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

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      Publication Details (including relevant citation   information):

      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   European Journal of Inorganic Chemistry Special Issue: Modern   Coordination Chemistry and Its Impact for Meeting Global   Challenges (Cluster Issue), 2012,   2012, 4750-4757; DOI:   10.1002/ejic.201200212


      Irradiation of 3-hydroxyflavonolato (3-Hfl) complexes of   MnII, CoII, NiII and   CuII (14) at 300 nm   under aerobic conditions results in dioxygenase-type reactivity   and the formation of the corresponding divalent metal   O-benzoylsalicylato (O-bs) complexes   811 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   14 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   811 reacts with one equiv. of   3-hydroxyflavonol to regenerate   14 and enable turnover   reactivity. Unlike what is observed for free 3-HflH, photoinduced   reactions involving 14 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.

      Address (URL): http://onlinelibrary.wiley.com/doi/10.1002/ejic.201200212/abstract