Mononuclear Metallacarboranes of Groups 6-10 Metals. Analogues of Metallocenes: Electrochemical and X-Ray Structural Aspects

Metallacarboranes containing carborane ligands possessing a pentagonal open face can coordinate metal atoms in a η5-manner quite similar to the cyclopentadienyl monoanion, thus affording metallocene analogues. By virtue of such an analogy, their electron transfer aptitude plays an important role in their physico-chemical characterisation. We review such an aspect, also providing evidence for the structural consequences of their electron transfer processes. At variance with metallocenes, electrochemical investigations on the metallacarboranes have not yet become a routine tool to search for their potential application in fields which require electronic mobility.