Synthesis and molecular structures of the 1,2-dihalogen derivatives of Ga(II) and In(II), [{GaI(ArMe6)}2], [{InCl(ArMe6)}2]2, [{InI(ArMe6)}2]2, and [{In4Cl2I2(ArMe6)4}], ArMe6=C6H3-2,6(C6H2-2,4,6-Me3)2

The reaction of LiArMe6 [Ar-Me6=C6H3-2,6(C6H2-2,4,6-Me-3)(2)] with InCl, [In(InI4)], InCl in the presence of Lil, or 'GaI' in toluene solution resulted in the isolation of the 1,2-diaryl-1,2-dihalogen derivatives [{InCl(Ar-Me6)}(2)](2) (1), [{InI(Ar-Me6)}(2)](2) (2), [{In4Cl2I2(Ar-Me6)(4)}] (3), and [{GaI(Ar-Me6)}(2)] (4). The indium derivatives 1-3 were isolated as tetrametallic complexes formed via the almost symmetric bridging by four halides of two In-In bonded, (ArIn)-In-Me6-InArMe6 moieties. In 1, the In4Cl4 core features almost parallel In-In units, linked by four almost symmetrically bridging chlorides. This yields a structure formed from two folded In2Cl2 rings, and two six-membered In4Cl2 boat-shaped rings that have common In-Cl edges. The structures of 2 and 3 also feature two (ArInInArMe6)-In-Me6 units bridged by four halides. However, there is a large torsion angle between the two In-In vectors, so that the In4I4 (2) and In4Cl2I2 (3) cores are formed from four five-membered In3I2 (2) or In3ClI (3) rings. Compound 4 has a simple Ga-Ga bonded dimeric structure, in which the gallium atoms are three coordinated, being bonded to each other as well as to an iodine and an Ar-Me6 ligand. All the compounds were characterized by H-1 and C-13 {H-1} NMR spectroscopy, and by X-ray crystallography. The structural differences between the gallium and indium derivatives is probably a result of the larger size and greater Lewis acidity of the indium centers. (C) 2012 Elsevier Ltd. All rights reserved.