Photo‐physical Properties of N‐methyl‐3,4‐fulleropyrrolidine and Its Derivatives: A DFT and TD‐DFT Investigation

Abstract

A series of N-methyl-3,4-fulleropyrrolidine (NMFP) derivatives were designed by selecting different pconjugated linkers and electron-donating groups as D-p-A and D-A systems. The optimised structures and photo-physical properties of NMFP and its derivatives have been determined using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods with the B3LYP functional and the 6-31G basis set. According to the computation analysis, both the p-conjugated linkers and the electron-donating groups can influence the electronic and photo-physical properties of the NMFP derivatives. Our calculated results demonstrated that the electron-donating groups, with significant electron-donating ability, had the tendency to increase the highest occupied molecular orbital (HOMO) energy. The p-conjugated linkers with lower resonance energy decreased the lowest occupied molecular orbital (LUMO) energy and caused a significant decrease in the energy gap (E g ) between the E HOMO and E LUMO . A Natural Bond Orbital (NBO) analysis examines the effect of the electron-donating group, p conjugated linker, and electron-withdrawing group for these NMFP derivatives. For the NMFP derivatives, a projected density of state (PDOS) analysis demonstrated that the electron density of HOMO and LUMO are concentrated on the electron-donating group and the p-conjugated linker, respectively. A TD-DFT/ B3LYP calculation was performed to calculate the electronic absorption spectra of these NMFP derivatives. Both the electron-donating group and the p-conjugated linker contribute to the major absorption peaks, which are assigned as HOMO to LUMO transitions and are red-shifted relative to those of non-substituted NMFP. CHEMICAL SOCIETY* r and a were defined as the bond length (bond angle) between the C atom of pyrrolidine moiety (NMFP) and substituted group and the calculated E HOMO and E LUMO values of NMFP are -5.850 and -3.212 eV, respectively.

Tuning the Polarity of Fullerene C60 Derivatives for Enhanced Photodynamic Inactivation†

“…4 and 5, upper panel) the HOMO was positioned on the phenylene amine substituent and the LUMO was located in the fullerene core. Similar calculations were obtained with fulleropyrrolidines substituted by electron-donating groups (46,47). The electron absorption spectra of these derivatives in the visible region were attributed to π-π* transitions.…”

BOPHY‐Fullerene C60 Dyad as a Photosensitizer for Antimicrobial Photodynamic Therapy

“…Similar calculations were obtained with fulleropyrrolidines substituted by electron-donating groups. [53,54] Our MO calculations were similar for both atropisomers, which exhibited the same HOMO-LUMO gap (2.6 eV). This suggests that the experimental observations should be independent on the C1'À C7 dihedral angle (Φ).…”