Synthesis, structure and characterization of Fe6 molecular clusters with peripheral sulfur atom-capped silver nanoparticles

Abstract

There are rare reports of high-nuclear transition metal clusters with thiol groups in their periphery. In this work, a novel cluster, [Fe₆O₂(OH)₂(O₂CC₆H₄SCH₃)₁₀(hep)₂]·CH₃CN·CH₂Cl₂ (Fe₆) has been constructed by coordinating an octahedral Fe(III) ion with 4-mercaptobenzoate and hepH (hepH = 2-(2-hydroxyethyl) pyridine). The functionalized thiomethyl groups around the periphery of the Fe₆ cluster may provide binding sites for the surfaces of some specific materials, such as noble metals. Therefore, silver nanoparticle coated Fe₆ (Ag@Fe₆) complexes have been prepared by spontaneous self-assembly reactions. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images show that the Fe₆ cluster layer is formed on the surface of the silver nanoparticles and the diameter of the Fe₆ cluster is about 2 nm. In addition, powder X-ray diffraction (XRD), UV-vis spectroscopy, surface enhanced Raman spectroscopy (SERS), and cyclic voltammetry of the Fe₆ and Ag@Fe₆ complexes were also investigated.