1,3,2‐Diselenaborolanes with an Annelated Dicarba‐closo‐dodecaborane(12) Unit: Synthesis, Molecular Structure and Reactivity

Abstract

AbstractExchange reactions of 2,2‐dimethyl‐1,3‐diselena‐2‐silacyclopentane and 2,2,3,3‐tetramethyl‐1,4‐diselena‐2,3‐disilacyclohexane, as the 4,5‐ and 5,6‐[1,2‐dicarba‐closo‐dodecaborano(12)] derivatives, respectively, with boron trihalides (BCl3, BBr3, BI3) and dichlorides (PhBCl2, iPr2NBCl2) afford the corresponding 1,3,2‐diselenaborolanes in essentially quantitative yield. The products were characterized in solution by multinuclear magnetic resonance spectroscopy (1H, 11B, 13C, 29Si, 77Se), and for two products, in the solid state by X‐ray structural analysis. Attempts to synthesize the boron fluoride failed, and the methoxy derivative was obtained in a mixture with a decomposition product. The gas‐phase structures of all relevant products were optimized by DFT hybrid methods [RB3LYP/6‐311+G(d.p) level of theory], and NMR parameters (shielding constants and spin–spin coupling constants) were calculated. The calculated data compare well with experimental data, both for the structures and the NMR spectroscopic parameters.