THEORETICAL SPECTRAL ANALYSIS OF CAFFEINE MOLECULE (IR, RAMAN, UV-VIS AND NLO) AND INTERACTION MECHANISM WITH DNA

SILK ROAD 5. INTERNATIONAL SCIENTIFIC RESEARCH CONGRESS, Antalya, Türkiye, 16 - 18 Ocak 2026, ss.297-309, (Tam Metin Bildiri)

In this study, a theoretical spectral analysis of caffeine, the second most widely consumed

substance in the world after water, was performed, and its interaction mechanism with DNA

molecules was explained. IR and Raman (4000-400 cm-1) spectra of the caffeine molecule were

calculated and graphed. Density functional theory was used to determine the geometric

parameters, vibrational frequencies, and NLO analysis of the optimized caffeine molecule.

Calculations were performed using the B3LYP method with the 6-311G basis set. Dipole

moment, linear polarizability, and first hyperpolarizability values were calculated on the same

basis set. HOMO-LUMO energy values and UV-Vis spectrum were calculated using a time-

dependent density functional theory approach to determine electronic properties. Vibrational

band assignments were determined using the VEDA 4 program. Additionally, a molecular

docking study was conducted to demonstrate the interaction between the caffeine molecule and

DNA (PDB ID:1BNA).

Using the MEP map of the caffeine molecule, it was determined that the strongest attraction

region is on the surfaces containing O1, O2, and N6 atoms, and the strongest repulsion region

is on the surfaces containing H15, H19, H21, and H22 atoms. The HOMO and LUMO energy

levels of the caffeine molecule were calculated as -6.3726 and -1.3788 eV, respectively. The

TD-6-311G basis set was used to obtain the UV-Vis spectrum. Two electronic transitions were

obtained in the calculations (267 and 221 nm). The best binding affinity of the caffeine molecule

on DNA (PDB ID: 1BNA) was calculated as -6.3 kcal/mol. Molecular docking calculations

revealed that van der Waals interactions, hydrogen bonds, pi-anion bonds, and pi-donor

hydrogen bonds can occur between the caffeine molecule and DNA.