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)](infinity) 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(mu-ONeP)(4)(py)Ti(ONep)](2) (6), [Rb(mu-DMP)Ti(DMP)(4)](infinity) (7), and [Rb(mu-DMP)(2)(mu-ONeP)(2)Ti(ONep)](infinity) (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 mu- and mu(3)-OR ligands and pi-interactions of neighboring OAr ligands. The double alkoxide 6 revealed a simple tetranuclear structure with mu-ONep acting as the bridge, terminal ONep ligands on the Ti, and one terminal py on the Rb. For 7 and 8, the pi-interaction facilitated the formation of extended polymeric systems. All complexes were further characterized by FT-IR and multinuclear NMR spectroscopy.