Collect. Czech. Chem. Commun.
2001, 66, 109-118
https://doi.org/10.1135/cccc20010109
Photoredox Reactions of Iodo Iron(III) Complexes Containing Tetradentate Ligands
Jozef Šimaa,*, Dáša Laukováa and Vlasta Brezováb
a Department of Inorganic Chemistry, Slovak Technical University, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
b Department of Physical Chemistry, Slovak Technical University, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
Abstract
Photoredox reactions occurring in irradiated methanolic solutions of trans-[FeIII(R,R'-salen)(CH3OH)I], where R,R'-salen2- are N,N'-ethylenebis(R,R'-salicylideneiminato), tetradentate open-chain N2O2-Schiff bases with R,R' = H, 5-Cl, 5-Br, 3,5-di-Br, 3,5-di-(CH3), 3-OCH3, 5-OCH3, have been investigated and their mechanism proposed. The complexes are redox-stable in the dark. Ultraviolet and/or visible irradiation of methanolic solution of the complexes induces photoreduction of Fe(III) to Fe(II). Depending on the composition of the irradiated solutions, •CH2OH radicals or solvated electrons were identified by the EPR spin trapping technique. The final product of the photooxidation coupled with the photoreduction of Fe(III) is formaldehyde and the molar ratio of Fe(II) and CH2O is close to 2 : 1. The efficiency of the photoredox process is strongly wavelength-dependent and influenced by the peripheral groups R,R' of the tetradentate ligands.
Keywords: Photoreduction; Iron(III) complexes; Iodo ligand; Schiff bases; Salen complexes; Chelates; Mechanism; EPR spin trapping.
References: 26 live references.
