Complexation equilibrium between iron(III) and N,N '-bis(2-hydroxyphenylmethyl)N,N '-bis(2-pyridylmethyl)-1,2-ethanediamine

摘要

Complexation equilibrium between iron(III) and N,N'-bis(2-hydroxyphenylmethyl)-N,N'-bis(2-pyridylmethyl)-1,2-ethanediamin e(H(2)bbpen), a colorless hydrophobic divalent hexadentate ligand, and potential use of the ligand far the spectrophotometric determination of iron(III) in aqueous solution was investigated. In the pH range 2.0 - 3.0, Fe(II) forms stable 1:1 complex with H(2)bbpen, and Fe(III) can be determined selectively as the purple Fe(bbpen)(+) complex (lambda(max) = 560 nm, epsilon = 4.3 x 10(3) dm(3) mol(-1) cm(-1), log beta(1) = 32.6 +/- 0.1). In this system, linear calibration range of Fe(III) was 5 x 10(-6) - 2 x 10(-4) mol dm(-3) (0.3 - 12 mu g cm(-3)) and detection limit was 3 x 10(-6) mol dm(-3) (0.2 mu g cm(-3)). Furthermore, most of foreign metal cations did not influence largely the determination of Fe(III). [References: 12]