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

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 [Ni-2(CH3COS)(4)center dot 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.