Solvent-dependent deprotonation of meso-pyrimidinylcorroles: absorption and fluorescence studies.

The absorption spectra of 10-(4,6-dichloropyrimidin-5-yl)-5,15-dimesitylcorrole have been studied in 15 solvents. The formation of deprotonated corrole species was found to account for the dramatic changes in the absorption spectra in several solvents. Careful analysis of the relationship between the formation of deprotonated species and solvent properties results in the conclusion that there is no single solvent parameter correlation, and either multiparameter correlations or specific solute-solvent interactions (preferential solvation of the most acidic NH tautomer or perturbation of intramolecular hydrogen bonding in the macrocycle core) should be considered. The fluorescence properties of the deprotonated pyrimidinylcorrole are also reported for the first time and compared to those of free-base and protonated species.