Application of Superhalogens in the Design of Organic Superconductors

Bechgaard salts, (TMTSF)2X (TMTSF = tetramethyl tetraselenafulvalene and X = complex anion), form the most popular series of organic superconductors. In these salts, TMTSF molecules act as super-electron donor and X as acceptor. We computationally examine the electronic structure and properties of X in commonly used (TMTSF)2X (X = NO3, BF4, ClO4, PF6) superconductors and notice 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, AuF6 and study their (TMTSF)2X complexes. Our findings suggest that these complexes behave more or less similar to those of established (TMTSF)2X superconductors, particularly for X = BO2 and B2F7. We, therefore, believe that the concept of superhalogen can be successfully applied in the design of novel organic superconductors.