A bis‐Pyrazolate Pincer on Reduced Cr Deoxygenates CO₂: Selective Capture of the Derived Oxide by Cr^II

Abstract

Reduction of the bis-(pyrazolyl)pyridine complex [LCr] 2 with stoichiometric KC 8 in THF producesaspecies that is reactive with CO 2 to produce an aggregate composed of paramagnetic K 2 L 2 Cr 2 (CO 3 )l inked by KCl into ap roduct of formula [K 2 L 2 Cr 2 (CO 3 )] 4 ·2KCl. X-ray diffraction reveals ap incer hydrocarbon exterior anda ni norganic interiorc omposed of K + ,C l À and carbonate oxygens.E very Cr is five coordinate and squarep yramidal, with the axial Nd onor weakly bonded to Cr due to the Jahn-Teller effect of ah igh spin d 4 configuration. Reaction with 13 CO 2 confirms that carbonate here is derived from CO 2 ,t hat oxide is derived from CO 2 , and that CO is indeedr eleased, since it is not ac ompetent ligandt oC r II .G uidingprinciples for selectivity in CO 2 reduction are deduced from the diverse successfulm olecular constructs to date.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Homogeneous Electrocatalytic Reduction of CO2 by a CrN3O Complex: Electronic Coupling with Redox-Active Terpyridine Fragment Favors Selectivity for CO

“…The calculated reduction potential for the neutral six-coordinate hydroxycarbonyl complex (Figure S27). [18][19][30][31] Alternate spin manifolds were considered for all intermediates and transition states, but were found to be higher in energy (see XYZ file). The relative energetic positioning of possible spin manifolds in the catalytic cycle also showed good agreement between the hybrid B3LYP functional [32][33][34][35] and the meta-GGA revised TPSS functional, [36][37] indicating the method was appropriate for these assignments (Table S7).…”

Homogeneous Electrocatalytic Reduction of CO2 by a CrN3O Complex: Electronic Coupling with Redox-Active Terpyridine Fragment Favors Selectivity for CO

“…The calculated reduction potential for the neutral six-coordinate hydroxycarbonyl complex (Figure S22). [18][19][30][31]…”

The Influence of Nucleophilic and Redox Pincer Character as well as Alkali Metals on the Capture of Oxygen Substrates: The Case of Chromium(II)

“…We have reported independently an example of K2Cr2L2(μ2-O). [15] The structure raises the question of why this (LCr)3O unit is not threefold symmetric with three identical 120 o CrOCr bond angles. This seems to reflect the importance of the fifth ligand for every chromium, even if that is a long distance, because that fifth ligand is present in the structure of (LCr)3O, even at Cr3, via THF.…”