Unravelling highly oxidized nickel centers in the anodic black film formed during the Simons process by in situ X-ray absorption near edge structure spectroscopy.

The Simons process is an electrochemical fluorination method to prepare organofluorine compounds. Despite the wide application, the underlying mechanism is still unclear. We report the investigation of the black film formed on the surface of the anodes in aHF by an in situ Ni K-edge X-ray absorption near edge structure (XANES) investigation. An electrochemical cell for in situ X-ray absorption spectroscopy (XAS) is presented.

Matrix Isolation Spectroscopic and Relativistic Quantum Chemical Study of Molecular Platinum Fluorides PtFn (n=1-6) Reveals Magnetic Bistability of PtF4.

Molecular platinum fluorides PtFn , n=1-6, are prepared by two different routes, photo-initiated fluorine elimination from PtF6 embedded in solid noble-gas matrices, and the reaction of elemental fluorine with laser-ablated platinum atoms. IR spectra of the reaction products isolated in rare-gas matrices under cryogenic conditions provide, for the first time, experimental vibrational frequencies of molecular PtF3 , PtF4 and PtF5 . Photolysis of PtF6 enabled a highly efficient and almost quantitative formation of molecular PtF4 , whereas both PtF5 and PtF3 were formed simultaneously by subsequent UV irradiation of PtF4 . The vibrational spectra of these molecular platinum fluorides were assigned with the help of one- and two-component quasirelativistic DFT computation to account for scalar relativistic and spin-orbit coupling effects. Competing Jahn-Teller and spin-orbit coupling effects result in a magnetic bistability of PtF4 , for which a spin-triplet (3 B2g , D2h ) coexists with an electronic singlet state (1 A1g , D4h ) in solid neon matrices.

Combining Theory and Experiment to Characterize the Voltammetric Behavior of Nickel Anodes in the Simons Process.

The Simons process, otherwise known as the electrochemical fluorination (ECF) method, is widely used in industry to electrolytically synthesize chemicals for various purposes. Even to this day, the exact mechanism of the ECF reaction remains unknown, but is believed to involve the formation of an anodic nickel fluoride film with highly oxidized nickel centers. In this study, experiments and density functional theory calculations are combined to characterize the initial anodic peak occurring at potentials typically required in an ECF cell. NiF2 is believed to form a passivating layer at low potentials. The calculations show that a potential of +3.1 V is required to oxidize surface Ni2+ centers to Ni3+ . This is in good agreement with the measured anodic peak at +3.57 V.