Metal cobalt complex containing N, N '-bis (5-isophthalic acid) naphthalimide as well as preparation method and application of metal cobalt complex

Abstract

The invention provides a metal cobalt complex containing N, N '-bis (5-isophthalic acid) naphthalimide as well as a preparation method and application of the metal cobalt complex, and belongs to the technical field of multi-stimulus response color-changing materials. The structural formula of the complex is as shown in formula 1. The metal cobalt complex is prepared by taking N, N '-bis (5-isophthalic acid) naphthalimide as a ligand and Co < 2 + > ions as a metal center in the presence of isophthalic acid through a solvothermal method. The metal cobalt complex prepared by the invention is a multi-stimulus response color-changing material, a solid product shows different color states under different stimuli, and detection of organic amine / ammonia is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of multi-stimulus responsive color-changing materials, and in particular relates to a metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide, and a preparation method and application thereof. Background Art

[0002] In recent years, with the increasing demand for smart materials and the advancement of smart technology, stimuli-responsive functional materials with multiple color states have received increasing attention. However, when subjected to multiple stimuli, it is easier to show multiple changes in the solution state, but it is more difficult to show multiple changes in the solid state. Therefore, their potential application areas are limited, and the synthesis of such state-stable materials with different responses to multiple stimuli remains a considerable challenge.

[0003] Magnetic materials can be divided into two categories: metal magnetic materials and ferrite magnetic materials. According to their magnetic properties and applications, they can be divided into soft magnetic, permanent magnetic, magnetic recording, moment magnetic, gyromagnetic, piezomagnetic, magneto-optical and other materials. Soft ferromagnetic materials have high saturation magnetization and low resistivity, and are suitable for manufacturing pole shoes, motor rotors and stators, small transformer cores, etc., but there are certain difficulties in synthesizing magnetic materials.

[0004] Through the above analysis, the problems and defects of the prior art are as follows: there are few methods for synthesizing magnetic multi-stimulus responsive color-changing materials. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide and its preparation method and application. The method of preparing a multi-stimulus responsive color-changing material by the technology of the present invention is relatively simple, and the solid product exhibits different color states under different stimuli.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The present invention first provides a metal cobalt complex containing N,N′-di(5-isophthaloyl)naphthalene diimide, which is [Co3(BINDI)(μ3-OH)(μ2-OH)·6H2O·3H2O](Co-1), and the structural formula is shown in Formula 1:

[0008]

[0009] The present invention also provides a method for preparing a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide, comprising:

[0010] With N,N′-di(5-isophthaloyl)naphthalene diimide (H4BINDI) as ligand, Co 2+ ions as the metal center, and the metal cobalt complex Co-1 was prepared by a solvothermal method in the presence of isophthalic acid (H2IPA).

[0011] Preferably, the method comprises the following steps:

[0012] Step 1: Co(NO3)2·6H2O, N,N′-di(5-isophthaloyl)naphthalene diimide (H4BINDI), isophthalic acid (H2IPA) and solvent are sealed in a reaction kettle;

[0013] Step 2: Heat the reaction kettle and cool it to room temperature to obtain a metal cobalt complex Co-1 containing N,N′-di(5-isophthalic acid)naphthalene diimide.

[0014] Preferably, the molar ratio of Co(NO3)2·6H2O, N,N′-di(5-isophthalyl)naphthalene diimide (H4BINDI), and isophthalic acid (H2IPA) is 0.1:0.025:0.0027.

[0015] Preferably, the solvent is a mixture of DMF and water.

[0016] Preferably, the heating in step 2 is heating to 100° C. and maintaining the temperature for 72 hours.

[0017] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material.

[0018] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material in detecting organic amines / ammonia.

[0019] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material in detecting ammonia vapor.

[0020] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material in detecting o-toluidine.

[0021] Beneficial effects of the present invention

[0022] First, under solvent thermal conditions, the present invention uses N, N'-di(5-isophthalic acid) naphthalene diimide (H4BINDI) as a ligand, Co 2+ions as the metal center, and a metal cobalt complex [Co3(BINDI)(μ3-OH)(μ2-OH)·6H2O·3H2O](Co-1) was prepared. X-ray analysis showed that the ligands connected the metal cobalt ions to form a one-dimensional ribbon structure with infinite extension. The one-dimensional ribbons were connected by hydrogen bond interactions to form a two-dimensional layer structure. The two-dimensional structure was further connected by hydrogen bond interactions to form a three-dimensional structure.

[0023] The metal cobalt complex Co-1 of the present invention exhibits reversible photochromic behavior under irradiation of a 300W xenon lamp, and its color changes from reddish brown to dark brown (Co-1P); when heated at 90°C for 3h, the solid complex changes from reddish brown to dark purple (Co-1D), and when distilled water is dripped onto Co-1D, the color quickly changes from dark purple to the original reddish brown, showing reversible dehydration color change behavior; when an applied voltage of -1V to -0.5V is applied, the complex Co-1 exhibits electrochromic behavior, and its color changes from colorless to light blue (Co-1Q), and when exposed to air or the power is turned off for a period of time, the color changes back to the original colorless, showing reversible electrochromic properties; when exposed to ammonia vapor, the color changes from reddish brown to khaki after 1min (Co-1@NH3); when in contact with an o-toluidine solution, the color of the complex changes from reddish brown to dark gray (Co-1@O).

[0024] Second, the metal cobalt complex prepared by the present invention is a multi-stimulus responsive color-changing material, and realizes the detection of organic amines / ammonia. Moreover, the method for detecting organic amines / ammonia is convenient, efficient and sensitive.

[0025] Third, the metal cobalt complex prepared by the present invention has an application CCDC number (2306262) and is a brand-new complex with an advanced, safe and environmentally friendly production process. The technical solution of the present invention is expected to fill the technical gap in the industry at home and abroad and has good commercial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the method for synthesizing a metal cobalt complex provided in Example 1 of the present invention;

[0027] Figure 2 It is a model diagram of an asymmetric unit of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0028] Figure 3 is a metal cobalt cluster structure diagram of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0029] Figure 4is a one-dimensional band structure diagram of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0030] Figure 5 is a two-dimensional structural diagram of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0031] Figure 6 is a three-dimensional structural diagram of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0032] Figure 7 Schematic diagram of the distance of NO between ligands of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0033] Figure 8 This is a model diagram of the asymmetric unit of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention after irradiation with blue light for 10 minutes;

[0034] Fig. 9 This is a comparison diagram of bond lengths between a metal cobalt complex containing N,N′-di(5-isophthaloyl)naphthalene diimide provided in Example 1 of the present invention and a metal in the complex after irradiation with blue light;

[0035] Fig.10 : is the infrared spectra of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before irradiation (black) and after irradiation (red);

[0036] Fig.11 is a schematic diagram of a TGA curve of a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0037] Fig.12 is the PXRD spectrum of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention;

[0038] Fig.13 The photographs and UV-visible spectra of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after irradiation;

[0039] Fig.14 is the ESR spectrum of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after light irradiation;

[0040] Fig.15 are photographs and UV-visible spectra of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after dehydration;

[0041] Fig.16 The ESR spectra of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after dehydration;

[0042] Fig.17 The color change photograph and CV curve of the metal cobalt complex containing N,N′-di(5-isophthaloyl)naphthalene diimide provided in Example 1 of the present invention at a voltage of -1V to -0.5V;

[0043] Fig.18 It is a photo and UV-visible spectrum of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after exposure to ammonia vapor;

[0044] Fig.19 is the ESR spectrum of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after exposure to ammonia vapor;

[0045] Fig. 20 are photographs and UV-visible spectra of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after contact with o-toluidine;

[0046] Fig.21 is the ESR spectrum of the metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention before and after contact with o-toluidine;

[0047] Fig. 22 The metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide provided in Example 1 of the present invention is M T and T spectrum (Inset Figure 1 / x M Relationship diagram for T);

[0048] Fig.23 The metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide provided in Example 1 of the present invention is χ after being irradiated with blue light. M T and T spectrum (Inset Figure 1 / x M Relationship diagram for T);

[0049] Fig.24 It is a variable field magnetization intensity (MH) curve of the metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0051] The present invention first provides a metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide, which is [Co3(BINDI)(μ3-OH)(μ2-OH)·6H2O·3H2O], abbreviated as Co-1. The metal cobalt complex is a complex with a three-dimensional structure, and the structural formula is shown in Formula 1:

[0052]

[0053] The present invention also provides a method for preparing a metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide, comprising:

[0054] With N,N′-di(5-isophthaloyl)naphthalene diimide (H4BINDI) as ligand, Co 2+ ion as the metal center, and the metal cobalt complex [Co3(BINDI)(μ3-OH)(μ2-OH)·6H2O·3H2O](Co-1) was prepared by a solvothermal method in the presence of isophthalic acid (H2IPA).

[0055] The method preferably comprises the following steps:

[0056] Step 1: Seal Co(NO3)2·6H2O, N,N′-di(5-isophthalic acid)naphthalene diimide (H4BINDI), isophthalic acid (H2IPA) and solvent in a reaction kettle; the solvent is preferably a mixture of DMF and water, the volume ratio of DMF and water is 3:5, and the molar ratio of Co(NO3)2·6H2O, N,N′-di(5-isophthalic acid)naphthalene diimide (H4BINDI) and isophthalic acid (H2IPA) is preferably 0.1:0.025:0.0027.

[0057] Step 2: Heat the reactor, preferably to 100°C, keep the temperature constant for 72h, and heat at 1.5°C / h -1 The reaction mixture was cooled to room temperature at a rate of , to obtain a metal cobalt complex (Co-1) containing N,N′-di(5-isophthalic acid)naphthalene diimide.

[0058] The present invention also provides the use of the metal cobalt complex Co-1 as a multi-stimulus responsive color-changing material.

[0059] The metal cobalt complex Co-1 of the present invention exhibits reversible photochromic behavior in the solid state under the irradiation of a 300W xenon lamp.

[0060] The metal cobalt complex Co-1 of the present invention is heated at 90° C. for 3 hours, and the solid complex can show a color change. When distilled water is added to the color-changed complex, the color-changed complex quickly changes back to its original color. The complex exhibits a rare reversible dehydration color change behavior.

[0061] The metal cobalt complex Co-1 of the present invention uses a CHI 660E electrochemical workstation to perform cyclic voltammetry (CV) technology. A traditional three-electrode system is used: in a 0.05M tetrabutylammonium hexafluorophosphate (TBAPF6) / DMF solution, a coated indium tin oxide glass (ITO) / glassy carbon electrode (GC) is used as a working electrode, a platinum sheet is used as a counter electrode, and a saturated Ag / AgCl electrode is used as a reference electrode. In the voltage range of -1V to -0.5V, a redox peak appears, and as the voltage increases, the color of the complex gradually deepens, and finally presents a color visible to the naked eye (colorless to light blue). When the power supply is disconnected or the sample is exposed to air for a period of time, the color will return to the original color. The complex exhibits reversible electrochromic behavior.

[0062] The present invention also provides the use of the metal cobalt complex (Co-1) as a multi-stimulus responsive color-changing material in detecting organic amines / ammonia.

[0063] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material in detecting ammonia vapor. When the metal cobalt complex Co-1 is exposed to ammonia vapor for 1 minute, the solid complex has an obvious color change, indicating that the complex can be used as one of the color-changing materials for detecting ammonia vapor by color change in the solid state.

[0064] The present invention also provides the use of the metal cobalt complex as a multi-stimulus responsive color-changing material in detecting o-toluidine. The metal cobalt complex Co-1 can detect the presence of o-toluidine by color change when it contacts an o-toluidine solution. Therefore, the solid complex can be used as a color-changing material for detecting the carcinogen o-toluidine.

[0065] The present invention is further described in detail below with reference to specific examples, in which the raw materials involved are all commercially available.

[0066] Example 1

[0067] like Figure 1As shown, a method for synthesizing a metal cobalt complex containing N,N′-di(5-isophthalic acid)naphthalene diimide comprises the following steps:

[0068] S101, 0.0291 g, 0.1 mmol Co(NO3)2·6H2O, 0.0150 g, 0.025 mmol N,N′-di(5-isophthalyl)naphthalene diimide, 0.0045 g, 0.0027 mmol isophthalic acid, 5 mL distilled water and 3 mL DMF were sealed in a polytetrafluoroethylene reactor;

[0069] S102, heat the reactor to 100°C and keep the temperature constant for 72h; and -1 The reaction mixture was cooled to room temperature at a rate of , to obtain a metal cobalt complex (Co-1) containing N,N′-di(5-isophthalic acid)naphthalene diimide.

[0070] The performance of the metal cobalt complex Co-1 containing N,N′-di(5-isophthalyl)naphthalene diimide prepared in Example 1 was tested as follows:

[0071] 1. Elemental analysis

[0072] Elemental analysis (C, H, N) was performed on a PerkinElmer 2400 CHN elemental analyzer. Fourier transform infrared absorption spectroscopy was performed on a PerkinElmer Frontier TM Measured on an infrared spectrometer, ranging from 4000 to 450 cm -1 , using pure potassium bromide tableting method. α radiation X-ray powder diffraction (PXRD) patterns were recorded on a Rigaku Ultima IV-185 diffractometer in the range of 2θ 5 to 60°. The PXRD model was simulated using single crystal X-ray diffraction data from Mercury v1.4.2. The UV-visible diffuse reflectance spectra of the solid powders at room temperature were measured using a Shimadzu UV-2600 UV-visible spectrophotometer. Electron spin resonance (ESR) spectra were recorded on a Jeol JES FA200 paramagnetic resonance electron spectrometer. Thermogravimetric analysis was performed on a Tarsus TG 209F3 thermogravimetric analyzer with a heating rate of 20°C / min in the temperature range of 35°C to 800°C. Fluorescence spectra were recorded on a Hitachi F-7000 fluorescence spectrometer. CHI 660E electrochemical workstation from Shanghai Chenhua Instrument Co., Ltd. The magnetic spectra were measured on an MPMS (SQUID) XL-7 from Quantum Design, USA. All chemicals used in the experiments were of reagent grade.

[0073] Example 1 obtained C60 H 60 Co5N4O 46 Elemental analysis (%): C, 38.55; H, 3.21; N, 3.00; Co 15.79%. Experimental value: C, 38.41; H, 3.02; N, 2.49; Co 15.41%

[0074] 2. Crystal structure test

[0075] The single crystal X-ray diffraction data of the complex Co-1 were collected at 296K using graphite monochromatized Mo Kα rays (λ=0.071073) in ω scanning mode on a Bruker SMART APEX CCD diffractometer. All data were corrected using the Lorentz polarization effect factor. The crystal structure was solved using the direct method in the SHELXS-2014 and OLEX2 structure analysis packages. The CCDC number of the complex Co-1 is 2306262. The complex Co-1 belongs to the triclinic system, the space group is P-1, and the unit cell parameters are: α=84.400(2)°, β=80.967(2)°, γ=76.329(2)°, V=1916.2(4), Z=1, D=1.619g·cm -3 , μ=1.166mm -1 , F(000) = 951.0. The bond length, bond angle and hydrogen bond table of metal cobalt complexes are shown in Table 1-3.

[0076] The single crystal X-ray diffraction data of the complex Co-1@blue after blue light irradiation were collected on a Bruker SMART APEX CCD diffractometer at 298K using graphite monochromatized Cu Kα rays (λ=1.54184) in ω scanning mode. All data were corrected using the Lorentz polarization effect factor. The crystal structure was solved using the direct method in the SHELXS-2014 and OLEX2 structure analysis packages. The CCDC number of the metal cobalt complex after blue light irradiation is 2362124. The complex Co-1@blue belongs to the triclinic system, the space group is P-1, and the unit cell parameters are: α=84.6220(10)°, β=80.8190(10)°, γ=76.3230(10)°, V=1916.74(7), Z=1, D=1.556g·cm -3 ,μ=9.176mm -1 , F(000)=911.0. The bond lengths and bond angles of the complexes are shown in Table 4-5.

[0077] Table 1 Bond lengths of complex Co-1

[0078]

[0079]

[0080]

[0081] Symmetric operation code: 1 2-X, 1-Y, -Z; 2 2-X, 1-Y, 1-Z; 3 +X,+Y,-1+Z; 4 +X,+Y,1+Z.

[0082] Table 2 Bond angle table of complex Co-1

[0083]

[0084]

[0085]

[0086] Symmetric operation code: 1 2-X, 1-Y, -Z; 2 2-X, 1-Y, 1-Z; 3 +X,+Y,-1+Z; 4 +X,+Y,1+Z.

[0087] Table 3 Hydrogen bond table of complex Co-1

[0088]

[0089] Symmetric operation code: 1 1-X, 1-Y, 2-Z; 2 +X,+Y,1+Z; 3 +X,-1+Y,+Z; 4 +X,+Y,-1+Z; 5 1-X, 1-Y, 1-Z; 6 2-X, 1-Y, 1-Z; 7 +X,1+Y,+Z.

[0090] Table 4 Bond lengths of complex Co-1@blue

[0091]

[0092]

[0093] Symmetric operation code: 1 2-X, 1-Y, -Z; 2 2-X, 1-Y, 1-Z;3 +X,+Y,-1+Z; 4 +X,+Y,1+Z.

[0094] Table 5 Bond angle table of complex Co-1@blue

[0095]

[0096]

[0097]

[0098] Symmetric operation code: 1 2-X, 1-Y, -Z; 2 2-X, 1-Y, 1-Z; 3 +X,+Y,-1+Z; 4 +X,+Y,1+Z.

[0099] Single crystal X-ray diffraction analysis shows that the complex Co-1 belongs to the triclinic P-1 space group. The asymmetric unit of Co-1 consists of three Co 2+ ion, a deprotonated N,N′-bis(5-isophthaloyl)naphthalene diimide (BINDI 4- ) anion, two hydroxide (OH-) ions, six coordinated water molecules, and three free water molecules ( Figure 2 ). Three Co 2+ The ions all show a hexacoordinated octahedral geometry. The Co1 ion is bound to a 4- The oxygen atom of the anion (O5), the two hydroxide ions (O2 and O20 3 ) and three water molecules (O1, O3 and O4), and the Co2 ion is coordinated with a 4- The oxygen atom of the anion (O16), two hydroxide ions (O2 3 and O20) and three water molecules (O17, O18, and O19), the Co3 ion is coordinated with four symmetry-related BINDI 4- The four oxygen atoms of the anion (O15, O15 1 、O6 2 and O6 3 ) and the two oxygen atoms in the two hydroxide ions (O20 and O20 1 ) coordination. The range of Co-O bonds is from arrive All of them are within the normal range (see Table 1). The bond angle of O-Co-O ranges from 81.92 (11)° to 180.0° (see Table 2). Two hydroxide ions exist in the form of μ3-OH and μ2-OH in the complex Co-1. The two μ3-OH bridges Co2 and Co1 with Co3 as the center. 2 、Co2 1 、Co1 3 , two μ2-OH connect Co2 and Co1 respectively 3 and Co1 2 、Co2 1 Forming a five-core cluster secondary building block ( Figure 3 ). In each BINDI 4- Two of the four carboxyl groups of the anion adopt κ 2 :κ 2 The mode connects two metal ions in a bidentate manner, and the other two are uncoordinated. 4- μ4-κ 2 :κ 2 The mode bridges adjacent penta-core cluster secondary building blocks to form a one-dimensional ribbon structure ( Figure 4 ). The one-dimensional band is formed by hydrogen bonding between water molecules and carboxyl oxygen (O3-H3A…O18 5 、O4-H4A…O7 1 ) forms a two-dimensional layer ( Figure 5 and Table 3), the two-dimensional layer further interacts through hydrogen bonds (OW1-HW1A...O14 2 、O17-H17A…O13 3 、O18-H18A…O14 3 、O1-H1B…O7 7 、O4-H4B…O15 2 、O4-H4A…O7 1 , O1-H1A…OW1) to form a three-dimensional supramolecular structure ( Figure 6 and Table 3). The distance between the atoms N and O of the two naphthalene rings is and ( Figure 7 ).

[0100] The structure of the complex Co-1@blue after blue light irradiation ( Figure 8 ) Compared with the structure of complex Co-1, the metal Co 2+ The distance between the ions is determined by the Get bigger ( Fig. 9 ).

[0101] 3. Infrared spectrum, thermogravimetric analysis and PXRD pattern of the complex (Co-1)

[0102] Fig.10 The infrared spectrum of the complex Co-1 is at 3464 cm -1 The peaks at 1633, 1571, 1419 and 1343 cm-1 are related to the presence of water molecules in the complex. -1 The peak observed at 1254 cm-1 is the characteristic absorption band of the carbonyl group of naphthalene diimide. -1 The peak at corresponds to the stretching vibration of the C=C bond.

[0103] The thermal stability of the complex Co-1 was studied by thermogravimetric testing at room temperature to 800°C in a nitrogen atmosphere. Fig.11 ). The thermal stability of the complex Co-1 was studied by thermogravimetric analysis. The complex Co-1 lost 2.90% (calculated value: 2.24%) of its weight at 61°C, which may be due to the loss of free water molecules. At 101°C, the mass loss was 8.69% (calculated value: 9.37%), which may be due to the loss of coordinated water molecules. At 248°C, the complex Co-1 began to decompose and the framework collapsed.

[0104] Fig.12 The PXRD patterns before and after illumination were measured. The PXRD spectrum simulated according to the single crystal structure is basically consistent with the spectrum of the experimental results, indicating that the synthesized sample contains relatively little impurities and is basically a pure phase. Some peaks cannot overlap, and the intensity of some peaks becomes weaker, which is caused by the anisotropy of the prepared complex.

[0105] Application Example 1

[0106] The metal cobalt complex containing N,N′-di(5-isophthalyl)naphthalene diimide provided in Example 1 of the present invention is used as a material for detecting organic amines / ammonia in a detection environment. The specific application method is as follows:

[0107] Finely grind the bulk crystals of the metal cobalt complex (Co-1) containing N,N′-di(5-isophthalic acid)naphthalene diimide and place them on filter paper. Then take 10-15 ml of ammonia water and pour it into a 25 ml beaker, put the filter paper on the beaker, and cover the beaker with a watch glass. Wait for 1 minute, and the color will change from reddish brown to khaki. Take the finely ground crystal powder, place it on a glass slide, use a rubber-tipped dropper to take the o-toluidine solution and drop it on the crystal powder. After drying in the air, the color changes from reddish brown to dark gray.

[0108] The color change performance test of the complex Co-1 is as follows:

[0109] 1. Photochromic performance

[0110] Generally speaking, materials containing naphthalene diimide will change color under light conditions. After irradiation with a 300W xenon lamp for 1 minute at room temperature, the complex Co-1 showed a significant color change from reddish brown to dark brown ( Fig.13 ). It is noteworthy that the complex Co-1 can quickly return to its original state in the absence of light or under heating conditions, indicating the reversibility of its photochromic process. In order to further clarify its photochromic behavior, the complex Co-1 was characterized by UV-visible diffuse reflectance spectroscopy and electron spin resonance (ESR) measurements. The UV-visible diffuse reflectance spectrum of the irradiated sample has a characteristic absorption band near 534nm. In addition, the ESR signal of Co-1 after irradiation is enhanced at g=2.0021 ( Fig.14 ), indicating that the color change may be due to the photoinduced charge transfer generating BINDI 4- Free radicals.

[0111] 2. Dehydration and discoloration

[0112] After heating the complex Co-1 at 90°C for 3 hours, a color change that is visible to the naked eye occurs, from reddish brown to dark purple (Co-1D) ( Fig.15 ), add distilled water drop by drop on Co-1D, it will restore to its original color. UV-Vis and ESR tests on Co-1D show that the visible absorption spectrum of Uv-Vis increases significantly at 480nm-675nm ( Fig.15 ), the ESR spectrum shows that the absorption intensity increases at g = 2.0025 ( Fig.16 ), indicating that BINDI was produced after heating 4- Free radicals.

[0113] 3. Electrochromic

[0114] The electrochromic properties of the complex Co-1 were studied by cyclic voltammetry (CV) with indium tin oxide (ITO) glass as the working electrode, Pt foil as the counter electrode and Ag / AgCl electrode as the reference electrode. Fig.17 The CV curve of the complex Co-1 shows a pair of redox peaks in the voltage range of -1 to -0.5V, indicating that it has single electron transfer behavior, confirming its electrochemical activity. The complex Co-1 changes from colorless to light blue in the voltage range of -1 to -0.5V, and the color returns to the original colorless after power failure or exposure to air for a period of time. This shows that the complex Co-1 has reversible electrochromic properties.

[0115] 4. Ammonia vapor detection

[0116] By exposing the complex Co-1 to saturated ammonia vapor, it was observed that the color of the complex changed from reddish brown to khaki after 1 min ( Fig.18). It is worth noting that by comparing the UV-Vis spectra of the complexes Co-1 and Co-1@NH3, it is found that the absorption peak at 534nm is significantly enhanced, indicating that the intermolecular electron transfer from ammonia to BINDI 4- The generation of free radicals was further confirmed by ESR (g = 2.0031) spectroscopy. Fig.19 ). Based on these findings, it can be reasonably inferred that the observed color change is attributed to the electron transfer and the generation of free radicals. Therefore, complex Co-1 can be used as one of the sensing materials for detecting ammonia vapor.

[0117] 5. Detection characteristics of o-toluidine

[0118] In the preliminary list of carcinogens published by the World Health Organization's International Agency for Research on Cancer on October 27, 2017, o-toluidine was listed as a Class 1 carcinogen. Therefore, the detection of o-toluidine is necessary. When the complex Co-1 comes into contact with o-toluidine solution, the color changes from reddish brown to dark gray ( Fig. 20 ). Comparing the UV-Vis spectra and ESR spectra of Co-1 and Co-1@O, it is found that the absorption peak of the UV-Vis spectrum of Co-1@O increases significantly at 534nm, and the ESR spectrum shows a strong free radical signal at g=2.0031 ( Fig.21 ), indicating that the complex Co-1 undergoes electron transfer to generate free radicals after contacting with o-toluidine. Therefore, the complex Co-1 can be used as one of the color-changing materials for the detection of o-toluidine.

[0119] 6. Magnetic properties

[0120] By paramagnetic Co 2+ Coordination compounds composed of ions, carboxylic acid ligands and nitrogen-containing compounds can usually exhibit magnetic coupling properties. 2+ The magnetic properties of the ionic complexes were investigated in the temperature range of 2-300K and the magnetic field strength of 1000Oe. The magnetic susceptibility of the complexes Co-1 and Co-1@blue was measured. M The T value is 13.86cm 3 ·K·mol -1 , than the five uncoupled high-spin Co 2+ The theoretical value of ions is 9.38 cm 3 ·K·mol -1 Slightly higher (S = 3 / 2). M The T value decreases gradually from 300 to 50 K as the temperature decreases, and drops sharply after 50 K. It increases at 17 K to 9 K, and then decreases rapidly, reaching the lowest value of 3.62 cm at 2 K. 3 ·K·mol -1, showing significant spin-orbit coupling (SOC) ( Fig. 22 ). At the same time, the 1 / χ M The linear fit of T yields the Curie constant (C) = 15.93 cm 3 ·K·mol -1 , Weiss constant (θ) = -277.49K ( Fig. 22 Inset), the negative θ value indicates the existence of antiferromagnetic interaction between metal ions. In addition, the magnetization intensity curve (MH) of the complex Co-1 was tested at a temperature of 2K. The magnetization curve did not reach saturation at a magnetic field of 70kOe ( Fig.24 ).

[0121] The χ value of the complex Co-1@blue obtained after blue light irradiation at 300K M T value is 11.80cm 3 ·K·mol -1 , slightly lower than Co-1's 13.86cm 3 ·K·mol -1 , but lower than the theoretical value of 9.38 cm for five uncoupled high-spin Co(II) ions. 3 ·K·mol -1 The χ of the complex Co-1@blue is higher (S=3 / 2). M The T value decreases first, then increases, and then decreases again as the temperature decreases. It decreases sharply from 50K to 21K, increases from 21K to 5K, decreases again from 5K to 2K, and reaches the lowest value of 6.62cm at 2K. 3 ·K·mol -1 ( Fig.23 ). At the same time, the 1 / χ M The linear fit of T yields the Curie constant (C) = 16.29 cm 3 ·K·mol -1 , Weiss constant (θ) = -218.93K ( Fig.23 illustration).

[0122] Before and after blue light irradiation, it was found that θ was negative, indicating that in the complexes Co-1 and Co-1@blue, the adjacent Co 2+ There is an antiferromagnetic interaction between ions. Comparing the absolute values ​​of θ before and after blue light irradiation, it is found that Co-1 (-277.49K) is larger than Co-1@blue (-218.93K), which may be due to the increase in the distance between metal (Co) and metal (Co) after blue light irradiation. This also proves that Co 2+The antiferromagnetic interaction between ions can be weakened by increasing the intermetallic distance through photomodulation.

[0123] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide, characterized in that: The structural formula is shown in Formula 1:

2. The method for preparing a metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide according to claim 1, characterized in that: include: With N,N'-di(5-isophthalic acid)naphthalene diimide as ligand, Co 2+ ions as the metal center, and the metal cobalt complex Co-1 was prepared by a solvothermal method in the presence of isophthalic acid.

3. The method for preparing a metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide according to claim 2, characterized in that: The method comprises the following steps: Step 1: Co(NO3)2·6H2O, N,N'-di(5-isophthalyl)naphthalene diimide, isophthalic acid and solvent are sealed in a reaction kettle; Step 2: Heat the reaction kettle and cool it to room temperature to obtain a metal cobalt complex Co-1 containing N,N'-di(5-isophthalic acid)naphthalene diimide.

4. The method for preparing a metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide according to claim 3, characterized in that: The molar ratio of Co(NO3)2·6H2O, N,N'-di(5-isophthaloyl)naphthalene diimide and isophthalic acid is 0.1:0.025:0.0027.

5. The method for preparing a metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide according to claim 3, characterized in that: The solvent is a mixture of DMF and water.

6. The method for preparing a metal cobalt complex containing N,N'-di(5-isophthalyl)naphthalene diimide according to claim 3, characterized in that: The heating in step 2 is heating to 100° C. and maintaining the temperature for 72 hours.

7. Use of the metal cobalt complex according to claim 1 as a multi-stimulus responsive color-changing material.

8. Use of the metal cobalt complex according to claim 7 as a multi-stimulus responsive color-changing material in detecting organic amines / ammonia.

9. Use of the metal cobalt complex according to claim 7 as a multi-stimulus responsive color-changing material in detecting ammonia vapor.

10. Use of the metal cobalt complex according to claim 7 as a multi-stimulus responsive color-changing material in the detection of o-toluidine.

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