Characteristic Vibrational Pattern for the Cyclic Dimer Carboxylic Acid Function in the Solid State

Abstract

The infrared and Raman characteristics of the cyclic dimer hydrogen-bonded carboxylic acid function in the solid state are fully reported. Some dicarboxylic acids (e.g., malonic, methylmalonic, di-methylmalonic, succinic, glutaric, and adipic acid) are reported as typical examples. The vibrational characteristics of the cyclic dimer hydrogen-bond pattern are studied through the effect of deuteration on the position of infrared and Raman bands and through the temperature effect on the behavior of the vibrational bands. The fundamentals can very well be compared with the fundamentals of the trans secondary amide function, and are therefore assigned as the acid I to acid VII fundamentals.