Dynamic behavior of hydrogen bonding in hydrogen 5,6-acenaphthenedicarboxylate

The dynamic hydrogen bond behavior of hydrogen 5,6-acenaphthenedicarboxylat e has been studied using NMR spectroscopy at variable concentration and tem perature. From the concentration experiments, it is clear that there is an equilibrium between monomeric (intramolecularly hydrogen bonded) and aggreg ated (intermolecularly hydrogen bonded) species at room temperature. Upon c ooling, the equilibrium shifts completely toward intramolecular hydrogen bo nding, thereby overcoming the steric cost required to form the necessary ei ght-membered ring. This compound is one of the few examples which exhibits such behavior, and the first within the series of hydrogen dicarboxylates w here it has been observed by NMR spectroscopy. (C) 2001 Elsevier Science Lt d. All rights reserved.