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Updated: Jan 22, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Interplay between conformational and solvent effects in UV-visible absorption spectra: curcumin tautomers as a case
Alessandra Puglisi1, Tommaso Giovannini1, Liudmil Antonov2
1Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy. chiara.cappelli@sns.it.
Abstract:
We present a combined theoretical and experimental study on the UV-vis spectra of enol-keto (EK) and keto-keto (KK) tautomeric forms of curcumin dissolved in aqueous solution. Solvent effects have been investigated by resorting to the implicit polarizable continuum model (QM/PCM) and non-polarizable and fully polarizable QM/MM approaches, the latter based on the fluctuating charges (FQ) force-field. In particular, all methods are challenged to rationalize the contribution of conformational, electrostatic and polarization effects in the calculation of the vertical excitation spectra of curcumin tautomers. The obtained results highlight that for both tautomers specific solute-solvent hydrogen-bond interactions play a minor role with respect to conformational and electrostatic effects.
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