Hydrogen-Bond Dynamics of CHO Interactions: The ChloroformAcetone Case

摘要

Spectroscopic evidence for CHO hydrogen bonding in chloroformacetone [Cl₃CHOC(CH₃)₂] mixtures was obtained from vibrational inelastic neutron scattering (INS) spectra. Comparison between the INS spectra of pure samples and their binary mixtures reveals the presence of new bands at about 82, 130 and 170 cm−1. Assignment of the 82 cm−1 band to the νOH anti-translational mode is considered and discussed. In addition, the βCH mode of CHCl₃ at 1242 cm−1 is split in the spectra of the mixtures, and the high-wavenumber component is assigned to the hydrogen-bonded complex. The plot of the integrated intensity of this component shows a maximum for x=0.5, in agreement with the 1:1 stoichiometry of the chloroformacetone complex, with a calculated complexation constant of 0.15 dm3 mol−1. Results also show that the complex behaves as an independent entity, that is, despite being weak, such interactions play a key role in supramolecular chemistry.