Retention of the B(3)X (X=Br, I) bond in closo-o-carborane derivatives after nucleophilic attack. The first synthesis of [3-X-7-R-7,8-nido-C2B9H10]− (X=Br, I). Crystal structure of [HNMe3][3-I-7,8-nido-C2B9H11]

The synthesis of new 3-halogeno nido derivatives of o-carborane, [3-X-7-R-7,8-nido-C2B9H10]− (X=Br, I; R=H, CH3, C6H5) is described, through deboronation of the compounds 3-X-1-R-1,2-closo-C2B10H10, previously synthesised in our laboratory. These nido products have been fully characterised using 1H-, 11B- and 13C-NMR spectroscopies, MALDI-TOF and, for [3-I-7,8-nido-C2B9H11]− by an X-ray crystallographic study. The influences of the halogen moiety on both the B(3) resonance and that of the bridge proton are discussed.