Analusis 26, 370-372 (1998)
DOI: 10.1051/analusis:1998187

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

N. Hirayama¹, N. Ichitani¹, N. Kuzuya¹, K. Kubono², H. Kokusen³ and T. Honjo<sup>1

1</sup>  Department of Chemistry, Faculty of Science, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
²  Division of Natural Science, Osaka Kyoiku University, Asahigaoka, Kashiwara 582-8582, Japan
³  Department of Chemistry, Faculty of Education, Tokyo Gakugei University, Nukui-Kita-machi, Koganei 184-8501, Japan

Abstract
Complexation equilibrium between iron(III) and N,N'-bis(2-hydroxyphenylmethyl)-N, N'-bis(2-pyridylmethyl)-1,2-ethanediamine (H₂bbpen), a colorless hydrophobic divalent hexadentate ligand, and potential use of the ligand for the spectrophotometric determination of iron(III) in aqueous solution was investigated. In the pH range 2.0 - 3.0, Fe(III) forms stable 1:1 complex with H₂bbpen, and Fe(III) can be determined selectively as the purple Fe(bbpen)⁺ complex (λ_max = 560 nm, ε = 4.3 × 10³ dm³ mol^-1 cm^-1, log β₁ = 32.6 ± 0.1). In this system, linear calibration range of Fe(III) was 5 × 10^-6 - 2 × 10^-4 mol dm^-3 (0.3 - 12 μg cm^-3) and detection limit was 3 × 10^-6 mol dm^-3 (0.2 μg cm^-3). Furthermore, most of foreign metal cations did not influence largely the determination of Fe(III).

Key words: N,N'-bis(2-hydroxyphenylmethyl)-N, N'-bis(2-pyridylmethyl)-1,2-ethanediamine / iron(III) / complexation / spectrophotometric determination.


© EDP Sciences, Wiley-VCH 1998