Stabilizing hydrogen-hydrogen interactions in cationic indopolycarbocyanine dyes

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 hydrogenhydrogen 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.

Theoretical study of the triplet state aryl cations recombination: A possible route to unusually stable doubly charged biphenyl cations

“…The QTAIM analysis of the biphenyl dication (Bph 2+ ) and benzidine dication (Bzd 2+ ) strongly suggests the presence of HH intramolecular bonding interactions like it was found before in the neutral planar biphenyl molecule or in cationic indopolycarbocyanine dyes . The H‐atoms, which are connected with the C(3), C(5), C(8), and C(12) carbon atoms, lie in relative vicinity to each other (1.896 Å in the Bph 2+ and 1.912 Å in the Bzd 2+ , respectively).…”

DFT and QTAIM study of the tetra-tert-butyltetraoxa[8]circulene regioisomers structure

“…It is very important that the electron density analysis at the QTAIM level allows to identify very weak hydrogen bonds and Van der Waals contacts (e.g. CHÁ Á ÁO, HÁ Á ÁH, SÁ Á ÁO, and CÁ Á ÁN [23][24][25][26]) which are characterized by extremely low q(r) values (at the critical point) measured experimentally by the high-precision X-ray diffraction analysis.…”