Synthesis, structure and electrochemical H2O2-sensing of two silver(I) complexes with bisbenzimidazole ligands

Two new binuclear Ag(I) complexes of the types, [Ag(2()Mebba)(2)(fumarate)].2C(2)H(5)OH (1) and [Ag-2(Meobb)(2)(mu-Cl)(2)] (2) (Mebba = bis(N-methylbenzimidazol-2-ylmethyl) aniline, Meobb = 1,3-bis(N-ethyl-benzimidazol-2-yl)-2-oxopropan), have been synthesized and characterized. Structural analysis showed that silver(I) centre in two complexes were both four-coordinated distorted tetrahedron geometry, but their bridging modes are significantly different: bridged by the fumarate in complex 1, mu(2)-Cl monoatomic bridging in complex 2. The electrochemical sensing performances of carbon paste electrode modified with silver(I) complex 1 (CPE-1) and complex 2 (CPE-2) towards H2O2 were investigated by chronoamperometry in 0.2 M phosphate buffer solution (PBS, pH = 6) at -0.2 V. The CPE-1 exhibits a wide linear detection range from 0.5 mu M to 4.0 mM and lower detection limit 0.61 mu M with a relatively high sensitivity of 9.9935 mu A/mM, and has excellent anti-interference ability and stability. There is not electrochemical H2O2-sensing performance for the CPE-2, which may be due to the fact that silver(I) ions and chloride ions form a more stable complex that is not easy to combine with hydrogen peroxide to form a catalytic transition state. The research results show that silver(I) complexes based on bisbenzimidazole ligands have the potential to become electrode materials.

Automated summary

Two new binuclear Ag(I) complexes have been synthesized and characterized, and their electrochemical sensing performances have been investigated. The results show that complex 1 exhibits good detection range, sensitivity, and stability, while complex 2 shows no sensing performance. The study suggests that silver(I) complexes based on bisbenzimidazole ligands have the potential to become electrode materials.