Inorganic Chemistry, Vol.52, No.24, 14216-14223, 2013
Synthesis and Characterization of the Titanium Bisamide Ti{N(H)(ArPr6)-Pr-i}(2) ((ArPr6)-Pr-i = C6H3-2,6-(C6H2-2,4,6-Pr-i(3))(2) and Its TiCl{N(H)(ArPr6)-Pr-i}(2) Precursor: Ti(II) -> Ti(IV) Cyclization
The titanium bisamido complex Ti{N(H)Ar-iPr6}(2) (Ar-iPr6 = C6H3-2,6-(C6H2-2,4,6-Pr-i(3))(2) (2), along with its three-coordinate titanium(III) precursor, TiCI{N(H)Ar-iPr6}(2) (1), have been synthesized and characterized. Compound 1 was obtained via the trimethylamine. Reduction of 1 with 1 equiv of KC8 afforded Ti{N(H)ArN2 (2) in, moderate yield. Both 1 and 2 were characterized by X-ray crystallography, NMR, and IR spectroscopy, magnetic studies, and by density functional theory (DFT) computations. The, arnido nitrogens and a chlorine as well as a secondary interaction to a flanlcing aryl ring of a terphenyl substituent. Compound 2 displays a very distorted four-coordinate metal environment in which the titanium atom is bound to two amido nitrogens and to two-carbons from a terphenyl aryl ring. This structure is in sharp contrast to the expected twocoordinate linear structure that was observed in its first row metal (V-Ni) analogues. Magnetic studies confirm a d' electron configuration for 1 but indicate that Ti{N(H)Ar-iPr6}(2) (2) is diamagnetic at ambient temperature consistent with the oxidation of titanium to Ti(IV). The different structure of 2 is attributed to the high reducing tendency of the Ti(II) in comparison to the other metals.