Solvatochromism of heteroaromatic compounds: IV. 2-Phenylpyrrole

Solvatochromism of the long-wave absorption band of 2-phenylpyrrole in vari ous media is studied and described in terms of universal and group Kamlet-T aft parameters. It is shown that the H-complex formation between 2-phenylpy rrole and a fairly strong H-bond acceptor causes polarization of the electr onic system of the donor; as a result, its first pi-->pi* transition no lon ger produces electron density redistribution. H-Complex formation by the pi system of 2-phenylpyrrole affects its sigma state. In strong acids, there is an equilirium between the parent molecule and the 5H-cation. The protona tion and H-bond formation involve different centers.