The electronic spectrum of 2-(2'-hydroxybenzoyl)pyrrole and 2-(2'-methoxybenzoyl)pyrrole: a theoretical study

The gas-phase electronic spectra of 2-(2'-hydroxybenzoyl)pyrrole and 2-(2'-methoxybenzoyl)pyrrole have been determined using multiconfigurational perturbation theory (CASPT2). Solvatochromic spectral shifts for these molecules have been measured in cyclohexane and methanol and the electrostatic components of these shifts have been estimated using the vertical electrostatic model (VEM 4.2) developed for the configuration interaction with single excitations model implemented with the intermediate neglect of differential overlap Hamiltonian. Comparison between theory and experiment and an interpretation of the main spectral differences between the two substituted pyrroles and their solvation are presented.