Photoinitiated Dioxygenase-Type Reactivity of Open-Shell 3d Divalent Metal Flavonolato Complexes

Irradiation of 3‐hydroxyflavonolato (3‐Hfl) complexes of MnII, CoII, NiII and CuII (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...

Full description

Saved in:
Bibliographic Details
Published in:European journal of inorganic chemistry 2012-10, Vol.2012 (29), p.4750-4757
Main Authors: Grubel, Katarzyna, Marts, Amy R., Greer, Samuel M., Tierney, David L., Allpress, Caleb J., Anderson, Stacey N., Laughlin, Brynna J., Smith, Rhett C., Arif, Atta M., Berreau, Lisa M.
Format: Article
Language:English
Subjects:
Bioinorganic chemistry
Carbon monoxide
Catalysis
Catalysts
Cobalt
Coordination compounds
Enzyme models
Formations
Homogeneous catalysis
Irradiation
Metal ions
Oxygen
Spectroscopic analysis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Irradiation of 3‐hydroxyflavonolato (3‐Hfl) complexes of MnII, CoII, NiII and CuII (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. UV irradiation of 3‐hydroxyflavonolato complexes of dn metal ions under aerobic conditions results in oxidative carbon–carbon bond cleavage and the formation of O‐benzoylsalicylato complexes and CO under stoichiometric or catalytic conditions. These results show that a variety of metal ions promote light‐induced flavonoloxidation and CO release under mildconditions.
ISSN:1434-1948
1099-0682
DOI:10.1002/ejic.201200212