Controlling photocatalytic reduction of CO₂ in Ru(ii)/Re(i) dyads via linker oxidation state

Abstract

Electronic communication between the linked metal centers in Ru(ii)–Re(i) dyads is tuned using the oxidation state (S and SO2) of sulfur-bridged ligands.

Water-Assisted Highly Efficient Photocatalytic Reduction of CO2 to CO with Noble Metal-Free Bis(terpyridine)iron(II) Complexes and an Organic Photosensitizer

“…Solar-driven reduction of CO 2 to value-added chemical fuels has attracted extensive attention in the past decade. − Among various catalysts for CO 2 reduction reaction (CO 2 RR), molecular metal complexes have shown promising catalytic efficiencies not only under electrochemical conditions but also upon visible-light irradiation due to their diverse chemical structures via tuning ligands and metals. − From the point of view of sustainable development, molecular photocatalysts based on earth-abundant metals are more appealing than noble metal complexes. − Recently, non-precious metal complexes such as Fe, ,− Co, − Ni, − Cu, and Mn − have been widely studied for photocatalytic CO 2 RR. However, those non-precious molecular catalysts are usually used together with precious photosensitizers such as [Ru­(bpy) 3 ] 2+ .…”

Sulfur-bridged chromophores for photofunctional materials: using sulfur oxidation state to tune electronic and structural properties

“…On the other hand, oxidation of a bridging sulfur in ligands is useful beyond altering the emission characteristics of luminescent metal complexes. These ligands can also be used to control electronic communication between two metal complexes, 99 and in turn, effect electron transfer rates, which is crucial for developing systems capable of artificial photosynthesis 100 or photocatalytic reactions. 101 Likewise, the use of a sulfur bridge can covalently tether the photosensitizer (PS) and catalyst together, and oxidation can potentially optimize these light-stimulated processes.…”

Rhenium(I) Complexes with Sulfur-Bridged Dipyridyl Ligands: Structural, Photophysical, and Computational Studies

“…Therefore, the sulfur bridge can serve as a handle to tune the photophysical properties without significant structural perturbation as the geometry of the sulfur remains constant in all three oxidation states. We have also studied the electronic communication in bimetallic ruthenium­(II)–rhenium­(I) dyads bridged by sulfur in different oxidation states and their photocatalytic activity for CO 2 reduction; however, the monometallic rhenium­(I) system has not been explored. Herein, we report a new class of rhenium­(I) tricarbonyl complexes supported by dipyridyl ligands with bridging sulfur in three different oxidation states.…”

“…All the complexes show one irreversible or quasi-reversible oxidation wave with the oxidation potential found in the range of +0.98 to +1.12 V vs Fc/Fc + , typically observed in rhenium (I) tricarbonyl diimine complexes and ascribed to Re I/II metalcentered oxidation. 9,19 The oxidation wave shows an anodic shift when the oxidation state of the sulfur increases from sulfide to sulfoxide or sulfone. This is due to the increase in the electron-withdrawing ability of the ligand when the sulfur is oxidized, so the electron density at the rhenium center is reduced, stabilizing the HOMO.…”