Visible-Light-Driven Photocatalytic CO2 Reduction by Re(I) Photocatalysts with N-Heterocyclic Substituents

Author(s)

Muller, Andressa, V ; Faustino, Leandro A. ; de Oliveira, Kleber T. ; Patrocinio, Antonio O. T. ; Polo, Andre S.

• Document type: Journal article
• Source: ACS CATALYSIS; v. 13, n. 1, p. 14-pg., 2022-01-06.

Abstract

The properties and reactivity of metal complex photocatalysts for solar-to-fuel conversion can be conveniently controlled by the molecular design of their ligands. In this work, rhenium(I) tricarbonyl polypyridyl compounds, fac- [Re(NN)(CO)3Cl], where NN is a 1,10-phenanthroline ligand having pyrrole (Re-pyr), indole (Re-ind), or carbazole (Re-cbz) groups attached to its 4 and 7 positions, were investigated as photocatalysts for reducing CO2 to CO. These complexes can harvest light in the visible region and displayed an exceptionally high photocatalytic performance, with an up to 10-fold increase in the TONCO values compared to the unsubstituted Re-phen parental complex. Re-pyr was the best performing photocatalyst in this series, with a TONCO of 125 after 24 h and phi CO = 0.22. The TONCO of Re-pyr, Re-ind, and Re-cbz surpassed even the most efficient Lehn-type photocatalysts reported to date to promote the photoreduction of CO2 using triethanolamine as the sacrificial electron donor, without a second molecule working as a light absorber. The excellent photocatalytic performance of this series was intimately related to the presence of N-heterocyclic substituents, which enhanced the visible-light absorption properties of the compounds, favored the kinetics and thermodynamics of each individual step of the photocatalysis, inhibited deactivation of the photocatalysts by dimerization, stabilized reduced intermediates, and unlocked an alternative CO2 photoreduction pathway that proceeds predominantly through a two-electron reduced species [Re(NN)(CO)3]-. (AU)

• FAPESP's process: 16/24020-9 - Evaluation of processes photoassisted by Ru(II) and Re(I) polypyridyl compounds
• Grantee: Andressa Vidal Muller
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/08038-0 - Investigation of electron transfer processes for energy conversion systems based on Ru(II)/Re(I)
• Grantee: Andressa Vidal Muller
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 19/27176-8 - Asymmetric photocatalysis applied to the synthesis of Brivaracetam: synthetic approaches employing enabling technologies for chemical synthesis
• Grantee: Kleber Thiago de Oliveira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 20/06874-6 - Applications of technologies and synthetic methodologies developed under continuous flow conditions at LQBO-UFSCar for the preparation of molecules with biological activities and APIs
• Grantee: Kleber Thiago de Oliveira
• Support Opportunities: Regular Research Grants