Inverse Sandwich Arene-Bridged Titanium Complexes Supported by a Bulky Tridentate [O, P, O] Ligand
Xueli Wang, Junnian Wei*, Zhenfeng Xi*.
Organometallics, 2023. DOI: 10.1021/acs.organomet.2c00627.
A bulky tridentate bis(3-methyl-5-aryl-hydroxyphenyl)phenylphosphine (aryl = 2,4,6-tri-isopropylbenzene, Tipp[O, P, O]) ligand 1 was synthesized. Reaction of 1 with TiCl3(THF)3 (THF = tetrahydrofuran) afforded bis{Tipp[O, P, O] titanium (THF)0.59(Et2O)0.41(μ-chloro)} (2). By reducing 2 with KC8 in toluene or C6D6, two arene-bridged dititanium complexes{Tipp[O, P, O]}2 titanium (μ-η6:η6-C6H5Me) (3) and {Tipp[O, P, O]}2 titanium (THF)0.58(Et2O)0.42(μ-η6:η6-C6D6) (4) were obtained, respectively, and structurally characterized. Complexes 3 and 4 featured an inverted sandwich-type structure consisting of a distorted η6-toluene or η6-benzene unit. Density functional theory calculations analyzed the reason for the loss of aromaticity in the distorted aromatic rings.
