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 P2(1), a = 3.7280(2), b= 18.349(1), c=4.9680(4) angstrom, beta = 101.134(5)degrees, V=333.44(4) angstrom(3), 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 center dot center dot center dot O hydrogen bonds. The layers are interconnected by 4-amino-1,2,4-triazol-1-ium cations via N-H center dot center dot center dot O hydrogen bonds. The addition compound 4-amino-1,2,4-triazole-succinic acid (H) crystallizes in the monoclinic space group P2(1)/c, a = 11.8130(5), b = 5.0690(3), c = 16.5280(5) angstrom, beta = 117.285(3)degrees, V= 879.58(7) angstrom(3), Z = 4, R = 0.0352 for 1701 observed reflections. The crystal structure is formed by zig-zag chains (parallel to b axis) of 4-amino-1,2,4-triazole molecules, connected by N-H center dot center dot center dot N hydrogen bonds, and isolated molecules of succinic acid which interconnect these chains by O-H center dot center dot center dot N and N-H center dot center dot center dot O hydrogen bonds. The addition compound 4-amino-1,2,4-triazole-adipicacid (2: 1) crystallizes in the monoclinic space group P2(1)/c, a = 6.3610(3), b = 8.0580(2), c = 14.8750(5) angstrom, beta = 104.072(2)degrees, V = 739.57(5) angstrom(3), Z = 2, R = 0.0487 for 1793 observed reflections. The crystal structure consists of pairs of parallel linear chains (mediated by N-H center dot center dot center dot N hydrogen bonds) of 4-amino-1,2,4-triazole molecules that are interconnected by isolated adipic acid molecules via O-H center dot center dot center dot N and N-H center dot center dot center dot O hydrogen bonds. Neighbouring chains, which are parallel to a axis, do not exhibit any H-bond contact between each other. The FTIR and FT Raman spectra of all three compounds were recorded, calculated and discussed. Quantitative measurements of second harmonic generation of powdered 4-amino-1,2,4-triazol-1-ium hydrogen oxalate at 800 nm were performed and a relative efficiency of 38% (compared to KDP) was observed. (c) 2007 Elsevier B.V. All rights reserved.