Photoinitiated dioxygenase-type reactivity of open-shell 3d divalent metal flavonolato complexes

Katarzyna Grubel, Amy R. Marts, Samuel M. Greer, David L. Tierney, Caleb J. Allpress, Stacey N. Anderson, Brynna J. Laughlin, Rhett C. Smith, Atta M. Arif, Lisa M. Berreau

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Irradiation of 3-hydroxyflavonolato (3-Hfl) complexes of Mn II, Co II, Ni II and Cu II (1-4) at 300 nm under aerobic conditions results in dioxygenase-type reactivity and the formation of the corresponding divalent metal O-benzoylsalicylato (O-bs) complexes 8-11 and CO. The latter were characterized by using multiple methods, including elemental analysis, X-ray crystallography, NMR and/or EPR spectroscopy, mass spectrometry and IR spectroscopy. Compounds 1-4 serve as catalysts for the photoinduced reactivity of 3-hydroxyflavonol (3-HflH) to produce O-benzoylsalicylic acid as the major product. Spectroscopic studies (UV/Vis and 1H NMR) show that each O-benzoylsalicylato complex 8-11 reacts with one equiv. of 3-hydroxyflavonol to regenerate 1-4 and enable turnover reactivity. Unlike what is observed for free 3-HflH, photoinduced reactions involving 1-4 and excess flavonol show only minor amounts of flavonol isomerization reactivity. These results indicate that the presence of a metal ion, whether under stoichiometric or catalytic conditions, facilitates the photoinduced degradation of 3-HflH to produce a carboxylic acid and CO as products.

Original languageEnglish (US)
Pages (from-to)4750-4757
Number of pages8
JournalEuropean Journal of Inorganic Chemistry
Issue number29
DOIs
StatePublished - Oct 2012

Keywords

  • Bioinorganic chemistry
  • Carbon monoxide
  • Enzyme models
  • Homogeneous catalysis
  • Oxygen

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