Synthesis and Characterization of a Series of Rubidium Alkoxides and Rubidium−Titanium Double Alkoxides

This report investigates the structural aspects of the products isolated from the reactions of a series of titanium alkoxides {[Ti(OR)₄]_n n = 2, OR = OCH₂C(CH₃)₃ (ONep) (1); n = 1, OC₆H₃(CH₃)₂-2,6 (DMP) (2)} with rubidium alkoxides {[Rb(OR)]_∞ where OR = (ONep) (3), (DMP) (4), and OC₆H₃(CH(CH₃)₂)₂-2,6 (DIP) (5)}. The resultant double alkoxides were determined by single crystal X-ray diffraction to be [Rb(μ-ONep)₄(py)Ti(ONep)]₂ (6), [Rb(μ-DMP)Ti(DMP)₄]_∞ (7), and [Rb(μ-DMP)₂(μ-ONep)₂Ti(ONep)]_∞ (8). Compound 1 is the previously reported dinculear species with trigonal bipyramidal Ti metal centers whereas compound 2 is a monomer with a tetrahedral Ti center. Suitable X-ray quality crystals of 3 were not isolated. Compounds 4 and 5 demonstrate extended polymeric networks with Rb coordination ranging from two to five utilizing terminal μ- and μ₃-OR ligands and π-interactions of neighboring OAr ligands. The double alkoxide 6 revealed a simple tetranuclear structure with μ-ONep acting as the bridge, terminal ONep ligands on the Ti, and one terminal py on the Rb. For 7 and 8, the π-interaction facilitated the formation of extended polymeric systems. All complexes were further characterized by FT-IR and multinuclear NMR spectroscopy.