Formation constants of 3,5,7,2',4', pentahydroxyflavone-Nd-III complexes by spectrophotometric and potentiometric studies

Complex formation of Nd [III] with 3,5,7,2',4'-pentahydroxyflavone has been studied by spectrophotometric and potentiometric methods at 25C and at mu = 0.1 M using NaClO4. The metal forms 1:1 and 1:2 complexes. The protonation constants of morin and the stepwise stability constants of its Nd complex have been determined. Free energy changes during protonation of the ligand as well as during complex formation are reported. The solid complex was prepared and studied to ascertain the mode of bonding