SiR3 = Si(SiMe3)(3) (7), SiPh2But (8)] were prepared by metathetic reactions of chloro triamido complexes (Me2N)(3)MCl (M = Ti, Zr, Hf) or (Me2N)(2)[(Me3Si)(2)N]ZrCl (6) with silyllithium reagents Li(THF)(3)Si(SiMe3)(3) or Li(THF)(3)SiPh2But. The structures of i, 3, 4, 5b, and 8 have been determined by X-ray crystallography and show that i, 3, and 8 adopt a distorted tetrahedral coordination geometry while 4 and 5b have a distorted trigonal bipyramidal geometry around the metal. The unit cell parameters are as follows. 1: space group R3c, a = 15.505(2) Angstrom, c = 19.308(4) Angstrom, V = 4019.9(13) Angstrom(3), Z = 6. 3: space group P2(1), a = 8.633(5) Angstrom, b = 14.790(7) Angstrom, c = 9.388(3) Angstrom, beta = 92.44(4)degrees, V = 1197.6(10) Angstrom(3), Z = 2. 4: space group Pbca, a = 16.538(9) Angstrom, b = 17.282(7) Angstrom, c = 18.566(8) Angstrom, V = 5306(4) Angstrom(3), Z = 8. 5b: space group Pna2(1), a = 17.463(6) Angstrom, b = 9.453(3) Angstrom, c = 17.800(6) Angstrom, V= 2938(2) Angstrom(3), Z = 4. 8: space group Pca2(1), a 19.775(5) Angstrom, b = 10.182(2) Angstrom, c = 15.752(5) Angstrom, V = 3172(2) Angstrom(3), Z = 4. The M-Si bond distances for i, 3, 1, 5b, and 8 are 2.781(2), 2.635(2), 2.803(2), 2.807(4), and 2.860(2) Angstrom, respectively. The Zr-Si bond in 8, to our knowledge, is the longest reported Zr-Si bond.