Photocatalytic Reduction of CO<sub>2</sub> by Highly Efficient Homogeneous Fe<sup>II</sup> Catalyst based on 2,6‐Bis(1’,2’,3’‐triazolyl‐methyl)pyridine. Comparison with Analogues.
Lisa‐Lou Gracia, Elham Barani, Jonas Braun, Anthony B. Carter, Olaf Fuhr, Annie K. Powell, Karin Fink, Claudia Bizzarri
Abstract
Abstract Fully earth‐abundant and highly efficient systems for producing syngas CO/H 2 through photocatalytic reduction from CO 2 are essential to approach a sustainable way of closing the carbon cycle. Herein, the synthesis and characterization of a new iron complex, Fe II L(NCS) 2 py, coordinated to an N,N,N‐pincer ligand 2,6‐bis(4’‐phenyl‐1’,2’,3’‐triazol‐1’‐yl‐methyl)pyridine (L), two isothiocyanate groups (NCS) and one pyridine is reported. Its catalytic activity in the photo‐driven reduction of carbon dioxide has been investigated and compared with its Co II analogue (CoL(NCS) 2 py) and their homoleptic complexes ML 2 . In this work, the catalysts are used in combination with the heteroleptic complex [Cu I (dmp)(DPEphos)], where dmp is 2,9‐dimethyl‐1,10‐phenanthroline and DPEPhos is bis[(2‐diphenylphosphino)phenyl] ether, to reach entirely earth‐abundant systems. The new iron heteroleptic complex Fe II L(NCS) 2 py showed considerable activity with a TON CO of 576 obtained after 4 h (TOF=144 h −1 ) through visible light (λ=420 nm) and a quantum yield of 7.1 %.