Synthesis and properties of zirconium(IV) and molybdate(II) morin complexes

Abstract

Morin, an excellent chelating agent, has been used to form complex with a metal cation (Zr4+) and a metal oxyanion (), isolating highly colored [Zr(C15H9O7)2(NO3)2] · 2H2O (1) and [MoO3(C15H9O7)2] · 3H2O (2). The structures were elucidated using different techniques (i.e., electrical conductance, elemental, and thermal analyses) as well as a series of spectroscopic techniques (i.e., UV-Vis, IR, and 1H NMR). The stoichiometry of the complexes is 1 : 2, confirmed by the molar ratio method. Zr4+ is useful for structural diagnosis of different flavonoids. The preferred site of complex formation of morin is the 3-hydroxy-4-keto system. Complex 2 is more stable than 1. Fluorescence and cyclic voltammetry were studied. Antioxidative study affirmed that both 1 and 2 are efficient antioxidants relative to morin.