The effect of pressure on charge-enhanced C-H⋯O interactions in aqueous triethylamine hydrochloride probed by high pressure Raman spectroscopy

The high pressure study of the C-H bands for a dilute protonated triethylamine/D2O solution yielded an unusual nonmonotonic pressure dependence. This result indicated charge-enhanced C-H⋯O hydrogen-bond formation at high pressure. Electron density loss from the bridging hydrogen atom, the amount of charge transferred from the proton-acceptor molecule to the donor, and cooperativity were also discussed.