A UV/VIS Spectra Investigation of pH-Sensitive Dyes Using Time-Dependent Density Functional Theory

The UV absorption spectra of neutral and charged hydroxy-, amino-, benzene-, naphtene, and quinoline derivated dyes are investigated with the PCM-TDDFT/6-311+g(2d,p) / /PCM-PBE0/6-311g(d,p) theoretical scheme using three popular hybrid functionals (O3LYP, PBE0, and BHandHLYP) and taking into account solvation effects (water, methanol, or ethanol). More precisely, we report herein the theoretical lambda(max) corresponding to the first dipole-allowed pi -> pi*. The raw results show that BHandHLYP is the less accurate (MAE of 36 nm) functional, though, after the statistical treatment, this hybrid becomes the most reliable and accurate functional for the evaluation of the absorption wavelengths. Indeed, the agreement between theory and experiment is satisfactory: The error on the excitation energies is close to 13 nm. In addition, our methodology has been applied to evaluate the UV spectra of nitrocatechol derivatives in aqueous solution, and the keto-enol tautomeric shift on the UV/VIS absoprtion spectrum of a beta-diketone derivative. (C) 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110: 2147-2154, 2010