126307-64-0Relevant academic research and scientific papers
Trichloro monophenoxide complexes of titanium(iv)
Nielson, Alastair J.,Schwerdtfeger, Peter,Waters, Joyce M.
, p. 529 - 537 (2007/10/03)
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(OC6H3Pr21-2, 6)] 5 partially disproportionates in solution into [TiCl2(OC6H3Pr21-2, 6)2] and reacts with dmbipy to give mer-[TiCl3(OC6H3Pr21-2, 6)(dmbipy)] 6 and [TiCl2(OC6H3Pr21-2, 6)2(dmbipy)]. Thermalisation of 2, 6-di-/4 in toluene caused debutylation but [TiCl3{OC6H2(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) A and Ti-Cl bonds longer than in TiCl4 but shorter than in [TiCl3(C5H5)] or [TiCl3{C5H3(CMe3)2-l, 3}]· 2, 4, 6-Tri-rcrt-butylphenol debutylates when thermalised with TiCl4 in toluene giving [TiCl3{OC6H4(CMe3)2-2, 4}] 8. The complexes [TiCl3{OC6H2(CMe3)2-2, 6-OMe-4}] 9, [TiCl3(OC6H3CMe3-2-Me-4)] 10, [TiCl3(OC6H4Ph-2)] 11 and the 1-naphthoxide complex [TiCl3(OC10H7)J 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-C=C (π*) donation weakens the Ti-O interaction in the phenoxide complex; CI(2p)-to-Ti(3d) donation is much reduced in the methoxide complex. The system [TiCl3(OC6H4CMe3-4)]/AlMe 3 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. The Royal Society of Chemistry 2000.
