The Organic Dynamics Program will support Professor Michael De Rosa's investigation of the "Studies on the Mechanism of Electrophilic Aromatic Substitution" in the Chemistry Department at Pennsylvania State University, Delaware County. He and undergraduate research students will develop new methodology that will unambiguously demonstrate how many intermediates are present in electrophilic substitution reactions. The kinetics and products of the dichloroethanoic acid catalyzed chlorination of pyrroles with N-chlorobenzamides and the carboxylic acid catalyzed chlorination of methoxybenzenes with N-chloroacetanilides are being studied. The intramolecular selectivity and intramolecular selectivity will be determined in order to elucidate the role of pi complexes in the electrophilic substitution mechanism.