Interaction adenine-scopolamine in aqueous medium combining experimental spectra with DFT calculations

IRAMAIN, MAXIMILIANO A.; CATALDO, PABLO G.; CASTILLO, MARÍA V.; MANZUR, MARÍA E.; ROMANO, ELIDA; BRANDÁN, SILVIA ANTONIA

JOURNAL OF MOLECULAR LIQUIDS

ELSEVIER SCIENCE BV

Año: 2025 vol. 439

0167-7322

Four different adenine-scopolamine complexes have been proposed to evaluate the characteristics of interactionsbetween both species in aqueous solution by using experimental FT-IR, FT-Raman and UV–Visible spectra insolution with hybrid B3LYP/6–311++G** and 6-31G* calculations. Comparisons of experimental spectra insolution with the predicted for four complexes have shown better concordances for the complex 4, as supportedby AIM and NBO calculations. A high gap value for this complex in solution suggests a higher kinetic stability andlow reactivity. The UV spectrum in solution is in concordance with the described for the interaction of scopolaminewith calf-thymus DNA. These studies have evidenced the clear formation of AS complex 4, as confirmed bythe Benesi-Hildebrand equation. The properties and reactivity of this complex are strongly governed by theinterplay of intra- and intermolecular hydrogen and halogen bonds. In addition, complete vibrational assignmentshave been reported for the AS complex revealing the strong shifts of vibration modes due to the presenceof Br in the AS complex, as compared with the adenine monomer and scopolamine hydrobromide. The findings ofthis study could inform the development of advanced drug delivery platforms, particularly for targeted CNStherapies. Although specific investigations of this interaction remain limited, adenine’s prominent role in supramolecularchemistry provides a theoretical framework for engineering a scopolamine carrier system.