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Oxidative Degradation of Amino Acids and Aminophosphonic Acids by 2,2′‐Bipyridine Complexes of Copper(II)
Author(s) -
Pap József S.,
El BakkaliTahéri Nadia,
Fadel Antoine,
Góger Szabina,
Bogáth Dóra,
Molnár Milán,
Giorgi Michel,
Speier Gábor,
Simaan A. Jalila,
Kaizer József
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201400133
Subject(s) - chemistry , denticity , copper , amino acid , medicinal chemistry , ligand (biochemistry) , oxidase test , redox , peroxide , stereochemistry , polymer chemistry , inorganic chemistry , organic chemistry , metal , enzyme , biochemistry , receptor
Copper(II)–amino acid (AA) complexes that contain 2,2′‐bipyridine (bpy) as supporting ligand were investigated. X‐ray structural analysis of three new bpy‐based complexes revealed a bidentate coordination of the AAs on the copper(II) centers similar to that proposed for the substrate on the iron(II) center of the 1‐aminocyclopropane‐1‐carboxylic acid oxidase (ACCO). Similar complexes with two aminophosphonic acids (APAs), 1‐aminocyclopropane‐1‐phosphonic acid (ACP) and (1‐amino‐1‐methyl)ethylphosphonic acid (AMEP), were also investigated, and the latter complex was structurally characterized. This structure reveals the bidentate coordination of α‐aminophosphonate on the copper(II) ion. The oxidation of the bound amino acids (AAs) and aminophosphonates (APAs), which model the reaction catalyzed by ACCO, was investigated. The complexes react with H 2 O 2 and give oxidation products that were identified by gas chromatography. Reduction of Cu II to Cu I was detected by UV/Vis spectroscopy upon reaction with H 2 O 2 or ascorbate. This reduction is proposed to be the initial step for the peroxide/copper activation prior to the oxidation of the AA and APA ligands by means of a radical mechanism.