Comparative Studies of Structures and Peroxidase-like Activities of Copper(II) and Iron(III) Complexes with an EDTA-Based Phenylene-Macrocycle and Its Acyclic Analogue

Melissa Beltran-Torres, Rocío Sugich-Miranda*, Hisila Santacruz-Ortega, Lorena Machi, Motomichi Inoue, Enrique F. Velázquez-Contreras, Yedith Soberanes, Herbert Höpfl, Refugio Pérez-González, Rosa Elena Navarro, Alex J. Salazar-Medina, Rogerio R. Sotelo Mundo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

With the objective of studying the conformational and macrocyclic effects of selected metal chelates on their peroxidase activities, Cu2+ and Fe3+ complexes were synthesized with a macrocyclic derivative of ethylenediaminetetraacetic acid and o-phenylenediamine (abbreviated as edtaodH2) and its new open-chain analogue (edtabzH2). The Fe3+ complex of edtaodH2 has a peroxidase-like activity, whereas the complex of edtabzH2 does not. The X-ray study of the former shows the formation of a dimeric molecule {[Fe(edtaod)]2O} in which each metal with an octahedral coordination is overposed over the macrocyclic cavity, as a result of rigid macrocyclic frame, to form an Fe-O-Fe bridge; the exposure of the central metal to the environment facilitates the capture of oxygen to drive the biomimetic activity. The peroxidase-inactive Fe3+ complex consists of a mononuclear complex ion [Fe(edtabz)(H2O)]+, the metal ion of which is suited in a distorted pentagonal bipyramid to be protected from environmental oxygen. The copper(II) complexes, which have mononuclear structures with high thermodynamic stability compared with the iron(III) complexes, show no peroxidase activity. The steric effects play a fundamental role in the biomimetic activity.

Original languageEnglish
Pages (from-to)22487-22496
Number of pages10
JournalACS Omega
Volume4
Issue number27
DOIs
StatePublished - 31 Dec 2019

Bibliographical note

Funding Information:
Authors acknowledge support from Consejo Nacional de Ciencia y Tecnología (CONACYT, Mexico): grant CB-I0017-236216; a postdoctoral training scholarship under agreement no. 291053-CIAD to Y.S.; grant 294810 “Red Temática en Química Supramolecular”; grant INFR-2014-01-225455 to acquire the single crystal X-ray diffractometer Bruker D8 QUEST. Also, we thank the Secretaría de Educación Pública, México (SEP) for grant PFCE 2016 and grant Promep/103.5/11/4462.

Publisher Copyright:
Copyright © 2019 American Chemical Society.

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