Ruthenium(ii) complexes of pyridinol and N-heterocyclic carbene derived pincers as robust catalysts for selective carbon dioxide reduction

Abstract

New methoxy substituted CNC pincers form ruthenium catalysts that are robust and convert CO2 to CO selectively using light energy.

Transition Metal Complexes Supported by N‐Heterocyclic Carbene‐Based Pincer Platforms: Synthesis, Reactivity and Applications

“…For pincer carbene chemistry, Ru is one of the most studied metal centers. In this regard, Papish's group presented a few examples of octahedral Ru II complexes ( 19 and 20 , Scheme 9), and tested their performance in photocatalytic reduction of CO 2 [19] . Similar to the case shown in Scheme 1, the group again found that the catalytic property can be largely affected by the remote substituent.…”

Impact of the Dissolved Anion on the Electrocatalytic Reduction of CO2 to CO with Ruthenium CNC Pincer Complexes

“…The study of ruthenium‐based molecular catalysts driving the CRR reaction remains an intense and attractive area of research . Recent studies on the photocatalytic CRR with [Ru II (bpy) 2 (CO) 2 ][PF 6 ] 2 ( Ru‐1 ) and a pyridinol‐derived pincer ligated ruthenium chloride complex ( Ru‐2 ) have revealed higher rates of reactivity and a higher durability of the pincer complex . Additionally, electrocatalysis appeared to be faster with Ru‐2 and halide‐free Ru‐3 (vs. Ru‐1 ) via preliminary cyclic voltammetry (CV) analysis .…”

“…Recent studies on the photocatalytic CRR with [Ru II (bpy) 2 (CO) 2 ][PF 6 ] 2 ( Ru‐1 ) and a pyridinol‐derived pincer ligated ruthenium chloride complex ( Ru‐2 ) have revealed higher rates of reactivity and a higher durability of the pincer complex . Additionally, electrocatalysis appeared to be faster with Ru‐2 and halide‐free Ru‐3 (vs. Ru‐1 ) via preliminary cyclic voltammetry (CV) analysis . Access to the active catalyst via ligand dissociation is an important step for coordinatively saturated metal centers.…”

Photocatalytic CO2 Reduction under Visible‐Light Irradiation by Ruthenium CNC Pincer Complexes

“…A similar CNC ruthenium complex, [(CNC OMe )RuCl(NCMe) 2 ]OTf, in which a 4‐methoxy group is introduced to the pyridyl moiety in CNC ligand, has been reported . The use of this complex for the photocatalytic CO 2 reduction in CH 3 CN with photosensitizer [Ir(ppy) 3 ] resulted in selective production of CO (TON CO =227; selectivity 97 %), but in DMF with photosensitizer [Ru(bpy) 3 ] 2+ production of formate was dominant (TON HCOOH =143; selectivity 90 %).…”