Single Electron Transfer Reaction Of Au₂₅（SC₂H₄Ph）₁₈^-TOA⁺

Gold is a very expensive transition metal. Whether it’s in life as jewelry or in materials science research, has been praised by people. Since Brust created a Bottom-up preparation of gold nanoparticles in1994, size-focus synthetic methods of gold nanoclusters have been fast developing, prompting atomically precise gold nanoclusters have been synthesized and through a series of characterization. Due to mature preparation methods and well known crystal structure, Au25, Au38and Au102nanoclusters has been the representative of organic monolayer protected gold nanoclusters, whose properties’ research have been a hot spot for nearly a decade.In this paper, on the basis of predecessors’ research work, using cyclic voltammetry (CV), ultraviolet-visible (UV-vis) absorption spectroscopy, nuclear magnetic resonance spectrum (1HNMR) and electron paramagnetic resonance (ESR) technique is to study single electron transfer properties of phenylethylthiolated gold nanoclusters Au25(SCH2CH2Ph)18-TOA+. According to the cyclic voltammograms (CV) spectra, we can predict whether electron transfer reaction between oxoammonium salt (2.2.6.6-Tetramethylpiperidine-1-oxoammonium Tetrafluoroborate, TEMPO+BF4-) or charge transfer complex (phenothiazine tetrachloro-p-benzoquinone, PTZ-TCBQ) can occur. Then, ultraviolet-visible absorption spectroscopy (UV-vis) is used to study changes during the reaction, nuclear magnetic resonance (1HNMR) analysis to monitor the methylene proton resonances of the thiolate ligands during the redox process and using electron paramagnetic resonance (ESR) spectrum to detect the signal come from single electron capture agent in reaction process. Through experimental contrast, looking for a suitable oxidant for synthesis of stable Au25+nanoclusters.The main research content in this article is as follows:Using phenylethyl mercaptan as thiol ligands, anionic Au25(SC2H4Ph)18TOA+nanoclusters crystal is obtained through rapid reduction method. According to the reported literature, we synthesize two kinds of oxidant-oxoammonium salt (TEMPO+BF4-) and charge transfer complex (PTZ-TCBQ). The research results shows that, two consecutive single-electron transfer reactions occur between TEMPO+and Au25-nanoclusters while Au25+nanoclusters can only transfer one electron to PTZ-TCBQ complexes. NMR spectrum shows that the gold nanoclusters’s thiolate ligands’ methylene shift up or down during redox reaction. It’s fortunate that UV-vis absorption spectra and proton magnetic resonance spectra can be obtain through single electron transfer reaction between Au25(SCH2CH2Ph)18-TOA+and oxoammonium salt.