Fullerene (C60) forms stable complex with nucleic acid base guanine

Interaction of C60 with nucleic acid base guanine was investigated at the DFT-B3LYP, MP2 and ONIOM(MP2:B3LYP) levels of theory using the 3-21G(d), 6-31G(d) and 6-31G(d,p) basis sets. It was found that C60 forms a stable complex with guanine through stacking interaction with binding energy of 8.1 kcal/mol at the MP2/6-31G(d) level. The ONIOM(MP2/6-31G(d):B3LYP/6-31G(d)) approach was found to be the most cost-effective method for such investigation. Neither the B3LYP method nor MP2 level with smaller basis set such as 3-21G(d) are found suitable for such investigation.