Toward understanding macrocycle specificity of iron on the dioxygen-binding ability: a theoretical study

Abstract

In an effort to examine the interaction between dioxygen and iron-macrocyclic complexes, and to understand how this interaction was affected by those different macrocyclic ligands, dioxygen binding with iron-porphyrin, iron-phthalocyanine, iron-dibenzotetraaza[14]annulene, and iron-salen complexes is investigated by means of quantum chemical calculations utilizing Density Functional Theory (DFT). Based on the analysis of factors influencing the corresponding dioxygen binding process, it showed that different macrocyclic ligands possess different O-O bond distances, and different electronic configurations for the bound O(2) and non-aromatic macrocyclic ligands favor dioxygen activation. Furthermore, the smaller the energy gap between the HOMO of iron-macrocyclic complexes and the LUMO of dioxygen, the more active the bound O(2) becomes, with a longer O-O bond distance and a shorter Fe-O bond length.

The relationships of catalytic activity of metal Schiff base catalysts and the Hammett constants of their anion–cationic substituents on ligand

“…The transition metal complexes are extensively investigated because of their importance in catalytic oxidation . Various conventional organic substituents on the ligand of metal complexes result in different catalytic effects .…”

Dioxygen Binding by Cobalt(II) Complexes of 8,8'-bis(aminomethyl)-2,2'-biquinoline

“…The deoxygenation may also be effected by evacuating the DMF or methanolic solutions. Solutions of {CoLI 2 .H 2 O} in methanol or DMF exhibited similar colour changes upon reaction with dioxygen, and E.S.R. spectroscopy indicated that the presence of the coordinating iodide ion facilitated dioxygen binding in methanolic solution.…”

“…In recent years our understanding of the molecular basis of in vivo oxygen binding and transport has been aided by a wide range of in vitro studies. Numerous simple chemical systems have been developed, which exhibit dioxygen binding that is reversible to variable degrees [1][2][3][4]. Although the common biological transport systems contain iron at the dioxygen binding site, coordination compounds of cobalt have proved to be valuable models for understanding and controlling the types of metaldioxygen interaction that may occur [5,6].…”

Intramolecular hydrogen bonding interaction, a mechanism for the bridging linkages to exert electronic influence on diiron models of [FeFe]-hydrogenase

“…In theoretical calculations related to transition metal complexes, it is not uncommon to use the combinations of the two basis sets [46][47][48]. For complexes 2, 5, 6 and 7, the atomic coordinates derived from the crystal structures [14,37,49] were used as a starting point for geometry optimisation in the calculations.…”