Synthesis and crystal structure of 2,5-di(pyridin-3-yl)-1,3,4-oxadiazolendium nitrate

In order to continue our studies on the synthesis, properties and coordination of s-tetrazine, 3,6-di-(pyridin-3-yl)-s-tetrazine (II, 3-dptz) was synthesized and characterized by H-1-NMR, MS and IR spectra. And the coordination reaction of 3-dptz with nitrate of Cu(II) was studied. 3-dptz reacting with Cu-II salt [Cu(NO3)(2)center dot 2H(2)O] generates a new salt, nitrate of 2,5-di-(pyridin-3-yl)-1,3,4-oxadiazolene (III). III was determined by IR spectra and single-crystal X-ray diffraction to give the following crystal data: space group P2(1)/c, a = 4.9112(1), b = 8.4101(3), c = 29.499(1) angstrom, beta = 93.266(2)degrees, V= 1216.44(7) nm(3), M-r = 287.24, Z = 4, D-c = 1.568 g/cm(3), mu = 0.122 mm(-1), F(000) = 592, R = 0.0430 and wR = 0.1240. The results show that III is composed of one cation and one nitrate anion. The cation consists of one H+ and one 2,5-di-(pyridin-3-yl)-1,3,4-oxadiazol molecule, with the former being attached to the latter via electrovalent bond with N3 atom. And the O(42) atom in the nitrate anion is disordered. Intra- and intermolecular H-bonds are observed in the crystal of the title compound. The mechanism of metal-assisted decomposition was also discussed briefly.