Advances in the Chemistry of 1,1′-Bis(o-carborane) and Its Derivatives

1,1′-Bis(o-carborane),a three-dimensional analogue of biphenyl,is formally formed by two o-carborane clusters with a direct linkage of a carbon-carbon single bond which is formed with one skeletal carbon atom from each subcluster.In this paper the syntheses,structure and properties of 1,1′-bis(o-carborane) are overviewed,with an emphasis on its reactivity.Where appropriate,a comparision is made with that of o-carborane.Research has shown that,similar to its monomer o-carborane,1,1′-bis(o-carborane) can undergo various reactions such as substitution at carbon,substitution at boron,partial degradation or deboronation,reduction(cage opening),and thermal rearrangement,while some reactions such as the reduction show different pattern.The potential applications of the biscarborane derivatives have also been briefly discussed.