Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1411379 | Journal of Molecular Structure | 2009 | 6 Pages |
Abstract
Temperature dependence of the relaxation time T1 (in the ranges: 10-200Â K at 24.667Â MHz; 105-460Â K at 90Â MHz) and the second moment of the NMR line for protons M2 (in the range: 130-400Â K, 24.667Â MHz) in a polycrystalline sample of 2,4-dichloro-5-sulfamoyl-benzoic acid (lasamide) an Active Pharmaceutical Ingredient of both diuretic and antiviral drugs have been measured. The results have revealed two activation processes: the concerted proton transfer in inter-molecular double hydrogen bonds (the low-temperature T1 minimum at about 92Â K; the activation energy 5.02Â kJ/mol) and the jumps of the -NH2 group (the high-temperature, 2Â Gs2 reduction of the second moment; the activation energy 48Â kJ/mol). The low-temperature flattening of the T1 dependence stretched up to the helium temperatures indicating the incoherent tunnelling in the proton transfer dynamics.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
J.N. LatosiÅska, M. LatosiÅska, W. Medycki,