《Metal-Ligand Cooperativity via Exchange Coupling Promotes Iron- Catalyzed Electrochemical CO2 Reduction at Low Overpotentials》 was written by Derrick, Jeffrey S.; Loipersberger, Matthias; Chatterjee, Ruchira; Iovan, Diana A.; Smith, Peter T.; Chakarawet, Khetpakorn; Yano, Junko; Long, Jeffrey R.; Head-Gordon, Martin; Chang, Christopher J.. Quality Control of 2,6-Dibromopyridine And the article was included in Journal of the American Chemical Society in 2020. The article conveys some information:
Biol. and heterogeneous catalysts for the electrochem. CO2 reduction reaction (CO2RR) often exhibit a high degree of electronic delocalization that serves to minimize overpotential and maximize selectivity over the hydrogen evolution reaction (HER). Here, we report a mol. iron(II) system that captures this design concept in a homogeneous setting through the use of a redox non-innocent terpyridine-based pentapyridine ligand (tpyPY2Me). As a result of strong metal-ligand exchange coupling between the Fe(II) center and ligand, [Fe(tpyPY2Me)]2+ exhibits redox behavior at potentials 640 mV more pos. than the isostructural [Zn(tpyPY2Me)]2+ analog containing the redox-inactive Zn(II) ion. This shift in redox potential is attributed to the requirement for both an open-shell metal ion and a redox non-innocent ligand. The metal-ligand cooperativity in [Fe(tpyPY2Me)]2+ drives the electrochem. reduction of CO2 to CO at low overpotentials with high selectivity for CO2RR (>90%) and turnover frequencies of 100 000 s-1 with no degradation over 20 h. The decrease in the thermodn. barrier engendered by this coupling also enables homogeneous CO2 reduction catalysis in water without compromising selectivity or rates. Synthesis of the two-electron reduction product, [Fe(tpyPY2Me)]0, and characterization by X-ray crystallog., Mossbauer spectroscopy, X-ray absorption spectroscopy (XAS), variable temperature NMR, and d. functional theory (DFT) calculations, support assignment of an open-shell singlet electronic structure that maintains a formal Fe(II) oxidation state with a doubly reduced ligand system. This work provides a starting point for the design of systems that exploit metal-ligand cooperativity for electrocatalysis where the electrochem. potential of redox non-innocent ligands can be tuned through secondary metal-dependent interactions. In the experiment, the researchers used many compounds, for example, 2,6-Dibromopyridine(cas: 626-05-1Quality Control of 2,6-Dibromopyridine)
2,6-Dibromopyridine(cas: 626-05-1) belongs to pyridine. Pyridine is a relatively complex molecule and exhibits a number of different bands in IR spectra. Among others, the bands characterizing the ν8a and ν19b modes have been found to be sensitive to the coordination or protonation of the molecule. Note that the band that is diagnostic for the PyH+ ion at about 1545 cm− 1 (ν19b mode) does not overlap with any of the other bands.Quality Control of 2,6-Dibromopyridine