APPARENT FORMATION CONSTANTS CORRELATION OF FLAVONOID–Ga(III) COMPLEXES. NOVEL SYNTHESIS OF 3,3´DIHYDROXIFLAVONE

FERRARI GABRIELA V.; PAPPANO NORA B.; MONTAÑA M.PAULINA; GARCIA NORMAN A.; DEBATTISTA NORA B.

JOURNAL OF CHEMICAL AND ENGINEERING DATA

AMER CHEMICAL SOC

Lugar: Washington; Año: 2010 vol. 2010 p. 3080 - 3083

0021-9568

Flavonoids are a wide variety of polyphenolic compounds. They have many biological properties. They also exhibit a metallic ion complexation capacity, which is important since it has been found that biological properties these ligands present can be enhanced when complexation occurs. In this work four flavonoid-Ga(III) complexes were studied: 2´,4´,3-trihydroxychalcone-Ga(III), 2´,3-dihydroxychalcone-Ga(III), 3,7,3´-trihydroxyflavone-Ga(III), and 3,3´-dihydroxyflavone-Ga(III). All ligands were synthesized by our working group, contributing a novel, cheaper, and more simple way to obtain 3,3´-dihydroxyflavone. The stoichiometry of the complexes was determined using the Yoe-Jones method. Both chalcone-Ga(III) complexes presented 1:1 L:M stoichiometry; meanwhile flavone-Ga(III) complexes presented 2:1 L:M stoichiometry. The pK values were determined by means of a spectrophotometric method. Values obtained were: 2´,4´,3-trihydroxychalcone-Ga(III), pK = 4.35±0.38; 2´,3-dihydroxychalcone-Ga(III), pK = 3.40±0.17; 3,7,3´-trihydroxyflavone-Ga(III), pK=7.74±0.19; and 3,3´-dihydroxyflavone-Ga(III), pK =8.46±0.27.