Photo‐ and Electrochemical Properties of a CO₂ Reducing Ruthenium–Rhenium Quaterpyridine‐Based Catalyst

Abstract

The bridging ligand 2,2',5',3'',6'',2'''-quaterpyridine was utilised to tether [(bpy) 2 Ru] 2 + and [Re(CO) 3 Cl] subunits for the purpose of photocatalytic CO 2 reduction. The photophysics and electrochemistry of the complex and associated mononuclear species are reported herein, in addition to photocatalytic, picosecond time-resolved infrared and computational studies. Photophysical, time-resolved IR, and electrochemical data together with quantum chemical calculations indicate weak communication between the two metal centres. As a result of the electronwithdrawing effect of the ligand on both the Ru and Re subunits, the reducing power of the photosensitiser and catalytic unit were significantly attenuated relative to the intermolecular approach utilising [(bpy) 3 Ru] 2 + and (bpy)Re(CO) 3 Cl.

Visible‐Light‐Driven Reduction of CO2 to CO and Its Subsequent Valorization in Carbonylation Chemistry and 13C Isotope Labeling

“…[7,8] Since then, researchers have tried to improve its efficiency by (i) modifying the nature of the ligands in the coordination sphere to improve catalysis and to shift the absorption properties in the visible range, [9][10][11][12][13][14][15] and/or (ii) incorporating photosensitizers to photo-activate the catalyst in the visible spectral window. [16][17][18][19][20][21][22][23][24][25][26] From turnover numbers (TON) of 5-20 when it was first published, current improvements show TONs of ca. 3000.…”

“…Visible light was used to drive an optimized photocatalytic reduction using a ruthenium trisbipyridine complex as a sensitizer and a rhenium bipyridyl carbonyl complex as a catalyst to perform an efficient reduction of CO 2 to CO, which was then simultaneously utilized in a palladium-catalyzed aminocarbonylation reaction at room temperature. [16][17][18][19][20][21][22][23][24][25][26] From turnover numbers (TON) of 5-20 when it was first published, current improvements show TONs of ca. There is a consensus that we have to develop a circular economy scheme in order to drop to a zero-carbon emission scenario.…”

Tuning the reaction pathways of phenanthroline-Schiff bases: routes to novel phenanthroline ligands

“…Complex 3 is a distorted octahedral complex and is shown to be the facial isomer and this is consistent with the three intense bands observed in the metal carbonyl stretching region of the IR spectrum. 22 The positions of Br1 and trans CO group (C33, O34) are disordered and these were modelled at 95 : 5% occupancy with restraints. See ESI Fig.…”

Cover Feature: Visible‐Light‐Driven Reduction of CO2 to CO and Its Subsequent Valorization in Carbonylation Chemistry and 13C Isotope Labeling (ChemPhotoChem 8/2018)

“…[7,8] Since then, researchers have tried to improve its efficiency by (i) modifying the nature of the ligands in the coordination sphere to improve catalysis and to shift the absorption properties in the visible range, [9][10][11][12][13][14][15] and/or (ii) incorporating photosensitizers to photo-activate the catalyst in the visible spectral window. [16][17][18][19][20][21][22][23][24][25][26] From turnover numbers (TON) of 5-20 when it was first published, current improvements show TONs of ca. 3000.…”