HYDROGEN-BOND ENERGIES OF HYDROGEN-CHLORIDE CARBONYL-COMPLEXES

Gas phase hydrogen bonding was studied via infrared spectroscopy in th e following systems: methyl acetate-hydrogen chloride, methyl formate- hydrogen chloride, 2-butanone-hydrogen chloride, and acetone-hydrogen chloride. The intensity of the H-CL stretching vibration was monitored as a function of temperature, and the hydrogen bond energies and enth alpies were determined. The hydrogen bond energy for all four complexe s was within 2.0 kJ mol(-1) of -18.3 kJ mol(-1), indicating that the h ydrogen bond energy is only minimally affected by nonlocal molecular s tructure. The acetone-hydrogen chloride complex was modeled by ab init io methods. The energy of formation of the complex, calculated at the MP2/6-311++G* level of theory, is -20.8 kJ mol(-1), in good agreement with the experiment.