Related Experiment Video
Updated: Aug 7, 2026

Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere
Published on: April 30, 2018
Effect of temperature and concentration on the structure of N-methylacetamide-water complexes: Near-infrared
Mirosław A Czarnecki1, Krzysztof Z Haufa
1Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland. mcza@wchuwr.chem.uni.wroc.pl
Abstract:
Generalized two-dimensional (2D) FT-NIR correlation spectroscopy and chemometric methods have been used to study temperature-dependent spectral changes in pure N-methylacetamide (NMA) and NMA-water mixtures. We also examined the effect of varying water content on the structure of the mixture. It has been found that the extent of self-association of NMA in CCl4 is very high; the association occurs even at concentration of 0.001 M. In the pure liquid NMA, the population of the monomers is negligible and the structure is dominated by the linear associates. An increase in temperature reduces the number of hydrogen bonds, but in contrast to alcohols their strength remains nearly the same. This reflects a difference in the mechanism of thermal breaking of the associates of NMA and alcohols. The present results reveal that the interaction between NMA and water in the NMA-rich region (X(H2O) < 0.1) does not have a significant effect on the intrinsic structure of NMA. The structure of NMA is dominant, and the molecules of water do not form separate clusters but are dispersed and incorporated into the structure of NMA. We did not observe the presence of the free OH groups in the mixture. This led to the suggestion that each molecule of water forms two hydrogen bonds to two different molecules of NMA. An analysis of the asynchronous spectra reveals that most of the peaks observed in the asynchronous spectra, constructed from the temperature-dependent data, simply result from the frequency shift. This assumption is supported by the simulation studies.
More Related Videos
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
10:28Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Spectroscopy of Carboxylic Acid Derivatives
In the...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
NMR Spectroscopy Of Amines
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations