Operando Methods for the Mechanistic Elucidation of an Electrochemically Driven Structural Transformation

Abstract

We present the use of operando methods for the mechanistic dilucidation of an electrochemically driven structural transformation of a Ni(II) thioacetate complex. Specifically, we employed operando Raman spectroscopy and electrochemistry, along with X-ray diffraction to characterize the electrochemically induced conversion of a paddle-wheel tetrakis-acetate dinickel(II) complex into the related dinickel acetate. Successive Raman spectra were obtained from the surface of a gold electrode immersed in an electrochemical cell containing the dinuclear complex [Ni2(CH3COS)4·EtOH] under a constant applied potential, to oxidize the complex, and effects its conversion/transformation into the unprecedented [Ni(CH3COO)2]n electrodeposited onto the electrode surface as microstructures. The crystal structure of the new electrogenerated compound [Ni(CH3COO)2]n was also examined by synchrotron X-ray diffraction. The observation of a disulfide species, generated during the electrochemical process via Raman spectroscopy was consistent with and served to confirm the proposed mechanism. These approaches can be readily applied to numerous electrode potential-induced transformations