Abstract
Infrared and 1H NMR spectra are reported for mixtures of chloroacetic acid and 2,6-dimethylpyridine with various acid-base ratios (2:1 and from 1:1 to 1:15) in benzene, dichloromethane, and acetonitrile. The pyridine ring stretching vibration bands demonstrate that two species, A H⋯B and A −⋯H B +, are present in the investigated solutions. In benzene and dichloromethane some uncomplexed acid is observed in 2:1 and 1:1 mixtures. In acetonitrile a complex between the acid and acetonitrile is formed even when there is a 1:10 mixture of acid and 2,6-dimethylpyridine. Both the chemical shift of hydrogen-bonded protons and the continuous absorption in IR spectra are affected when an excess of base is added to the equimolar mixture of 2,6-dimethylpyridine with chloroacetic acid. This is caused by the presence of the 2:1 complex [B + H(A −⋯HA)] in the equimolar mixture. The excess of base shifts complexation to the 1:1 acid-base complex. The continuous absorption due to strong hydrogen bonds was separated numerically from that of the skeletal ones due to the 2,6-dimethylpyridine and acid. The observed increase of the extent of proton transfer and the continuous absorption due to changes in solvent polarity is explained by the increasing interaction of the dipole of the hydrogen bond with the reaction field from the environment.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
