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ORTEP plot and labeling...](publication/282043008/figure/fig7/AS:340486830215207@1458189795013/X-ray-structure-of-CoLH2OClO42-ORTEP-plot-and-labeling-scheme-of-CoLH2O2_Q320.jpg)
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In this work, we present the synthesis and characterization of two new mononuclear complexes with the ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol (HL), [Co(L)(H2O)](ClO4)2 (1), [Ni(HL)](ClO4)2 (2), as well as the known complex [Cu(HL)](ClO4)2 (3) for comparison. Their abilities to catalyze the dismutation of H2O2 and the oxidation of cyclohexane...
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Citations
... These mimetic complexes are usually mononuclear iron, manganese derivatives or dinuclear manganese species [19]. In this sense, very few copper complexes [18,[20][21][22][23][24] have been reported to display CAT activity. Although the reaction of hydrogen peroxide dismutation via catalase mimics requires two electrons, in some cases, monomeric complexes can catalyze this reaction. ...
In the present work, we report a neutral dinuclear copper(II) complex, [Cu2(L1)(OH)], derived from a new [N,O] donor Schiff base ligand L1 that was formed after the endogenous hydroxylation of an initial carbamate Schiff base H2L coordinated with copper ions in an electrochemical cell. The copper(II) complex has been fully characterized using different techniques, including X-ray diffraction. Direct current (DC) magnetic susceptibility measurements were also performed at variable temperatures, showing evidence of antiferromagnetic behavior. Its catalase-like activity was also tested, demonstrating that this activity is affected by temperature.
... Several electrochemical techniques are suitable for the analysis of ZnO and ZnO 2 nanoparticles, including cyclic voltammetry [27], square wave voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy [28][29][30], and faradaic charge transfer measurement of the pseudocapacitance [31]. Cyclic voltammetry (CV) had previously been reported for the electrochemical sensing of ZnO nanoparticles deposited on a graphite electrode [32], electrochemical deposition of reduced graphene oxide on carbon fibers [33], and electrochemical characterization of Co(III), Ni(II), and Cu(II) mononuclear complexes on a glassy carbon electrode [34]. This electrochemical technique takes advantage of intuitive theory, simple operation, rapid analysis, and easy training. ...
An electrochemical method was developed to investigate the redox properties of zinc oxide (ZnO), zinc peroxide (ZnO2), and sodium-doped zinc peroxide (Na-ZnO2) nanoparticles. The intention was to distinguish the identity of these nanoparticles among themselves, and from other transition metal oxide nanoparticles (TMONPs). Analysis of 3 mM sodium metabisulfite by cyclic voltammetry (CV) produced anodic/cathodic peak currents that are linearly related to the mass of deposited nanoparticles. A graphite working electrode was essential to the oxidation of metabisulfite. ZnO nanoparticles were crucial to the enhancement of metabisulfite oxidation current, and PPy coating could suppress the current enhancement by covering all nanoparticle surfaces. Furthermore, meso-tetrakis(4-carboxyphenyl) porphyrin was demonstrated to be a good chemical reagent that facilitates the differentiation of ZnO from ZnO2 and nanoparticles by CV analysis.
... So far, the majority of bioinspired mimics have been mononuclear Fe or Mn porphyrinic complexes [18,23], with the ligand porphyrin being easily oxidizable and participating in the bi-electronic exchange, and di-nuclear non-heme Mn complexes [17,24]. A few examples of nanoparticles and metal-organic framework (MOF) nanoparticles have also been identified as CAT mimics [25,26], as well as a few copper complexes [27][28][29][30][31][32]. However, their catalytic activity was often reported in organic solvents or at non-physiological pH because of their low solubility in aqueous pH 7.5 conditions or the need for an external base. ...
... A Clark-type electrode can be used to monitor O2 formation when H2O2 is added to the complex solution (see Figure S5 for representative experiments). The catalase activity of many complexes mimicking CAT has only been studied in organic solvents or at relatively high pH [29,32,35], except for a few [31,[35][36][37]. With peptidyl complexes, aqueous solubility at pH around 7 allowed us to conduct studies in more biologically relevant conditions, namely, in aqueous MOPS buffer (50 mM) at pH 7.5. ...
... A Clark-type electrode can be used to monitor O 2 formation when H 2 O 2 is added to the complex solution (see Figure S5 for representative experiments). The catalase activity of many complexes mimicking CAT has only been studied in organic solvents or at relatively high pH [29,32,35], except for a few [31,[35][36][37]. With peptidyl complexes, aqueous solubility at pH around 7 allowed us to conduct studies in more biologically relevant conditions, namely, in aqueous MOPS buffer (50 mM) at pH 7.5. ...
Catalase mimics are low molecular weight metal complexes that reproduce the activity of catalase, an antioxidant metalloprotein that participates in the cellular regulation of H2O2 concentration by catalyzing its dismutation. H2O2 is a reactive oxygen species that is vital for the normal functioning of cells. However, its overproduction contributes to oxidative stress, which damages cells. Owing to their biocompatibility, peptidyl complexes are an attractive option for clinical applications to regulate H2O2 by enzyme mimics. We report here the synthesis and characterization of four new peptidyl di-copper complexes bearing two coordinating sequences. Characterization of the complexes showed that, depending on the linker used between the two coordinating sequences, their catalytic activity for H2O2 dismutation, their thermodynamic stability and their resistance to H2O2 degradation are very different, with (CATm2)Cu2 being the most promising catalyst.
... In addition, the presence of a vacant site on the Mn ion is required to coordinate H 2 O 2 , but the complex stability is reduced by the protonation of the bridging ligand. 31 Few mononuclear copper complexes 30,[32][33][34][35][36] have been reported as CAT mimics as well but examples of dinculear copper complexes are very rare. [37][38][39][40] Generally, CAT mimics have been studied in organic solvents or have exhibited activity only at pH above 8. ...
... Hydrogen peroxide degradation can occur at room temperature but at a very low reaction rate, requiring the use of a catalyst with greater expressiveness [17]. Several studies have been extensively carried out to enable metal complexes to act as catalase, an enzyme capable of degrading hydrogen peroxide to O 2 and H 2 O. Coordination compounds with Schiff base ligands have also been evaluated for their ability to catalyze the H 2 O 2 degradation reaction and can be verified in the literature with several metal centers (Co, Cu, Mn, and Ni) [18][19][20][21][22] being considered catalase mimetics. ...
... The literature reports coordination compounds that catalyze the H 2 O 2 degradation reaction [19,21] ...
The fuel cell is a continuously operating, low environmental impact, highly energy-efficient electrochemical device that has been cited as a clean energy source to replace fossil fuels. However, noble metals, such as platinum, are used as electrocatalysts to improve reaction kinetics, which raises the cost of this renewable energy source. This work aimed to evaluate a graphite paste electrode, modified with a copper(II) coordination compound containing N,O-donor groups, as an electrocatalyst in oxygen reduction reactions (ORR) and its catalase-like activity. Through electrochemical analyses, such as cyclic voltammetry and chronoamperometry, the modified electrode activity was investigated at different pH values and scan rates. Catalase activity was also investigated at different pH values in order to establish which would be the most active. The modified electrode proved to be a promising electrocatalyst in ORR in alkaline medium, and the copper(II) complex actively degraded hydrogen peroxide under alkaline conditions, which can help to increase the lifetime of the fuel cell device.Graphical Abstract
Copper(II) complex with electrocatalytic activity in the ORR and catalase-like
... The activity of the enzyme was affected by pH and temperature, so its application is limited. To improve acid resistance and performance stability, some researches have used inorganics as catalysts, such as nano-Pt, nano-Au, and metal oxides ZnO, MnO 2 and Co 3 O 4 nanoparticles, to prepare the hydrogen peroxide gas sensor [2][3][4]. In recent years, nanomaterials with unique properties due to high surface area, nanoeffect and powerful catalyst activity were selected as suitable catalyst in different fields. ...
... In addition to metal nanoparticles, the carbon materials were also used to prepare hydrogen peroxide sensor. Based on the three-dimensional foamed nickel as a porous scaffold and the graphene nano-Cu as catalyst, Zhu et al. prepared a hydrogen peroxide sensor, which detection limit was up to 1 μM [2][3][4]. Although the detection limit and sensitivity of Long Zhu's sensor are lower than those sensor prepared by nano-Pt, nano-Au, etc., it is a great improvement and innovation for the hydrogen peroxide sensor which is insensitive of the temperature and pH. ...
As the flashing hydrogen peroxide (H2O2) vapor was used widely in disinfection and sterilization, the monitoring of gas H2O2 concentration has become a widespread concern. A gas sensor for hydrogen peroxide monitor was prepared based on the Cu(II) chelating chitosan as catalyst and polyvinyl alcohol/sodium nitrite as a solid polymer electrolyte. The characters and structure of the sensor were characterized by SEM, FTIR, and TG. Finally, the electrochemical performance of the sensor and the detection effect of hydrogen peroxide gas content were detected by an electrochemical workstation. When the concentration of chitosan chelate copper is 0.15 wt% and the concentration of solid electrolyte is 0.1 wt%, the response performance of the sensor is the best. The results show that the low detection limit of the prepared sensor is below 1 ppm, the average response time is 2–5 s, and the usage temperature is relatively stable below 80 ℃. Solid-state electrolyte and electrode are combined by solution permeated, which would reduce the response time, implement consecutive period measurement and simplify the correction step. It would be potentially used for real-time monitoring of H2O2 vapor.
... Complexos ou compostos de coordenação como modelos funcionais da enzima catalase têm sido abordados em diversos trabalhos, como por Matos et al. (2011), Kupcewicz et al. (2012), Noritake et al., (2013), Ibrahim et al. (2014), Pires et al. (2015), dentre outros, o que demonstra o interesse crescente de grupos de pesquisa pelo estudo de sistemas miméticos. ...
... Motivated by the results of previous study [115], Lodeiro and co-workers [66] studied catalytic decomposition of H 2 O 2 into H 2 O and O 2 by Co(II) to Zn(II) metal complexes of hexaazamacrocycles 17b (Chart 3) bearing hydrazine arms. The catalytic activity followed the trend Ni(17b) > Zn(17b) > Cu(17b) > 17b (Table 1). ...
This review gives an account of the coordination chemistry, metallo-supramolecular chemistry and application of mono- and oligopyridine-based macrocyclic ligands. For this purpose, recently reported ligands and their metal complexes possessing at least one pyridyl donor group in a cyclic structure as the metal binding site have been selected. The application and prospects of such compounds in different scientific areas have been delineated.
... Copper and the mixed metal treatment showed to increase overall npun_R4582 relative mRNA levels more than the other metal treatments. The different expression response levels for the metals may be attributed to the metals with higher catalase activity such as manganese, cobalt, and nickel increasing the efficiency at which Npun_R4582, as well as other enzymes decompose the peroxide produced by actively photosynthesizing N. punctiforme cells (Pires et al. 2015;Rodriguez et al. 1990;Whittaker 2012). The increase in npun_R4582 relative mRNA levels for cells treated with copper and the mixed metal solution may be attributed to the cells being stressed by these treatments. ...
This study investigated the role of a novel metal-dependent catalase (Npun_R4582) that reduces hydrogen peroxide in the cyanobacterium Nostoc punctiforme. Quantitative real-time PCR showed that npun_R4582 relative mRNA levels were upregulated by over 16-fold in cells treated with either 2 μM added Co, 0.5 μM added Cu, 500 μM Mn, 1 μM Ni, or 18 μM Zn. For cells treated with 60 μM H2O2, no significant alteration in Npun_R4582 relative mRNA levels was detected, while in cells treated with Co, Cu, Mn, Ni, or Zn and 60 μM peroxide, relative mRNA levels were generally above control or peroxide only treated cells. Disruption or overexpression of npun_R4582 altered sensitivity to cells exposed to 60 μM H2O2 and metals for treatments beyond the highest viable concentrations, or in a mixed metal solution for Npun_R4582⁻ cells. Moreover, overexpression of npun_R4582 increased cellular peroxidase activity in comparison with wild-type and Npun_R4582⁻ cells, and reduced peroxide levels by over 50%. The addition of cobalt, manganese, nickel, and zinc increased the capacity of Npun_R4582 to reduce the rate or total levels of peroxide produced by cells growing under photooxidative conditions. The work presented confirms the function of NpunR4582 as a catalase and provides insights as to how cells reduce potentially lethal peroxide levels produced by photosynthesis. The findings also show how trace elements play crucial roles as enzymatic cofactors and how the role of Npun_R4582 in hydrogen peroxide breakdown is dependent on the type of metal and the level available to cells.
... 9 Furthermore, no reports exist on the catalase-like activity of cobalt(III) complexes except one report of low activity under homogeneous conditions. 10 Herein, we report that metallosupramolecular ionic crystals containing cobalt(III) centers, [Au I 4 Co III 2 (dppe) 2 (D-pen) 4 ]X n ([1]X n , dppe ¼ 1,2-bis(diphenylphosphino)ethane, D-pen ¼ D-penicillaminate, X n ¼ (Cl À ) 2 , (ClO 4 À ) 2 (NO 3 À ) 2 or SO 4 2À , Fig. 1), which were recently synthesized and structurally characterized, 11 exhibit high catalase-like activity under heterogeneous conditions. This class of ionic crystals, which we refer to as 'non-coulombic ionic solids (NCIS)', consists of Au I 4 Co III 2 hexanuclear complex cations, [1] 2+ , and inorganic anions, X À or X 2À , and adopts an unusual non-alternate arrangement of cationic and anionic species governed by non-coulombic interactions; complex cations [1] 2+ are self-assembled into octahedron-shaped cationic supramolecules, {[1] 2+ } 6 , and anions X À or X 2À are aggregated into adamantane-or octahedron-shaped anionic clusters, {X À } 10 or {X 2À } 6 ( Fig. 1, S1 and S2 in the ESI †). ...
Unique heterogeneous catalase-like activity was observed for metallosupramolecular ionic crystals [AuI4CoIII2(dppe)2(d-pen)4]X
n
([1]X
n
; dppe = 1,2-bis(diphenylphosphino)ethane; d-pen = d-penicillaminate; X
n
= (Cl-)2, (ClO4-)2, (NO3-)2 or SO42-) consisting of AuI4CoIII2 complex cations, [1]2+, and inorganic anions, X- or X2-. Treatment of the ionic crystals with an aqueous H2O2 solution led to considerable O2 evolution with a high turnover frequency of 1.4 × 105 h-1 for the heterogeneous cobalt complexes, which was dependent on their size and shape as well as the arrangement of cationic and anionic species. These dependencies were rationalized by the presence of cobalt(ii) centers on the crystal surface and their efficient exposure on the (111) plane rather than the (100) plane based on morphological and theoretical studies.
