The oxygenation of flavonol by copper(I) and copper(II) flavonolate complexes. The crystal and molecular structure of bis(flavonolato)copper(II)

Flavonol is oxygenated to the corresponding depside catalysed by Cu1 and CuII flavonolate complexes; X-ray structure determination of bis(flavonolato)copper(II)·2CHCl3 shows that the two flavonolate ligands are coordinated to CuII through their 3-hydroxy and 4-carbonyl groups to result in a square planar geometry around copper(II).