Syntheses, characterizations, and X-ray structures of alkali metal derivatives of titanium(IV) neopentoxides

Reactions of titanium(IV) neopentoxide, [Ti(mu-Oneo-Pe)(Oneo-Pe)(3)](2) (1, Oneo-Pe = OCH2CMe3), with alkali neopentoxides (AOneo-Pe) resulted in the isolation of the dimeric complexes [ATi(Oneo-Pe)(5)](2) [A = Li (2), Na (3) , and K (4)], independent of the alkali metal investigated. Each compound w as characterized by solution and solid-state multinuclear NMR, isopiestic m olecular 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-bipyramida l geometry and each alkali metal center is four-coordinated. Suitable cryst als of 3 were not isolated, but solid-state MAS (O-17, C-13, (x)A) NMR spec troscopy indicated that the solid-state structure of 3 was consistent with its congeners. Multinuclear (H-1, Li-7, C-13, O-17, Na-23) solution NMR spe ctroscopy data in toluene revealed that 2 exists in a complex multinuclear equilibrium, whereas 3 and 4 exist as mononuclear species in solution.