Copper complex containing N-acylhydrazone as catalyst in ethanol electro-oxidation reaction

doi:10.21203/rs.3.rs-3338546/v1

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Copper complex containing N-acylhydrazone as catalyst in ethanol electro-oxidation reaction

https://doi.org/10.21203/rs.3.rs-3338546/v1

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This study discusses the synthesis and characterization of a novel copper complex, whose molecular structure was previously determined through various analytical techniques such as FTIR, elemental analysis (CHN), and ¹H NMR. Further analysis involving geometry, vibrational frequencies, and electron excitations was conducted using density functional theory (BP86/Def2-TZVPP/D3BJ method). The Cu(MFMH)₂Cl₂ complex exhibits three absorption bands at 420 nm, associated with π → π* transitions (between ligands); at 477 nm, linked to σ* → π transitions (involving donation from the metallic center to ligands) and π → σ* transitions (involving retro-donation from ligands to the metallic center); and at 514 nm, associated with σ* → π transitions (involving donation from the metallic center to ligands). Additionally, the use of Cu(MFMH)₂Cl₂ as a catalyst for the ethanol oxidation reaction in acidic conditions was investigated through cyclic voltammetry and chronoamperometry. The results show that the peak-current density for the Cu-CPE 30% (p/p) catalyst (complex/graphite) was higher compared to other CPEs.

Fuel cells

copper complexes

acylhydrazone

ethanol electro-oxidation

The quest for clean and sustainable energy sources is a global priority as we face critical challenges related to climate change and the depletion of natural resources. In this context, fuel cells emerge as a promising technology to provide efficient and environmentally friendly energy [1–3].

One of the central reasons for the importance of fuel cells is the urgent need to mitigate climate change and reduce greenhouse gas emissions. Fuel cells offer a promising alternative to fossil fuels as they operate efficiently without harmful emissions. They use chemical reactions to directly convert fuels like hydrogen or methanol into electricity, producing only water or non-polluting byproducts [3].

Furthermore, fuel cells can store energy effectively, making them ideal for intermittent energy applications such as generating electricity from renewable sources like solar and wind. They also have the advantage of operating quietly and with superior efficiency compared to traditional internal combustion engines.

In this context, the study of fuel cells encompasses a range of scientific and technological challenges, including the development of more efficient materials, increased durability, and reduced production costs. As we advance in this field, we are building a more sustainable future with greater independence from conventional energy sources. Therefore, the study of fuel cells plays a fundamental role in the search for cleaner and more efficient energy solutions to meet global energy needs.

However, many fuel cells heavily rely on platinum-based catalysts, whose high cost and limited availability pose significant barriers that restrict their widespread use. Although platinum is an excellent catalyst for the ethanol oxidation reaction, it has some disadvantages, including high cost, limited availability, limited durability—Pt is susceptible to corrosion and degradation during long-term fuel cell operation—and catalyst poisoning. During the ethanol oxidation reaction, impurities present in the fuel can adsorb onto the platinum surface, inhibiting catalytic activity and reducing fuel cell efficiency [4–6].

Due to these disadvantages, there is a growing interest in researching alternatives to platinum catalysts for direct ethanol fuel cells (DEFCs). In this context, coordination compounds, transition metals, and other materials have been explored as potential substitutes, aiming to overcome the limitations associated with platinum use in DEFCs and make fuel cells more accessible, durable, and sustainable[7–12].

Moreover, by reducing dependence on platinum-based catalysts, we can make fuel cells more economically viable and accessible for a variety of applications, from electric vehicles to stationary energy systems. These compounds offer several advantages, including potentially lower costs, greater availability of raw materials, and the ability to adjust their catalytic properties through chemical modifications [13, 14].

This research is crucial to advance the adoption of fuel cells as viable alternative energy sources in various applications.

Reagents

All reagents used in this study were of analytical grade and used without further purification: copper chloride hexahydrate, CuCl₂·6H₂O (Merck); isoniazid (Merck); 4-dimethylaminobenzaldehyde (Dinâmica); ethanol, CH₃CH₂OH (Dinâmica); sodium hydroxide, NaOH (Merck); potassium sulfate, K₂SO₄ (Merck); potassium ferricyanide, K₃[Fe(CN)₆] (Merck); synthetic graphite powder with a particle size smaller than 20 µm (Aldrich); sulfuric acid, H₂SO₄ (Aldrich); tetrabutylammonium hexafluorophosphate, TBAPF6 (Merck); acetone, CH₃COCH₃ (Merck); dimethylformamide, (CH₃)₂-N-COH (Merck).

Equipment

The infrared spectra were recorded using a SHIMADZU IRTracer-100 spectrometer with a range of 4000 − 400 cm-1 with pressed discs (1% by weight in KBr).

For the electronic spectrum, a SHIMADZU UV-1650 PC spectrofluorometer was used in the range of 200–800 nm in HPLC-grade DMF.

Hydrogen Nuclear Magnetic Resonance (1H NMR) analyses were conducted on a Varian 500 MHz instrument, using deuterated chloroform (CDCl₃) as the solvent and tetramethylsilane (TMS) as the internal reference.

Melting points were determined without correction using a Fisatom® brand instrument.

To measure molecular electrical conductivity, a MARCONI MA-521 conductivity meter was used. Measurements were carried out with solutions in DMF at a concentration of 1.0 × 10^− 3 mol L^− 1.

Thermogravimetric (TGA) and derivative thermogravimetric (DTG) curves were obtained using a simultaneous TGA-DTA module, the SDT-Q600, controlled by Thermo Advantage® software (version 4.2.1), both from TA Instruments. The studies were conducted with a sample mass of approximately 6.0 mg in open α-alumina crucibles within a temperature range of 30°C to 800°C, with a heating rate of 10°C min-1 under a dynamic N2 atmosphere flowing at 20 mL min^− 1.

To theorical calculus, the unrestricted Kohn-Sham equations were solved in order minimize the compounds geometry employing BP86[15–17] density functional, with Def2-TZVPP[18, 19] basis function, corrected by range separated D3BJ,[20, 21] as implemented at ORCA 5.0.3 package.[22] Numerical frequencies was also calculated in order to confrm that optimization step reach the true minima. The excited states (the first 50 excitation’s) were calculated at TDDFT[23–27] method, keeping the same density functional but decreasing the size of basis set (here, it was used Def2-SVP), as implemented at ORCA package. The solvent effect (ethanol) was modeled by CPCM[28] method. All the images was rendered by Chimera,[29] and Chemcraft software’s.

The solution voltametric analyses were conducted using a µAutolab Type III potentiostat, maintained at a temperature of 25°C. The system employed a platinum disk electrode (4 mm diameter) as the working electrode, along with a counter electrode (2 mm diameter). Additionally, an Ag/AgCl electrode was used as the reference electrode, and the solutions contained DMF with a concentration of 1.0 × 10^− 3 mol L^− 1 of tetrabutylammonium hexafluorophosphate (TBAPF₆) as the supporting electrolyte. For the cyclic voltammetry measurements of the synthesized compounds, DMF solutions with a concentration of 1.0 × 10^− 3 mol L^− 1 were used.

Compounds synthesis

Synthesis of ligand 2-[4-(dimetilamino)fenil]metileno]hidrazida (MFMH)

The MFMH was synthesized by a method adapted from the literature [30, 31]. 4-Pyridinecarboxylic acid hydrazide and 4-(dimethylamino)benzaldehyde in equimolar ratios were added to 20 mL of ethanol and an acidic aqueous solution (3 drops of glacial acetic acid) and refluxed for six hours. The suspension was filtered, and the yellow solid was recrystallized with ethanol and dried under vacuum over silica gel. Yellow powder. Yield 70%. IR (KBr, cm^− 1) (Fig. S2): ν(N-H), 3404; ν(C-HAr), 3188; ν(C = N), 1595; ν(C = O), 1664 and ν(N-N), 935 cm^− 1. ¹H NMR (400 MHz, DMSO-d6, 25°C) (Fig.S1): δ/ppm:7,28–7,30 (d, J = 5.5 Hz, ²H, ²H’); 7.65–7,49 (m, ⁵H, ⁵H, ¹H, ¹H’⁸H); 12,65 (s, ³H); 8,63 (s, ⁴H); 6.95–6.93 (d, J = 9 Hz, ⁶H, ⁶H’); 3,98 (s, ⁷H, ⁷H’). ΛM = 4.10 ohm^− 1 cm² mol^− 1 (non-electrolyte in methanol).

Synthesis of complex [Cu(MFMH)₂Cl₂]

The copper complex was synthesized using a method described in literature [31]. A methanolic solution of MFMH (2.0 mmol) was mixed with CuCl₂.6H₂O (1.0 mmol), and the system was heated to 50°C for four hours. Brown-red powder was obtained, filtered, washed with methanol, and dried under vacuum. Yield 36%. IR (KBr, cm^− 1) (Fig. S2): ν(C-HAr/C-HAlf), 3589–3422; ν(C = N), 1598; ν(C = O), 1660; ν(N-N), 948 and ν(Cu-Cl), 750 cm^− 1. ¹H NMR (400 MHz, DMSO-d6, 25°C) (Fig.S1): δ/ppm: 7,45–7.43 (d, J = 5.5 Hz, ²H, ²H’); 7.59–7.57 (m, ⁵H, ⁵H^,); 7.78–7.73 (d, J = 5.5 Hz, ¹H, ¹H’⁸H); 9.73 (s, ³H); 8,63 (s, ⁴H); 6.5–6.7 (d, J = 9 Hz, ⁶H, ⁶H’); 3,17 (s, ⁷H, ⁷H’). Elemental analysis: calc. for C₃₀H₃₀Cl₂CuN₈O₂ (FW: 718.30 g mol^− 1) calc. (found): C, 53.85 (54.36); H, 4.52 (4.68); N, 16.75 (17.27)%. ΛM = 3.62 ohm^− 1 cm² mol^− 1 (non-electrolyte in methanol).

Preparation of carbon‑paste electrodes

The CPE (Carbon Paste Electrode) was prepared by mechanical mixing of 0.02 g of graphite powder and 25 µL of mineral oil. The paste was placed in the cavity of a glass electrode (diameter = 3.32 mm, depth = 2.2 mm), connected to a platinum wire to ensure electrical contact. The Cu-CPE was prepared similarly but with the addition of the Cu(II) complex. The percentage of Cu(II)-modified CPE was 5% and 30% (w/w) complex/graphite.

Evaluation of the electrochemically active area of the modified electrode

The electrochemically active area (EAA) of the Cu-CPE was assessed through cyclic voltammetry experiments using the ferricyanide/ferrocyanide redox system. The EAA values for the CPE, Cu-CPE 5%, and Cu-CPE 30% electrodes were 0.018 cm², 0.00682 cm², and 0.055 cm², respectively.

Characterization of MFMH and [Cu(MFMH)₂Cl₂]

The infrared (IR) spectra of MFMH and Cu(MFMH)₂Cl₂ are depicted in Figure S2. In the case of MFMH, distinct peaks are observed. Notably, the peak at 3404 cm^− 1 is attributed to the stretching vibrations of the N–H bond from the amide group [31–33]. The stretching vibration of C = O appears at 1664 cm^− 1 for MFMH and at 1660^− 1 for the Cu(MFMH)₂Cl₂, respectively. Additionally, the stretching vibration of N-N is noted at 935 cm^− 1 for MFMH and at 948 cm^− 1 for Cu(MFMH)₂Cl₂, respectively. Furthermore, the stretching vibration of copper-chloride bond (ν(Cu-Cl)) appears at 750 cm^− 1.

The analysis of the electronic spectra of NFMH and Cu(MFMH)₂Cl₂ shown in Figure S3 reveals valuable information about the structural and electronic characteristics of the molecules under study. In the case of the MFMH, we observe the presence of a band with an absorption maximum at 358 nm, which can be attributed to the n-π* transition of the C = O bond. This transition is an indication of the presence of the imide group functionality in the molecule, providing information about its chemical structure.

On the other hand, when analyzing the electronic spectrum of the Cu(MFMH)₂Cl₂ complex, we notice the presence of two distinct bands with maxima at 385 nm and 401 nm. These bands can be attributed to the n-π* and π→π* transitions of the imine group, respectively. These transitions indicate the presence of the imine group in the complex and suggest a change in the electronic structure of the bonds within the molecule compared to free MFMH.

This information is crucial for understanding the molecular interactions and structural changes that occur when forming the copper complex. Furthermore, these electronic transitions can play an important role in the catalytic properties of the complex, making this data essential for the study of its electrocatalytic activity in ethanol oxidation.

From the theoretical calculations, we observe that octahedral metallic center oriented the acylhydrazone ligands at equatorial position, meanwhile the chloride anions are displaced at longitudinal axes, keeping the compound symmetry at C2 point group, as shown at Fig. 1.

The TDDFT calculations showed the states associated with the absorption bands, considering the Cu(MFMH)₂Cl₂ at alcoholic milieu. At Fig. 2a is possible to see a little band at the near infrared region which are associated at ß HOMO-1 (π orbitals from ligands) → ß LUMO (σ* orbital at metallic center).

From Fig. 2b is possible to see that mainly three states are associated with bands 3at visible spectrum. The very frst state (420 nm) is associated at electronic transition occurred from π→ π* at ligands. Our data suggest that transition depicted at Fig. 3 is twice representative than the transition showed at Fig. 4. This last transition, also have a small metal-to-MFMH σ* character.

Our calculations demonstrated that 477 nm band is ruled by metal-ligand bond situation. At Fig. 5, is depicted the σ* orbital (between metallic center and its ligands) where electron departures to π de-localized orbitals at MFMH ligands. This transition is also responsible (in part) for 514 nm band.

There is also a π back-donation (Fig. 6) that comes from both, molecular phenyl portions and localized Lewis pairs of chloride ligands, arriving at internuclear regions (σ*) between copper center and all ligands.

As mentioned before, the 514 nm band is composed majoritarily by the transition depicted at Fig. 5, and minoritarily by the the transition depicted at Fig. 7, which have some π → π * characteristic.

Considering the MFDF ligand, our calculations showed that the main light absorption occurred at 355 nm, 385 nm, and 642 nm Figure S5. These excitations are due HOMO → LUMO + 1 transition (Figure S6), HOMO-1 → LUMO transition (Figure S7), and HOMO → LUMO transition (Figure S8).

The thermal stability of MFMH, Cu(MFMH)₂Cl₂, and CPE-30% was characterized by the thermogravimetric analysis (TGA). The data from Thermal Gravimetric Analysis are shown in Figure S9.

MFMH exhibited two decomposition stages, with the first attributed to a 5% mass loss of the solvent and the second corresponding to 93.87% of the molecule's mass. The complex displayed a two-stage decomposition pattern only. The first stage is attributed to the elimination of water or solvent, and the second stage to the loss of one ligand molecule. It is worth noting that within the experiment's temperature range (30°C to 600°C), approximately 52% of residual mass remained. There was no weight loss indicating the presence of coordinated water molecules in the complex.

For CPE 30%, the decomposition pattern showed two stages, with the first related to solvent and/or nujol loss, which was used in the carbon paste preparation, and the second, more pronounced, linked to ligand loss. In terms of thermal stability, we observed that among the three compounds, the carbon paste was the most stable, followed by the complex, and lastly, the MFMH ligand. It is highly likely that the inclusion of graphite increases stability, resulting in a higher residual mass.

The cyclic voltammogram of MFMH displays an irreversible oxidation process at 1.29 V and a reduction process at -0.74 V, corresponding to electrochemical processes characteristic of the molecule itself. The oxidative process remains unchanged after complexation with the Cu(II) metal ion. However, at a scan rate of 10 mV/s, in the cathodic region, two processes are observed at -0.86 V and − 1.05 V, attributed to the ligand and the reduction of Cu(II) to Cu(I), as shown in Figure S4.

Electrochemical analysis

Eletrocatalytic experiments on ethanol oxidation.

Figure 8: Cyclic voltammogram in acidic medium (0.5 mol L^-1 H₂SO₄) in the presence of ethanol (1.0 mol L^-1) for Cu-CPE 30% and Cu(MFMH)₂Cl₂ (insert) both at a scan rate of 10 mV s^-1 and 25°C.

As differences observed in the cyclic voltammograms between Cu(MFMH)₂Cl₂ in solution and Cu-CPE 30% in the presence of ethanol in an acidic medium are significant and indicate crucial differences in the electrochemical behavior of these materials.

In the cyclic voltammogram of Cu(MFMH)₂Cl₂ in solution, it can be observed that the current remains close to zero around the potential of 0.4V in the presence of ethanol. This indicates that, at this specific potential, there is no significant ethanol oxidation occurring. This response is typical of a material that does not act as an efficient catalyst for ethanol oxidation. On the other hand, in the cyclic voltammogram of Cu-CPE 30%, under the same acidic pH conditions and in the presence of ethanol, a clear ethanol oxidation is observed around the potential of 0.4V, as evidenced by the substantial increase in current in this region. This suggests that Cu-CPE 30% is an effective catalyst for ethanol oxidation, allowing this reaction to occur at a lower potential.

pH variation

We investigated the behavior of the Cu-CPE 30% catalyst in an acidic environment at pH values of 1.16, 1.44, 1.93, 2.81, and 5.44 in relation to the electrocatalytic oxidation of ethanol, as shown in Fig. 9.

The voltammograms of ethanol electrocatalytic oxidation at different pH values reveal a correlation between pH and catalytic performance. The analysis of the catalytic system at various pH levels indicates that maximum efficiency is achieved at pH 1.16, decreasing as pH increases and reaching a minimum at pH 5.0. This suggests that the increased concentration of H + ions facilitated the electrocatalytic oxidation by removing adsorbed intermediates. This result was confirmed through chronoamperometry at different concentrations. However, there is a limit, as no current was obtained when cyclic voltammetry was conducted at pH 0.9, indicating that the paste is not stable under these conditions.

Variation in ethanol concentration

We investigated the electrocatalytic oxidation of ethanol catalyzed by Cu-CPE 30% through cyclic voltammetry and chronoamperometry at different ethanol concentrations (0.1; 0.2; 0.4; 0.6; 0.8; and 1.0 mol L^− 1), as illustrated in Figs. 10a-b.

The results were obtained in an environment with a pH of 1.16 and ethanol, applying an anodic potential of 0.6 V versus the Ag/AgCl reference electrode. These experiments allowed us to determine catalytic activity at a constant potential over a specific time period, thus eliminating transient phenomena associated with variations in the electric field of the electrodes. In other words, we measured only the average rate of alcohol electro-oxidation under investigation.

When analyzing the chronoamperometry results, we observed a clear trend where the current density decreases as the ethanol concentration is reduced. This direct decrease in current density can be attributed to the adsorption of the adsorbate on the surface of the electrocatalyst.

As the ethanol concentration decreases, there are fewer ethanol molecules available at the electrode-solution interface. This results in a lower rate of adsorption of these molecules on the surface of the electrocatalyst. The adsorption of ethanol is a crucial step in the electrocatalytic oxidation reaction of this compound, and the reduction in the availability of ethanol on the catalyst's surface can negatively impact the reaction rate.

Therefore, the decrease in current density observed with decreasing ethanol concentration suggests that the adsorption of the adsorbate on the electrocatalyst's surface plays a crucial role in the kinetics of the ethanol oxidation reaction. This highlights the importance of understanding the interaction between the reacting species and the catalyst's surface when designing electrocatalytic systems for ethanol oxidation at different concentrations.

Temperature variation

To investigate the performance of the Cu-CPE 30% catalyst at different temperatures, we conducted cyclic voltammetry in an ethanol medium (1.0 mol L^− 1) at a pH of 1.16. The evaluated temperatures were 24.5°C, 30°C, 40°C, 50°C, and 60°C, as shown in Fig. 9b.

We observed that the peak current for ethanol oxidation exhibited a gradual and direct increase with the rise in the system's temperature within the range of 24.5°C to 50°C. This behavior aligns with theory, as elevated temperatures typically promote faster and more efficient chemical reactions, including electrochemical processes.

However, when the system temperature reached 60°C, we noticed a significant decrease in the peak current for ethanol oxidation. This decline can be attributed to various factors, such as electrode stability and potential alterations in the adsorption of reactant species on the electrode's surface, as well as changes in reaction kinetics. Additionally, higher temperatures can lead to increased volatility of ethanol, which might affect its availability at the electrode-solution interface.

In summary, our findings suggest that the performance of the Cu-CPE catalyst in ethanol oxidation is directly linked to the system's temperature. Nevertheless, there appears to be a threshold beyond which excessively high temperatures can adversely impact the efficiency of the electrochemical reaction.

Considering that long-term structural stability is equally critical for electrocatalysts [13, 15], we assessed this property for the Cu-CPE catalyst. This was done through continuous cyclic voltammetry, ranging from 0.05 V to 1.1 V, in a pH 1.16 environment, using a 1.0 mol L-1 ethanol solution, all at room temperature (Fig. 13).

When analyzing the cyclic voltammetry data obtained with Cu-CPE 30%, we observed an intriguing phenomenon related to the peak current for ethanol oxidation. As we increased the number of cycles, a significant increase in current density was noticeable after 20 cycles compared to the first cycle.

This rise in current density strongly implies that the modified electrode maintained its electrochemical catalytic activity throughout these repeated cycles. In other words, the electrode exhibited stability under test conditions, a crucial characteristic for its application as an effective electrocatalyst.

The fact that the current density increased approximately tenfold after 20 cycles in the ethanol oxidation region (0.25 V) indicates that the modified electrode did not undergo significant degradation during the test, which is a positive indicator of its durability and ability to maintain consistent performance over time.

These findings hold promise for the practical application of the modified electrode in ethanol oxidation systems, as they suggest that it can deliver stable and reliable performance under continuous usage conditions.

A new copper complex containing an N-acylhydrazone ligand was synthesized and characterized. Our TDDFT calculations showed that Cu(MFMH)2Cl2 absorbs light at 420 nm, 477 nm, and 514 nm. The absorption at 422 nm wavelength occurs through π → π*, meanwhile the the absorption at 477 nm occur by σ* → π and also by π → π* at metallic center. The absorption band at 514 nm also has σ* → π as the transition observed at 477 nm band and a little contribution from π → π* orbitals. These transitions can be future explored by changing chloride ligands, or the metallic center in order to increase/decrease the interaction of such compounds with the light, once we have showed that the bond situation between the metallic center and chloride ligands are involved with the most expressive bands.

Cyclic voltammetry in solution of Cu(MFMH)₂Cl₂ did not exhibit good electrocatalytic properties for the ethanol oxidation reaction. However, in the cyclic voltammogram of Cu-CPE 30%, under acidic pH and in the presence of ethanol, a clear ethanol oxidation is observed around the potential of 0.4V, as evidenced by the substantial increase in current in that region. This suggests that Cu-CPE 30% is an effective catalyst for ethanol oxidation, allowing this reaction to occur at a lower potential.

These differences are of great importance for the development of DEFC systems and have direct implications on the efficiency and performance of these devices. While Cu-CPE 30% proves to be an effective catalyst for ethanol oxidation, Cu(MFMH)₂Cl₂ in solution does not seem to possess this catalytic capability under the same conditions. Therefore, this analysis highlights the importance of selecting suitable catalysts in optimizing DAFC systems for practical applications.

Acknowledgments

The authors would like to acknowledge Programa de Pós-Graduação em Ciência e Tecnologia para Recursos Amazônicos (PPGCTRA–UFAM), Fundação de Amparo à Pesquisa do Estado do Amazonas–FAPEAM (process no. 005/2019), PROPESP/UFAM-CNPq (process no. 041/2016 and 008/2018), Fundação Carlos Chagas de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ (grant number E-26/210.070/2022; SEI-260003/015957/2021; SEI-260003/015018/2021-APQ1 and E-26/201.248/2022 –SEI-260003/003411/2022–BBP), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Brazil (CAPES) and Conselho Nacional de Desenvolvimento Científico – CNPq for financial support.

Funding: No funds, grants, or other support was received.

Competing Interests: The authors have no financial or proprietary interests in any material discussed in this article.

Ethics approval e Consent to Participate: not applicable.

Consent to Publish: not applicable.

Availability of data and materials: The authors declare that the data supporting the findings of this study are available within the paper and its Supplementary Information files. Should any raw data files be needed in another format they are available from the corresponding author upon reasonable request.

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Copper complex containing N-acylhydrazone as catalyst in ethanol electro-oxidation reaction

Status:

Version 1

Abstract

Figures

Introduction

Experimental section

Reagents

Equipment

Compounds synthesis

Synthesis of ligand 2-[4-(dimetilamino)fenil]metileno]hidrazida (MFMH)

Synthesis of complex [Cu(MFMH)₂Cl₂]

Preparation of carbon‑paste electrodes

Evaluation of the electrochemically active area of the modified electrode

Results and discussion

Characterization of MFMH and [Cu(MFMH)₂Cl₂]

Electrochemical analysis

Conclusion

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1

Copper complex containing N-acylhydrazone as catalyst in ethanol electro-oxidation reaction

Status:

Version 1

Abstract

Figures

Introduction

Experimental section

Reagents

Equipment

Compounds synthesis

Synthesis of ligand 2-[4-(dimetilamino)fenil]metileno]hidrazida (MFMH)

Synthesis of complex [Cu(MFMH)2Cl2]

Preparation of carbon‑paste electrodes

Evaluation of the electrochemically active area of the modified electrode

Results and discussion

Characterization of MFMH and [Cu(MFMH)2Cl2]

Electrochemical analysis

Conclusion

Declarations

References

Additional Declarations

Supplementary Files

Status:

Version 1

Synthesis of complex [Cu(MFMH)₂Cl₂]

Characterization of MFMH and [Cu(MFMH)₂Cl₂]