Photochemical CO₂ Reduction Catalyzed by Phenanthroline Extended Tetramesityl Porphyrin Complexes Linked with a Rhenium(I) Tricarbonyl Unit

Abstract

A series of heterodinuclear complexes (M-1-Re) based on a phenanthroline (phen) extended tetramesityl porphyrin ligand (H2-1) has been prepared. The phen moiety of this ligand selectively coordinates a Re(I) tricarbonyl chloride unit, whereas the metal in the porphyrin moiety has been varied: namely, Cu, Pd, Zn, Co, or Fe was used. These dinuclear complexes were fully characterized by standard analytical methods. Additionally, a crystal structure of Cu-1-Re·5.5(C7H8)·0.5(C6H6) could be obtained, and extended time-resolved emission lifetime measurements were conducted. Furthermore, their ability to catalyze the photochemical reduction of CO2 to CO was investigated. Light-driven CO2 reduction experiments were performed in dimethylformamide (DMF) using triethylamine (TEA) as the sacrificial electron donor. The TONs (turnover numbers) of CO were determined and revealed a surprising catalytic activity that is obviously independent from the redox activity of the porphyrin metal. We have recently shown that the parent M-1 compounds are active photocatalysts, but the catalytic activity was dependent on the redox activity of the porphyrin metal. In the case of the new heterodinuclear complexes M-1-Re reported in this study, the catalytic active center seems to be the Re(I) moiety and not the porphyrin. Surprisingly, Zn-1-Re proved to be the most active compound in this series showing a TONCO of 13 after 24 h of illumination using a >375 nm cutoff filter while all other compounds showed minimal activity under this condition.

Synthesis and Characterization of a Ruthenium(II) Complex for the Development of Supramolecular Photocatalysts Containing Multidentate Coordination Spheres

“…Since PMDs (photochemical molecular devices) do not rely on diffusion‐controlled electron‐transfer processes, contrary to intermolecular systems, multiple supramolecular photocatalysts for the light‐driven reduction of water and CO 2 have been developed . Especially systems based on the tpphz bridging ligand (tetrapyrido[3,2‐ a :2′,3′‐c:3′′,2′′‐ h :2′′′,3′′′‐ j ]phenazine), which was first introduced by Bolger et al,, are well investigated , , .…”

Enhanced Electrochemical Reduction of CO2 to CO upon Immobilization onto Carbon Nanotubes Using an Iron‐Porphyrin Dimer

“…In this project, a new urea iron-tetraphenylporphyrin-dimer (Fe-TPP-Dimer) was synthesized and applied for electrocatalytic CO 2 reduction under both homogeneous and heterogeneous conditions to selectively reduce CO 2 to CO. Immobilization of the catalyst onto carbon nanotubes (CNTs) in aqueous solution resulted in remarkable enhancement of its electrocatalytic abilities, with exceptional turnover frequencies (10 s À 1 ), high faradic efficiency (FE) of ∼ 90%, and a current density of 16 mA/cm 2 at À 0.88 V vs. RHE. [12][13][14][15][16][17][18][19][20] Extensive research has been conducted on both homogeneous and heterogeneous molecular catalysts for CO 2 RR. [1][2][3][4][5] Although the capture and conversion of CO 2 to value-added synthons has become a desirable solution to this problem, challenges in regard to the species' general lack of reactivity and the costs associated with deployment and stability of such strategies remain prevalent.…”

“…[1][2][3][4][5] Although the capture and conversion of CO 2 to value-added synthons has become a desirable solution to this problem, challenges in regard to the species' general lack of reactivity and the costs associated with deployment and stability of such strategies remain prevalent. [12][13][14][15][16][17][18][19][20] Extensive research has been conducted on both homogeneous and heterogeneous molecular catalysts for CO 2 RR. [12][13][14][15][16][17][18][19][20] Extensive research has been conducted on both homogeneous and heterogeneous molecular catalysts for CO 2 RR.…”

Heterogene molekulare Systeme für eine photokatalytische CO2‐Reduktion mit Wasseroxidation

“…[43,45-47, 60,210-212] Der erste Bericht über eine homogene photochemische CO 2 -Reduktion mit Re I -Komplexen (Abbildung 10 a) stammt aus dem Jahr 1983 von Lehn. [215] Später folgten zweikernige Ru II -Re I -, [188] Metalloporphyrin-Re I - [200][201][202] und Os II -Re I -Systeme. Auch wenn diese Arten von Katalysatoren hohe Quantenausbeuten (8.7 %) und eine Selektivitätf ürd ie CO-Bildung (16 %) zeigten, war die Stabilitätn icht besonders hoch, was zu einer niedrigen TON führte.A ußer Re-basierten Katalysatoren wurden auch Ir-, Ru-und Os-Komplexe [60] fürh omogene Systeme entwickelt.…”