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.