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

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)]center dot CH3CN center dot CH2Cl2 (Fe-6) 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 Fe-6 cluster may provide binding sites for the surfaces of some specific materials, such as noble metals. Therefore, silver nanoparticle coated Fe-6 (Ag@Fe-6) complexes have been prepared by spontaneous self-assembly reactions. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images show that the Fe-6 cluster layer is formed on the surface of the silver nanoparticles and the diameter of the Fe-6 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 Fe-6 and Ag@Fe-6 complexes were also investigated.