263547-05-3

Upstream product

• 1134-35-6 4,4'-dimethyl-2,2'-bipyridines 
• 139416-07-2 bis(2,6-diisopropylphenolato)titanium(IV) dichloride 
• 263546-99-2 mer-trichloro(4,4'-dimethyl-2,2'-bipyridyl)mono(2,6-diisopropylphenoxide)titanium(IV) 

Relevant academic research and scientific papers

Synthesis, structure, coordination expansion and theoretical modelling of dichlorobis(phenoxo) titanium(IV) complexes

Thermalisation of TiCl4 and two equivalents of a phenol in toluene is found to be the best preparative method for quantitative yields of a variety of dichlorobis(phenoxo) complexes. [TiCl2(OC 6H4CMe3-4)2] (1) is monomeric in benzene, a phenoxo-bridged dimer in the solid state and undergoes coordination expansion with 4,4′-dimethyl-2,2′-bipyridine (dmbipy) to give [TiCl2(OC6H4CMe3-4) 2(dmbipy)] (2). Also monomeric are [TiCl2(OC 6H2Me3-2,4,6)2] (3) and [TiCl 2(OC6H3iPr2-2,6)2] (5) which expand their coordination with dmbipy to give [TiCl2(OC 6H2Me3-2,4,6)2(dmbipy)] (4) and [TiCl2(OC6H3iPr2-2,6) 2(dmbipy)] (6). In contrast [TiCl2(OC6H 2{CMe3}2-2,6-Me-4)2] (7) is only partially formed by the thermolysis reaction and does not coordinatively expand with dmbipy. [TiCl2(OC6H3Me2-2,4) 2] (8) is monomeric in benzene and reacts to form [TiCl 2(OC6H3Me2-2,4)2(dmbipy)] (9). [TiCl2(OC6H3{CMe3} 2-2,4)2] (10) forms along with the tri-phenoxo complex [TiCl{OC6H3(CMe3)2-2,4} 3]. [TiCl2(OC6H3CMe 3-2-Me-6)2] (11) is monomeric in benzene and forms [TiCl2(OC6H3CMe3-2-Me-6) 2(dmbipy)] (12). 2-Phenylphenol and 1-napthol form [TiCl 2(OC6H4Ph-2)2] (13) and [TiCl 2(OC10H9)2] (14) which are monomeric in benzene. DFT calculations give structural parameters for monomeric [TiCl2(OC6H5)2] (15) in good agreement with the X-ray data for [TiCl2(OC6H 3Me2-2,6)2]. Each oxygen of the phenoxo ligand in 15 acts essentially as a 2π donor to titanium and there is substantial pπ(O)-pπ*(C=C) backbonding with the phenyl ring, which is absent in [TiCl2(OCH3)2] (16). The global minimum for the dimer [(TiCl2{OC6H 5}{μ-OC6H5})2] is in almost perfect agreement with the crystal structure obtained for [(TiCl 2{OC6H5}{μ-OC6H 5})2] or [(TiCl2{OC6H 4CMe3-4}{μ-OC6H4CMe 3-4})2] (1). The dimerisation energy for 15 is -26.2 kJ·mol-1.

Trichloro monophenoxide complexes of titanium(iv)

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.