Manganese and iron flavonolates as flavonol 2,4-dioxygenase mimics

Abstract

Mononuclear manganese(II) and iron(III) flavonolates were synthesized as synthetic enzyme-substrate complexes, and their oxygenation reactions as biomimetic functional models with relevance to flavonol 2,4-dioxygenases are briefly described.

Iron and Manganese-Containing Flavonol 2,4-Dioxygenase Mimics

“…6 together with selected data, shows a distorted octahedral geometry around the iron(III) center, and that the flavonolate anion is coordinated as a bidentate ligand with a strongly twisted conformation of the salen ligand. The difference in M-O distances ( M-O ) are somewhat bigger (0.184 Å) than those in Fe(4'MeOfla) 3 (0.154 Å) (Kaizer et al, 2007). 57 Mösbauer spectrum of the complex exhibits a dominant doublet with isomer shift,  = 0.49 mm/s and quadrupole splitting, E Q = 1.44 mm/s, indicating a high spin Fe(III) compound (Fig.…”

“…Cu1-O1 Cu1-O2 (Pap et al, 2010); b (Kaizer et al, 2007); c (Grubel et al, 2010); d (Baráth et al, 2009 (Grubel et al, 2010). somewhat shorter, which may be assigned to delocalization of the -system over the whole molecule (Pap et al, 2010).…”

“…3) (Baráth et al, 2009;Kaizer et al, 2007). Compounds Mn(fla) 2 (py) 2 (flaH = flavonol) Fe(4'MeOfla) 3 and Fe (4'Rfla)(salen) (salenH 2 = 1,6-bisz(2-hydroxyphenyl)-2,5-diaza-hexa-1,5-diene, R = H, MeO, Cl, NMe 2 ) have very similar IR and electronic spectra.…”

“…The GLC-MS analysis of the residue of the hydrolyzed complexes, after treatment with ethereal diazomethane, showed the presence of the O-benzoylsalicylic acid methylester. Oxygenations were also carried out under an atmosphere containing (Baráth et al, 2009;Kaizer et al, 2007).…”

“…, and all reactions were entropy driven ( Table 2), indicating that the rate-determining step is bimolecular (Baráth et al, 2009;Kaizer et al, 2007 Table 2. Kinetic data for the oxygenation of metal flavonolates (Baráth et al, 2009;Kaizer et al, 2007;Pap et al, 2010).…”