Application of superhalogens in the design of organic superconductors

Bechgaard salts, (TMTSF)(2)X (TMTSF = tetramethyl tetraselenafulvalene and X = complex anion), form the most popular series of organic superconductors. In these salts, TMTSF molecules act as a super-electron donor and X as an acceptor. We computationally examined the electronic structure and properties of X in commonly used (TMTSF)(2)X (X = NO3, BF4, ClO4, PF6) superconductors and noticed that they belong to the class of superhalogens due to their higher vertical detachment energy than halogen anions. This prompted us to choose other superhalogens such as X = BO2, BH4, B2F7, and AuF6 and study their (TMTSF)(2)X complexes. Our findings suggest that these complexes behave more or less similar to those of the established (TMTSF)(2)X superconductors, particularly for X = BO2 and B2F7. We, therefore, believe that the concept of superhalogens can be successfully applied to the design of novel organic superconductors.