Determination of the solubility of 2-Methyl-1,3-benzothiazol-5-amine molecule with aqueous ethanol by NMR spectroscopy

Herein, solubility of 2-Methyl-1,3-benzothiazol-5-amine molecule is studied at different alcohol concentrations and at different temperatures in water-ethanol solvents using NMR spectroscopy. The hydrogen bonds between title molecule and solvent molecules, bond lengths, energy values and C-13, N-15 NMR chemical shifts of the title molecule were calculated using B3LYP/6-311++G(d,p) basis set. In addition, experimental results are supported by theoretical results. Alcohol concentrations and different temperatures dramatically affected N-15 NMR spectra. At low concentrations and different temperatures more shift toward higher magnetic area region were observed in the N-15 NMR chemical shift values of the nitrogen atom (N15). In addition, this shift affects the carbon atoms neighbor to nitrogen atom as well as the nitrogen atom itself, thereby causing the chemical shift values of these atoms to change. This is because of the hydrogen bonds between nitrogen atom of title molecule and ethanol and water molecules. It has also been observed that the number of hydrogen bonds remains constant in higher solvent concentration values. (C) 2018 Published by Elsevier B.V.