Negatively Charged Metallacarborane Redox Couples with Both Members Stable to Air

The metallacarborane [3,3′‐Co(1,2‐ closo ‐C 2 B 9 H 11 ) 2 ] − has been synthesized. This species allows the formation of redox couples in which both partners are negatively charged. The E 1/2 potential can be tuned by adjusting the nature and number of substituents on B and C. The octaiodinated species [3,3′‐Co(1,2‐ closo ‐C 2 B 9 H 7 I 4 ) 2 ] − is the most favorable, as it is isolatable and stable in air. A DFT study on stability and redox potentials of complexes has been performed.