1258497-96-9Relevant articles and documents
Electrocatalytic Reduction of CO2 to Formate by an Iron Schiff Base Complex
Nichols, Asa W.,Chatterjee, Sayanti,Sabat, Michal,MacHan, Charles W.
, p. 2111 - 2121 (2018)
The synthesis, structural characterization, and reactivity of an iron(III) chloride compound of 6,6′-di(3,5-di-tert-butyl-2-hydroxybenzene)-2,2′-bipyridine (Fe(tbudhbpy)Cl), under electrochemically reducing conditions is reported. In the presence of carbon dioxide (CO2) under anhydrous conditions in N,N-dimethylformamide (DMF), this complex mediates the 2e- reductive disproportionation of two equivalents of CO2 to carbon monoxide (CO) and carbonate (CO32-). Upon addition of phenol (PhOH) as a proton source under CO2 saturation, catalytic current is observed; product analysis from controlled potential electrolysis experiments shows the majority product is formate (68 ± 4% Faradaic efficiency), with H2 as a minor product (30 ± 10% Faradaic efficiency) and minimal CO (1.1 ± 0.3% Faradaic efficiency). On the basis of data obtained from cyclic voltammetry and infrared spectroelectrochemistry (IR-SEC), the release of CO from intermediate Fe carbonyl species is extremely slow and undergoes competitive degradation, limiting the activity and lifetime of this catalyst. Mechanistic studies also indicate the phenolate moieties coordinated to Fe are sensitive to protonation in the reduced state, suggesting the possibility of cooperative pendent proton interactions being involved in CO2 reduction.
Cobalt bipyridine bisphenolate complex in controlled/living radical polymerization of vinyl monomers
Lin, Yi-Chien,Hsieh, Yi-Liang,Lin, Yuan-Deng,Peng, Chi-How
, p. 7362 - 7369 (2014)
Cobalt(II) bipyridine bisphenolate (CoII(BpyBph)) was applied to mediate the controlled/living radical polymerization of vinyl acetate (VAc), methyl acrylate (MA), and other vinyl monomers such as N-vinylpyrrolidone (NVP) and acrylonitrile (AN). The living characters of linear increased molecular weight with monomer conversion, relatively narrow molecular weight distribution, and the synthesis of block copolymer demonstrated by the formation of PVAc-b-PNVP were all observed. The polymerization of VAc was proposed to be mediated by the degenerative transfer (DT) process, but the polymerization of MA should be mainly controlled by the reversible termination (RT) process since the equilibrium constant (Keq = [CoIII-R]/[CoII][R?]) between cobalt(II) and organocobalt(III) was measured as 8.6 × 107 M-1. The correlation between Keq and the redox potential (E1/2) of cobalt complexes was preliminarily observed as a higher E1/2 leading to a larger Keq.
Electrocatalytic Reduction of Dioxygen to Hydrogen Peroxide by a Molecular Manganese Complex with a Bipyridine-Containing Schiff Base Ligand
Hooe, Shelby L.,Rheingold, Arnold L.,MacHan, Charles W.
, p. 3232 - 3241 (2018/03/13)
The synthesis and electrocatalytic reduction of dioxygen by a molecular manganese(III) complex with a tetradentate dianionic bipyridine-based ligand is reported. Electrochemical characterization indicates a Nernstian dependence on the added proton source for the reduction of Mn(III) to Mn(II). The resultant species is competent for the reduction of dioxygen to H2O2 with 81 ± 4% Faradaic efficiency. Mechanistic studies suggest that the catalytically active species has been generated through the interaction of the added proton donor and the parent Mn complex, resulting in the protonation of a coordinated phenolate moiety following the single-electron reduction, generating a neutral species with a vacant coordination site at the metal center. As a consequence, the active catalyst has a pendent proton source in close proximity to the active site for subsequent intramolecular reactions.
