A zinc complex crystal material for fluorescent detection of metal ions and a preparation method and use thereof

Abstract

The application discloses a zinc complex crystal material for fluorescent detection of metal ions and a preparation method and application thereof. 72 H 56 N2O8Zn2, a molecular weight is 1207.92, a cell parameter alpha is 70.7410 (10) °, beta is 84.2950 (10) °, gamma is 68.2890 (10) °; the prepared material has a clear space structure and an accurate molecular formula; the crystal material can efficiently and rapidly detect Cr 3+ , Al 3+ and Fe 3+ ions, and has a wide application prospect as a fluorescent sensor. The technology has the advantages of simple operation, low cost and stable performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of crystal material chemistry, and particularly relates to a zinc complex crystal material for fluorescent detection of metal ions and a preparation method and application thereof. BACKGROUND

[0002] Metal coordination compound crystal material, also known as metal-organic framework material (MOFs) in brief, is an organic-inorganic hybrid material, which is formed by self-assembly of organic ligand and metal ion or cluster through coordination bond to form intramolecular pores. The MOFs material has been widely applied in gas adsorption separation, catalysis, ion detection and other fields. In human life, heavy metals are everywhere. Although some heavy metal elements such as iron, chromium and manganese are essential trace elements for life activities, like other heavy metal elements necessary for non-living things, they will cause great harm to the body when their content in the body exceeds a certain concentration. Therefore, it is of great significance to realize the detection of metal ions in water body for the timely treatment of contaminated water body.

[0003] The MOFs fluorescent probe is a special type of sensor, which has attracted people's attention in the field of analysis sensing and optical imaging due to its high sensitivity, fast response time and simple technology. And the compound based on fluorescence has strong electronic conjugation, which means large electron delocalization and high fluorescence efficiency. In recent years, anthraquinone, pyrene derivative, biphenyl, styrene, imidazole and polyurethane have become the main raw materials of fluorescent probes. Among them, fluorene is a rigid plane composed of a five-membered ring connecting two benzene rings, which is a fluorescent group with strong fluorescence. Their derivatives have unique effects in photoluminescence and electroluminescence materials due to the physical properties of the biphenyl unit. SUMMARY

[0004] The application provides a zinc complex crystal material for fluorescent detection of metal ions and a preparation method and application thereof, and aims at the problems in the prior art. The zinc complex crystal material is synthesized by using fluorenyl carboxylic acid ligand and pyridine ligand and metal zinc, and the rapid detection of iron, chromium and aluminum ions can be realized by using fluorescence emission spectrum.

[0005] The technical scheme adopted by the application to solve the above technical problems is that the composition structure of the zinc complex crystal material is [Zn2(L)2(L1)] n (L=3,3'-(9,9-diethyl-9H-fluorene-2,7-diyl)dibenzoic acid, L1=4,4'-bipyridine), the crystal belongs to triclinic system, and the space group is The molecular formula is C 72 H 56 N2O8Zn2, molecular weight is 1207.92, unit cell parameters α=70.7410(10)°, β=84.2950(10)°, γ=68.2890(10)°; Figure 1 The asymmetric structural unit of the crystalline material consists of a Zn(II) ion, an L ligand, and an L1 ligand with an occupancy of 0.5. The Zn(II) ion adopts a hexacoordinated octahedral configuration, with four oxygen atoms coming from the carboxyl group of the ligand L, one nitrogen atom coming from the pyridinic nitrogen of the ligand L1, and the other position being occupied by Zn–Zn. The distance between Zn–Zn is ( Figure 2 ), Figure 2 For clarity, hydrogen atoms are ignored; the coordination structural unit forms a two-dimensional layered structure through the bridge of ligands L and L1 ( Figure 3 ), Figure 3 For clarity, hydrogen atoms are ignored; the two-dimensional structure is affected by intermolecular forces, CH…O and π…π action (the distance between adjacent surfaces is ), forming a three-dimensional network structure ( Figure 4 ), Figure 4 For clarity, hydrogen atoms are ignored.

[0006] The present invention also provides a method for preparing the crystalline material, which comprises the following steps:

[0007] A certain amount of ligand L, ligand L1 and zinc salt are weighed and placed in a glass bottle, and dissolved in a mixed solution consisting of N,N-dimethylformamide (DMF), anhydrous ethanol and distilled water; the vial containing the mixed solution is heated at 75-95° C. for 48-72 hours, and then cooled to room temperature to obtain yellow block crystals, which are the zinc complex crystal material.

[0008] The zinc salt is zinc nitrate hexahydrate;

[0009] The molar ratio of the ligand L, L1 and zinc salt is 1:1:2;

[0010] The ligand L, whose English name is 3,3'-(9,9-diethyl-9H-fluorene-2,7-diyl)dibenzoic acid, has a molecular formula of C 31 H 26 O4, with a molecular weight of 462.55, has a simplified structural formula as shown in formula (I):

[0011]

[0012] The ligand L1 is 4,4'-bipyridine, and its molecular formula is C 10 H8N2, and its molecular weight is 156.18, and its structural formula is shown as formula (II):

[0013]

[0014] The substances or solvents participating in the reaction are all chemically pure.

[0015] The application also provides the use of the zinc complex crystal material as a fluorescent detection metal ion material, which can efficiently and rapidly detect Cr 3+ , Al 3+ and Fe 3+ ions, and the zinc complex crystal material as a fluorescent sensor has a wide application prospect.

[0016] Compared with the prior art, the application has the following characteristics:

[0017] The zinc complex crystal material is synthesized by a solvent thermal method and a mixed ligand method, the material has a high sensitivity and a selective response to Cr 3+ , Al 3+ and Fe 3+ trivalent metal ions, and the crystal material has a specific fluorescent “turn-on” reaction in the presence of Cr 3+ , Al 3+ and Fe 3+ ions.

[0018] The ligands L and L1 used in the application have a specific conjugated π system and a specific spatial structure, and the formed two-dimensional and three-dimensional structures have specific spatial structures; the two-dimensional layers have specific intermolecular forces, specific hydrogen bonds and C-H…O interactions and π…π interactions (the distance between adjacent surfaces is ); and the distance between Zn-Zn in the coordination unit is These specific structures and parameters determine that the prepared crystal material has high stability, specific fluorescent properties and specific fluorescent response properties to specific metal ions, so that the prepared crystal material has a wide application prospect as a fluorescent detection reagent material or as a fluorescent sensor. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The zinc complex crystal material is a basic structural unit of the zinc complex crystal material.

[0020] Figure 2 The zinc complex crystal material is a basic structural unit of the zinc complex crystal material.

[0021] Figure 3 a two-dimensional layer structure of the zinc complex crystal material along the b-axis direction according to the present application;

[0022] Figure 4 a three-dimensional network structure of the zinc complex crystal material along the c-axis direction according to the present application;

[0023] Figure 5 a thermogravimetric spectrum of the zinc complex crystal material according to the present application;

[0024] Figure 6 a fluorescence response graph of the zinc complex crystal material suspension to different metal ions according to the present application;

[0025] Figure 7 a anti-interference test graph of the zinc complex crystal material according to the present application, Figure 7 (a) in FIG. 1 is a histogram of the fluorescence detection of ions by the crystal material suspension, Figure 7 (b) in FIG. 1 is a comparison of the fluorescence intensity of the crystal under the interference of different metal ions in the presence and absence of Al(III) ions, wherein the probe is the crystal material suspension and the interference ions are K + , Na + , Ag + , Co 2+ , Ba 2 + , Cu 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Mg 2+ , Pb 2+ , Cr 3+ , Fe 3+ , Figure 7 (c) in FIG. 1 is a comparison of the fluorescence intensity of the crystal material suspension under the interference of different metal ions in the presence and absence of Cr(III) ions, wherein the probe is the crystal suspension and the interference ions are K + , Na + , Ag + , Co 2+ , Ba 2+ , Cu 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Mg 2+ , Pb 2+ , Al 3+ , Fe 3+ , Figure 7 (d) in FIG. 1 is a comparison of the fluorescence intensity of the crystal material suspension under the interference of different metal ions in the presence and absence of Fe(III) ions, wherein the probe is the zinc complex crystal suspension and the interference ions are K+ , Na + , Ag + , Co 2+ , Ba 2+ , Cu 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Mg 2+ , Pb 2+ , Cr 3+ , Al 3+ ;

[0026] Figure 8 Fig. 1 is a sensitivity test chart of the zinc complex crystal of the present application, Figure 8 Fig. 1(a) is a fluorescence spectrum of the crystal material suspension in the presence of different concentrations of aluminum ions, Figure 8 Fig. 1(b) is a linear fitting curve of the crystal material suspension in the presence of different concentrations of aluminum ions, Figure 8 Fig. 1(c) is a fluorescence spectrum of the crystal material suspension in the presence of different concentrations of chromium ions, Figure 8 Fig. 1(d) is a linear fitting curve of the crystal material suspension in the presence of different concentrations of chromium ions, Figure 8 Fig. 1(e) is a fluorescence spectrum of the crystal material suspension in the presence of different concentrations of iron ions, Figure 8 Fig. 1(f) is a linear fitting curve of the crystal material suspension in the presence of different concentrations of iron ions. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in conjunction with examples.

[0028] Example 1:

[0029] Zn(NO3)2·6H2O (5.95 mg, 0.02 mmol), L (4.63 mg, 0.01 mmol), L1 (1.56 mg, 0.01 mmol) were respectively placed in a 5 mL glass bottle, dissolved in a mixed solution composed of N,N-dimethylformamide (DMF) (1.5 mL), anhydrous ethanol (1 mL), distilled water (1 mL) with a volume ratio of 1.5:1:1. The small bottle containing the mixed solution was heated to react at 90°C for 48 hours, and then cooled to room temperature. Yellow block-shaped crystals were obtained.

[0030] Example 2:

[0031] Zn(NO3)2·6H2O (11.9 mg, 0.04 mmol), L (9.26 mg, 0.02 mmol), L1(3.12 mg, 0.02 mmol) were placed in 5 ml glass bottles respectively, dissolved in a mixed solution of DMF (1.5 mL), anhydrous ethanol (1 mL), distilled water (1 mL) with a volume ratio of 1.5:1:1. The small bottle containing the mixed solution was heated at 75°C for 72 hours, and then cooled to room temperature. Yellow block crystals were obtained.

[0032] Example 3:

[0033] Zn(NO3)2·6H2O (2.98 mg, 0.01 mmol), L (2.31 mg, 0.005 mmol), L1(0.78 mg, 0.005 mmol) were placed in 5 mL glass bottles respectively, dissolved in a mixed solution of DMF (1.5 mL), anhydrous ethanol (1 mL), distilled water (1 mL) with a volume ratio of 1.5:1:1. The small bottle containing the mixed solution was heated at 95°C for 60 hours, and then cooled to room temperature. Yellow block crystals were obtained.

[0034] The yellow block crystals prepared in the above Example 1 were subjected to single crystal X-ray diffraction analysis test, and crystals with appropriate size and regular shape were selected at room temperature and fixed on the test needle with epoxy resin glue, and then the test needle was placed on the Rigaku Oxford XtaLAB PRO diffractometer, using graphite monochromatic MoKα ray The sample was tested, and the data was collected, the diffraction points were screened, the lattice type was determined and the absorption correction and data reduction were performed by CrysAlisPro-Agilent software; the crystal structure was solved by direct method of ShelXS program, and anisotropic refinement was performed by ShelXL, and F 2 The above uses full matrix least squares method for refinement correction, the coordinates of non-hydrogen atoms in the structure are determined step by step by difference Fourier peak synthesis and anisotropic refinement, hydrogen atoms are obtained by theoretical hydrogenation, all hydrogen atoms are isotropic refinement, and complete Cif file is obtained, in the cif, the residual factor R1 value (R_factor_gt) is 0.0349, the goodness of fit S or GooF value (goodness_of_fit_ref) is 1.039, and the final refinement process average shift value (shift / su_mean) is 0.000, which has met the crystallographic requirements of crystal structure analysis of accurate data requirements; the X-ray single crystal diffraction test analysis result shows that the structure formula of the prepared zinc complex crystal material is [Zn2(L)2(L1)] n belongs to triclinic system, and the space group is The molecular formula is C 72 H 56 N2O8Zn2, the molecular weight is 1207.92, the cell parameters are a=0.7660(3)nm, b=1. 0000(3)nm, c=1. 0000(3)nm, α=70.7410(10)°, β=84.2950(10)°, γ=68.2890(10)°, V=0. 7660(3)nm3, Z=2, Dc=1. 755 Mg / m3, F(000)= 1207, μ=1. 230 mm-1, Rint=0. 000, R=0. 0301, wR=0. 0707. α=70.7410(10)°, β=84.2950(10)°, γ=68.2890(10)°; Figure 1 The crystal [Zn2(L)2(L1)] n The asymmetric structural unit of the crystal includes one Zn(II) ion, one L ligand and one L1 ligand with an occupancy of 0.5; the Zn(II) ion adopts a six-coordinated octahedral configuration, four oxygen atoms come from the carboxyl groups of the ligand L, one nitrogen atom comes from the pyridine nitrogen of the ligand L1, and the other position is occupied by Zn-Zn, the distance between Zn-Zn is ( Figure 2 );the coordination structural unit is bridged by the ligands L and L1, forming a two-dimensional layered structure ( Figure 3 );the two-dimensional structure forms a three-dimensional network structure ( Figure 4 ) through intermolecular forces, C-H…O interactions and π…π interactions (the distance between adjacent planes is ). The test results show that the yellow block crystal prepared is the zinc complex crystal material.

[0035] The zinc complex crystal material prepared above is subjected to thermogravimetric analysis ( Figure 5 ), and the results show that the skeleton of the crystal material prepared can be kept stable at about 320℃, indicating that the crystal has good thermal stability.

[0036] In order to evaluate the detection effect of the prepared crystal material on metal ions in water, 3.9 mg of the prepared crystal material is dissolved in deionized water to prepare a crystal material suspension with a concentration of 100 μM. Subsequently, 200 μL of different metal ion nitrate solutions (metal ions are K + , Na + , Ag + , Co 2+ , Ba 2+ , Cu 2+ , Ni 2+ , Zn 2+ , Cd 2+ , Mg 2+ , Pb 2+ , Cr 3+ , Al 3+ , Fe 3+ ; the concentration of each metal ion is 10 -4 M) is added to 1800 μL of the crystal material suspension, and then fluorescence spectrum analysis test is carried out, and the fluorescence spectrum is recorded. The results show that when the prepared crystal material suspension contains Cr3+ 、Al 3+ or Fe 3+ ions, the fluorescence intensity of the test was significantly enhanced, and the fluorescence intensity increased by about 9.5 times, 8.7 times and 7.2 times, respectively, showing that the prepared crystal material has a strong effect on Cr 3+ 、Al 3+ or Fe 3+ Ions have specific response properties ( Figure 6 ).

[0037] Anti-interference test ( Figure 7 In a real water environment, taking tap water as an example, multiple metal ions coexist, and an anti-interference test experiment is carried out to evaluate the detection performance of the prepared crystal material for metal ions. The interfering ion is K + ,Na + ,Ag + ,Co 2+ ,Ba 2+ ,Cu 2+ ,Ni 2+ ,Zn 2+ ,Cd 2+ ,Mg 2+ ,Pb 2+ In the absence of interfering ions, the prepared crystal material has a strong affinity for the test ion Cr 3+ 、Al 3+ and Fe 3+ The fluorescence intensity response of ions is significantly enhanced ( Figure 7 Each test ion (Cr 3+ , Al 3+ and Fe 3+ ) were tested for fluorescence spectra in the presence of 13 interfering ions other than themselves ( Figure 7 b- Figure 7 d). The test results show that in the presence of interfering ions, the test ion Cr 3+ 、Al 3+ or Fe 3+ The fluorescence intensity of the prepared crystal material is still significantly enhanced under complex conditions. 3+ 、Al 3+ and Fe 3+ Ions have good selective recognition and detection, and they have broad application prospects as ion detection sensors.

[0038] Sensitivity test ( Figure 8 ). Since the prepared crystal material has a strong affinity for Cr 3+ 、Al 3+ and Fe 3+The ions have obvious recognition and detection performance. The zinc complex crystal material is analyzed and tested by quantitative fluorescence titration method to evaluate the test sensitivity of the zinc complex crystal material as a sensor. With the increase of the concentration of Cr 3+ , Al 3+ or Fe 3+ ions, the fluorescence increases significantly. Within a certain concentration range, the fluorescence intensity has a good linear relationship with the ion concentration. The detection limit of Al 3+ is 0.30 μM, the detection limit of Fe 3+ is 0.37 μM, and the detection limit of Cr 3+ is 0.19 μM.

Claims

1. A zinc complex crystal material for fluorescent detection of metal ions, characterized in that: The composition structure of the zinc complex crystal material is [Zn2(L)2(L1)] n ; The crystal belongs to the triclinic system and the space group is The molecular formula is C 72 H 56 N2O8Zn2, molecular weight is 1207.92, unit cell parameters α=70.7410(10)°,β=84.2950(10)°,γ=68.2890(10)°;the asymmetric structural unit of the crystalline material includes a Zn(II) ion, an L ligand and an L1 ligand with an occupancy of 0.5;the Zn(II) ion adopts a hexacoordinated octahedral configuration, four oxygen atoms come from the carboxyl group of the ligand L, one nitrogen atom comes from the pyridinic nitrogen of the ligand L1, and the other position is occupied by Zn-Zn, and the distance between Zn-Zn is The coordination structural unit forms a two-dimensional layered structure through the bridging of ligands L and L1; the two-dimensional structure forms a three-dimensional network structure through intermolecular forces, CH…O interactions and π…π interactions, where the distance between H…O is The distance between adjacent surfaces acting on π…π is The structural formula [Zn2(L)2(L1)] n The ligand L in the middle is 3,3'-(9,9-diethyl-9H-fluorene-2,7-diyl)dibenzoic acid, and its molecular formula is C 31 H 26 O4, with a molecular weight of 462.55, has a simplified structural formula as shown in formula (I): The structural formula [Zn2(L)2(L1)] n The middle ligand L1, whose English name is 4,4'-bipyridine, has a molecular formula of C 10 H8N2, with a molecular weight of 156.18, has a simplified structural formula as shown in formula (II):

2. A method for preparing a zinc complex crystal material for fluorescent detection of metal ions according to claim 1, characterized in that: The preparation method comprises the following steps: Weigh a certain amount of ligand L, ligand L1 and zinc salt into a glass bottle, dissolve them in a mixed solution of DMF, anhydrous ethanol and distilled water, heat the vial containing the mixed solution at 75-95°C for 48-72 hours, and then cool to room temperature to obtain yellow block crystals, which are the zinc complex crystal material; The zinc salt is zinc nitrate hexahydrate; The molar ratio of the ligands L, L1 and the zinc salt is 1:1:

2.

3. Use of the zinc complex crystal material according to claim 1 or the zinc complex crystal material prepared by the preparation method of the zinc complex crystal material according to claim 2, characterized in that: The zinc complex crystal material is used as a material for fluorescent detection of metal ions in detecting Cr 3+ 、Al 3+ and Fe 3+ The zinc complex crystal material has application as a fluorescent sensor.

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