Double-layer metal crown ether complex with electrocatalytic performance, preparation method and application

Abstract

The present invention belongs to the technical field of rare earth transition complex preparation, and discloses a double-layer metal crown ether type complex with electrocatalytic performance, a preparation method and an application. The preparation method provided by the present invention is as follows: organic ligands H3sha, Y(CF3SO3)3, NaHCO3, and H2ip are dissolved in a DMF solution in a certain proportion, and stirred with a magnetic stirrer for 30 minutes. Mn(OAc)2 is added to a C2H5OH solution, and an ultrasonic instrument is used to accelerate its dissolution. The prepared solution is added to the previous solution, and the mixed solution is stirred for 9 hours, filtered, transferred to a beaker and allowed to stand for two weeks to obtain dark brown block crystals. The dark brown block crystals are double-layer metal crown ether type complexes with electrocatalytic performance, which can be used in the preparation of electrocatalytic materials.

Description

Technical Field

[0001] The invention belongs to the technical field of rare earth complex preparation, and relates to a double-layer metal crown ether complex with electrocatalytic performance, a preparation method and application. Background Art

[0002] Crown ethers are the earliest artificially synthesized macrocyclic compounds with multiple repeating ether groups, marking the birth of supramolecular chemistry. They have rich electronic and pore controllable, structural flexibility, easy change and multiple motion characteristics (Chem. Soc. Rev., 2017, 46 (9), 2459-2478). They play an important role in supramolecular systems. The number of oxygen atoms in the crown ether ring is large, and their coordination and coordination effects can be utilized to selectively enclose target molecules of different shapes and sizes according to the size of the crown ether cavity. Metal crown ether is a functional macrocyclic supramolecular with an innovative pore structure, showing a wide range of application prospects. The system is composed of different metal ions and organic ligands, in which the metal ions on the metal crown ether ring can interact with donor functional groups such as N, O, and S on the ligand. Since Pecoraro, Lah et al. first published the structure of metal crown ethers internationally in 1989 (J.Am.Chem.Soc, 1989, 111(18), 7258-7259), it has attracted widespread attention and research internationally. A series of metal crown ether complexes with novel structures and unique properties have been synthesized. Metal crown ether complexes have important applications in new functional materials such as medicine, water treatment, magnetic materials, and electrocatalytic materials (AdvFunctMater, 2021, 31(2), 2002578). Summary of the Invention

[0003] The present invention aims to provide a double-layer metal crown ether complex, a preparation method and an application thereof, and to provide a method for preparing the metal crown ether complex as an electrocatalytic material.

[0004] The technical solutions provided by the present invention are as follows:

[0005] A double-layer metal crown ether complex having electrocatalytic properties, the double-layer metal crown ether complex belongs to the tetragonal system, and the molecular formula is {Y III Na I [12-MC sha,Mn(III) -4](H2O)4}2(ip)4 (H3sha = salicylic acid, H2ip = isophthalic acid), the space group is I4. The unit cell parameters are: α=90°, β=90°, γ=90°,

[0006] A method for preparing the aforementioned double-layer metal crown ether complex comprises dissolving organic ligands H3sha, Y(CF3SO3)3, NaHCO3, and H2ip in a DMF solution in a certain proportion and stirring with a magnetic stirrer. Mn(OAc)2 is added to a C2H5OH solution and dissolves it using an ultrasonic device. The prepared solution is added to the previous solution, and the mixed solution is further stirred to obtain the target complex 1 as dark brown block crystals.

[0007] The synthetic route of the double-layer metal crown ether complex is shown below:

[0008]

[0009] In the above formula, complex 1 is {Y III Na I [12-MC sha,Mn(III) 4](H2O)4}2(ip)4.

[0010] Furthermore, in the above-mentioned complex preparation method, the molar ratio of the organic ligands H3sha, Y(CF3SO3)3, NaHCO3, H2ip and Mn(OAc)2 is 4:1:16:2:4.

[0011] Furthermore, in the above-mentioned method for preparing the complex, the amount of DMF to be added per 0.1 mmol of H3sha is 3 mL, and the amount of C2H5OH to be added per 0.1 mmol of Mn(OAc)2 is 2 mL.

[0012] The present invention also provides a use of the double-layer metal crown ether type complex or the double-layer metal crown ether type complex prepared by the above preparation method in preparing an electrocatalytic material.

[0013] Compared with the prior art, the present invention adopts a synthesis strategy of room temperature volatilization method to obtain a double-layer metal crown ether type complex with electrocatalytic performance. The preparation method is simple, the raw materials are easily available, and it can be applied to the preparation of electrocatalytic materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Molecular structure of complex 1;

[0015] Figure 2 (a)Y Ⅲ Coordination configuration diagram of ions; (b) Mn II Coordination configuration diagram of ions;

[0016] Figure 3 IR spectrum of complex 1;

[0017] Figure 4 Thermogravimetric diagram of complex 1;

[0018] Figure 5 HER performance test diagram; (a) linear voltammogram; (b) overpotential comparison bar graph of different current densities; (c) Tafel slope curve; (d) C dl Figure; (e) EIS impedance curve; (f) CV graph;

[0019] Figure 6 OER performance test diagram; (a) LSV polarization curve; (b) overpotential comparison bar graph at different current densities; (c) Tafel slope curve; (d) C dl Figure; (e) EIS impedance curve; (f) CV graph. Specific implementation plan

[0020] The present invention will be further described with reference to specific embodiments. It should be understood that these embodiments are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that equivalent changes or modifications also fall within the scope defined by the claims of this application.

[0021] It should be noted that all reagents in the following examples were purchased directly from the market and were of analytical grade and were not further purified before use.

[0022] Example 1: Complex {Y III Na I [12-MC sha,Mn(III) Preparation of -4](H2O)4}2(ip)4(1)

[0023] {Y III Na I [12-MC sha,Mn(III )-4](H2O)4}2(ip)4(1): Organic ligand H3sha (15.3 mg, 0.1 mmol), Y(CF3SO3)3 (0.025 mmol, 13.4 mg), NaHCO3 (0.4 mmol, 33.6 mg) and H2ip (0.05 mmol, 8.3 mg) were weighed and dissolved in 2 mL of DMF solution and stirred with a magnetic stirrer for 30 minutes. Mn(OAc)2 (0.1 mmol, 15.2 mg) was added to 2 mL of C2H5OH solution and dissolved using an ultrasonic device. The prepared solution was added to the previous solution and the mixed solution was stirred for 9 hours. The mixed solution was filtered and transferred to a beaker and allowed to stand for two weeks to obtain the target complex 1 as dark brown block crystals.

[0024] Example 2: Crystal structure determination

[0025] High-quality single crystals were selected for structure determination. Data for complex 1 were collected at 120 K using a Rigaku Oxford diffractometer with Mo Kα radiation from a graphite monochromator. The diffraction data were collected and processed using the SHELXS-2014 and SHELXL-2014 packages.

[0026] Single crystal X-ray diffractometer results show that complex 1 crystallizes in tetragonal I4 space group, and its smallest asymmetric unit consists of a Mn III ions, a quarter of Na I ion and one eighth Y III ions. The complex consists of four dicarboxyl ligands and a building block {Y[12-MC Mn(III) -4]}. Among them, {Y[12-MC Mn(III) -4]} is through four H3sha ligands, four Mn III ions and a Y III The complex 1 is finally formed into a dimeric cage molecule with a double layer of metal crown ether ( Figure 1 ).

[0027] The coordination geometry of all metal ions in complex 1 was calculated using Shape software (Table 1, Table 2). III The ion has an octagonal inverse prism configuration and is composed of eight oxygen atoms, four of which come from the carboxyl group in the bridging ligand H2ip and the other four from the oxygen atoms in H3sha. The average bond length of YO is The bond angle of OYO ranges from 63.9° to 142.2°, forming a distorted tetragonal anti-prism configuration ( Figure 2 a) Mn III The coordination structure of the ion is a six-coordinate distorted octahedral structure ( Figure 2 b) On the plane, the three oxygen atoms and one nitrogen atom are provided by the ligand H₃₁ ...

[0028] Table 1 Partial CShM values of Y ions in complex 1

[0029]

[0030] Table 2 CShM values of Mn ions in complex 1

[0031]

[0032] The infrared spectrum of complex 1 is shown in Figure 3As shown, complex 1 has a wavelength of 3300 cm -1 to 2500cm -1 There is a broad peak around 1660cm, which is the stretching vibration of -OH. -1 There is C=O stretching vibration at 1650cm -1 、1570cm -1 The two absorption peaks at 900-650cm are the skeleton vibration of the benzene ring and -1 Out-of-plane deformation vibration of CH on the aromatic ring appears in this region.

[0033] The structural thermal stability analysis of complex 1 was carried out between 30 and 800 °C under N2 atmosphere (heating rate: 10 °C / min -1 ).like Figure 4 As shown, the first step weight loss of complex 1 is 31%, which can be attributed to the loss of lattice solvent and coordination solvent. The structure of complex 1 is relatively stable within 300℃. Above 300℃, the organic ligand decomposes and the framework collapses.

[0034] Example 3: Electrocatalytic Properties

[0035] Preparation of powder: Place the prepared complex 1 in a tube furnace, first introduce nitrogen for 30 minutes to evacuate the air in the tube furnace, perform a pyrolysis reaction under a N2 atmosphere, set the program to heat the tube furnace to 250°C at 2°C / min, then keep the temperature constant for 2 hours, and then cool to room temperature to obtain a black powder complex 1A. After collecting the powder of complex 1A, add 5μL of perfluorinated resin solution and 1mL of anhydrous ethanol solution, and sonicate for 30 minutes to obtain a suspension. Use a pipette to draw 5μL of solution, apply it to the electric rod to be tested, dry it under infrared light, and repeat the application three to four times.

[0036] Electrochemical test: The electrolyte used was 1.0 mol / L KOH alkaline solution. The electrode coated with the test sample 1A was used as the working electrode, the standard Hg / HgO (0.098 V) was used as the reference electrode, and the carbon rod was used as the counter electrode. The HER and OER tests were performed on the three electrode systems. At a scan rate of 5 mV / s, a 1×10 -5 The experimental results were analyzed and processed using electrochemical impedance spectroscopy (EIS) technology with a frequency of up to 100 kHz and iR correction. The Tafel slope directly indicates the efficiency of water electrolysis to produce hydrogen and oxygen. Figure 5 To test the electrocatalytic HER performance of complex 1, Figure 5 (a) The onset potential of complex 1A is 0.28 V vs. RHE. Figure 6 To test the electrocatalytic OER performance of complex 1A, Figure 6 (a) The onset potential of the complex is 0.28 V vs. RHE. Electrocatalytic tests show that the Tafel slope of the HER of complex 1A is 653.8 mV·dec -1 The slope of the Tatel curve of OER is 1000 mV·dec -1 . Its HER C dl The slope is 0.2213 mF·cm -2 , C of OER dl The slope is 0.3191 mF·cm -2 Complex 1A exhibited significant electrocatalytic performance, demonstrating the feasibility of double-layer metal crown ether complexes in electrocatalytic applications.

Claims

1. A double-layer metal crown ether complex with electrocatalytic performance, characterized in that: The double-layer metal crown ether complex belongs to the tetragonal system and has the molecular formula {Y III Na I [12-MC sha,Mn(III) -4](H2O)4}2(ip)4, the space group is I 4. The unit cell parameters are: a = 17.5184(3) Å, b = 17.5184(3) Å, c = 32.0838(12) Å, α = 90°, β =90°, γ = 90°, V = 9846.3(4) Å 3 , wherein sha is protonated salicyl oxime acid and ip is protonated isophthalic acid.

2. A method for preparing the double-layer metal crown ether complex according to claim 1, characterized in that: The organic ligands H3sha, Y(CF3SO3)3, NaHCO3 and H2ip are mixed and dissolved in a DMF solution, and then Mn(OAc)2 and ethanol are added. After stirring, the mixture is filtered and transferred to a beaker and allowed to stand to obtain dark brown block crystals, namely the double-layer metal crown ether complex, wherein H3sha is salicyloxime acid and H2ip is isophthalic acid.

3. The preparation method according to claim 2, characterized in that The molar ratio of organic ligands H3sha, Y(CF3SO3)3, NaHCO3, H2ip and Mn(OAc)2 is 4:1:16:2:

4.

4. The preparation method according to claim 3, wherein The amount of DMF to be added for every 0.1 mmol of organic ligand H3sha is 3 mL, and the amount of ethanol to be added for every 0.1 mmol of Mn(OAc)2 is 2 mL.

5. Use of the double-layer metal crown ether complex according to claim 1 or the double-layer metal crown ether complex prepared by the preparation method according to any one of claims 2 to 4 in the preparation of electrocatalytic materials.

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