Nitrobenzene thiophenol cadmium complex as well as preparation method and application thereof

Abstract

The invention provides a nitrothiophenol cadmium complex as well as a preparation method and application thereof. The complex is formed by two molecules of Cd and four molecules of 4-nitrothiophenol. According to the composition structure of the material, the nitro functional group covers the outer side of the CdS nanowire, so that the complex can effectively eliminate interference of water vapor in the process of detecting ammonia gas and volatile organic amine, the specificity and sensitivity of material testing are improved, and the material has certain application value in industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and particularly relates to a cadmium 4-nitrothiophenolate complex, a preparation method thereof, and an application thereof. Background Art

[0002] Ammonia detection is a common environmental monitoring method, which is often used in fields such as agriculture, animal husbandry, chemical industry, and environmental protection. Currently, the more common testing method is to utilize the principle of infrared spectroscopy to detect the ammonia concentration by measuring the absorption degree of the sample to infrared rays. However, the infrared vibration peak positions of ammonia and water are close, so the detection of ammonia is extremely susceptible to interference by water. Summary of the Invention

[0003] To solve the above technical problems, the present invention first provides a cadmium 4-nitrothiophenolate complex Cd-NTP, which is a complex formed by 2 molecules of Cd and 4 molecules of 4-nitrothiophenol, where NTP is 4-nitrothiophenol.

[0004] According to an embodiment of the present invention, the cadmium 4-nitrothiophenolate complex Cd-NTP is a single crystal, belonging to the triclinic system, and the space group of the crystal is the P-1 space group; the crystal parameters are: α = 89.135(2)°, β = 88.052(2)°, γ = 89.067(10)°, Z = 4.

[0005] According to an embodiment of the present invention, in the complex, Cd is connected to S atoms in a four-coordinated manner to form a slightly distorted tetrahedral structure. Each tetrahedron is connected to each other by sharing vertices, forming an infinitely extended {Cd2S4} n one-dimensional chain along the a-axis. On the outer side of the {Cd2S4} n inorganic chain, the nitro group is covalently connected to the C atom through the thiol ligand and covers the surface of the one-dimensional chain to form an independent structural unit, and the independent structural units are connected to each other by van der Waals forces to form a complete three-dimensional structure.

[0006] According to an embodiment of the present invention, the cadmium 4-nitrothiophenolate complex Cd-NTP has a nanowire structure, and its longitudinal diameter size is below 80 nm, and the transverse diameter size is above 100 nm.

[0007] The present invention also provides a preparation method of the cadmium 4-nitrothiophenolate complex Cd-NTP as described above, including the following steps: ultrasonicating a cadmium source and 4-nitrothiophenol in a solvent and then heating and reacting.

[0008] According to an embodiment of the present invention, the cadmium source is a cadmium salt, such as Cd(NO)3 or its crystalline hydrate, such as Cd(NO)3 . 4H2O.

[0009] According to an embodiment of the present invention, the molar ratio of the cadmium source to 4-nitrobenzenethiol is (1-5):1, such as (1-3):1, such as 3:1.

[0010] According to an embodiment of the present invention, the temperature of the heating reaction is 70-100 °C, and the reaction is carried out for 6-96 h, such as reacting at 80-90 °C for 12-48 h.

[0011] According to an embodiment of the present invention, the solvent is a mixed solvent of alcohols and water, such as a mixed solvent of ethanol and water.

[0012] According to an embodiment of the present invention, the method includes:

[0013] a. Mix deionized water and absolute ethanol, then dissolve 4-nitrobenzenethiol in the mixed solvent, and ultrasonically dissolve it;

[0014] b. Add Cd(NO)3 . 4H2O to the solution obtained in step a, and ultrasonically dissolve it;

[0015] c. React the solution obtained in step b at 70-100 °C for 6-96 h.

[0016] According to an embodiment of the present invention, when nanowires of cadmium 4-nitrobenzenethiol complex Cd-NTP are required, the preparation method further includes: dissolving the cadmium 4-nitrobenzenethiol complex Cd-NTP in an organic solvent, and optionally further ultrasonically treating and / or stirring.

[0017] The present invention also provides the application of the cadmium 4-nitrobenzenethiol complex Cd-NTP as described above in detecting alkaline gases.

[0018] According to an embodiment of the present invention, the alkaline gas is ammonia or a volatile organic amine, such as triethylamine.

[0019] According to an embodiment of the present invention, the detection can be carried out at a humidity of 90% or less, such as 50% or less.

[0020] According to an embodiment of the present invention, the concentration of the alkaline gas (such as ammonia or a volatile organic amine) is 2.54 ppm or more, such as 10 ppm.

[0021] Beneficial effects

[0022] The present invention provides a cadmium nitrophenylthiolate complex Cd-NTP. In the complex, Cd is connected to S atoms in a four-coordinate manner to form a slightly distorted tetrahedral structure. Each tetrahedron is connected to each other by sharing vertices, forming an infinitely extended {Cd2S4} n one-dimensional chain along the a-axis. On the outer side of the {Cd2S4} n inorganic chain, the nitro group is covalently connected to the C atom through the thiol ligand and covers the surface of the one-dimensional chain, forming an independent structural unit. The independent structural units are connected to each other by van der Waals forces, thus forming a complete three-dimensional structure. From the composition and structure of the material, it can be seen that the nitro functional group covers the outer side of the CdS nanowires. Therefore, the complex can effectively exclude the interference of water vapor during the detection of ammonia and volatile organic amines, improving the specificity and sensitivity of material testing, and having certain application value in industrial production. Description of the Drawings

[0023] Figure 1 is an optical photograph of needle-shaped single crystals of cadmium nitrophenylthiolate complex Cd-NTP.

[0024] Figure 2 is a scanning electron microscope image of cadmium nitrophenylthiolate complex Cd-NTP nanowire material.

[0025] Figure 3 is an atomic force microscope image of cadmium nitrophenylthiolate complex Cd-NTP nanowire material.

[0026] Figure 4 is the PXRD spectra of cadmium nitrophenylthiolate complex Cd-NTP nanowire material obtained by theoretical simulation and actual measurement.

[0027] Figure 5 is the I-V curves of cadmium nitrophenylthiolate complex Cd-NTP material at different temperatures.

[0028] Figure 6 is the response results of the device prepared from cadmium nitrophenylthiolate complex Cd-NTP nanowire material to different humidity atmospheres.

[0029] Figure 7 is the contact angle test results of cadmium nitrophenylthiolate complex Cd-NTP nanowires.

[0030] Figure 8 is the response results of the device prepared from cadmium nitrophenylthiolate complex Cd-NTP nanowire material to different atmospheres.

[0031] Figure 9 is the response results of the device prepared from cadmium nitrophenylthiolate complex Cd-NTP nanowire material to ammonia at different humidities.

[0032] Figure 10 Response value diagram of the device prepared from the cadmium nitrophenylthiolate complex Cd-NTP nanowire material under different concentrations of ammonia gas.

[0033] Figure 11 Single crystal structure diagram of cadmium nitrophenylthiolate complex Cd-NTP. Specific embodiments

[0034] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative purposes to explain the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0035] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

[0036] Example 1

[0037] The synthesis steps of the cadmium nitrophenylthiolate complex Cd-NTP single crystal are as follows:

[0038] S1: Prepare the cadmium nitrophenylthiolate complex (Cd-NTP, NTP = 4-nitrophenylthiol) crystal material, including the following steps:

[0039] a. Take 3 mL of deionized water and 5 mL of absolute ethanol and mix them evenly. Then dissolve 0.045 g of NTP in this mixed solvent and ultrasonicate for 5 min to completely dissolve it;

[0040] b. Add 0.030 g of Cd(NO)3 . 4H2O to the solution obtained in step a, ultrasonicate for 1 min to completely dissolve it, and mix evenly;

[0041] c. Transfer the solution obtained in step b to a 20 mL glass bottle, place it in an 85 °C oven for 48 h, and then take it out after using a programmed temperature reduction to 20 °C for 24 h;

[0042] d. Place the sample in the glass bottle in step c in a funnel, wash and filter it with absolute ethanol, and then observe it under a high-power microscope to obtain needle-shaped single crystals (Cd-NTP), the optical photograph of which is as Figure 1 shown. The single crystal structure is as Figure 11 shown.

[0043] Example 2

[0044] The method for using the cadmium nitrophenylthiolate complex material prepared as in Example 1 above to prepare a chemiresistive gas sensor for detecting ammonia gas under high humidity conditions is as follows:

[0045] S2: Prepare cadmium nitrophenylthiolate complex (Cd-NTP) nanowires;

[0046] a. First, weigh 25 mg of the Cd-NTP powder sample prepared in Example 1, then dissolve it in 10 mL of ethanol and 10 mL of acetonitrile, and ultrasonicate for 3 min to completely dissolve it and mix it evenly;

[0047] b. After ultrasonic mixing, stir the above mixed solution with a magnetic stirrer at room temperature for 12 h. The scanning electron microscope image of the sample is as Figure 2 shown. As can be seen from Figure 2 , the obtained material is relatively thin and uniform nanowires. Its AFM is as Figure 3 shown. The longitudinal diameter of the nanowires is below 80 nm, and the transverse diameter is about several hundred nanometers. Its PXRD pattern is as Figure 4 shown. Figure 4 The simulated PXRD spectrum of Cd-NTP is also provided in

[0048] Example 3

[0049] Semiconductor performance test of cadmium nitrophenylthiolate complex material, including the following steps:

[0050] a. Use the two-electrode method to test the electrical conductivity of the powder tablet sample prepared in step c of Example 1. Before testing the conductivity of Cd-NTP, first press the sample into a circular tablet with a diameter of 2.50 mm, and the thickness can be controlled by the amount of sample added and measured with a vernier caliper. Then use silver paste and a gold wire (diameter 50 μm) to connect the electrodes, and fix the sample on a glass slide to prevent the electrodes from falling off;

[0051] b. Measure the I-V curves of the sample at different temperatures through a Keithley 4200, and the test results are as Figure 5 shown. As can be seen from Figure 5 , the obtained cadmium nitrophenylthiolate complex material has semiconductor performance.

[0052] Example 4

[0053] The cadmium nitrophenylthiolate complex nanowire material is used to prepare a chemiresistive gas sensor for the detection of humidity and ammonia. The specific detection method is as follows:

[0054] a. Disperse 5 mg of the Cd-NTP nanowire powder prepared in Example 2 in isopropanol to prepare a paste-like sample;

[0055] b. Connect gold wires to both ends of the interdigital electrodes on the Al2O3 substrate with silver paste and dry overnight in a vacuum oven at 60 °C;

[0056] c. Drop the paste-like sample in step a onto the substrate in step b and dry at 60 °C to obtain a chemiresistive sensor for detecting humidity and ammonia;

[0057] d. Connect the sensor to a Keithley source meter, introduce dry air, and age for 1 h at 1 V to remove the impurities attached to the surface;

[0058] e. Introduce air with different humidities into the sensor in step d and use a Keithley source meter to monitor the current change caused by the introduced humidity to detect humidity and ammonia. The response of the chemiresistive sensor to different humidity atmospheres is as Figure 6 shown. As can be seen from Figure 6 , the response of the above device to 100% humidity is only 123.52%. It shows that the material has a low response to water vapor. In addition, the contact angle test was also carried out, and the results are as Figure 7 shown. As can be seen from Figure 7 , the above nanowire material has good hydrophobicity.

[0059] f. When different gases are introduced into the sensor, the response results of the chemiresistive sensor to different atmospheres are as Figure 8 shown. As can be seen from Figure 8 , the above nanowire material has good selectivity for the alkaline gases triethylamine and ammonia. It has basically no response to common volatile gases such as ethanol, acetone, toluene, acetylene, ethylene, methane, CO, hydrogen, carbon disulfide, and hydrogen sulfide.

[0060] g. Test the response of the device to different concentrations of ammonia, and the results are as Figure 10 shown. As can be seen from Figure 10 , when taking 10% of the response value as the theoretical detection limit, the detection limit of the material for ammonia is as low as 2.54 ppm.

[0061] h. Connect the chemiresistive sensor to a power supply and apply a voltage of 1 V to detect ammonia at different humidities. The response results of the chemiresistive sensor to ammonia at different humidities are as Figure 9 shown. As can be seen from Figure 9 , at 90% humidity, the response value of the device to ammonia is as high as 679.89%, and the CV value of the ammonia response at different humidities is only 7.39%. It shows that the device has good cycle stability.

[0062] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cadmium nitrophenylthiol complex Cd-NTP, characterized in that, It is a complex formed by 2 molecules of Cd and 4 molecules of 4-nitrobenzenethiol, where NTP is 4-nitrobenzenethiol.

2. The cadmium nitrothiophenolate complex Cd-NTP according to claim 1, characterized in that, The cadmium nitrothiophenol complex Cd-NTP is a single crystal, belonging to the triclinic system, and the space group of the crystal is the P-1 space group; the crystal parameters are as follows: α = 89.135(2)°, β = 88.052(2)°, γ = 89.067(10)°, Z = 4.

3. The cadmium nitrophenylthiolate complex Cd-NTP according to claim 1 or 2, characterized in that, In the complex, Cd is connected to S atoms in a four-coordinate manner, forming a slightly distorted tetrahedral structure; each tetrahedron is connected to each other by sharing vertices, forming an infinitely extended {Cd2S4} n one-dimensional chain along the a-axis; on the outer side of the {Cd2S4} n inorganic chain, the nitro group is covalently connected to the C atom through the thiol ligand and covers the surface of the one-dimensional chain, forming an independent structural unit, and the independent structural units are connected to each other by van der Waals forces, thus forming a complete three-dimensional structure.

4. The cadmium nitrothiophenolate complex Cd-NTP according to any one of claims 1-3, characterized in that, The cadmium 4-nitrobenzenethiol complex Cd-NTP has a nanowire structure, with its longitudinal diameter dimension less than 80 nm and its transverse diameter dimension more than 100 nm.

5. The preparation method of cadmium nitrophenylthiolate complex Cd-NTP according to any one of claims 1-4, characterized in that, It includes the following steps: ultrasonically treating a cadmium source and 4-nitrobenzenethiol in a solvent and then heating them for reaction.

6. The preparation method according to claim 5, wherein The cadmium source is a cadmium salt, such as Cd(NO)3 or its hydrate; Preferably, the molar ratio of the cadmium source to 4-nitrobenzenethiol is (1-5):

1.

7. The preparation method according to claim 5 or 6, characterized in that, The heating reaction is carried out at 70-100 °C for 6-96 h.

8. The preparation method according to any one of claims 5-7, characterized in that, The method includes: a. Mix deionized water and absolute ethanol, then dissolve 4-nitrobenzenethiol in this mixed solvent, and ultrasonically dissolve it; b. Add Cd(NO)3 . 4H2O to the solution obtained in step a and dissolve it by ultrasound; c. React the solution obtained in step b at 70-100 °C for 6-96 h.

9. Use of the cadmium 4-nitrobenzenethiol complex Cd-NTP according to any one of claims 5-7 in detecting alkaline gases.

10. The application according to claim 9, wherein The alkaline gas is ammonia or volatile organic amine; Preferably, the detection is carried out at a humidity of 90% or less. Preferably, the concentration of the alkaline gas is 2.54 ppm or more.

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