Capping the thiaborate anion [7-nido-SB10H11]−

The salt [HNEt3][7-nido-SB10H11] isolated from the room temperature reaction between B10H14, elemental S and NEt3 by the method of Štíbr and co-workers is essentially pure. The salt has been structurally characterised by X-ray diffraction and its 11B NMR spectrum fully assigned, correcting a previous mis-assignment. Deprotonation of the [7-nido-SB10H11]− anion followed by treatment with HBBr2·SMe2 affords the icosahedral thiaborane 1-closo-SB11H11 in good yield at ambient temperature. Similarly, deprotonation of [7-nido-SB10H11]− followed by metallation affords the metallathiaboranes 2-(η-C5H5)-2,1-closo-CoSB10H10 (2), 2-(η-C9H7)-2,1-closo-CoSB10H10 (3) and 2-(η-C10H14)-2,1-closo-RuSB10H10 (4) in good to excellent yields. Compounds 2–4 have all been characterised spectroscopically and crystallographically. Comparative electrochemical study of 2 and the related species 3-(η-C5H5)-3,1,2-closo-CoC2B9H11 shows that the [7-nido-SB10H10]2− ligand is a poorer e-doner to Co than is the analogous carborane ligand [7,8-nido-C2B9H12]2−.