Spectroscopic and electric properties of C.I. Mordant Blue 29: a theoretical and experimental study

Abstract

Hydroxytriphenylmethane dyes are organic compounds whose properties suggest a potential use in nonlinear optics. They are also widely used in chemical analysis. The most commonly used is C.I. Mordant Blue 29. However, in the literature there are no complete spectroscopic characteristics of the dye and there is a lack of detailed information on the electrical properties of C.I. Mordant Blue 29 dye. The optimum geometry of C.I. Mordant Blue 29 was determined by minimizing the energy with respect to all geometrical parameters without imposing molecular symmetry constraints. The UV-VIS spectra of C.I. Mordant Blue 29 and its charged species were computed with time-dependent density functional theory (TDDFT) by employing the B3LYP functional together with the 6-31++G(d,p) basis set at optimized geometries. The calculations of UV-VIS spectra also considered the presence of a solvent in terms of the polarized continuum model (PCM). The calculated spectra were compared with those obtained experimentally. The dipole moment (μ), polarizability (α), and first hyperpolarizability (β) of C.I. Mordant Blue 29 were calculated using the time-dependent Hartree–Fock method, and the electron correlation contribution to the electric properties was introduced by DFT using the functionals B3LYP, PBE0, and HCTH. Calculations were performed using several basis sets from 6-31G to 6-311++G(d,p).