COMPLEX-FORMATION BETWEEN WATER AND FORMAMIDE

The infrared spectrum of the water-formamide complex in argon matrices has been recorded from 10 to 4000 cm-1. The interaction energy of the complex forming molecules has been calculated from a theoretical pote ntial. One global and three different local minima have been found for this potential. Intermolecular vibration frequencies have been calcul ated for each minimum. The results are compared with the experimentall y observed far infrared spectrum. In agreement with microwave measurem ents and ab initio calculations, the global minimum of the complex is found, both from calculations and experiment, to have a cyclic structu re with water forming a hydrogen bond to the amide oxygen and receivin g a hydrogen bond from an amide hydrogen. In addition to the cyclic co mplex, we observe one of the local minimum structures of the complex, where water accepts a hydrogen bond from the amide NH on the CH side o f the amide.