Yusuf Tunde L, Ogundare Segun A, Pillay Michael N, van Zyl Werner E
School of Chemistry and Physics, Westville Campus, University of KwaZulu-Natal, Chiltern Hills, Durban 4000, South Africa.
Department of Chemical Sciences, Olabisi Onabanjo University, Ago-Iwoye 120107, Nigeria.
Molecules. 2022 Aug 16;27(16):5223. doi: 10.3390/molecules27165223.
We report on the design, synthesis, and characterization of the first silver hydride clusters solely protected and stabilized by dithiophosphonate ligands and their application for the in situ generation of silver nanoparticles towards the catalytic reduction of 4-nitrophenol in an aqueous system. The synthesis of the silver monohydride cluster involves the incorporation of an interstitial hydride using sodium borohydride. Poly-nuclear magnetic resonance and mass spectrometry were used to establish the structural properties. The structural properties were then confirmed with a single-crystal X-ray diffraction analysis, which showed a distorted tetracapped tetrahedron core with one hydride ion encapsulated within the core of the silver framework. Additionally, the synthesized heptanuclear silver hydride was utilized as a precursor for the in situ generation of silver nanoparticles, which simultaneously catalyzed the reduction of 4-nitrophenol. The mechanism of the catalytic activity was investigated by first synthesizing AgNPs, which was subsequently used as a catalyst. The kinetic study showed that the pseudo-first constant obtained using the cluster (2.43 × 10 s) was higher than that obtained using the synthesized AgNPs (2.43 × 10 s). This indicated that the silver monohydride cluster was more active owing to the release of the encapsulated hydride ion and greater reaction surface prior to aggregation.
我们报道了首例仅由二硫代膦酸酯配体保护和稳定的氢化银簇合物的设计、合成与表征，以及它们在水体系中原位生成银纳米颗粒用于催化还原4-硝基苯酚的应用。单氢化银簇合物的合成涉及使用硼氢化钠引入间隙氢化物。利用多核磁共振和质谱确定其结构性质。然后通过单晶X射线衍射分析证实结构性质，结果表明其为扭曲的四帽四面体核，一个氢化物离子封装在银骨架的核内。此外，合成的七核氢化银用作原位生成银纳米颗粒的前体，银纳米颗粒同时催化4-硝基苯酚的还原。通过首先合成用作催化剂的银纳米颗粒来研究催化活性的机理。动力学研究表明，使用簇合物获得的准一级速率常数（2.43×10⁻² s⁻¹）高于使用合成银纳米颗粒获得的准一级速率常数（2.43×10⁻³ s⁻¹）。这表明单氢化银簇合物由于封装的氢化物离子的释放和聚集前更大的反应表面而更具活性。
