(1H-Benzimidazole-5-carboxylic acid-κN 3)(1H-benzimidazole-6-carboxylic acid-κN 3)silver(I) perchlorate

The reaction of 1H-benzimidazole-5-carboxylic acid with silver nitrate in the presence of perchloric acid under hydrothermal conditions yielded the title complex, [Ag(C8H6N2O2)2]ClO4, which comprises of an [Ag(C8H6N2O2)2] mononuclear cation and a perchlorate anion. The AgI ion is coordinated by two N atoms from two different neutral 1H-benzimidazole-5-carboxylic acid ligands with an N—Ag—N bond angle of 163.21 (14)°, forming an [Ag(C8H6N2O2)2] mononuclear cation. Although both ligands in the mononuclear cation are monodentate with one N atom coordinated to the metal ion, they are different: one is N3 coordinated to the Ag I ion and the N1 atom protonated, the other with the N1 coordinated to the Ag I ion and the N3 atom protonated (and thus formally a 1H-benzimidazole-6-carboxylic acid rather than a 1H-benzimidazole-5-carboxylic acid ligand). The planes of the two planar ligands are roughly perpendicular, making a dihedral angle of 84.97 (2)°. The packing of the ions is stablized by extensive O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, and by remote Ag⋯O interactions [3.002 (3), 3.581 (5) and 3.674 (5) Å].

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