Carbon dioxide reduction: A new heteroleptic iron complex can produce carbon monoxide from CO2 via photo-driven catalysis, induced by a CuI-photosensitizer. This earth-abundant system gives CO with a turnover number of 576 and a quantum yield up to 7 %. Competitive H2 formation leads to syngas generation. This accomplishment is a further step toward sustainable CO2 employment.
Fully earth-abundant and highly efficient systems for producing syngas CO/H2 through photocatalytic reduction from CO2 are essential to approach a sustainable way of closing the carbon cycle. Herein, the synthesis and characterization of a new iron complex, FeIIL(NCS)2py, 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 CoII analogue (CoL(NCS)2py) and their homoleptic complexes ML2. In this work, the catalysts are used in combination with the heteroleptic complex [CuI(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 FeIIL(NCS)2py showed considerable activity with a TONCO of 576 obtained after 4 h (TOF=144 h−1) through visible light (λ=420 nm) and a quantum yield of 7.1 %.Zum Volltext