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

Exchange reactions of 2,2-dimethyl-4,5-[1,2-dicarba-closo-dodecaborano(12)]-1,3-diselena-2-silacyclopentane with phosphorus trihalides PX3 (X = Cl, Br, I) led to the corresponding phospholanes in high yield. The solid-state structure of the iodide was determined by X-ray crystallography. Treatment of the bromide with nBu3SnH afforded the parent phosphane. The reaction of the iodide with LiAlH4 in [D8]toluene proceeded very slowly and mainly gave the deuterated phosphane. All products were characterised in solution by multinuclear magnetic resonance methods (1H, 13C, 31P and 77Se NMR). Molecular gas-phase geometries were optimised at the B3LYP/6-311+G(d,p) level of theory, and NMR parameters were calculated.