The role of hydrogen bonds in the crystals of 2-amino-4-methyl-5-nitropyridinium trifluoroacetate monohydrate and 4-hydroxybenzenesulfonate - X-ray and spectroscopic studies

Two new organic-organic salts, 2-amino-4-methyl-5-nitropyridinium trifluoroacetate monohydrate (AMNP-TFA), and 2-amino-4-methyl-5-nitropyridinium 4-hydroxybenzenesulfonate (AMNP-HBS), were obtained and characterized by means of FT-IR, FT-Raman and single crystal X-ray crystallography. In the former crystal, the cations, anions and water molecules are linked into layers by three types of hydrogen bonds, N-P-H center dot center dot center dot O, N-A-H center dot center dot center dot O and O-H center dot center dot center dot O. These layers are connected by weaker C-H center dot center dot center dot O hydrogen bonds. In the latter crystal, the cations and anions form one-dimensional structure through a number of hydrogen-bonding interactions involving the OH, NH+ and NH2 groups as donors. In this case the NP-H center dot center dot center dot O and N-A-H center dot center dot center dot O hydrogen bonds are formed. The combination of interactions between cations and anions results in the formation of columns. Additionally, there are pi-pi stacking interactions between the columns. The obtained X-ray structural data are related to the vibrational spectra of the studied crystals. (C) 2013 Elsevier B.V. All rights reserved.