CN111484478A - Linear C2 symmetry compound, lanthanide polynuclear complex and preparation method and application thereof - Google Patents

Abstract

其通过将叠氮化合物和炔烃化合物在50～70℃下进行三氮唑关环反应得到。所述镧系多核配合物具有通式Ln_2nL_3n，其中Ln选自镧系元素，L为选自所述线性C2对称性化合物的有机配体，n选自1或2；其制备方法包括将镧系元素Ln前驱体和有机配体L在30～50℃下反应。根据本申请的线性C2对称性化合物包含三氮唑‑吡啶‑酰胺螯合基团，其可提高配体中间发色团到稀土中心能量传递的效率，并改善镧系高核数配合物的构筑，由此得到的配合物具有强的发光性能，且包括高核数的镧系有机多面体笼。The present application discloses a linear C2 symmetry compound, a lanthanide series multinuclear complex and a preparation method and application thereof, belonging to the field of photochemical supramolecules. The linear C2 symmetry compound structural formula is as follows:

It is obtained by subjecting an azide compound and an alkyne compound to a triazole ring-closure reaction at 50-70°C. The lanthanide polynuclear complex has the general formula Ln _2n L _3n , wherein Ln is selected from lanthanide elements, L is an organic ligand selected from the linear C2 symmetry compound, and n is selected from 1 or 2; the preparation method thereof includes: The lanthanide Ln precursor and the organic ligand L are reacted at 30-50°C. The linear C2 symmetry compound according to the present application contains a triazole-pyridine-amide chelating group, which can improve the efficiency of energy transfer from the intermediate chromophore of the ligand to the rare earth center and improve the construction of lanthanide high nuclear number complexes , the resulting complexes have strong luminescence properties and include lanthanide organic polyhedral cages with high nuclear numbers.

Description

Linear C2 symmetry compound, lanthanide polynuclear complex and preparation method and application thereof

technical field

The present application relates to a linear C2 symmetry compound, a lanthanide polynuclear complex, a preparation method and application thereof, and belongs to the field of photochemical supramolecules.

Background technique

Coordination-driven self-assembly has gradually become a mature technology for constructing functional supramolecular structures. However, compared with the widely studied transition metal ions, studies on the construction of supramolecular assemblies with trivalent lanthanide metal ions as nodes are rarely reported. Despite the rich optical, electrical and magnetic properties of lanthanides, the synthesis of their high nuclear number assemblies is still limited by their weak coordination ability, variable coordination number, and poor stereoselectivity. In addition, the current fluorescence quantum yield of multinuclear rare earth complexes is difficult to exceed 6%, which greatly limits the application research of polynuclear rare earth complexes in the field of optics. Therefore, it is of great significance to carry out research to design and construct lanthanide organic complexes with fine structures and complex functions.

In the construction of three-dimensional metal supramolecular structures, the introduction of lanthanides is expected to impart unique optical properties, such as sharp linear spectra, large Stokes shifts, and long fluorescence lifetimes. However, so far, the fluorescence quantum yield of multinuclear lanthanide complexes is still very limited. In most cases, lanthanides only serve as connecting nodes, which is a big pity for lanthanide organic complexes. Therefore, from the viewpoint of improving the luminescence intensity, it is urgent to synthesize new organic ligands to realize the synthesis of lanthanide multinuclear complexes with strong luminescence.

In the synthesis of lanthanide organic polyhedral complexes, from the perspective of symmetry, the construction of polyhedral complexes should introduce symmetry elements in the synthesis of organic ligands. For example, to construct _Ln2L3 complexes with _D3 symmetry, _C2 and _C3 symmetry axes should be introduced into the design _of ligand and lanthanide coordination geometries. Compared with ectopic C2 _- symmetric ligands, the design of linear ligands is more favorable to maximize the internal cavity and window size of the cage. However, so far, almost all Ln ₂ L ₃ triple helixes have been assembled by linear ligands bridged by benzene or biphenyl and lanthanides. Therefore, the synthesis of high-nucleus lanthanide organic polyhedra based _on linear C symmetric ligands is still an urgent problem to be solved.

SUMMARY OF THE INVENTION

According to one aspect of the present application, there is provided a linear C2 symmetric compound comprising a triazole-pyridine-amide (tpa) chelating group, which can not only improve the chelation of linear C2 ligands by It can improve the construction of lanthanide complexes with high nuclear number, and can improve the efficiency of energy transfer from the intermediate chromophore of the ligand to the rare earth center by overcoming the energy dissipation caused by the vibration of the internal amide bond.

The linear C2 symmetry compound is characterized in that it has the structural formula shown in formula I:

中的一种，k＝1～6；wherein, R is selected from C ₃ -C ₁₂ alkyl, C ₈ -C ₁₂ aralkyl and

One of them, k=1～6;

选自以下基团中的一种：

One of the following groups:

Illustratively, in the above groups, the dashed lines indicate that a bond, such as a covalent bond, can be formed at the corresponding position. Hereinafter, dashed lines drawn in similar cases have the same meaning as here.

Alternatively, in formula I, R is selected from one of the following groups:

选自具有式I-1所示结构式的基团中的一种：Optionally, in formula I,

One of the groups selected from the group having the structural formula shown in formula I-1:

where m=1, 2 or 3.

选自

中的一种。In one embodiment,

selected from

one of the.

According to another aspect of the present application, there is provided a preparation method of the linear C2-symmetrical compound, which can modify a triazole-pyridine-amide (tpa) chelating group on a linear C2 _- symmetrical ligand.

The preparation method of the linear C2 symmetry compound is characterized in that, comprising:

reacting the mixture containing the azide compound and the alkyne compound at 50-70° C. to obtain the linear C2 symmetry compound;

Wherein, the reaction is a triazole ring-closing reaction;

The azide compound is selected from at least one of the compounds having the structural formula shown in formula II:

The alkyne compound is selected from at least one of the compounds having the structural formula shown in formula III:

The azide compound can be prepared by using suitable raw materials by referring to known methods, for example, by the method described in the examples of the present application.

The alkyne compound can be prepared by using suitable raw materials by referring to known methods, for example, by the methods described in the examples of the present application.

Optionally, the upper limit of the temperature of the reaction is selected from 70°C, 68°C, 66°C, 64°C, 62°C, 60°C, 58°C, 56°C, 54°C, 52°C, and the lower limit is selected from 50°C, 52°C °C, 54 °C, 56 °C, 58 °C, 60 °C, 62 °C, 64 °C, 66 °C, 68 °C.

Preferably, the temperature of the reaction is 60°C.

Optionally, the reaction time is 12-36 hours.

Optionally, the upper limit of the reaction time is selected from 36 hours, 32 hours, 28 hours, 24 hours, 20 hours, 16 hours, and the lower limit is selected from 12 hours, 16 hours, 20 hours, 24 hours, 28 hours, 32 hours. Hour.

Preferably, the reaction time is 24 hours.

Optionally, the molar ratio of the azide compound to the alkyne compound is 1:2˜1:4.

Optionally, the upper limit of the molar ratio of the azide compound to the alkyne compound is selected from 1:4, 1:3.75, 1:3.5, 1:3.25, 1:3, 1:2.75, 1:2.5, 1:2.25, the lower limit is selected from 1:2, 1:2.25, 1:2.5, 1:2.75, 1:3, 1:3.25, 1:3.5, 1:3.75.

Preferably, the molar ratio of the azide compound to the alkyne compound is 1:2.5˜1:3.

Optionally, the mixture further comprises ketone sulfate and sodium ascorbate.

Optionally, the molar ratio of the ketone sulfate to the azide compound is 0.8:1 to 1:1.

Optionally, the upper limit of the molar ratio of the sulfate ketone to the azide compound is selected from 1:1, 0.99:1, 0.98:1, 0.97:1, 0.96:1, 0.95:1, 0.94:1, 0.93: 1, 0.92:1, 0.91:1, 0.9:1, the lower limit is selected from 0.8:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, 0.86:1, 0.87:1, 0.88 :1, 0.89:1, 0.9:1, 0.91:1.

Preferably, the molar ratio of the sulfate ketone to the azide compound is 0.9:1 to 0.91:1.

Optionally, the molar ratio of the sodium ascorbate to the azide compound is 1.5:1˜2.5:1.

Optionally, the upper limit of the molar ratio of the sodium ascorbate to the azide compound is selected from 2.5:1, 2.4:1, 2.3:1, 2.2:1, 2.1:1, 2:1, 1.9:1, 1.8 :1, 1.7:1, 1.6:1, the lower limit is selected from 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1.

Preferably, the molar ratio of the sodium ascorbate to the azide compound is 2.1:1.

Optionally, the mixture further comprises a solvent.

Optionally, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethylsulfoxide/methanol.

Preferably, the solvent is N,N-dimethylformamide.

Optionally, the reaction is carried out with stirring.

Optionally, after the reaction, the resultant is separated and purified.

In a specific embodiment, the preparation method of the linear C2 symmetry compound comprises:

Among them, HATU is 2-(7-azobenzotriazole)-N,N,N',N'-tetramethylurea hexafluorophosphate, DMF is N,N-dimethylformamide, THF is tetrahydrofuran, TMSA is trimethylsilylacetylene, TEA is triethylamine, RT is room temperature, and SA is sodium ascorbate.

According to yet another aspect of the present application, a lanthanide polynuclear complex is provided, the lanthanide polynuclear complex has strong luminescence properties, and includes a lanthanide organic polyhedral cage with a high nuclear number (based on linear C ₂ symmetry ligands ).

The lanthanide polynuclear complex is characterized in that it has the general formula shown in formula VI:

Ln _2n L _3n formula IV wherein, Ln is selected from a kind of lanthanide;

L is an organic ligand, which is selected from one of the above-mentioned linear C2 symmetric compounds and the linear C2 symmetric compounds prepared according to the above method;

n is selected from 1 or 2;

Among them, nitrogen atoms and oxygen atoms in L coordinate with Ln.

Optionally, Ln is selected from one of Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm and Yb.

Optionally, n=2, and the lanthanide polynuclear complex is a lanthanide tetrahedral cage.

Optionally, the lanthanide tetrahedral cage is selected from at least one of compounds having the structural formula shown in formula V:

代表Ln；in,

represents Ln;

选自以下基团中的一种：

One of the following groups:

Illustratively, in Formula V, the dashed lines between the O and N atoms and the lanthanide Ln indicate the formation of coordinate bond linkages. Hereinafter, dashed lines drawn in similar cases have the same meaning as here.

Optionally, n=1, and the lanthanide polynuclear complex has a triple helix structure.

选自以下基团中的一种：Optionally,

One of the following groups:

According to yet another aspect of the present application, there is provided a preparation method of the lanthanide polynuclear complexes, which can quantitatively and efficiently synthesize lanthanide polynuclear complexes with strong luminescence properties, especially based on linear C ₂ symmetry ligands of lanthanide organic polyhedral cages with high nuclear numbers.

The preparation method of the lanthanide polynuclear complex is characterized in that, comprising:

The lanthanide polynuclear complex is obtained by reacting the mixture containing the lanthanide Ln precursor and the organic ligand L at 30-50°C.

Optionally, the lanthanide Ln precursor is selected from at least one of Eu(OTf) ₃ , Sm(OTf) ₃ , Eu(OTf) ₃ , DyOTf) ₃ .

Optionally, the molar ratio of the lanthanide Ln precursor to the organic ligand L is 1:1 to 1:2, wherein the mole number of the lanthanide Ln precursor is the corresponding mole of the lanthanide Ln. count.

Optionally, the upper limit of the molar ratio of the lanthanide Ln precursor to the organic ligand L is selected from 1:2, 1:1.9, 1:1.8, 1:1.7, 1:1.6, 1:1.5, 1:1.4, 1:1.3, 1:1.2, 1:1.1, the lower limit is selected from 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7 , 1:1.8, 1:1.9, wherein the moles of lanthanide Ln precursors are calculated by the moles of the corresponding lanthanide Ln.

Preferably, the molar ratio of the lanthanide Ln precursor to the organic ligand L is 1:1.5, wherein the moles of the lanthanide Ln precursor are counted as the moles of the corresponding lanthanide Ln.

Optionally, the upper limit of the temperature of the reaction is selected from 50°C, 48°C, 46°C, 44°C, 42°C, 40°C, 38°C, 36°C, 34°C, 32°C, and the lower limit is selected from 30°C, 32°C °C, 34 °C, 36 °C, 38 °C, 40 °C, 42 °C, 44 °C, 46 °C, 48 °C.

Preferably, the temperature of the reaction is 40°C.

Optionally, the reaction time is 0.5-1.5 hours.

Optionally, the upper limit of the reaction time is selected from 1.5 hours, 1.25 hours, 1 hour, and 0.75 hours, and the lower limit is selected from 0.5 hours, 0.75 hours, 1 hour, and 1.25 hours.

Preferably, the reaction time is 1 hour.

Optionally, the mixture further comprises a solvent.

Optionally, the solvent is selected from at least one of acetonitrile, methanol, and nitromethane.

Preferably, the solvent is a mixture of acetonitrile and methanol in a volume ratio of 4:1.

Optionally, the reaction is carried out with stirring.

In one embodiment, the preparation method of the lanthanide polynuclear complex comprises the following steps:

Weigh organic ligands and lanthanide metal salts (molar ratio of 3:2) respectively, dissolve them in a certain volume of deuterated acetonitrile/deuterated methanol (v/v=4:1) mixed solution, and heat them at 40 °C. After stirring for about 1 hour, the reaction solution was observed to gradually become clear from turbidity, and the reaction progress was monitored by nuclear magnetic resonance. After the reaction, the product can be obtained by distillation under reduced pressure.

In a specific embodiment, the lanthanide polynuclear complex is a lanthanide tetrahedral cage, which is prepared by the following process:

代表Ln³⁺；in,

represents Ln ³⁺ ;

选自以下基团中的一种：

One of the following groups:

According to yet another aspect of the present application, at least one of the above-mentioned linear C2-symmetric compound, the linear C2-symmetrical compound prepared according to the above-mentioned method, the above-mentioned lanthanide polynuclear complex, and the lanthanide series polynuclear complex prepared according to the above-mentioned method is provided An application in photochemical supramolecular devices.

In the context of the present application, the expressions "C ₃ -C ₁₂ ", "C ₈ -C ₁₂ ", etc. refer to the number of carbon atoms contained in the compound or group.

In the context of this application, the term "alkyl" means a group formed by the loss of any hydrogen atom on the molecule of an alkane compound, including straight chain alkanes, branched chain alkanes, cycloalkanes, branched Naphthenic.

In the context of this application, the term "aralkyl" means a group consisting of an alkyl moiety and an aryl moiety through which the alkyl moiety is attached to the body of the molecule.

In the context of this application, the term "OTf" means _CF3SO3- , a group formed by the loss _of one hydrogen atom of trifluoromethanesulfonic acid.

In the context of this application, the symbol "*" means a chiral center in a molecule or group.

In the present application, in view of the problems of how to improve the fluorescence properties of lanthanide polynuclear complexes and how to efficiently construct high-nucleus lanthanide organic polyhedra, the applicant has made creative work and has now found that: 1) By introducing tpa as a chelating agent group, which can overcome the energy dissipation caused by the vibration of the original internal amide bond, thereby improving the efficiency of energy transfer from the intermediate chromophore of the ligand to the rare earth center; 2) Using tpa as a chelating group can effectively improve the linear C ₂ complex The chelation angle of the body is favorable for the construction of high nuclear number lanthanide complexes.

Specifically, in this application, by modifying the triazole-pyridine-amide (tpa) chelating arm on a linear C symmetric ligand, not only the chelation angle (coordination vector and direction along the bridging unit ₎ can be effectively optimized The symmetry axis of lanthanide), constructing lanthanide organic polyhedra with higher nuclear number, and can greatly improve the sensitization efficiency of lanthanide elements. Different from the related art in which the C ₂ symmetrical ligand using biphenyl as the linker can only obtain Ln ₂ L ₃ triple helix, according to the present application, the organic ligand using tpa as the chelating group is more inclined to form Ln ₄ L The tetrahedral structure of ₆ is mainly attributed to the large chelation angle that effectively inhibits triple helix formation. Among them, the chelation angle can be increased from the conventional 60° (in the case of the ligand with pyridine diamide as the chelating group) to 95.8°. From this, it can be expected that the method of increasing the chelation angle on the C2 _- symmetric ligands provides a new route for the construction of lanthanide complexes with higher nuclear numbers.

The beneficial effects that this application can produce include:

1) The linear C2 symmetry compound provided by this application, the tpa chelating group contained in it can not only improve the efficiency of energy transfer from the intermediate chromophore of the ligand to the rare earth center, but also improve the construction of lanthanide high nuclear number complexes .

2) The linear C2 symmetry compound provided by the present application can realize the extension of the excitation window to the visible light region through ligand design, thereby providing the possibility for biological imaging research.

3) The lanthanide polynuclear complexes provided by the present application have strong luminescence properties and include lanthanide organic polyhedral cages with high nuclear numbers based on linear C ₂ symmetric ligands.

4) The preparation method provided in this application can quantitatively synthesize target products, synthesize rare earth polyhedral cages with strong fluorescence properties by introducing suitable sensitizing groups, and can efficiently synthesize rare earth polyhedral cages with high nuclei.

Description of drawings

Fig. 1 is the ultraviolet-visible absorption spectra of the organic ligands L ₁ ^SS , L ₂ ^SS and L ₃ ^SS prepared in Example 1 of the present application (the solvent is dichloromethane, c=1×10 ^-5 M).

Fig. 2 is the ultraviolet-visible absorption spectrum (solvent) of the lanthanide polynuclear complexes Eu ₄ (L ₁ ^SS ) ₆ , Eu ₄ (L ₂ ^SS ) ₆ and Eu ₂ (L ₃ ^SS ) ₃ prepared in Examples 3-5 of the present application as acetonitrile, c=1 x ^10-5 M).

3 is the excitation spectrum (λ _ex =615nm) and emission spectrum (λ _em =615nm, c=1.0×10 ⁻⁵ M) of the lanthanide polynuclear complex Eu ₂ (L ₃ ^SS ) ₃ prepared in Example 5 of the present application .

Detailed ways

As mentioned above, in the research field of rare earth polyhedral cages, the lack of research on cages with high nuclear number and the poor luminescence properties of cages need to be solved urgently. In this application, a series of ligands with triazole-pyridine-amide (tpa) as the chelating group are designed and synthesized, which not only improves the chelation angle of the ligands, but also effectively inhibits the formation of low-nucleus-number assemblies. , and significantly improved the fluorescence quantum yield of multinuclear rare earth cages (for example, up to 42.4%), realizing the efficient preparation of a series of strong fluorescent lanthanide polynuclear complexes, especially lanthanide polyhedral cages.

The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials and reagents in the examples of this application were purchased through commercial channels, and were not further purified before use, wherein the deuterated solvent was purchased from Adamas and Bailingwei Technology Co., Ltd., and triethylamine was prepared with calcium hydride. In addition to water.

The analytical method in the embodiment of the present application is as follows:

One-dimensional and two-dimensional NMR spectra were measured by Bruker Biospin Avance III (400MHz) NMR analyzer. The determination of the chemical shift value of the hydrogen spectrum is based on the residual peak of the deuterated solvent. High-resolution mass spectrometry (ESI-TOF-MS) was measured by Bruker Impact II UHR-TOF mass spectrometer, Germany. Fluorescence excitation and emission spectra were measured by a FS5 fluorescence spectrometer in Edinburgh, UK. Fluorescence quantum yields were measured with a SC-30 integrating sphere in Edinburgh, UK. UV-Vis absorption spectra were measured on a Shimadzu UV-2700 spectrophotometer.

Example 1: Synthesis of organic ligands L ₁ ^SS , L ₂ ^SS and L ₃ ^SS

In the present embodiment, benzene, biphenyl and terphenyl are used as linkers respectively, and the bridging periphery is naphthylethylamine, and the synthetic route of the corresponding organic ligand is as follows:

(1) Synthesis of Intermediate 2

6-Bromopicolinic acid (5g, 24.8mmol), S-naphthylethylamine (4.25g, 24.8mmol), HATU (18.8g, 49.50mmol), DMF (30mL) and triethylamine (3mL) were added to a 100mL two-necked flask middle. The reaction solution was then stirred at 0°C for 15 hours. After the reaction, the solvent was distilled off under reduced pressure, and the product was separated by column chromatography (eluent: V (dichloromethane)/V (petroleum ether)=5:1) to obtain a colorless oil (6.25 g, 71% yield). ¹ H NMR (400MHz, CDCl ₃ , 298K) δ 8.19 (d, J=7.7 Hz, 2H), 8.11 (d, J=8.3 Hz, 1H), 7.88 (d, J=7.8 Hz, 1H), 7.82 (d, J=8.2Hz, 1H), 7.67 (t, J=7.8Hz, 1H), 7.62 (d, J=7.1Hz, 1H), 7.58–7.52 (m, 2H), 7.48 (dd, J= 10.2, 5.2Hz, 2H), 6.15 (s, 1H), 1.79 (d, J=6.8Hz, 3H); ¹³ C NMR (101MHz, CDCl ₃ , 298K) δ 161.77, 150.97, 140.58, 139.64, 138.14, 133.97, 131.15, 130.79, 128.88, 128.44, 126.59, 125.85, 125.36, 123.33, 122.77, 121.51, 44.91, 21.16; ESI-TOF-MS:calcd for C ₉ H ₁₁ BrN ₂ O,m/z377.0260[M+Na] ⁺ ; found: 377.0256. The above-mentioned method obtained the target product intermediate 2.

(2) Synthesis of Intermediate 3

Intermediate 2 (5.0 g, 14.1 mmol), CuI (537.1 mg, 2.82 mmol) and Pd(PPh ₃ ) ₄ (814.7 mg, 0.705 mmol) were added to a three-necked round bottom flask, and the reaction mixture was dissolved in anhydrous TEA/ In a mixed solvent of THF (80 mL, v/v=1:1), trimethylsilylacetylene (2.08 g, 21.2 mmol) was added dropwise, and the mixture was stirred at room temperature overnight. After the reaction, the solvent was distilled off under reduced pressure, and the product was separated by column chromatography (eluent: V (dichloromethane)/V (petroleum ether)=2:1) to obtain a colorless oil (3.6 g, Yield 68.3%). ¹ H NMR (400MHz, DMSO, 298K)δ8.97(d,J=8.5Hz,1H),8.20(d,J=8.3Hz,1H),8.04(d,J=6.8Hz,1H),7.97( t, J=7.8Hz, 1H), 7.93(d, J=7.8Hz, 1H), 7.83(d, J=8.2Hz, 1H), 7.71(d, J=7.6Hz, 1H), 7.65(d, J=7.0Hz, 1H), 7.55 (t, J=6.8Hz, 1H), 7.53–7.44 (m, 2H), 6.00 (p, J=6.9Hz, 1H), 1.66 (d, J=6.9Hz, 3H), 0.22(s, 9H); ¹³ C NMR (101MHz, DMSO, 298K) δ 162.38, 150.52, 140.78, 139.34, 138.39, 133.32, 130.46, 130.18, 128.66, 127.45, 126.23, 125.55, 125.3 103.48, 95.32, 44.39, 20.93, -0.50; ESI-TOF-MS: calcd for C ₁₄ H ₂₀ N ₂ OSi, m/z395.1550[M+Na] ⁺ ; found: 395.1545. The above method obtained the intermediate of the target product body 3.

(3) Synthesis of Intermediate 4

To a solution of Intermediate 3 (3.6 g, 9.7 mmol) in methanol (80 mL) was added KF (620.0 mg, 10.7 mmol), followed by stirring at room temperature for 6 hours. After the reaction, the solvent was distilled off under reduced pressure, and the product was separated by column chromatography (eluent: dichloromethane) to obtain a colorless oil (2.9 g, yield 99.8%). ¹ H NMR (400 MHz, CDCl ₃ ) δ 8.24 (t, J=8.8 Hz, 2H), 8.18 (d, J=8.4 Hz, 1H), 7.86 (d, J=7.9 Hz, 1H), 7.81 (t , J=7.8Hz, 2H), 7.62 (d, J=7.1Hz, 1H), 7.59–7.55 (m, 1H), 7.54–7.50 (m, 1H), 7.50–7.45 (m, 2H), 6.14 ( m, J=13.9, 6.9Hz, 1H), 3.16 (s, 1H), 1.78 (d, J=6.8Hz, 3H); ¹³ C NMR (101MHz, CDCl ₃ , 298K) δ 162.39, 150.25, 140.75, 138.23, 137.65,133.96,131.19,129.97,128.71,128.37,126.53,125.79,125.31,123.39,122.76,122.32,82.19,77.87,44.79,21.10; ESI-TOF-MS: _calcd , forC z ₁₁ H ₁₂ 323.1155[M+Na] ⁺ ; found: 323.1154. The above method obtained the target product Intermediate 4.

(4) Synthesis of 1,4-diazidobenzene

Under a nitrogen atmosphere, 1,4-dibromobenzene (2.36 g, 10 mmol), NaN ₃ (2.6 g, 40 mmol), CuI (0.38 g, 2.0 mmol) and NaOH (0.24 g, 3.0 mmol) were dissolved in THF /H ₂ O (20 mL, V(THF)/V(H ₂ O)=7:3). The reaction mixture was stirred at 95°C for 4 hours. After the reaction was completed, the reaction solution was cooled to room temperature, an equal volume of a mixture of ethyl acetate and water was added, the layers were separated, the lower organic phase was taken out, and the ethyl acetate was spin-dried. The product was isolated by column chromatography (eluent: petroleum ether) to give a yellow powder (456 mg, 60.0% yield). ¹ H NMR (400MHz, CDCl ₃ , 298K): 7.01 (s, 4H, ArH). The above method obtained the target product 1,4-diazidobenzene.

(5) Synthesis of 4,4'-Diazidebiphenyl

An aqueous solution (c=2.4 mol/L) of sodium nitrite (1.65 g, 24 mmol) was added to a dilute acid solution (c=2.0 mol/L) of benzidine (737 mg, 4 mmol). After stirring for two hours, an aqueous solution of sodium azide (650 mg, 10 mmol) (c=1.0 mol/L) was added dropwise, and stirring was continued for 2 hours. Filtration and drying gave pale yellow powder (756 mg, 80.0% yield). ¹ HNMR (400MHz, CDCl ₃ , 298K)δ7.55(d,J=8.4Hz,4H),7.10(d,J=8.4Hz,4H). The above method obtained the target product 4,4'-diazide Biphenyl.

(6) Synthesis of 4,4'-diazide terphenyl

An aqueous solution of sodium nitrite (1.93 g, 28 mmol) (c=2.8 mol/L) was added to a dilute acid solution of terbenzidine (1.0 g, 3.84 mmol) (c=2.0 mol/L). After stirring for two hours, an aqueous solution of sodium azide (624 mg, 9.6 mmol) (c=0.96 mol/L) was added dropwise, and stirring was continued for 2 hours. Filtration and drying gave pale yellow powder (546 mg, 45.6% yield). ¹ H NMR (400MHz, CDCl ₃ , 298K)δ7.53(d,J=7.4Hz,4H),7.43(d,J=7.4Hz,4H),7.25(s,4H). The above method obtained the target product 4,4'-Diazide terphenyl.

(7) Synthesis of organic ligand L ₁ ^SS

1,4-Benzene diazide (160 mg, 1.0 mmol) and intermediate ₄ (901 mg, 3 mmol) were added to sodium ascorbate (411 mg, 2.1 mmol) and CuSO4.5H2O ( ₂₂₅ mg, 0.9 mmol) in DMF (50 mL) ) in the solution. The reaction solution was stirred at 60°C for 24 hours. The reaction solution was filtered, the filtrate was distilled under reduced pressure, and further separated by column chromatography (eluent: V (dichloromethane)/V (methanol)=100:1) to obtain a pale yellow solid powder (456 mg, the yield was 60.0%). ¹ H NMR (400MHz, CDCl ₃ , 298K) δ 8.59 (d, J=8.5 Hz, 2H), 8.46 (s, 2H), 8.21 (d, J=7.6 Hz, 4H), 8.11 (d, J= 8.4Hz, 2H), 7.95(t, J=7.8Hz, 2H), 7.80(d, J=7.9Hz, 2H), 7.77(s, 4H), 7.74(d, J=8.2Hz, 2H), 7.59 (d, J=7.1Hz, 2H), 7.50–7.43 (m, 2H), 7.43–7.35 (m, 4H), 6.05 (p, J=6.9Hz, 2H), 1.77 (d, J=6.8Hz, 6H)； ¹³ C NMR(101MHz,CDCl ₃ ,298K)δ163.24,149.82,148.14,148.08,138.53,138.37,136.58,133.88,131.15,128.78,128.33,126.49,125.82,125.13,123.38,123.12,122.84,122.16, 121.54, 120.25, 45.21, 20.93; ESI-TOF-MS: calcd forC ₅₇ H ₅₁ N ₁₅ O ₃ , m/z 783.2915[M+Na] ⁺ ; found: 783.2910. The above method obtained the target product organic ligand L ₁ ^SS .

(8) Synthesis of organic ligand L ₂ ^SS

4,4' _- Diazidebiphenyl (236 mg, 1.0 mmol) and Intermediate ₄ (901 mg, 3 mmol) were added to sodium ascorbate (411 mg, 2.1 mmol) and CuSO4.5H2O (225 mg, 0.9 mmol) in DMF (50 mL) solution. The reaction solution was stirred at 60°C for 24 hours. The reaction solution was filtered, the filtrate was distilled under reduced pressure, and further separated by column chromatography (eluent: V (dichloromethane)/V (methanol)=100:1) to obtain a pale yellow solid powder (628 mg, the yield was 75.1%). ¹ H NMR (400MHz, CDCl ₃ , 298K) δ 8.41 (s, 2H), 8.37 (dd, J=7.8, 0.8 Hz, 2H), 8.32 (d, J=8.6 Hz, 2H), 8.27 (dd, J=7.8,0.8Hz,2H),8.20(d,J=8.4Hz,2H),8.00(t,J=7.8Hz,2H),7.87(d,J=7.8Hz,2H),7.82(dd, J=8.2,6.3Hz,6H),7.72(d,J=8.6Hz,4H),7.64(d,J=7.1Hz,2H),7.53(t,J=7.0Hz,2H),7.47(dd, J=14.7, 7.2Hz, 4H), 6.17-6.09 (m, 2H), 1.84 (d, J=6.8Hz, 6H); ¹³ CNMR (101 MHz, CDCl ₃ , 298K) δ 163.04, 149.76, 148.57, 148.11, 140.14 ,138.44,138.36,136.40,134.00,131.27,128.84,128.45,128.30,126.60,125.90,125.20,123.56,123.18,122.91,122.04,121.00,119.99,45.23,21.11；ESI-TOF-MS:calcd for C ₅₇ H ₅₁ N ₁₅ O ₃ , m/z 859.3228[M+Na] ⁺ ; found: 859.3213. The above method obtained the target product organic ligand L ₂ ^SS .

(9) Synthesis of organic ligand L ₃ ^SS

4,4' _- Diazide terphenyl (312 mg, 1.0 mmol) and intermediate ₄ (901 mg, 3 mmol) were added to sodium ascorbate (411 mg, 2.1 mmol) and CuSO4.5H2O (225 mg, 0.9 mmol) in DMF (50 mL) solution. The reaction solution was stirred at 60°C for 24 hours. The reaction solution was filtered, the filtrate was distilled under reduced pressure, and further separated by column chromatography (eluent: V (dichloromethane)/V (methanol)=100:1) to obtain a pale yellow solid powder (502 mg, the yield was 55.0%). ¹ H NMR (400MHz, CDCl ₃ , 298K) δ 8.40 (d, J=8.6 Hz, 2H), 8.38 (s, 2H), 8.33 (d, J=7.8 Hz, 2H), 8.24 (t, J= 8.1Hz, 2H), 8.18(d, J＝8.4Hz, 2H), 7.95(t, J＝7.8Hz, 2H), 7.84(d, J＝7.7Hz, 2H), 7.78(d, J＝8.2Hz ,2H),7.74(d,J＝8.5Hz,4H),7.70–7.59(m,10H),7.50(dd,J＝11.2,4.1Hz,2H),7.44(dd,J＝16.3,8.2Hz, 4H), 6.16-6.06 (m, 2H), 1.83 (d, J=6.8Hz, 6H); ¹³ C NMR (101MHz, CDCl ₃ , 298K) δ 163.11, 149.74, 148.61, 148.00, 140.89, 138.98, 138.41, 136.00 , _{133.97,131.26,128.83,128.40,128.09,127.54,126.57,125.88,125.19,123.53,123.12,122.93,121.98,120.85,120.05,45.20,29.72,21.11.CalcESId for} C ₁₅ O ₃ , m/z 935.3541[M+Na] ⁺ ; found: 935.3531. The target product organic ligand L ₃ ^SS was obtained by the above method.

Example 2: Synthesis of Lanthanide Polynuclear Complex Eu ₄ (L ₁ ^SS ) ₆

To a mixed solution of organic ligand L ₁ ^SS (5 mg, 6.6 μmol) in 500 μL of CD ₃ CN/CD ₃ OD (v/v=4:1) was added Eu(OTf) ₃ (2.64 mg, 4.4 μmol), and Stir at 40°C for 1 hour. The white suspension gradually turned into a clear yellow solution. The reaction solution was spin-dried to obtain a pale yellow powder (7.2 mg, 94% yield). ¹ H NMR (400MHz, CD ₃ CN, 298K) δ 9.57(d, J=8.1Hz, 12H), 9.37(s, 12H), 8.85(s, 24H), 8.65(s, 12H), 8.12(t , J=7.3Hz, 12H), 7.57–7.41 (m, 24H), 6.94 (d, J=8.3Hz, 12H), 6.14 (t, J=7.7Hz, 12H), 5.53 (t, J=7.9Hz) ,12H),5.40(d,J＝6.7Hz,12H),4.34-4.16(m,24H),2.36(d,J＝5.5Hz,36H); 13C NMR(101MHz,CD3CN,298K)δ171.02,159.78, 150.93,149.81,140.40,140.22,135.96,135.67,133.57,130.33,129.98,129.70,127.68,127.65,126.78,124.86,123.36,122.67,122.54,119.87,119.36,113.20,103.93,94.60,91.46,85.37,82.09, 22.79.ESI-TOF-MS:calcd.For[Eu ₄ (L ₁ ^SS ) ₆ (OTf) ₄ ] ⁸⁺ 721.1636,found 721.1652; calcd.For[Eu ₄ (L ₁ ^SS ) ₆ (OTf) ₅ ] ^{7 +} 845.4659, found 845.4669; calcd.For[Eu ₄ (L ₁ ^SS ) ₆ (OTf) ₆ ] ⁶⁺ 1011.2022, found 1011.2031; calcd.For[Eu ₄ (L ₁ ^SS ) ₆ (OTf) ₇ ] ⁵⁺ 1243.2332 , found1243.2347; calcd.For[Eu ₄ (L ₁ ^SS ) ₆ (OTf) ₈ ] ⁴⁺ 1591.2795, found 1591.2808. The above method obtained the target product lanthanide multinuclear complex Eu ₄ (L ₁ ^SS ) ₆ , which For the lanthanide tetrahedral cage.

Example 3: Synthesis of Lanthanide Polynuclear Complex Eu ₄ (L ₂ ^SS ) ₆

Eu(OTf) ₃ (1.0 mg, 1.6 μmol) was added to a mixed solution of organic ligand L ₂ ^SS (2 mg, 2.4 μmol) in 500 μL of CD ₃ CN/CD ₃ OD (v/v=4:1), and Stir at 40°C for 1 hour. The white suspension gradually turned into a clear yellow solution. The reaction solution was spin-dried to obtain a pale yellow powder (2.86 mg, 95.3% yield). ¹ H NMR (400MHz, CD ₃ CN, 298K) δ 9.57(d, J=8.1Hz, 12H), 9.37(s, 12H), 8.85(s, 24H), 8.65(s, 12H), 8.12(t , J=7.3Hz, 12H), 7.57–7.41 (m, 24H), 6.94 (d, J=8.3Hz, 12H), 6.14 (t, J=7.7Hz, 12H), 5.53 (t, J=7.9Hz) , 12H), 5.40 (d, J=6.7Hz, 12H), 4.34-4.16 (m, 24H), 2.36 (d, J=5.5Hz, 36H); ¹³ C NMR (101MHz, CD ₃ CN, 298K) δ170 .71,150.74,142.02,140.41,135.85,134.18,133.65,130.01,129.75,129.11,127.75,127.60,126.75,124.94,123.35,122.47,122.16,119.90,114.28,103.42,94.54,85.13,22.79.ESI-TOF-MS :calcd.For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₂ ] ¹⁰⁺ 592.7593, found592.7594; calcd.For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₃ ] ⁹⁺ 675.1717, found 675.1723; calcd.For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₄ ] ⁸⁺ 778.1872, found 778.1869; calcd.For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₅ ] ⁷⁺ 910.6357, found 910.6357; calcd. For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₆ ] ⁶⁺ 1087.2337, found 1087.2337; calcd.For[Eu ₄ (L ₂ ^SS ) ₆ (OTf) ₇ ] ⁵⁺ 1334.4709, found 1334.4706; calcd.For[ Eu ₂ (L ₂ ^SS ) ₃ (OTf) ₀ ] ⁶⁺ 469.1406, found 469.1415; calcd.For[Eu ₂ (L ₂ ^SS ) ₃ (OTf) ₁ ] ⁵⁺ 592.7590, found 592.7594; calcd.For[Eu ₂ (L ₂ ^SS ) ₃ (OTf) ₂ ] ⁴⁺ 778.1 871,found 778.1869; calcd.For[Eu ₂ (L ₂ ^SS ) ₃ (OTf) ₃ ] ³⁺ 1087.2336, found 1087.2337; calcd.For[Eu ₂ (L ₂ ^SS ) ₃ (OTf) ₄ ] ²⁺ 1705.3267, found1705.3273. The above method obtained the target product lanthanide polynuclear complex Eu ₄ (L ₂ ^SS ) ₆ , which is a lanthanide tetrahedral cage.

Example 4: Synthesis of Lanthanide Polynuclear Complex Eu ₂ (L ₃ ^SS ) ₃

To the organic ligand L ₃ ^SS (3 mg, 3.3 μmol) in 500 μL of CD ₃ CN/CD ₃ OD (v/v=4:1) mixed solution was added Eu(OTf) ₃ (1.3 mg, 2.2 μmol), and Stir at 40°C for 1 hour. The white suspension gradually turned into a clear yellow solution. The reaction solution was spin-dried to obtain a pale yellow powder (4.2 mg, yield 97.6%). ¹ H NMR (400MHz, CD ₃ CN, 298K) δ 8.48 (s, 6H), 8.09 (d, J=8.2 Hz, 6H), 7.97 (d, J=8.1 Hz, 6H), 7.75 (t, J =7.3Hz,6H),7.72-7.66(m,6H),7.63(d,J=8.3Hz,6H),7.42(d,J=8.2Hz,12H),7.30(d,J=8.1Hz,12H) ),7.20(s,12H),7.05(t,J＝7.7Hz,6H),6.89(d,J＝7.0Hz,6H),6.63(t,J＝8.0Hz,6H),6.36(s,6H) ), 5.40 (d, J=7.8Hz, 6H), 5.26 (d, J=7.8Hz, 6H), 1.86 (d, J=5.6Hz, 18H); ¹³ C NMR (101MHz, CD ₃ CN, 298K) δ167.53,160.20,153.35,142.78,142.55,140.18,138.83,134.67,132.72,130.58,130.21,128.58,128.25,128.13,127.70,127.10,126.06,123.01,120.93,32.50,30.19,22.26,14.17.ESI-TOF- MS:calcd.For[Eu ₂ (L ₃ ^SS ) ₃ (OTf) ₀ ] ⁶⁺ 507.1563, found507.1578; calcd.For[Eu ₂ (L ₃ ^SS ) ₃ (OTf) ₁ ] ⁵⁺ 638.3781, found 638.3789 ;calcd.For[Eu ₂ (L ₃ ^SS ) ₃ (OTf) ₂ ] ⁴⁺ 835.2107, found 835.2121; calcd.For[Eu ₂ (L ₃ ^SS ) ₃ (OTf) ₃ ] ³⁺ 1163.2651, found 1163.2667. above The method obtained the target product lanthanide multinuclear complex Eu ₂ (L ₃ ^SS ) ₃ , which has a triple helix structure.

Example 5: UV-Vis Absorption Spectrum Test

The UV-Vis absorption spectra of organic ligands were tested with dichloromethane as solvent (c=1×10 ^-5 M) at room temperature, and the results are shown in Figure 1. With the extension of the intermediate bridging unit of organic ligands (L ₁ ^SS <L ₂ ^SS <L ₃ ^SS ), the planar aromaticity of the ligands also increases, and the corresponding gradual red shift of the maximum absorption wavelength is observed from the UV-Vis spectrum.

The ultraviolet-visible absorption spectrum of lanthanide polynuclear complexes was tested with acetonitrile as solvent (c=1×10 ^-5 M), and the results are shown in Fig. 2 . Similar to the results observed for the UV-Vis absorption spectra of organic ligands, the UV-Vis absorption spectra of lanthanide multinuclear complexes also exhibit a corresponding red-shift phenomenon, which indicates that with the extension of the intermediate bridging unit, the energy of the ligands increases. The level is gradually reduced, thereby realizing the continuous regulation of the ligand energy level.

Example 6: Fluorescence performance test

The excitation spectra, emission spectra, luminescence lifetimes and fluorescence quantum yields of the lanthanide multinuclear complexes were measured on an Edinburgh FS5 fluorescence spectrometer, respectively.

Taking the excitation and emission spectra of the lanthanide polynuclear complex Eu ₂ (L ₃ ^SS ) ₃ as an example, as shown in Figure 3, the characteristic emission peaks of europium ions are located at 580, 594, 615, 649, and 693 nm, corresponding to ⁵ D ₀ → ⁷ FJ ( _J =0,1,2,3,4) transition absorption. Among the three complexes of Eu ₄ (L ₁ ^SS ) ₆ , Eu ₄ (L ₂ ^SS ) ₆ and Eu ₂ (L ₃ ^SS ) ₃ , the maximum excitation wavelength of Eu ₂ (L ₃ ^SS ) ₃ is the highest, and Its excitation window can be extended to 370nm. It is worth noting that the fluorescence quantum yield of Eu ₂ (L ₃ ^SS ) ₃ is the highest among the above three complexes, reaching 42.4%, which is very rare in rare earth multinuclear complexes.

The optical properties measurement results of the lanthanide polynuclear complexes Eu ₄ (L ₁ ^SS ) ₆ , Eu ₄ (L ₂ ^SS ) ₆ and Eu ₂ (L ₃ ^SS ) ₃ are summarized in Table 1, where λ _abs ^max represents the ultraviolet maximum absorption wavelength , ε is the molar absorption coefficient, λ _ex is the maximum excitation wavelength, τ _obs is the fluorescence lifetime, and Ф _FL is the fluorescence quantum yield.

Table 1 Optical properties measurement data of lanthanide multinuclear complexes

It can be seen from the results in Table 1 that the excitation wavelength of 344 nm for the lanthanide polynuclear complex Eu ₂ (L ₃ ^SS ) ₃ is the largest among the three complexes listed, and the corresponding fluorescence quantum yield is also the highest (42.4%). This result is significantly better than the optical performance data of conventional rare earth multinuclear complexes.

The above are only a few embodiments of the present application, and are not intended to limit the present application in any form. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Without departing from the scope of the technical solution of the present application, any changes or modifications made by using the technical content disclosed above are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims (10)

1. a linear C2 symmetry compound, is characterized in that, has the structural formula shown in formula I:

wherein, R is selected from C ₃ -C ₁₂ alkyl, C ₈ -C ₁₂ aralkyl and

One of them, k=1～6;

One of the following groups:

2. linear C2 symmetry compound according to claim 1 is characterized in that, in formula I, R is selected from a kind of in following group:

Preferably, in formula I,

One of the groups selected from the group having the structural formula shown in formula I-1:

where m=1, 2 or 3. 3. the preparation method of the linear C2 symmetry compound described in claim 1 or 2, is characterized in that, comprises: reacting the mixture containing the azide compound and the alkyne compound at 50-70° C. to obtain the linear C2 symmetry compound; Wherein, the reaction is a triazole ring-closing reaction; The azide compound is selected from at least one of the compounds having the structural formula shown in formula II:

The alkyne compound is selected from at least one of the compounds having the structural formula shown in formula III:

4. method according to claim 3, is characterized in that, the time of described reaction is 12～36 hours; Preferably, the molar ratio of the azide compound to the alkyne compound is 1:2 to 1:4; Preferably, the mixture further comprises ketone sulfate and sodium ascorbate; More preferably, the molar ratio of the ketone sulfate to the azide compound is 0.8:1 to 1:1; More preferably, the molar ratio of the sodium ascorbate to the azide compound is 1.5:1 to 2.5:1; Preferably, the mixture further comprises a solvent; More preferably, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethylsulfoxide/methanol. 5. A lanthanide polynuclear complex, characterized in that the lanthanide polynuclear complex has the general formula shown in formula VI: Ln _2n L _3n Formula IV Wherein, Ln is selected from one of the lanthanides; L is an organic ligand, which is selected from the linear C2 symmetry compound according to claim 1 or 2 and the linear C2 symmetry compound prepared by the method according to claim 3 or 4; n is selected from 1 or 2; Among them, nitrogen atoms and oxygen atoms in L coordinate with Ln. 6. The lanthanide polynuclear complex according to claim 5, wherein n=2, and the lanthanide polynuclear complex is a lanthanide tetrahedral cage; Preferably, the lanthanide tetrahedral cage is selected from at least one compound having the structural formula shown in formula V:

in,

represents Ln;

One of the following groups:

7. The lanthanide polynuclear complex according to claim 5, wherein n=1, and the lanthanide polynuclear complex has a triple helix structure; Preferably,

One of the following groups:

8. The preparation method of the lanthanide polynuclear complex according to any one of claims 5 to 7, characterized in that, comprising: The lanthanide polynuclear complex is obtained by reacting the mixture containing the lanthanide Ln precursor and the organic ligand L at 30-50°C. 9. The method according to claim 8, wherein the lanthanide Ln precursor is selected from at least one of Eu(OTf) ₃ , Sm(OTf) ₃ , Eu(OTf) ₃ , DyOTf) ₃ kind; Preferably, the molar ratio of the lanthanide Ln precursor to the organic ligand L is 1:1 to 1:2, wherein the mole number of the lanthanide Ln precursor is the corresponding mole number of the lanthanide Ln count; Preferably, the reaction time is 0.5 to 1.5 hours; Preferably, the mixture further comprises a solvent; More preferably, the solvent is selected from at least one of acetonitrile, methanol, and nitromethane. 10. The linear C2 symmetric compound according to claim 1 or 2, the linear C2 symmetric compound prepared by the method according to claim 3 or 4, and the lanthanide polynuclear complex according to any one of claims 5 to 7 The application of at least one of the lanthanide polynuclear complexes prepared by the method according to claim 8 or 9 in a photochemical supramolecular device.

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