Crystal structure of 1,1-bis[(2-phenylazo)imidazol-1-yl]methane, C19H16N8

Abstract

Source of materialThe title compound, 1-bis[(2-phenylazo)imidazol-1-yl]-methane, was prepared by using the phase-transfer organic synthesis method. 2-Phenylazoimidazole (0.68 g, 4mmol) was added to a single-neck flask, then KOH (0.24 g, 4mmol) and Bu 4 NBr (0.1 g, 0.3 mmol) was added. After mixing, 10 ml CH 2 Cl 2 was added and stirred at room temperature for 2days. The solvent was removed in vaccum and the solid resident was subjected to flash column chromatography. Orange-yellow single crystals suitable for Xray analysis were obtained by the slowly evaporation of the solution of ethyl acetate and petroleum ether. DiscussionPolyazolylmethanes have attracted considerable attention in the fields of biochemistry, materials, heterocyclic and coordination chemistry [1,2]. Recently, some inorganic-organic hybrid compounds based on the ligand bis(imidazol-1-yl)methane have been documented [3,4]. The crystal structure analysis shows that there are two phenylazoimidazole moieties in an asymmetric unit. The azo group, benzene and imidazole ring in each phenylazoimidazole moiety are planar with the mean deviation of 0.0049(2) Å and 0.0078(2) Å, respectively. The dihedral angle between the two least-squares planes is 62.2°.T he N=N bond lengths are 1.260(2) Å and 1.229(2) Å,r espectively, which is smaller than as imilar compound [Ag(3'-PyaiEt)] 2(NO3)2 with the N=N bond length being 1.248 (7) . This suggests that the extent of orbital overlap is more between azo and imidazole moieties than between azo and phenyl moieties to form aC-Nsbond. The two phenylazoimidazole moieties in the same molecule were connected by the -CH 2 -group in anti-conformation.