Special Theory and Computation Seminar - Aromaticity-Modulated Hydrogen Bonding

Fri, Nov 2 1:00pm
MSB 3440
Speaker Prof. Judy Wu
UC Irvine
Department of Chemistry

Abstract: Aromaticity and hydrogen bonding interactions are traditionally considered to be largely separate chemical concepts. We show, however, that their reciprocal effects are significant and have relevance for many areas of chemical research, including: molecular recognition, self-assembly, proton-coupled electron transfer, and enzyme catalysis. Quantum chemical calculations and experiments document the effects of aromaticity-modulated hydrogen bonding (AMHB). According to the AMHB concept, hydrogen-bonding interactions that increase cyclic 4n+2 π electron delocalizations (enhanced aromaticity) in heterocycles are strengthened (by up to 60%!), while those that decrease (reduced aromaticity) cyclic 4n+2 π electron delocalization are weakened. At specific excited states, these trends reverse following Baird’s Rule for excited-state aromaticity. Representative examples will be discussed.