Magnesium Reagents Featuring a 1,1′-Bis(o-carborane) Ligand Platform

Abstract

The synthesis of two bis(carboranyl) (bc) magnesium reagents is described. Treatment of 1,1′-bis(o-carborane) (H2-bc) or 8,8′,9,9′,10,10′,12,12′-octamethyl-1,1′-bis(o-carborane) (H2-Mebc) with Mg(nBu)2 in 1,2-dimethoxyethane (DME) affords (bc)Mg(DME)2 (1a,b) as crystalline solids. The magnesium compounds, which have been characterized by NMR spectroscopy and single-crystal X-ray crystallography in the case of 1a, serve as competent Grignard-type reagents to generate bc-containing species of tin from Me2SnCl2 (2a,b). The type of substitution of the bis(o-carboranyl) ligand framework is found to strongly affect the electronic character of the tin center, as judged by 119Sn NMR spectroscopy. The disclosed compounds, which are stable solids under an atmosphere of dry nitrogen gas at room temperature, provide a new class of bc-transfer reagents.