Importance of structural factor in the catalytic activity of copper(II) complexes for the oxidation of TMPD by dioxygen

New Insight into Toxicity due to Oligomeric Amyloid-b Peptide and Alpha-Synuclein Protein induced by Copper(II) ion

“…The similar reactions as observed for the binuclear iron(III) compounds are also found for the binuclear copper(II) compounds, i.e., some binuclear copper(II) complexes can effectively give hydrogen peroxide in the presence of TMPD, without changing the oxidation state of copper(II) ion Nishida, Oishi, Kuramoto, & Kida, 1982;Nishida, Shimo, Maehara, & Kida, 1985b). In addition to this, we also reported that some binuclear copper(II) compounds exhibit high activity for two-electron oxidation of catechols and ascorbic acid by O 2 , but this reactivity was never observed for any mono-nuclear copper(II) complexes .…”

“…The Nishida Reaction is very specific for the binuclear metal chelates with M-M distance 3.0-3.5 A, i.e., the distance between two metal ions is a very important factor Nishida, Oishi, Kuramoto, & Kida, 1982). Our report that A (1-40) can interact with several copper(II) chelates to induce the formation of copper(II) species with short Cu-Cu distance (Kishita, Nishino, & Nishida, 2005), implying that the interaction with oligomeric A and copper(II) ions in plasma may facilely give some copper(II) species with short Cu-Cu distance (Hureus & Faller, 2009), which can produce hydrogen peroxide in the presence of reducing agents such as ascorbate and catechols, etc.…”

Synthesis, characterization and antimicrobial activity of macrocylic phenoxo-bridged di- and tetra-nuclear complexes from N,N-bis[2,6-diiminomethyl-4-methyl-1-hydroxyphenyl]succinoyl/sebacoyldicarboxamides

“…This is due to the high molecular weight (548) of the compound; the molecular ion (M + ) formed during the fragmentation is unstable and thereby it underwent sudden fragmentation before reaching the detector. However the molecular ion (M + ) on fragmentation gave a fragment ion peak at m/z 419 (M + AC 4 …”

“…These types of complexes have contributed to a better knowledge of oxygen transport and activation by metalloenzymes such as haemocyanin (Cu 2 ) [1] and cytochrome-C-oxidase (CuFe) [1] as well as of some industrial catalytic processes [2]. A number of magnetically interacting dinuclear copper(II) complexes have been shown to be catalytically active in the oxidation of two electron reducing substrates like ascorbic acid, 3,5-di-t-butylcatechol (3,5-DTBC) [3] and one-electron reducing substrate N,N,N¢,N¢-tetra-methyl-p-phenylenediamine (TMPD) by oxygen [4]. Recently, considerable attention has been paid to the preparation and properties of binuclear complexes due to their potential applications in bioinorganic chemistry, material sciences and homogeneous catalysis [5,6].…”

Kinetics and mechanisms of decomposition reaction of hydrogen peroxide in presence of metal complexes

“…In the catalysis by copper enzymes, such as laccase, the high potential of the active center is attributed mainly to the great stabilization provided by the ligands [39]. It has also been reported that binuclear complexes with appropriate Cu -Cu distances exhibit a higher activity than mononuclear ones [40]. Whereas other investigations reported that monomeric Cu(II) complex is the catalytically active and the dimmer is inactive [33].…”