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)<sub>4</sub>]<i><sub>n</sub></i> <i>n </i>= 2, OR = OCH<sub>2</sub>C(CH<sub>3</sub>)<sub>3</sub> (ONep) (<b>1</b>); <i>n </i>= 1, OC<sub>6</sub>H<sub>3</sub>(CH<sub>3</sub>)<sub>2</sub>-2,6 (DMP) (<b>2</b>)} with rubidium alkoxides {[Rb(OR)]<sub>∞</sub> where OR = (ONep) (<b>3</b>), (DMP) (<b>4</b>), and OC<sub>6</sub>H<sub>3</sub>(CH(CH<sub>3</sub>)<sub>2</sub>)<sub>2</sub>-2,6 (DIP) (<b>5</b>)}. The resultant double alkoxides were determined by single crystal X-ray diffraction to be [Rb(μ-ONep)<sub>4</sub>(py)Ti(ONep)]<sub>2</sub> (<b>6</b>), [Rb(μ-DMP)Ti(DMP)<sub>4</sub>]<sub>∞</sub> (<b>7</b>), and [Rb(μ-DMP)<sub>2</sub>(μ-ONep)<sub>2</sub>Ti(ONep)]<sub>∞</sub> (<b>8</b>). Compound <b>1</b> is the previously reported dinculear species with trigonal bipyramidal Ti metal centers whereas compound <b>2</b> is a monomer with a tetrahedral Ti center. Suitable X-ray quality crystals of <b>3</b> were not isolated. Compounds <b>4</b> and <b>5</b> demonstrate extended polymeric networks with Rb coordination ranging from two to five utilizing terminal μ- and μ<sub>3</sub>-OR ligands and π-interactions of neighboring OAr ligands. The double alkoxide <b>6</b> 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 <b>7 </b>and <b>8</b>, the π-interaction facilitated the formation of extended polymeric systems. All complexes were further characterized by FT-IR and multinuclear NMR spectroscopy.