Two binuclear silver(I) complexes containing V‐shaped bis (benzimidazole) ligands: Syntheses, structures, and electrochemical sensing toward hydrogen peroxide

Two new silver(I) complexes, formulated as [Ag 2 L 1 2 (isophthalate)]·(C 2 H 5 OH) 5 (1) , [Ag 2 L 2 2 (isophthalate)] (2) (L 1 = 1,3‐bis[(N‐methyl‐benzimidazole)methylene]‐2‐aniline, L 2 = 1,3‐bis[(N‐ethyl‐benzimidazole)methylene]‐2‐aniline), were synthesized by volatilization method and characterized by X‐ray crystallography, elemental analysis, IR and UV/Vis spectroscopy. The crystal analysis showed that although complexes 1 and 2 were both binuclear, their Ag(I) centers exhibited different coordination geometric structures: four‐coordinated distorted tetrahedron in complex 1 , whereas three‐coordinated planar triangle in complex 2 . The electrochemical sensing performances of carbon paste electrode modified with Ag(I) complexes (CPE‐1 for complex 1 and CPE‐2 for complex 2 ) toward H 2 O 2 were evaluated by cyclic voltammogram and chronoamperometry in 0.2 M phosphate‐buffered saline (PBS, pH = 6.0) at −0.2 V. The results show that both CPE‐1 and CPE‐2 showed excellent electrocatalytic activity, quick response time (≤5 s) and high selectivity toward H 2 O 2 . The linear response range was from 5.0 × 10 −7 to 4.0 × 10 −3 M. The CPE‐1 exhibits better sensitivity and limit of detection (LOD) than CPE‐2, which is related to the coordination environment of Ag(I) ions. Sensors based on Ag(I) complexes have great application prospects in the field of electrochemical sensing.