Syntheses, Characterizations, and X-ray Structures of Alkali Metal Derivatives of Titanium(IV) Neopentoxides

Reactions of titanium(IV) neopentoxide, [Ti(μ-O neo -Pe)(O neo -Pe) 3 ] 2 ( 1, O neo -Pe = OCH 2 CMe 3 ), with alkali neopentoxides (AO neo -Pe) resulted in the isolation of the dimeric complexes [ATi(O neo -Pe) 5 ] 2 [A = Li ( 2 ), Na ( 3 ), and K ( 4 )], independent of the alkali metal investigated. Each compound was characterized by solution and solid-state multinuclear NMR, isopiestic molecular weight determination, and/or single-crystal X-ray diffraction. In the solid state, both 2 and 4 were found to adopt a standard [MM‘(OR) 5 ] 2 arrangement, wherein the Ti metals are in a distorted trigonal-bipyramidal geometry and each alkali metal center is four-coordinated. Suitable crystals of 3 were not isolated, but solid-state MAS ( 17 O, 13 C, x A) NMR spectroscopy indicated that the solid-state structure of 3 was consistent with its congeners. Multinuclear ( 1 H, 7 Li, 13 C, 17 O, 23 Na) solution NMR spectroscopy data in toluene revealed that 2 exists in a complex multinuclear equilibrium, whereas 3 and 4 exist as mononuclear species in solution.