Rhoda- and iridacarborane halide complexes (η-9-SMe2-7,8-Me2-7,8-C2B9H8)MX2 (M = Rh, Ir; X = Cl, Br, I)

•Rhoda- and iridacarborane halide complexes were synthesized.•The pseudocloso-structure of these complexes was established by X-ray diffraction.•DFT calculations revealed that the cleavage of the cage C–C bond is accompanied by a sharp change of halide ligands orientation.

Reaction of (η-9-SMe2-7,8-Me2-7,8-C2B9H8)M(cod) with hydrohalic acids affords the 16-valence-electron complexes (η-9-SMe2-7,8-Me2-7,8-C2B9H8)MX2 (M = Rh, X = Cl (3a), Br (3b), I (3c); M = Ir, X = Cl (4a), Br (4b), I (4c)). According to X-ray analysis, 3a, 3b, 4b, and 4c have monomeric pseudocloso-structures with a long cage C⋯C distance (2.122, 1.985, 2.238, and 2.186 Å, respectively), in contrast to dimeric closo-structures of the cage-non-methylated analogs. The structural difference was explained using DFT calculations. 3b and 4b react with SMe2 and Tl[Tl(η-7,8-C2B9H11)] giving closo-metallacarboranes (η-9-SMe2-7,8-Me2-7,8-C2B9H8)M(SMe2)Br2 (M = Rh (5), Ir (6)) and (η-9-SMe2-7,8-Me2-7,8-C2B9H8)M(η-7,8-C2B9H11) (M = Rh (7), Ir (8)).

Graphical abstractThe pseudocloso-metallacarboranes (η-9-SMe2-7,8-Me2-7,8-C2B9H8)MX2 (M = Rh, Ir; X = Cl, Br, I) were prepared by reaction of cyclooctadiene derivatives (η-9-SMe2-7,8-Me2-7,8-C2B9H8)M(cod) with hydrohalic acids. Their reactivity and structures are discussed.Figure optionsDownload full-size imageDownload as PowerPoint slide