Electrostatic interactions between positively charged porphyrins and nucleotides or amides: buffer-dependent dramatic changes of binding affinities and modesSupramolecular Chemistry, Part 93; Part 92: V. A. Palyulin, S. V. Emets, V. A. Chertkov, C. Kasper and H.-J. Schneider, Eur. J. Org. Chem., 1999, in the press.

Abstract

The association strength of positively charged porphyrins with anionic species can be orders of magnitude higher than reported in the literature, depending on the chosen buffer; the buffer also determines the dominating interaction mechanism, leading to stronger stacking contributions at higher salt concentrations; even electroneutral amides show a hitherto not recognized interaction between the negatively charged carbonyl oxygen and the positively charged π-surface of the porphyrin system.