Crystal structure, vibrational and theoretical studies of bis(4-amino-1,2,4-triazolium) hexachloridostannate(IV)

X-ray structure of new hybrid organic-inorganic compound, bis(4-amino-1,2,4-triazolium) hexachloridostannate(IV), [1t(4at)](2)SnCl6 (P (1) over bar space group) was determined. Crystal structure of 4-amino-1,2,4-triazole (Pbca space group) was reinvestigated. Non-planar orientation of NH2 group was found. The geometry of the amino group does not significantly change upon protonation. The route of protonation of 4-aminotriazole and tautomer equilibrium constants for the cationic forms were theoretically studied by means of B3LYP/6-31G* method. The most stable monoprotonated species is 1H-trans-4-amino-1,2,4-triazole, 1t(4at)(+), whereas the final product of the protonation route is 12(4at)(2+). Potential Energy Distribution (PED) analysis was carried out for two conformers, 1c(4at)(+) and 1t(4at)(+). Very good agreement between theoretical and experimental frequencies was achieved due to very weak interactions existing in [1t(4at)](2)SnCl6. Infrared and Raman bands were assigned on the basis of PED analysis. Comparison of vibrational spectra of [1t(4at)](2)SnCl6 and [1t(4at)]Cl indicates significantly weaker intermolecular interactions in the former compound. (C) 2012 Elsevier B.V. All rights reserved.