Density functional theory study on the influence of pyrrolidine substituent of C60 bisadduct on its supramolecular interaction with porphine

- DFT calculations on porphine/C60 bisadducts were carried out.
- Pyrrolidine ring appended on C60 has influence on its interaction with porphine.
- Interaction was found between pyrrolidine ring appended on C60 and porphyrin.
- Charger transfer between pyrrolidine ring and porphine was observed.
- The red shift of absorption was predicted for fullerene/porphine complexes.

Calculation using three kinds of density functional theory (DFT) methods revealed that the nonbonded interaction of pyrrolidine-functionalized C60 bisadducts with porphine derivatives (MP: M = Zn, 2H) was significantly affected by pyrrolidine substituents. Several types of the stable interaction configurations of trans-3 C60 bisadduct/ZnP complex (abbreviated as tran-3/ZnP) were compared. The association energy predicted by the wB97XD method was larger than that predicted by CAM-B3LYP and BHandH functionals. The results showed that the closer approach of porphine ring to the two pyrrolidine substituents, the larger the association energy of the complex. This trend was ascribed to the additional C-H⋯π interaction between the pyrrolidine and porphine rings. The natural bond orbital analysis proved the existence of an additional charge transfer process between the porphine and pyrrolidine rings for the t-I type of trans-3/porphine complexes. The red shift of absorption peaks of porphine were predicted in consistent with general experimental results.