STABILIZING HYDROGEN-HYDROGEN INTERACTIONS IN CATIONIC INDOPOLYCARBOCYANINE DYES
G. V. Baryshnikov, B. F. Minaev, V. A. Minaeva
Keywords: polymethine dyes, Bader method, functional density theory, bond critical point, binding energy, fluorescence quenching
Pages: 1090-1095
Abstract
A quantum chemical DFT method with the hybrid B3LYP functional in the 6-31G(d) basis set is employed to calculate the equilibrium geometric parameters of the ground and excited states of cationic symmetric indopolycarbocyanine dyes. Based on the Bader topological analysis of the electron density distribution function, it is found that there are hydrogen-hydrogen bonding interactions in the ground, first singlet, and first triplet states of the studied compounds. These interactions are assumed to have the dispersion character. The effect of the stabilization of the conformational position of methyl groups due to hydrogen-hydrogen interatomic interactions on fluorescence deactivation processes is shown. The total stabilization energy of hydrogen-hydrogen interatomic interactions in dye cations is found, which is ≈9 kcal/mol.
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