Presentation Information
[PY1-10]Redox properties of metal complexes with catechol and its derivatives
○Xinlong - Li1, Kosuke Naruwa1, Carlito Baltazar Tabelin1, Mayumi Ito1, Naoki Hiroyoshi1 (1. Hokkaido University)
Keywords:
CME,Redox properties,Organic chemistry,Electronic theory
Carrier Microencapsulation (CME) has been proposed as a method to suppress pyrite oxidation. In CME, metal catechol complexes are adsorbed and oxidatively decomposed to form oxy-hydroxy metal coating on pyrite surface, acting as protective barrier against oxidation of the mineral. In this study, using Fe3+ and Ti4+ as metal ions, the effects of additional functional group in ligand (catechol derivatives) on the oxidative decomposition of the complexes were investigated by cyclic voltammetry.
In comparison with catechol complex, complexes with catechol derivatives having H3C-, H5C2- and HO- as a functional group were oxidized at lower potentials, while the complexes with catechol derivatives having HOOC- and O2N- were oxidized at higher potentials. This indicates that the electron-donating groups (H3C-, H5C2- and HO-) could accelerate oxidative decomposition of complexes and electron-withdrawing group (HOOC- and O2N-) suppresses the decomposition. The tris-catecholate complex with Ti4+ was oxidized at higher potentials than that of Fe3+-catechol complex, implying that central atoms (metal ions) also effect on the oxidative decomposition of the complexes.
In comparison with catechol complex, complexes with catechol derivatives having H3C-, H5C2- and HO- as a functional group were oxidized at lower potentials, while the complexes with catechol derivatives having HOOC- and O2N- were oxidized at higher potentials. This indicates that the electron-donating groups (H3C-, H5C2- and HO-) could accelerate oxidative decomposition of complexes and electron-withdrawing group (HOOC- and O2N-) suppresses the decomposition. The tris-catecholate complex with Ti4+ was oxidized at higher potentials than that of Fe3+-catechol complex, implying that central atoms (metal ions) also effect on the oxidative decomposition of the complexes.