Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

Area of Science:

• Inorganic Chemistry
• Photochemistry
• Materials Science

Background:

• Development of efficient photosensitizers (PS) is crucial for photocatalysis.
• Copper(I) complexes offer tunable electronic and photophysical properties.
• Understanding structure-property relationships guides the design of advanced catalytic systems.

Purpose of the Study:

• Synthesize and characterize novel heteroleptic Cu(I) photosensitizers.
• Investigate the influence of ligand modification on photophysical and electrochemical properties.
• Evaluate the performance of these PS in photocatalytic hydrogen (H2) evolution.

Main Methods:

• Synthesis of [Cu(Xantphos)(NN)]PF6 complexes (NN = biq, dmebiq).
• Structural, photophysical (absorption, emission, lifetimes), and electrochemical (cyclic voltammetry) characterization.
• Photocatalytic H2 evolution experiments using varying Cu(I) PS, electron donors (DMA), and Rh-based water reduction catalysts (WRCs).

Main Results:

• Cu(I) PS exhibit extended light absorption into the visible spectrum.
• Significant differences in excited-state lifetimes were observed between the two PS.
• Photocatalytic H2 evolution was achieved only with the [Cu(Xantphos)(biq)]+ PS.
• Water reduction catalyst (WRC) choice critically influenced H2 evolution rates and turnover numbers.

Conclusions:

• Ligand modification in Cu(I) PS allows fine-tuning of light absorption, excited-state, and redox properties.
• Tuning of PS and WRC properties is essential for optimizing photoinduced electron transfer and catalytic activity.
• The study highlights the potential of rationally designed Cu(I) complexes for efficient photocatalytic H2 production.