作者:Alastair J. Nielson、Peter Schwerdtfeger、Joyce M. Waters
DOI:10.1039/a908435e
日期:——
Thermalisation of TiCl4 and phenol (1∶1) in toluene gave [TiCl3(OC6H5)] 1. The more soluble complex [TiCl3(OC6H4CMe3-4)] 2 is monomeric in benzene and reacts with 4,4′-dimethyl-2,2′-bipyridyl (dmbipy) to give mer-[TiCl3(OC6H4CMe3-4)(dmbipy)] 3 and the disproportionation product [TiCl2(OC6H4CMe3-4)2(dmbipy)]. The complex [TiCl3(OC6H2Me3-2,4,6)] 4 is monomeric in benzene whereas [TiCl3(OC6H3Pri2-2,6)] 5 partially disproportionates in solution into [TiCl2(OC6H3Pri2-2,6)2] and reacts with dmbipy to give mer-[TiCl3(OC6H3Pri2-2,6)(dmbipy)] 6 and [TiCl2(OC6H3Pri2-2,6)2(dmbipy)]. Thermalisation of 2,6-di-tert-butyl-4-methylphenol and TiCl4 in toluene caused debutylation but [TiCl3OC6H2(CMe3)2-2,6-Me-4}] 7 forms in light petroleum (bp range 40–60 °C). Complex 7 is monomeric in benzene and does not form adducts with dmbipy or other sigma donors. A crystal structure determination of 7 showed a monomer with distorted tetrahedral co-ordination, a Ti–O bond length of 1.750(2) Å and Ti–Cl bonds longer than in TiCl4 but shorter than in [TiCl3(C5H5)] or [TiCl3C5H3(CMe3)2-1,3}]. 2,4,6-Tri-tert-butylphenol debutylates when thermalised with TiCl4 in toluene giving [TiCl3OC6H4(CMe3)2-2,4} ] 8. The complexes [TiCl3OC6H2(CMe3)2-2,6-OMe-4}] 9, [TiCl3(OC6H3CMe3-2-Me-4)] 10, [TiCl3(OC6H4Ph-2)] 11 and the 1-naphthoxide complex [TiCl3(OC10H7)] 12 were also prepared. Density functional calculations performed on the models 4 and [TiCl3(OMe)] showed both lone pairs on oxygen donate electron density to titanium but O(2p)-to-CC (π*) donation weakens the Ti–O interaction in the phenoxide complex; Cl(2p)-to-Ti(3d) donation is much reduced in the methoxide complex. The system [TiCl3(OC6H4CMe3-4)]/AlMe3 is 280 times more active than [TiCl3Cp] (Cp = cyclopentadienyl)/AlMe3 for low pressure (6 psi) ethylene polymerisation but
1//3 less active than TiCl4/AlMe3.
将TiCl4和苯酚(1∶1)在甲苯中加热得到[TiCl3(OC6H5)] 1。在苯中,更易溶的复合物[TiCl3(OC6H4CMe3-4)] 2是单体的,并与4,4′-二甲基-2,2′-联吡啶(dmbipy)反应生成mer-[TiCl3(OC6H4CMe3-4)(dmbipy)] 3和歧化产物[TiCl2(OC6H4CMe3-4)2(dmbipy)]。复合物[TiCl3(OC6H2Me3-2,4,6)] 4在苯中是单体的,而[TiCl3(OC6H3Pri2-2,6)] 5在溶液中部分歧化成[TiCl2(OC6H3Pri2-2,6)2],并与dmbipy反应生成mer-[TiCl3(OC6H3Pri2-2,6)(dmbipy)] 6和[TiCl2(OC6H3Pri2-2,6)2(dmbipy)]。将2,6-二叔丁基-4-甲基苯酚和TiCl4在甲苯中加热导致脱叔丁基反应,但在石油醚(沸点范围40–60°C)中形成[TiCl3OC6H2(CMe3)2-2,6-Me-4}] 7。复合物7在苯中是单体的,并且不与dmbipy或其他σ供体形成加合物。对7的晶体结构测定显示为扭曲的四面体配位单体,Ti–O键长为1.750(2) Å,Ti–Cl键长于TiCl4但短于[TiCl3(C5H5)]或[TiCl3C5H3(CMe3)2-1,3}]。2,4,6-三叔丁基苯酚在甲苯中与TiCl4加热时脱叔丁基生成[TiCl3OC6H4(CMe3)2-2,4}] 8。还制备了复合物[TiCl3OC6H2(CMe3)2-2,6-OMe-4}] 9、[TiCl3(OC6H3CMe3-2-Me-4)] 10、[TiCl3(OC6H4Ph-2)] 11和1-萘酚复合物[TiCl3(OC10H7)] 12。对模型4和[TiCl3(OMe)]进行的密度泛函计算表明氧上的孤对电子向钛捐赠电子密度,但O(2p)-到CC(π*)的捐赠削弱了酚酸盐复合物中的Ti–O相互作用;在甲氧基复合物中Cl(2p)-到Ti(3d)的捐赠大大减少。系统[TiCl3(OC6H4CMe3-4)]/AlMe3对于低压(6 psi)乙烯聚合的活性是[TiCl3Cp](Cp = 环戊二烯基)/AlMe3的280倍,但活性是TiCl4/AlMe3的1/3。