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Solvatochromism and preferential solvation of Brooker's merocyanine in water–methanol mixtures
Author(s) -
Tanaka Yuichi,
Kawashima Yukio,
Yoshida Norio,
Nakano Haruyuki
Publication year - 2017
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.24902
Subject(s) - solvation , chemistry , solvatochromism , merocyanine , excited state , implicit solvation , mole fraction , methanol , excitation , computational chemistry , solvent , chemical physics , molecule , atomic physics , organic chemistry , physics , electrical engineering , engineering
The excitation energy of Brooker's merocyanine in water–methanol mixtures shows nonlinear behavior with respect to the mole fraction of methanol, and it was suggested that this behavior is related to preferential solvation by methanol. We investigated the origin of this behavior and its relation to preferential solvation using the three‐dimensional reference interaction site model self‐consistent field method and time‐dependent density functional theory. The calculated excitation energies were in good agreement with the experimental behavior. Analysis of the coordination numbers revealed preferential solvation by methanol. The free energy component analysis implied that solvent reorganization and solvation entropy drive the preferential solvation by methanol, while the direct solute–solvent interaction promotes solvation by water. The difference in the preferential solvation effect on the ground and excited states causes the nonlinear excitation energy shift. © 2017 Wiley Periodicals, Inc.