Chemical Stability of 2-[(E)-(1-Propylbenzimidazol-2-yl)Iminomethyl]Phenole in Silver(I) Complexation

In this work, silver(I) complexation with the benzimidazole-containing imine Bz–N=CH–C6H5OH (where Bz is 1-propylbenzimidazole) with a linking –N=CH– group in the presence of competitive inorganic anions—nitrate anion, closo-decaborate [B10H10]2–, and closo-dodecaborate [B12H12]2– anions—has been studied for the first time. Chemical instability of this benzimidazole derivative has been observed during the studied reactions, accompanied by degradation at the linker bond –N=CH– with the formation of 1-propyl-2-aminobenzimidazole (Bz–NH2) as a result of hydrolysis. An approach to stabilizing the Bz–N=CH–C6H5OH structure has been proposed. Depending on the synthesis conditions, heteroleptic complexes [Ag2(Bz–N=CH–C6H5OH)4(μ-NO3)2] (1) and [Ag(Bz–NH2)2NO3] (2), as well as the first examples of polymeric benzimidazole-containing silver(I) complexes {Ag2(Bz–NH2)2[μ-BnHn]}m (n = 10 (3), 12 (4)) with coordinated boron cluster anions, have been obtained and characterized. A single crystal X-ray diffraction study has been performed for complexes 1 and 4.