Bis(2-mercapto-1-R-imidazolyl)hydroborato complexes of aluminium, gallium, indium and thallium: compounds possessing gallium–gallium bonds and a trivalent thallium alkyl

Abstract

The reactions of bis(mercaptoimidazolyl)hydroborato derivatives [Bm^R]M′ (R = Me, Bu^t; M′ = Li, Na, Tl) with MX₃ trihalides of aluminium, gallium and indium yield both 1 : 1 and 2 : 1 complexes of the types [Bm^R]MX₂ and [Bm^R]₂MX, respectively. Structurally characterized examples of the [Bm^R]MX₂ series include [Bm^Me]AlCl₂, [Bm^Me]GaI₂, [Bm^Me]InI₂, [Bm^But]AlCl₂ and [Bm^But]GaX₂ (X = Cl, Br, I), while structurally characterized examples of the [Bm^R]₂MX series include [Bm^But]₂InX (X = Cl, Br, I). In addition to the halide complexes, the trivalent dimethyl thallium complex [Bm^But]TlMe₂ has been synthesized via the reaction of [Bm^But]Tl with Me₂TlCl. The reactions of [Bm^R]M′ with the monovalent halides, “GaI”, InCl and InI, result in disproportionation. In the case of indium, the mononuclear complexes [Bm^But]₂InI and [Bm^But]InCl(κ²-mim^But) are obtained, whereas for gallium, dinuclear compounds that feature Ga–Ga bonds, namely [Bm^R](GaI)(GaI)[Bm^R] (R = Me, Bu^t) have been isolated.