Effect of "X" Ligands on the Photocatalytic Reduction of CO2 to CO with Re(pyridylNHC‐CF3)(CO)3X Complexes. Issue 19 (29th April 2020)

• Record Type: Journal Article
• Authors: Shirley, Hunter; Sexton, Thomas More; Liyanage, Nalaka P.; Palmer, C. Zachary; McNamara, Louis E.; Hammer, Nathan I.; Tschumper, Gregory S.; Delcamp, Jared H.
• Is Part Of: European journal of inorganic chemistry. Issue 19(2020)
• Page Start: 1844
• Page End: 1851
• Publication Date: 2020-04-29
• Subjects: Photocatalysis -- Reduction -- Carbon dioxide -- Dissociation -- Photophysics; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.202000283
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : A series of five Re(pyNHC‐aryl)(CO)3 X complexes varying the "X" ligand where pyNHC is a pyridyl N‐heterocyclic carbene have been synthesized and characterized through NMR, UV/Vis absorption spectroscopy, IR, mass spectrometry, time‐correlated single photon counting, computational analysis, and cyclic voltammetry. The photocatalytic reduction of CO2 to CO in the presence of a sacrificial electron donor with these complexes is evaluated using a simulated solar spectrum (AM 1.5G). Comparison of Br and CH3 CN as the "X" ligand shows the same photocatalytic activity (both 32 TON). The use of Cl, NCS and P(OEt)3 "X" ligands all led to diminished reactivity with as little as 2 TON for the P(OEt)3 complex. These results were rationalized through computational analysis of "X" dissociation and excited‐state lifetime measurements. These results highlight the importance of the "X" ligand selection on catalysis with Re‐pyNHC complexes. Abstract : An in‐depth look at a series of rhenium‐based photocatalysts with a pyridyl‐NHC ligand framework that facilitate the reduction of CO2 to CO. The importance of selecting an appropriate "X" ligand is described through detailed photocatalytic, electrochemical, computational, and photophysical studies which reveal a weakly binding "X" ligand is key to catalysis.