An Air‐ and Moisture‐stable Zinc(II) Carbene Dithiolate Dimer Showing Fast Thermally Activated Delayed Fluorescence and Dexter Energy Transfer Catalysis. Issue 23 (15th March 2023)

• Record Type: Journal Article
• Authors: Mrózek, Ondřej; Mitra, Mousree; Hupp, Bejamin; Belyaev, Andrey; Lüdtke, Nora; Wagner, Dorothee; Wang, Cui; Wenger, Oliver S.; Marian, Christel M.; Steffen, Andreas
• Is Part Of: Chemistry. Volume 29:Issue 23(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-15
• Subjects: carbenes -- luminescence -- photocatalysis -- TADF -- zinc; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202203980
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A dimeric Zn II carbene complex featuring bridging and chelating benzene‐1, 2‐dithiolate ligands is highly stable towards air and water. The donor‐Zn‐acceptor structure leads to visible light emission in the solid state, solution and polymer matrices with λ max between 577–657 nm and, for zinc(II) complexes, unusually high radiative rate constants for triplet exciton decay of up to k r =1.5×10 5 s −1 at room temperature. Variable temperature and DFT/MRCI studies show that a small energy gap between the 1/3 LL/LMCT states of only 79 meV is responsible for efficient thermally activated delayed fluorescence (TADF). Time‐resolved luminescence and transient absorption studies confirm the occurrence of long‐lived, dominantly ligand‐to‐ligand charge transfer excited states in solution, allowing for application in Dexter energy transfer photocatalysis. Abstract : Steric protection of the Zn‐Carbene bond by a bridging coordination mode of 1, 2‐dithiolate ligands leads to air‐ and moisture‐stable complexes. Efficient TADF with high radiative rate constants at room temperature is observed from 1/3 LL/LMCT states according to variable temperature, transient absorption and DFT/MRCI studies. Application in Dexter energy transfer catalysis is demonstrated, exemplifying the potential of this new class of abundant 3d photoactive systems.