Stability and molecular dynamics of solid lasamide (API of diuretic and antivirial drugs) studied by 1H NMR spectroscopy and DFT methods
2009; Elsevier BV; Volume: 931; Issue: 1-3 Linguagem: Inglês
10.1016/j.molstruc.2009.05.033
ISSN1872-8014
AutoresJolanta Natalia Latosińska, Magdalena Latosińska, W. Medycki,
Tópico(s)Solid-state spectroscopy and crystallography
ResumoAbstract Temperature dependence of the relaxation time T 1 (in the ranges: 10–200 K at 24.667 MHz; 105–460 K at 90 MHz) and the second moment of the NMR line for protons M 2 (in the range: 130–400 K, 24.667 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 T 1 minimum at about 92 K; the activation energy 5.02 kJ/mol) and the jumps of the –NH 2 group (the high-temperature, 2 Gs 2 reduction of the second moment; the activation energy 48 kJ/mol). The low-temperature flattening of the T 1 dependence stretched up to the helium temperatures indicating the incoherent tunnelling in the proton transfer dynamics.
Referência(s)