Group 4 and 5 metal derivatives of 2,2′-methylene-bis(6-phenylphenoxide)
Group 4 and 5 metal derivatives of 2,2′-methylene-bis(6-phenylphenoxide)
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2,2-亚甲基-双(6-苯酚)的第4族和第5族金属衍生物
DOI：
10.1016/s0277-5387(99)00319-8
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发表时间：
2000
期刊：
影响因子：
2.6
通讯作者：
I. Rothwell
中科院分区：
文献类型：
--
作者：
Douglas R. Mulford;P. Fanwick;I. Rothwell
苯酚2，2‘-亚甲基-双(6-苯基苯酚)[(HOC6H3Ph)2CH2](1)(1当量。在[TiCl4]或[Ti(OPri)4]的碳氢化合物溶液中生成二聚体[Ti{(OC6H3Ph)2CH2}Cl2]2(2)和[Ti{(OC6H3Ph)2CH2}(μ-OPri)(OPri)]2(3)。结构研究表明，2(CHCl3溶剂)存在于两个四面体钛中心的固态中，两个四面体钛中心由两个二芳氧基的一端相连。相反，3含有五配位的钛原子，通过两个桥联的异丙醇氧配体直接连接。[MCl5](M=Nb，Ta)与1当量。与吡啶反应生成可溶性加合物[M{(OC6H3Ph)2CH2}Cl3(Py)](M=Nb，6；M=Ta，7)。化合物6和7在固态(苯溶剂)中是等结构的，具有氯基的聚体排列，并且吡啶反式为二芳氧基氧原子之一。用PMe2Ph与7反应生成产物[Ta{(OC6H3Ph)2CH2}Cl3(PMe2Ph)](8)和[HPMe2Ph][Ta{(OC6H3Ph)2CH2}Cl4](9)。结构表征的9(苯溶剂酸盐)可能是由于在工作过程中存在微量的水而产生的。根据化学计量比，1与[Ta(NMe2)5]反应可以分离出[Ta{(OC6H3Ph)2CH2}2(NMe2)(HNMe2)](10)(顺式氮原子)和[H2NMe2][Ta{(OC6H3Ph)2CH2}3](11)。结晶学结果表明，11中的阴离子在金属钽的中心附近含有氧原子的八面体排列。11的结晶学研究因三种苯溶剂型分子的阳离子和部分占位的无序而变得复杂。三氯化Nb4作为苯加氢的催化剂前体，尽管其活性低于报道的单齿芳氧基前体的活性。在催化过程中，二芳氧基配体的邻苯环不会氢化。
Addition of the phenol 2,2′-methylene-bis(6-phenylphenol) [(HOC6H3Ph)2CH2] (1) (1 equiv. per Ti) to hydrocarbon solutions of [TiCl4] or [Ti(OPri)4] leads to dimeric products [Ti{(OC6H3Ph)2CH2}Cl2]2(2) and [Ti{(OC6H3Ph)2CH2}(μ-OPri)(OPri)]2(3). Structural studies show 2 (CHCl3solvate) to consist in the solid state of two tetrahedral titanium centers linked by one end of two di-aryloxide ligands. In contrast, 3 contains five-coordinate titanium atoms linked directly by two bridging isopropoxide ligands. Treatment of [MCl5] (M=Nb, Ta) with 1 equiv. of 1 leads to sparingly soluble trichlorides 4 and 5 which react with pyridine to form soluble adducts [M{(OC6H3Ph)2CH2}Cl3(py)] (M=Nb, 6; M=Ta, 7). Compounds 6 and 7 are isostructural in the solid state (benzene solvates) with a mer arrangement of chloride groups and the pyridine trans to one of the di-aryloxide oxygen atoms. Treatment of 7 with PMe2Ph leads to the products [Ta{(OC6H3Ph)2CH2}Cl3(PMe2Ph)] (8) and [HPMe2Ph][Ta{(OC6H3Ph)2CH2}Cl4] (9). Structurally characterized 9 (benzene solvate) presumably arises via the presence of trace amounts of water during workup. Reaction of 1 with [Ta(NMe2)5] allows isolation of derivatives [Ta{(OC6H3Ph)2CH2}2(NMe2)(HNMe2)] (10) (cis-nitrogen atoms by NMR) and [H2NMe2][Ta{(OC6H3Ph)2CH2}3] (11) depending on the stoichiometry. The anion in 11 was shown by crystallography to contain an octahedral arrangement of oxygen atoms about the tantalum metal center. The crystallographic study of 11 is complicated by a disorder of the cation and partial occupancies for the three types of benzene solvate molecule. The niobium trichloride 4 acts as a catalyst precursor for benzene hydrogenation although with lower activity than reported for monodentate aryloxide precursors. During the catalysis the ortho-phenyl rings of the di-aryloxide ligand are not hydrogenated.