Synthesis, electrochemistry, and catalytic behavior of the Fe(III) complex of a tetradentate macrocyclic triamide ligand

INOR 191

Erich S. Uffelman, uffelmane@wlu.edu, Johnathan T. Coleman, Jessica C. Lloyd, Jared J. Meyer, and Matthew J. Reilley. Department of Chemistry, Washington and Lee University, Lexington, VA 24450
A macrocyclic tetradentate triamide ligand system has been successfully metalated with anhydrous ferric chloride and reacted with cyanide to produce an axial bis-cyano complex that has been characterized by paramagnetic NMR spectroscopy, electrospray MS, IR, and cyclic voltammetry. The X-ray structure of the free ligand is compared to the X-ray structure of a tetraamido macrocyclic ligand (TAML) that has generated over 100 patents in iron chemistry that catalyzes environmentally friendly Green oxidation with hydrogen peroxide. Preliminary catalytic results indicate that the new complex does fewer turnovers, but at much faster rates, than the Fe TAML complex. The electrochemistry indicates an unusually low Fe(III)/Fe(IV) couple, and preliminary efforts at isolating the oxidized species are presented.