Novel compounds of 4-amino-1,2,4-triazole with dicarboxylic acids – crystal structures, vibrational spectra and non-linear optical properties

Three novel 4-amino-1,2,4-triazole compounds with oxalic, succinic and adipic acids have been prepared and X-ray structural analysis has been carried out. The organic salt 4-amino-1,2,4-triazol-1-ium hydrogen oxalate crystallizes in the monoclinic space group P21, a=3.7280(2), b=18.349(1), c=4.9680(4)Å, β=101.134(5)°, V=333.44(4)Å3, Z=2, R=0.0284 for 1328 observed reflections. The crystal structure consists of periodically alternating layers (parallel to a axis) formed by chains of hydrogen oxalate anions connected by strong O–H⋯O hydrogen bonds. The layers are interconnected by 4-amino-1,2,4-triazol-1-ium cations via N–H⋯O hydrogen bonds.