Journal article

Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))-H bond functionalisation

Milena L Czyz, Geethika K Weragoda, Tyra H Horngren, Timothy U Connell, Daniel Gomez, Richard AJ O'Hair, Anastasios Polyzos

CHEMICAL SCIENCE | ROYAL SOC CHEMISTRY | Published : 2020

Abstract

Herein we report the photophysical and photochemical properties of palladacycle complexes derived from 8-aminoquinoline ligands, commonly used auxiliaries in C-H activation. Spectroscopic, electrochemical and computational studies reveal that visible light irradiation induces a mixed LLCT/MLCT charge transfer providing access to synthetically relevant Pd(iii)/Pd(iv) redox couples. The Pd(ii) complex undergoes photoinduced electron transfer with alkyl halides generating C(sp3)-H halogenation products rather than C-C bond adducts. Online photochemical ESI-MS analysis implicates participation of a mononuclear Pd(iii) species which promotes C-X bond formation via a distinct Pd(iii)/Pd(iv) pathwa..

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Grants

Awarded by ARC


Funding Acknowledgements

MLC acknowledges the ARC Industrial Transformation Training Centre Post-Doctoral Fellowship; GKW acknowledges CSIRO ResearchPlus Post-Doctoral Fellowships program; THH acknowledges the University of Melbourne, Melbourne Research Scholarship (MRS); AP acknowledges the University of Melbourne and CSIRO for the joint Establishment Grant and the ARC (IC1701000020). RAJO thanks the ARC (DP180101187). We thank the Bio21 Mass Spectrometry and Proteomics Facility for access to the Thermo OrbiTrap Fusion Lumos mass spectrometer. The authors acknowledge Prof. Jonathan White for XRD analysis, and Dr Carol Hua for advice on processing of XRD data.