DFT, NBO, HOMO-LUMO, NCI, stability, Fukui function and hole-Electron analyses of tolcapone

Parkinson's disease is a neurodegenerative disorder that damages the nervous system. The treatment of this disease is carried using tolcapone as a drug combination with Levodopa. Tolcapone is investigated by the B3LYP/ 6-311G method by using DFT calculations. HOMO-LUMO results and fingerprint analysis reveal that it is a hard, stable molecule with hydrogen bond donor and acceptor system. According to NBO analysis, the presence of hydrogen bond, conjugation of double bonds, and CT nature enhances the stability. Fukui function analysis suggests that this molecule is more prone to nucleophilic attack. Multiwfn 3.8 is used to interpret the following results. NCI interaction study reveals that it is having steric effect, Van der Waals force, and hydrogen bond. Hole-electron interaction studies reveal that S1, S5, and S6 undergo a charge transfer excitation. The simulated Scanning Tunneling Microscope (STM) analysis shows that the tunneling current is located at C12 and H26.

Automated summary

Tolcapone is a stable molecule with hydrogen bond donor and acceptor system, which enhances its stability. Various analyses suggest that the molecule is more prone to nucleophilic attack and exhibits steric effect, Van der Waals force, and hydrogen bond interactions.