Electrocatalytic and photocatalytic activities of two alkynyl Ag20 cage clusters involved ligand exchange between PhCOO− and CF3COO−

Abstract

Two silver alkynyl clusters, [(CO₃²⁻)@Ag₂₀(^tBuC≡C)₁₄(PhCOO)₃(CF₃COO)] (1) and [(CO₃²⁻)@Ag₂₀(^tBuC≡C)₁₄(PhCOO)(CF₃COO)₃] (2), composed of alkynyl Ag₂₀ shell templated by a CO₃²⁻ anion and supported by carboxyl ligands PhCOO⁻ and CF₃COO⁻, were synthesized successfully by conventional methods. Single crystal X–ray diffractometer (SCXRD) was used to determine the precise structures of 1 and 2. Although compounds 1 and 2 have the [(CO₃²⁻)@Ag₂₀(^tBuC≡C)₁₄]⁴⁺ unit, the numbers of PhCOO⁻ and CF₃COO⁻ ligands along with Ag···Ag interactions were affected by the steric hindrance of different carboxyl ligands and their concentrations. That is, compounds 1 and 2 separately contain the [(CO₃²⁻)@Ag₂₀(^tBuC≡C)₁₄(PhCOO)(CF₃COO)]²⁺ unit, which is involved in the ligand exchange between PhCOO⁻ and CF₃COO⁻. Powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA) were used to characterized compounds 1 and 2. The photocurrent responses, absorption spectra, as well as luminescence of 1 and 2 have been studied. In addition, the reduction of H₂O₂ for GCE–1 and GCE–2 showed good electrocatalytic activity, and catalysts 1 and 2 showed good photocatalytic degradation efficiency of methylene blue (MB). The results suggest that 1 and 2 can act as new electrocatalysts and photocatalysts to detect and decompose organic pollutants and hazardous materials in wastewater.