A novel route for designing C60 derivatives with large first hyperpolarizability: Cage-opened cases

Systematic density functional investigations on the structural and electronic properties of C55O5 and C54O6, two open-cage oxo-fullerene derivatives, have been performed. Those formed from topmost pentagon and hexagon of C60 cleaved with oxygen atoms, have a large circular opening 4.92 Å and 5.99 Å, respectively. The size of the opening is large enough to allow guest atoms or small molecules penetrating, thus C55O5 and C54O6 may act as promising candidates for fuel storage. The calculations on their nonlinear optical (NLO) properties with ZINDO/SCI–SOS method show that the investigated compounds possess remarkably larger static first hyperpolarizability (β) values amounting to −239.48 and −339.83 × 10−30 esu for C55O5 and C54O6, respectively, which are comparable to the reported exohedral C60 derivatives. It opens a new route to explore new type of NLO materials based on C60 derivatives.