Synthesis, Characterization, and Redox Reactions at the Solid-Liquid Interface of Submicron-Size Ru(edta) Complex

A submicron-sized colloidal ruthenium coordination compound was synthesized from a supersaturated solution of K[Ru^III(Hedta)Cl] complex (edta^4- = ethylenediaminetetraacetate) using the antisolvent method. Electron microscopy (SEM/STEM) and spectroscopic (UV-vis and IR) studies revealed that the resulting submicron particles of K[Ru^III(edta)(H₂O)], denoted as K[Ru^III(edta)(H₂O)]_SP, undergo ligand substitution with thiourea (TU) to form K[Ru^III(edta)(TU)]_SP, as well as redox reaction with hydrogen peroxide (H₂O₂) yielding K[Ru^V(edta)(O)]_SP at the solid-liquid interface of a multiphase system. Furthermore, K[Ru^III(edta)(H₂O)]_SP exhibited catalytic activity toward oxidative degradation of methylene blue (MB) in the presence of H₂O₂. The present study demonstrates that the characteristic coordination and redox reactivity of the Ru(edta) system are retained upon conversion to submicron particles, providing a model platform for investigating transition metal complex chemistry at solid-liquid interfaces.