氧钒(V) 三乙醇胺化物1 和氧钒(V) 三2-丙醇胺化物2 的结构已经确定。在每种情况下,V(V) 原子都表现出扭曲的三角双锥配位与轴向位置的氮原子和氧代基团。观察到变形是因为钒原子在双键氧的方向上移出三乙醇胺氧的平面。化合物1在单斜空间群P2 1 中结晶,a=7.051(2) A, b=7.429(2) A, β=93.46(3) o , V=417.2(2) A 3 , Z=2
Early Transition Metal Alkoxide Complexes Bearing Homochiral Trialkanolamine Ligands
作者:William A. Nugent、Richard L. Harlow
DOI:10.1021/ja00093a011
日期:1994.7
Enantiomerically pure trialkanolamines of the formula N(CH(2)CHROH)(3), where R = methyl (3a), cyclohexyl (3b), tert-butyl (3c), or phenyl (3d), are readily synthesized by the reaction of ammonia with 3 equiv of an enantiopure epoxide. Trialkanolamines 3a-d replace n-propanol in tri-n-propyl vanadate to afford corresponding complexes 4a-d of the formula LV=O, where L is the deprotonated trialkanolamine. Similarly, (S,S,S)-triisopropanolamine 3a reacts with Ti((OPr)-Pr-i)(4) to produce monomeric LTi((OPr)-Pr-i), 7a, which upon treatment with acetyl chloride gives the chloro complex LTiCl, 7b. The later group 5 ethoxides react with 3a to produce LM(OEt)(2) (M = Nb, Ta). Partial hydrolysis of the Nb and Ta derivatives produces tetrameric mu-oxo-bridged structures which retain the trialkanolamine ligands. In all complexes the transition metal resides in a highly asymmetric environment, suggesting that this class of complexes may find use in the field of asymmetric catalysis. The X-ray crystal structures of complexes 4c and 7b are reported.