Hydrogen Bond Energies of Hydrogen Chloride−Carbonyl Complexes

Abstract

Gas phase hydrogen bonding was studied via infrared spectroscopy in the following systems: methyl acetatehydrogen 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 enthalpies were determined. The hydrogen bond energy for all four complexes was within 2.0 kJ mol -1 of -18.3 kJ mol -1 , indicating that the hydrogen bond energy is only minimally affected by nonlocal molecular structure. The acetone-hydrogen chloride complex was modeled by ab initio 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.

Computations of medium strength hydrogen bonds–complexes of mono- and bi-functional carbonyl and nitrile compounds with hydrogen chloride

“…The shift in the HCl stretching mode of the acetone complex has been reported by Nowak et al32 in a matrix but was only observed as a broad band in the gas phase in more recent work. 14 The measured anharmonic HCl shifts in the complexes with HCN, and are shown in Table 3. The CH 3 CN C 2 H 5 CN observed shifts are much greater in the matrix phase than in the gas phase.…”

Theoretical Characterization of Hydrogen Bonding Interactions between RCHO (R = H, CN, CF3, OCH3, NH2) and HOR′(R′ = H, Cl, CH3, NH2, C(O)H, C6H5)

“…[38][39][40] Their further role in protein structure, folding and stability can be well anticipated. 37,[41][42][43] There are numerous reports on hydrogen bonded carbonyl complexes by theoreticians and experimentalists [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61] in the past and even today. [62][63][64][65][66][67][68] For example, the earlier work by Bobadova-Parvanova and his co-worker investigated the hydrogen bonded complexes between open-chain substituted aliphatic carbonyl compounds and hydrogen fluoride at the HF/6-31G * * level.…”

Infrared Matrix Isolation Study of Acetone and Methanol in Solid Argon

“…Information on the structure and the internal dynamics of weakly bound complexes has been a fundamental basis to gain an insight into the interactions in bioorganic and organic molecular systems. − For example, in conjunction with the fact that carbonyl groups are common in biologically interesting molecules, extensive studies have been made to elucidate the binding properties of carbonyl groups with water − and hydrogen halides. − Weakly bound complexes have also been regarded as molecular analogues of physi- or chemisorbed molecules at surfaces…”