Can CF(3)-functionalized La@C(60) be isolated experimentally and become superconducting?

Abstract

Superconducting behavior even under harsh ambient conditions is expected to occur in La@C(60) if it could be isolated from the primary metallofullerene soot when functionalized by CF(3) radicals. We use ab initio density functional theory calculations to compare the stability and electronic structure of C(60) and the La@C(60) endohedral metallofullerene to their counterparts functionalized by CF(3). We found that CF(3) radicals favor binding to C(60) and La@C(60), and have identified the most stable isomers. Structures with an even number m of radicals are energetically preferred for C(60) and structures with odd m for La@C(60) due to the extra charge on the fullerene. This is consistent with a wide HOMO-LUMO gap in La@C(60)(CF(3))(m) with odd m, causing extra stabilization in the closed-shell electronic configuration. CF(3) radicals are both stabilizing agents and molecular separators in a metallic crystal, which could increase the critical temperature for superconductivity.