Trimethylsilylverbindungen der Vb-Elemente, HI [1]. Tris(trimethylsilyl)- und Tris(trimethylstannyl)bismutan sowie Tetrakis(trimethylsilyl)dibismutan / Trimethylsilyl Derivatives of Vb-Elements, III [1]. Tris(trimethylsilyl)- and Tris(trimethylstannyl)bismuthine as well as Tetrakis(trimethylsilyl)dibismuthine

Abstract

Chlorotrimethylsilane and sodium/potassium bismuthide, easily prepared from finely powdered bismuth and sodium potassium alloy in 1,2-dimethoxyethane (DME), react to give tris(trimethylsilyl)bismuthine (1) in 48% yield. When compound 1 is treated with chlorotrimethylstannane all trimethylsilyl substituents are successively replaced by stannyl groups, and tris(trimethylstannyl)bismuthine (4) is obtained. As in analogous reactions of other tris(trimethylsilyl) derivatives of Vb-elements with methyl lithium in diethylether/tetrahydrofuran (THF), one trimethylsilyl group of tris (trimethylsilyl)-bismuthine (1) can also be removed, and lithium bis(trimethylsilyl)bismuthide · 2 THF (5) is formed. With 1,2-dibromoethane bismuthide 6 reacts with metal halogen exchange to give green lustrous needles of tetrakis(trimethylsilyl)dibismuthine (6). In contrast to other dibismuthines described in the literature, this compound is thermally rather stable and can be isolated in preparative amounts. Similar to several distibines a colour change from green to red, resp. orange-red occurs on melting or dissolving dibismuthine 6 in organic solvents.