A spectrophotometric investigation of the complex between titanyl oxalate and 3-hydroxyflavone in water ethanolic mixtures

It has been established, by the application of suitable spectrophotometric methods and pH-metric measurements, that titanyl oxalate anion and 3-hydroxyflavone (3HF) form a [TiO(C2O4)2(C15H9O3)2]4 complex. The investigation of the composition and the concentration stability constant of the complex were carried out in a 50 % aqueous ethanol solution at room temperature (20°C), in the pH range from 1.9 to 9.0. The concentration stability constant of the complex, log b2, ranged from 16.65 at pH 5.0 to 13.96 at pH 7.0. The conditions for the spectrophotometric determination of 3HF by means of the complex formation were investigated in the concnetration range from 2.5×10 5 to 3.0×10 4 mol dm 3 3HF.