Study On Compounds Containing Nitrogne And Sulfur Constructed Via Hydrogen Bond

A series of supramolecular compounds and complexes were synthesized through units of 2,5- dithiol-l,3,4-thiadiazole(DMTD) and isonicotinic acid by hydrogen bonds such as N—H ... S, N—H ... N, N—H ... O in the thesis. Crystal structures of four supramolecular compounds and complexes were obtained,including C₁₀H₉N₂⁺·C₂HN₂S₃^-(2a),(C₅H₇N₂)₂⁺·C₄N₄S₆2^-·H₂O(3a),Er[(C₆H₄NO₂)₃(C₁₂H₈N₂)H₂O](4a), [Fe(C₁₂H₈N₂)₃]₂⁺·[C₂N₂S₃]₂^-(5a), (C₆H₄NO₂=4-pyridine carboxylic acid,C₁₂H₈N₂=l,10^-phenanthroline, C₂N₂S₃H₂=2,5^-dithiol^-l,3,4^-thiadiazole ). In these compounds, many forms of hydrogen bonds existed, such as N—H...S...H—C, S...H—O—H...N, O...H—N—H...S, [N—H]2...S...H—O. It proved that it was feasible in construction of hydrogen bonds using sulfur atoms as hydrogen bond acceptor. In experiments, the study found that disulfide bonds could be constructed between two molecular of DMTD by the catalysis of ammonium molybdate in water solution of pH value 8 to 10 . The method provided a viable reference for the construction of disulfide bonds in biology, and base units for supramolecular compound building.Analyzed on the crystal structure of these compounds by Mercury and Diamond, one-dimensional left-handed helical chain was formed by hydrogen bonds in supramolecular compound (2a); twenty-four ring structural unit with 12 sulfur atom was formed by hydrogen bonds in compound (3 a); and complex 4a was of grid in two^-dimensional structure. Founded from the crystal structure, these types of hydrogen played important roles in one-dimension to three dimension structure, which made these supramolecular compounds and complexes become more stable.The study researched the effect of hydrogen bonds on melting point, infrared absorption and UV absorption. The result showed that the intensity of absorption peak for functional groups decreased significantly in IR spectra. The author found many different functional groups had red shift or blue shift phenomenon in the supramolecular compounds. In different solvent, the same supra-molecular compound varied significantly. These obvious differences could be attributed to the existence of hydrogen bonds. The study discovered the molecular stability through thermal stability analysis.