Year: 2025
Type: article
Abstract: The electron-deficient oxidant 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has recently emerged as a promising visible-light photoredox catalyst. However, its excited-state behavior remains poorly understood. Here, we investigate the ultrafast dynamics of photoexcited DDQ in acetonitrile using transient electronic and infrared absorption spectroscopy, supported by quantum chemical calculations. Upon 395 nm excitation, we identify rapid intersystem crossing (ISC) from the singlet to triplet manifold within 1.5 ps, followed by internal conversion and vibrational relaxation on a 10.9 ps time scale. Our findings demonstrate that DDQ exhibits near-unity ISC quantum yield and long triplet lifetime. Together with the high reduction potential of the triplet state, these properties make it a viable metal-free alternative to conventional iridium- and ruthenium-based photocatalysts.
Institution: University of Bristol
Language: English
Subfield: Physical and Theoretical Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: Selective Electrochemical Nucleophilic Fluorination, G1417047297, Ultrafast Photochemical Dynamics in Complex Environments, A Universal Approach for Solving Real-World Problems Using Quantum Dynamics: Coherent States for Molecular Simulations (COSMOS), EPSRC Centre for Doctoral Training in Technology Enhanced Chemical Synthesis
OpenAlex ID: W4414085391