HYDROGEN-BOND PATTERNS IN SOLID-STATE CARBOXYLIC-ACIDS - VIBRATIONAL STUDY OF THE HYDROGEN-BOND PATTERNS IN OXAMIC, MALONAMIC AND SUCCINAMIC ACID

The vibrational spectra of oxamic, malonamic and succinamic acid are r eported, Although these molecules exhibit identical functional groups, their solid state hydrogen bond patterns can be divided in two differ ent types, which can be clearly distinguished through the combination of infrared and Raman spectroscopy at variable temperatures and throug h the vibrational behaviour of the deuterated compounds, Oxamic acid b ehaves as a linear hydrogen bonded polymer with cyclic acid-acid and c yclic amide-amide dimers while the other discussed carboxylic acid der ivatives exhibit a cyclic acid-amide hydrogen bond pattern, A model is proposed to investigate the peculiar vibrational behaviour of oxamic ai:id theoretically. Spectroscopic studies of the cyclic heterogenic a cid-amide hydrogen bond pattern are studied for the first time.