Izvorni znanstveni članak

https://doi.org/10.5562/cca2584

Kinetics and Mechanism of Electron Transfer Reaction of an Adipato Bridged Iron(III)-Salen Complex with Dithionite Ion in Perchloric Acid Medium

Pius O. Ukoha ; Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria
Simeon Atiga ; Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria
Oguejiofo T. Ujam orcid.org/0000-0002-5628-209X ; Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria
Jonnie N. Asegbeloyin ; Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria
Obinna C. Okpareke ; Department of Pure and Industrial Chemistry, University of Nigeria, Nsukka, Enugu State, Nigeria
Solomon O. E. Okereke ; Department of Pure and Industrial Chemistry, Abia State University, Uturu, Imo State, Nigeria

Sažetak

Redox kinetics of the reaction of an adipato bridged iron(III)-salen complex, [(Fe(salen))₂adi] with dithionite ion, S₂O₄2–, was investigated in perchloric acid at I = 0.05 mol dm–3 (NaClO₄) and T = 29 ± 1 °C. Spectrophotometric titrations indicated consumption of one mole of S₂O₄2– per mole of [(Fe(salen))₂adi] reduced. Under pseudo-first order conditions of [S₂O₄2–] above ten-fold excess of concentration of [(Fe(salen))₂adi], observed rates increased with increase in [S₂O₄2–] and second order rate constants were fairly constant (0.285 ± 0.01 dm3 mol–1 s–1) indicating first order dependence of the rate on [(Fe(salen))₂adi]. A plot of logk_obs versus log[S₂O₄2–] was linear and gave a slope of 1.0 indicating first order dependence of the rate on [S₂O₄2–]. The reaction rate increased with increase in [H+] within 3 × 10–3 mol dm–3 ≤ [H+] ≤ 14 × 10–3 mol dm–3. The reaction was unaffected by variation of ionic strength and dielectric constant of the medium. Addition of anion and cation did not catalyze the reaction. The reaction has been analyzed on the basis of an inner-sphere mechanism mediated by proton transfer.

Ključne riječi

kinetics; mechanism; dithionite; electron transfer reduction; iron(III)-salen complex

Hrčak ID:

150531

URI

https://hrcak.srce.hr/150531

Datum izdavanja:

30.12.2015.

Posjeta: 2.258 *