Electrochemical synthesis and characterization of redox-tunable organometallic complexes via controlled potential electrolysis

The development of clean and controllable synthesis methods for organometallic complexes is a key challenge in coordination chemistry, with significant implications for catalysis and materials science. Traditional synthetic routes often suffer from harsh conditions and limited redox control. To address this gap, this study investigates controlled potential electrolysis (CPE) as a green and selective method for synthesizing redox-active organometallic complexes. The objective was to evaluate the structural, thermal, and spectroscopic properties of Fe-bipyridine, Ru-triphenylphosphine, and Co-phenanthroline complexes prepared electrochemically. Using cyclic voltammetry, optimized redox potentials were applied for selective metal-ligand assembly. Characterization was performed via NMR, FTIR, UV-Vis, PXRD, TGA/DSC, and spectroelectrochemical techniques. The Fe– bipyridine complex showed high thermal stability (stable up to 245 °C), a 25 cm⁻¹ red shift in C=N stretching, and strong MLCT absorbance at 442 nm (ε = 8.2 × 10³ M⁻¹cm⁻¹). The Ru complex exhibited dual MLCT bands (at 420 and 498 nm) and a 34% higher absorptivity than Fe. Time-resolved UV-Vis confirmed redox interconversion, with >130% increase in oxidized species at 520 nm. These results demonstrate that CPE provides precise control over redox state and achieves high product purity. This method offers a sustainable approach to complex design, and future research will focus on enhancing catalytic performance and exploring multi-metal systems.