Tetraphenylthionium salt probe molecules for detecting polymer conformation in solution

Abstract

This invention discloses a tetraphenylethylene thionium salt probe molecule for detecting the conformation of polymers in solution. The structural formula of the tetraphenylethylene thionium salt probe molecule is shown in formula (I). Since tetraphenylethylene may exhibit weak or no fluorescence in solution, but its fluorescence is significantly enhanced in aggregated states (such as solid or high-concentration solutions), this characteristic allows it to detect the conformation of polymers in solution by means of changes in fluorescence intensity. As the polymer changes from an extended chain state to an aggregated state, the fluorescence increases, thus acting as a probe. This invention effectively solves the problem of the poor solubility of organic AIE molecules in aqueous phase by modifying the tetraphenylethylene core with different onionium salt functional groups, making it soluble in both aqueous and organic phases. This allows it to be effectively used as a probe in commonly used polymer systems.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent probes, specifically relating to a tetraphenylthionium salt probe molecule for detecting polymer conformations in solution. Background Technology

[0002] A fluorescent probe is a molecule or material that emits fluorescence under specific conditions. Its working principle is based on the phenomenon of fluorescence, where certain substances absorb high-energy light and then re-emit lower-energy light within a short period. Fluorescent probes are widely used in biomedicine, environmental monitoring, and chemical analysis, attracting significant attention due to their high sensitivity and selectivity. In biomedicine, fluorescent probes are widely used for cell imaging and drug monitoring, enabling real-time observation of intracellular biological processes. In environmental monitoring, fluorescent probes can detect pollutants in water bodies, such as heavy metal ions and organic pollutants, achieving real-time monitoring through changes in fluorescence signals. Furthermore, fluorescent probes are also used in chemical analysis as reaction indicators to track reaction progress. However, currently, most fluorescent probe molecules are made of materials such as quantum dots, requiring specific wavelengths of light to produce fluorescence. Some systems are not affected by external light or energy, which limits the application of fluorescent probes.

[0003] Polymers may exhibit different conformations in solution, and these conformational changes directly affect their physical and chemical properties, such as solubility, viscosity, elasticity, and thermal stability. Understanding these conformational changes helps scientists delve deeper into the phase behavior, interactions, and interaction mechanisms of polymers with solvent molecules. Furthermore, in materials science, polymer conformational studies are crucial for developing novel functional materials. Conformational changes can influence the mechanical, thermal, and electrical properties of polymers, thereby affecting the final application performance of the materials. Therefore, the detection of polymer conformations in solvents is essential. Studying polymer conformations in water not only helps in understanding their fundamental properties but also provides important theoretical foundations and practical guidance for applications in biomedicine, environmental science, and materials science. However, detecting polymer conformations in solution is not straightforward. Based on this, this invention provides an AIE molecule with tetraphenylethylene as its core and its application in detecting conformational changes in polymers in solution. Summary of the Invention

[0004] The purpose of this invention is to provide a polythionium salt fluorescent molecular probe based on tetraphenylethylene. Tetraphenylethylene may exhibit weak or no fluorescence in solution, but its fluorescence is significantly enhanced in aggregated states (such as solids or high-concentration solutions). This characteristic allows it to detect the conformation of polymers in solution by observing changes in fluorescence intensity. As the polymer transitions from an extended chain state to an aggregated state, the fluorescence increases, thus acting as a probe. This invention modifies the tetraphenylethylene core with different onionium salt functional groups, enabling it to dissolve in both aqueous and organic phases, effectively solving the problem of the poor solubility of organic AIE molecules in aqueous phases. This allows it to be effectively used as a probe in commonly used polymer systems.

[0005] The structural formula of the compound provided by this invention is shown below:

[0006]

[0007] Among them, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 Whether the same or different, each is independently selected from -S + R S1 R S2 -OC 1-15 Alkyl-C 6-20 Aryl-S + R S1 R S2 or group Z, wherein group Z is H, unsubstituted, or optionally substituted with one, two, or more R groups. A The following groups are substituted: C 1-15 Alkyl, C 1-15 Alkoxy, C 3-20 cycloalkyl, C 6-20 Aryl, 5-20 membered heteroaryl, 3-20 membered heterocyclic, -C 1-15 Alkyl-C 6-20 Aryl, -C 1-15 Alkyl-5-20 heteroaryl, -C 1-15 Alkyl-CO-C 6-20 Aryl, -C 1-15 Alkyl-CO-5-20-membered heteroaryl, -C 1-15 Alkyl-CO-C 1-15 Alkyl, -C 1-15 Alkyl-CO-C3-20 cycloalkyl;

[0008] R A Selected from =O, NO2, C 1-15 Alkyl, C 1-15 Alkoxy, C 3-20 cycloalkyl;

[0009] R S1 R S2 Whether identical or different, each is independently selected from unsubstituted or arbitrarily selected by one, two or more R B The following groups are substituted: C 1-15 Alkyl, C 3-20 cycloalkyl, C 6-20 Aryl, -C 1-15 Alkyl-C 6-20 Aryl, 5-20 heteroaryl, deuterated C 1-15 Alkyl groups (such as deuterated methyl groups), or R S1 R S2 Together with the S connected thereto, they form an unsubstituted or optionally substituted group of one, two or more R groups. B The substituted 5-8 member sulfur-containing heterocyclic group; the 5-8 member sulfur-containing heterocyclic group optionally further contains 1-2 oxygen or sulfur atoms; the 5-8 member sulfur-containing heterocyclic group is also optionally fused with one or two benzene rings;

[0010] R B They may be the same or different, and are independently selected from H, oxo (=O), nitro, CN, and C. 1-15 Alkyl, C 1-15 Alkoxy;

[0011] X – It is an anion selected from halide ions, carboxylate ions, sulfate ions, alkyl sulfonates, haloalkyl sulfonates (such as trifluoromethanesulfonate, perfluoropropyl sulfonate, perfluorobutyl sulfonate), p-toluenesulfonate, anions of sulfonamides, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate, or bis(trifluoromethanesulfonyl)imide ions.

[0012] n equals the thionium salt group -S in the molecule. + R S1 R S2 S + The number of S + and X – To make the compound as a whole electrically neutral, n has an integer value of 2-4; that is, the compound of formula (I) has 2-4 -S groups. + R S1 R S2 .

[0013] In some embodiments of the present invention, the compound shown in formula (I) has 2-4 -S groups.+ R S1 R S2 For example, having 2, 3, or 4 thioonium salt groups -S + R S1 R S2 .

[0014] In some embodiments of the present invention, R1-R20 have four thionium salt groups -S + R S1 R S2 And each phenyl group has one thionium salt group -S + R S1 R S2 .

[0015] In some embodiments of the present invention, the thionium salt group -S + R S1 R S2 It is located at the ortho, meta, or para position of the benzene ring it substituted.

[0016] Preferably, the -S + R S1 R S2 Selected from the following groups that are unsubstituted or optionally substituted by one, two or more R1':

[0017]

[0018] in, Indicates a connection key; R 1a and R 1b They can be the same or different, each independently selected from unsubstituted or substituted R. C The following groups are substituted: C 1-15 Alkyl, C 3-20 cycloalkyl, -C 1-15 Alkyl-C 6-20 Aryl, -C 1-15 Alkyl-5-20 heteroaryl, -C 6-20 Aryl-C 1-15 Alkyl, deuterated C 1-15 Alkyl; R C R1' may be the same or different, and are independently selected from =O, nitro, C 1-15 Alkyl, C 1-15 Alkyl group; m is selected from integers from 0 to 5; Y is selected from CH2, O, S, C(O).

[0019] Preferably, the R 1a and the R 1b Choose one of the following structures:

[0020]

[0021] in, Indicates a connection key.

[0022] In some embodiments of the present invention, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 Whether the two are the same or different, they are each independently selected from H or -S. + R S1 R S2 ;R S1 R S2 Whether the two are the same or different, each is independently selected from C. 1-6 Alkyl, -C 6-12 Aryl, -C 1-6 Alkyl-C 6-12 Aryl;

[0023] In some embodiments of the present invention, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 Whether the two are the same or different, they are each independently selected from H and -S. + (C 1-6 Alkyl)2, -S + (C 6-12 Aryl)2, -S + (-C 1-6 Alkyl-C 6-12 Aryl)(C 1-6 alkyl);

[0024] In some embodiments of the present invention, the compound shown in formula (I) has a symmetrical structure, that is, the structures on the four outer benzene rings are completely identical.

[0025] As an example, the compound shown in formula (I) has the following structure:

[0026]

[0027] The present invention also provides a method for preparing the compound, comprising the following steps a) or b):

[0028] a) Combine the compound shown in Formula II with compound R S1 -L and MX are mixed and reacted to give the compound shown in formula (I);

[0029]

[0030] Among them, R1 ’ R2 ’ R3 ’ R4 ’ R5 ’ R6 ’ R7 ’ R8 ’ R9 ’ R 10 ’ R 11 ’ R 12 ’ R 13 ’ R 14 ’ R 15 ’ R 16 ’ R 17 ’ R 18 ’ R 19 ’ R 20 ’ The group Z or -SR in the compound shown in formula (I) S2 L is the leaving group; MX is the metal salt of X, M is selected from silver, and X is defined as the compound shown in formula (I);

[0031] b) The compound shown in formula II' was mixed with diphenyl sulfoxide and trifluoromethanesulfonic anhydride to obtain the compound shown in formula (I);

[0032]

[0033] Where n and X - The definition is the same as that of the compound shown in formula (I).

[0034] The compounds provided by this invention can be used as fluorescent probes for detecting polymer conformations in solution.

[0035] In application, the compound is added as an additive to the polymer solution.

[0036] Preferably, the polymer includes, but is not limited to: polyurethane, polyacrylic acid, polymethacrylic acid, acrylic resin, poly(N-isopropylacrylamide), polyvinyl alcohol, polyethyleneimine, etc.

[0037] The polymer solution was prepared using the following solvents:

[0038] One, two, or more of the following: tetrahydrofuran, N,N-dimethylformamide, dimethylformamide, dichloromethane, cyclohexanone, water, ethanol, acetonitrile, isopropanol, and acetone;

[0039] In the solution of the polymer, the concentration of the polymer is 0.1-10 g / L, and the concentration of the compound is 0.1-100 mmol / L.

[0040] Preferably, the compound is used to detect polymer conformational changes caused by conditions such as temperature, pH, light, metal ions in solution, and externally applied magnetic field or voltage.

[0041] Changes in polymer conformation can be detected by detecting changes in the fluorescence intensity of the solution or the shift in the position of the fluorescence peak.

[0042] The present invention has the following beneficial technical effects:

[0043] 1. This invention effectively solves the problem of organic AIE molecules being difficult to dissolve in aqueous phase by modifying the tetraphenylethylene core with different onium salt functional groups, enabling them to dissolve in both aqueous and organic phases.

[0044] 2. The polythioonium salt fluorescent molecular probe based on tetraphenylethylene can be effectively used as a probe in commonly used polymer systems.

[0045] 3. The raw materials for the tetraphenylethylene polythionium salt fluorescent molecular probe of this invention are readily available and the preparation process is simple. Attached Figure Description

[0046] Figure 1 This refers to the changes in fluorescence intensity of the polymer solution at different pH values ​​in Example 7.

[0047] Figure 2 This refers to the change in fluorescence intensity of the polymer solution under different calcium ion concentrations in Example 8.

[0048] Figure 3 This refers to the change in fluorescence intensity of the polymer solution at different temperatures in Example 9.

[0049] Figure 4 This refers to the changes in fluorescence intensity of the polymer solution under different calcium ion concentrations in Example 10.

[0050] Figure 5This refers to the changes in fluorescence intensity of the polymer solution at different pH values ​​in Example 11. Detailed Implementation

[0051] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0052] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0053] Terms and Definitions

[0054] Unless otherwise defined, all technical terms herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains.

[0055] "More than three" means three or more.

[0056] Term "C" 1-15 "Alkyl" should be understood as referring to a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 15 carbon atoms. For example, "C 1-6 "Alkyl" means a straight-chain or branched alkyl group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, or their isomers.

[0057] Term "C" 1-15 "Alkoxy" should be understood as -OC 1-15 Alkyl, wherein C 1-15 Alkyl groups have the above definition.

[0058] Term "C" 3-20"Cycloalkyl" should be understood as representing a saturated monovalent monocyclic, bicyclic, or polycyclic hydrocarbon ring (also called a fused ring hydrocarbon ring) with 3-20 carbon atoms. Bicyclic or polycyclic cycloalkyl includes fused cycloalkyl, bridged cycloalkyl, and spirocyclic cycloalkyl; fused ring refers to a fused ring structure formed by two or more cyclic structures sharing two adjacent ring atoms (i.e., sharing a bond). Bridged ring refers to a fused ring structure formed by two or more cyclic structures sharing two non-adjacent ring atoms. Spirocyclic refers to a fused ring structure formed by two or more cyclic structures sharing a single ring atom. For example, the C 3-20 Cycloalkyl groups can be C 3-8 Monocyclic cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or C 7-12 Circoalkyl, such as decahydronaphthalene ring; or C 7-12 Bridged cycloalkyl groups, such as norbornane, tripterene, and bicyclo[2,2,2]octane.

[0059] The term "3-20 membered heterocyclic group" refers to a saturated or unsaturated monovalent monocyclic or bicyclic hydrocarbon ring containing 1-5 heteroatoms independently selected from N, O, and S, preferably a "3-10 membered heterocyclic group". The term "3-10 membered heterocyclic group" also refers to a saturated monovalent monocyclic or bicyclic hydrocarbon ring containing 1-5, preferably 1-3, heteroatoms selected from N, O, and S. The heterocyclic group can be connected to the rest of the molecule via any one of the carbon atoms or a nitrogen atom (if present). Specifically, the heterocyclic group can include, but is not limited to: 4-membered rings, such as azirmonobutyl or oxobutyl; 5-membered rings, such as tetrahydrofuranyl, dioxacyclopentenyl, pyrrolyl, imidazoyl, pyrazolyl, or pyrrololinyl; or 6-membered rings, such as tetrahydropyranyl, piperidinyl, morpholinyl, dithiaalkyl, thiomorpholinyl, piperazinyl, or trithiaalkyl; or 7-membered rings, such as diazacycloheptyl. Optionally, the heterocyclic group may be benzo-fused. The heterocyclic group may be bicyclic, for example, but not limited to, a 5,5-membered ring, such as a hexahydrocyclopenta[c]pyrrole-2(1H)-yl ring, or a 5,6-membered bicyclic ring, such as a hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl ring. The nitrogen-containing ring may be partially unsaturated, i.e., it may contain one, two, or more double bonds, for example, but not limited to, 2,5-dihydro-1H-pyrrole, 4H-[1,3,4]thiadiazinyl, 4,5-dihydrooxazolyl, or 4H-[1,4]thiazinyl, or it may be benzo-fused, for example, but not limited to, dihydroisoquinolinyl, 1,3-benzooxazolyl, or 1,3-benzodioxacyclopentenyl. According to the invention, the heterocyclic group is non-aromatic.

[0060] Term "C" 6-20"Aryl" should be understood as representing a monocyclic, bicyclic, or tricyclic hydrocarbon ring with 6 to 20 carbon atoms that is monovalent and partially aromatic, preferably "C". 6-14 "Aromatic". The term "C" 6-14 "Aryl" should be understood to preferably represent a monovalent aromatic or partially aromatic monocyclic, bicyclic, or tricyclic hydrocarbon ring ("C") having 6, 7, 8, 9, 10, 11, 12, 13, or 14 carbon atoms. 6-14 Aryl), particularly a ring with 6 carbon atoms (“C6 aryl”), such as phenyl; or biphenyl, or a ring with 9 carbon atoms (“C9 aryl”), such as indenyl or indenyl, or a ring with 10 carbon atoms (“C9 aryl”). 10 Aryl groups, such as tetrahydronaphthyl, dihydronaphthyl, or naphthyl, or rings with 13 carbon atoms (“C”). 13 Aryl groups, such as fluorene groups, or rings with 14 carbon atoms (“C”). 14 Aryl), for example, anthracene. When the C 6-20 When the aryl group is substituted, it can be monosubstituted or polysubstituted. Furthermore, there are no restrictions on the substitution site; for example, it can be ortho, para, or meta substituted.

[0061] The term "5-20-membered heteroaryl" should be understood to include monovalent monocyclic, bicyclic, or tricyclic aromatic ring systems having 5 to 20 ring atoms and containing 1 to 5 heteroatoms independently selected from N, O, and S, such as "5-14-membered heteroaryl". The term "5-14-membered heteroaryl" should also be understood to include monovalent monocyclic, bicyclic, or tricyclic aromatic ring systems having 5, 6, 7, 8, 9, 10, 11, 12, 13, or 14 ring atoms, particularly 5, 6, 9, or 10 carbon atoms, and containing 1 to 5, preferably 1 to 3, heteroatoms independently selected from N, O, and S, and in each case, may be benzofused. Specifically, the heteroaryl group is selected from thienyl, furanyl, pyrroleyl, oxazolyl, thiazolyl, imidazoleyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, thia-4H-pyrazolyl, and their benzo[derivatives], such as benzofuranyl, benzothienyl, benzooxazolyl, benzoisooxazolyl, benzoimidazolyl, benzotriazolyl, indazole, indolyl, isindolyl, etc.; or pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, and their benzo[derivatives], such as quinolinyl, quinazolinyl, isoquinolinyl, etc.; or acrylinyl, inazinyl, purinyl, and their benzo[derivatives]; or terpenolyl, phthalazinyl, quinazolinyl, quinoxolinyl, naphridinyl, pteridinyl, carbazolyl, acridineyl, phenazinyl, phenothiazinyl, phenothiazinyl, etc.

[0062] The term "C" above 1-15 The definition of "alkyl" also applies to other C-containing compounds. 1-15 Alkyl groups, such as -C1-15 Alkyl-C 6-20 Aryl, -C 1-15 Alkyl-5-20 heteroaryl, -C 1-15 Alkyl-CO-C 6-20 Aryl, -C 1-15 Alkyl-CO-5-20-membered heteroaryl, -C 1-15 Alkyl-CO-C 1-15 Alkyl, -C 1-15 Alkyl-CO-C 3-20 Cycloalkyl groups, etc.

[0063] Similarly, C 6-20 Aryl, 5-20 heteroaryl, C 3-20 The cycloalkyl group has the same definition throughout the text.

[0064] Example 1: Preparation of compound II-1

[0065] The synthesis route is as follows:

[0066]

[0067] In a 250 mL Schlenk flask, tetrabromotetraphenylene (5 g, 7.7 mmol, 1.0 eq), 4-methylthiophenylboronic acid (6.1 g, 37.1 mmol, 4.8 eq), and 20 mL of dioxane were added. The mixture was heated and stirred until completely dissolved at 50 °C. Anhydrous potassium carbonate (4.3 g, 37.1 mmol, 4.8 eq) was dissolved in 5 mL of deionized water and added to the flask, then stirred until homogeneous. The mixture was evacuated and purged with nitrogen three times. Tetra(triphenylphosphine)palladium catalyst (197 mg, 0.17 mmol, 0.025 eq) was added under a nitrogen atmosphere, and the mixture was heated under reflux for 10 h. After cooling to room temperature, the solvent was removed by vacuum distillation, followed by extraction with dichloromethane / water. The organic phases were combined, dried over anhydrous magnesium sulfate, and the solvent was removed by vacuum distillation to obtain a yellowish-brown oil. The product was dissolved in a small amount of dichloromethane. Separation was performed by column chromatography to give a pale yellow solid in 70% yield.

[0068] Example 2: Preparation of compound I-1

[0069] The synthesis route is as follows:

[0070]

[0071] Compound II-1 (3.0 g, 3.7 mmol, 1.0 eq), silver trifluoromethanesulfonate (5.9 g, 22.2 mmol, 6 eq), and 45 mL of dry dichloromethane were added to a 50 mL single-necked reaction flask. Iodomethane (2.9 g, 22.2 mmol, 6 eq) was dissolved in 5 mL of dichloromethane and added slowly dropwise. After the addition was complete, the reaction mixture was allowed to stand at room temperature for 3 h in the dark. The reaction mixture was allowed to stand and the supernatant was discarded. The solid was dissolved in acetonitrile. The AgI precipitate in the reaction mixture was removed by filtration, yielding a pale yellow solution. The solvent was removed by vacuum distillation to obtain a pale yellow foamy solid. Recrystallization was performed using methanol as the recrystallization solvent to obtain a pale yellow powdery solid in 65% yield. 1 H NMR (400MHz, Acetonitrile-d3) δ 7.93 (d, J = 7.8Hz, 8H), 7.78 (d, J = 7.8Hz, 8H), 7.59 (d, J = 7.7Hz, 8H), 7.29 (d, J = 7.7Hz, 8H), 3.21 (s, 24H); MS (ESI): m / z = 220.08, calculated value C 58 H 56 S4 4+ m / z = 220.08 ([M]) 4+ m / z = 148.95, calculated value CF3SO3 - m / z = 148.95 ([M]) - ).

[0072] Example 3: Preparation of compound I-2

[0073] The synthesis route is as follows:

[0074]

[0075] Following the preparation method of Example 1, compound II-2 was prepared by replacing 4-methylthiophenylboronic acid with 3-methylthiophenylboronic acid.

[0076] Compound II-1 (3.0 g, 3.7 mmol, 1.0 eq), silver trifluoromethanesulfonate (5.9 g, 22.2 mmol, 6 eq), and 45 mL of dry dichloromethane were added to a 50 mL single-necked reaction flask. Iodomethane (2.9 g, 22.2 mmol, 6 eq) was dissolved in 5 mL of dichloromethane and added slowly dropwise. After the addition was complete, the reaction mixture was allowed to stand at room temperature for 3 h in the dark. The reaction mixture was allowed to stand and the supernatant was discarded. The solid was dissolved in acetonitrile. The AgI precipitate in the reaction mixture was removed by filtration, yielding a pale yellow solution. The solvent was removed by vacuum distillation to obtain a pale yellow foamy solid. Recrystallization was performed using methanol as the recrystallization solvent to obtain a pale yellow powdery solid in 70% yield. 1H NMR (400MHz, Acetonitrile-d3) δ 8.11 (s, 4H), 8.00 (d, J = 7.9Hz, 4H), 7.86 (d, J = 8.1Hz, 4H), 7.75 (t, J = 7.8Hz, 4H), 7.61 (d, J = 7.7Hz, 8H), 7.31 (d, J = 7.7Hz, 8H), 3.17 (s, 24H); MS (ESI): m / z = 220.08, calculated C 58 H 56 S4 4+ m / z = 220.08 ([M]) 2+ m / z = 148.95, calculated value CF3SO3 - m / z = 148.95 ([M]) - ).

[0077] Example 4: Preparation of compound II-5

[0078] The synthesis route is as follows:

[0079]

[0080] The specific steps are the same as the preparation process of II-1 in Example 1, except that 4-methylthiophenylboronic acid is replaced with phenylboronic acid, and the reaction yield is 70%. 1 H NMR (400MHz, Acetonitrile-d3): δ 7.78 (t, J = 7.8Hz, 8H), 7.65–7.62 (m, 16H), 7.50–7.48 (m, 8H), 7.41 (d, J = 7.7Hz, 4H); MS (MALDI): m / z = 636.28, calculated C 50 H 36 m / z = 636.28 ([M]) + ).

[0081] Example 5: Preparation of compound I-5

[0082] The synthesis route is as follows:

[0083]

[0084] Compound II-5 (4 g, 6.3 mmol, 1 eq) and methyl phenyl sulfoxide (10.7 g, 37.7 mmol, 6 eq) were added to a 250 mL round-bottom flask and dissolved in 20 mL of dry dichloromethane. The reaction mixture was placed in an acetonitrile bath, and 20 mL of a dichloromethane solution of trifluoromethanesulfonic anhydride (10.6 g, 37.7 mmol, 6 eq) was added dropwise. After the addition was complete, the reaction was carried out in the dark for 6 h (reaction temperature: -42 °C). Most of the reaction mixture was removed by rotary evaporation. A pale yellow precipitate was obtained by adding the precipitate dropwise to diethyl ether, with a yield of 60%. 1 H NMR (400MHz, Acetonitrile-d3): δ 7.99 (d, J = 7.7Hz, 8H), 7.79 (d, J = 7.7Hz, 8H), 7.59 (d, J = 7.7Hz, 8H), 7.35–7.31 (m, 20H), 7.25 (d, J = 7.7Hz, 8H), 3.26 (s, 12H); MS (ESI): m / z = 282.10, calculated value C 78 H 64 S4 4+ m / z = 282.10 ([M]) 4+ m / z = 148.95, calculated value CF3SO3 - m / z = 148.95 ([M]) - ).

[0085] Example 6: Preparation of compound I-6

[0086] The synthesis route is as follows:

[0087]

[0088] Compound II-5 (4 g, 6.3 mmol, 1 eq) and diphenyl sulfoxide (13.8 g, 41.6 mmol, 9 eq) were added to a 250 mL round-bottom flask and dissolved in 20 mL of dry dichloromethane. The reaction mixture was placed in an acetonitrile bath, and 20 mL of a dichloromethane solution of trifluoromethanesulfonic anhydride (10.6 g, 37.7 mmol, 6 eq) was added dropwise. After the addition was complete, the reaction was carried out in the dark for 6 h (reaction temperature: -42 °C). Most of the reaction mixture was removed by rotary evaporation. A pale yellow precipitate was obtained by adding the precipitate dropwise to diethyl ether, with a yield of 70%. 1 H NMR (400MHz, Acetonitrile-d3): δ 7.95 (d, J = 7.8Hz, 8H), 7.81 (d, J = 7.8Hz, 8H), 7.58 (d, J = 7.7Hz, 8H), 7.40–7.34 (m, 40H), 7.30 (d, J = 7.7Hz, 8H), 3.22 (s, 12H); MS (ESI): m / z = 344.36, calculated value C98 H 72 S4 4+ m / z = 344.36 ([M]) 4+ m / z = 148.95, calculated value CF3SO3 - m / z = 148.95 ([M]) - ).

[0089] Example 7

[0090] 0.2 g of polyethyleneimine was dissolved in 100 mL of water and stirred for 10 min. Then, 0.1 mmol of compound I-2 shown in Example 3 was added and stirred for 10 min to obtain a polymer solution. The pH of the polymer solution was adjusted to 3, 4, 5, and 6 using hydrochloric acid and sodium hydroxide, respectively, and allowed to stand for 10 min. The fluorescence spectrum of the polymer solution was detected using a fluorescence spectrometer. Figure 1 As shown, the changes in fluorescence intensity of the polymer solution at different pH values ​​(pH 3, 4, 5, and 6) indicate that the polymer conformation has changed.

[0091] Example 8

[0092] 0.2 g of polyacrylic acid was dissolved in 100 mL of a water-ethanol mixture and stirred for 10 min. Then, 0.1 mmol of compound I-2 shown in Example 3 was added and stirred for 10 min to obtain a polymer solution. Different concentrations of calcium chloride were added, namely 0, 0.01, 0.05, 0.1, 0.5, and 1 mmol / L; the solution was allowed to stand for 10 min. The fluorescence spectrum of the polymer solution was detected using a fluorescence spectrometer. Figure 2 As shown, the changes in fluorescence intensity of the polymer solution under different calcium ion concentrations (0, 0.01, 0.05, 0.1, 0.5, 1 mmol / L) indicate that the polymer conformation has changed.

[0093] Example 9

[0094] 0.2 g of poly(N-isopropylacrylamide) was dissolved in 100 mL of a tetrahydrofuran solution and stirred for 10 min. Then, 0.1 mmol of compound I-2 shown in Example 3 was added and stirred for 10 min to obtain a polymer solution. The fluorescence spectra of the polymer solution at different temperatures were studied using a fluorescence spectroscopy method at 20, 30, 40, 50, and 60 °C. Figure 3 As shown, the changes in fluorescence intensity of the polymer solution at different temperatures indicate that the polymer conformation has changed.

[0095] Example 10

[0096] 0.2 g of polymethacrylic acid was dissolved in 100 mL of water and stirred for 10 min. Then, 0.1 mmol of compound I-5 shown in Example 3 was added and stirred for 10 min to obtain a polymer solution. Different concentrations of calcium chloride were added, namely 0, 0.01, 0.05, 0.1, 0.5, and 1 mmol / L; the solution was allowed to stand for 10 min. The fluorescence spectrum of the polymer solution was detected using a fluorescence spectrometer. Figure 4 As shown, the fluorescence intensity gradually increases with increasing calcium ion concentration, indicating a conformational change in the polymer.

[0097] Example 11

[0098] 0.2 g of acrylic resin was dissolved in 100 mL of ethanol and stirred for 10 min. Then, 0.1 mmol of compound I-6 shown in Example 3 was added and stirred for 10 min to obtain a polymer solution. The pH of the polymer solution was adjusted to 6, 7, 8, and 9 using hydrochloric acid and sodium hydroxide, respectively, and allowed to stand for 10 min. The fluorescence spectrum of the polymer solution was detected using a fluorescence spectrometer. Figure 5 As shown, the fluorescence intensity gradually decreased with increasing pH (from 5 to 9), indicating a change in polymer conformation.

[0099] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The compound shown in formula (I); in, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 R 11 R 12 R 13 R 14 R 15 R 16 R 17 R 18 R 19 R 20 Whether the same or different, each is independently selected from -S + R S1 R S2 -OC 1-15 Alkyl-C 6-20 Aryl-S + R S1 R S2 or group Z, wherein group Z is H, unsubstituted, or optionally substituted with one, two, or more R groups. A The following groups are substituted: C 1-15 Alkyl, C 1-15 Alkoxy, C 3-20 cycloalkyl, C 6-20 Aryl, 5-20 membered heteroaryl, 3-20 membered heterocyclic, -C 1-15 Alkyl-C 6-20 Aryl, -C 1-15 Alkyl-5-20 heteroaryl, -C 1-15 Alkyl-CO-C 6-20 Aryl, -C 1-15 Alkyl-CO-5-20-membered heteroaryl, -C 1-15 Alkyl-CO-C 1-15 Alkyl, -C 1-15 Alkyl-CO-C 3-20 cycloalkyl; R A Selected from =O, NO2, C 1-15 Alkyl, C 1-15 Alkoxy, C 3-20 cycloalkyl; R S1 R S2 Whether identical or different, each is independently selected from unsubstituted or arbitrarily selected by one, two or more R B The following groups are substituted: C 1-15 Alkyl, C 3-20 cycloalkyl, C 6-20 Aryl, -C 1-15 Alkyl-C 6-20 Aryl, 5-20 heteroaryl, deuterated C 1-15 Alkyl, or R S1 R S2 Together with the S connected thereto, they form an unsubstituted or optionally substituted group of one, two or more R groups. B The substituted 5-8 member sulfur-containing heterocyclic group; the 5-8 member sulfur-containing heterocyclic group optionally further contains 1-2 oxygen or sulfur atoms; the 5-8 member sulfur-containing heterocyclic group is also optionally fused with one or two benzene rings; R B They may be the same or different, and are independently selected from H, oxo (=O), nitro, CN, and C. 1-15 Alkyl, C 1-15 Alkoxy; X – It is an anion selected from halide ions, carboxylate ions, sulfate ions, alkyl sulfonates, haloalkyl sulfonates, p-toluenesulfonate ions, sulfonamide anions, tetrafluoroborate ions, hexafluoroantimonate ions, hexafluorophosphate ions, or bis(trifluoromethanesulfonyl)imide ions. n equals the thionium salt group -S in the molecule. + R S1 R S2 S + The number of S + and X – To make the compound electrically neutral as a whole, n is an integer between 2 and 4.

2. The compound according to claim 1, characterized in that: The -S + R S1 R S2 Selected from the following groups that are unsubstituted or optionally substituted by one, two or more R1': in, Indicates a connection key; R 1a and R 1b They can be the same or different, each independently selected from unsubstituted or substituted R. C The following groups are substituted: C 1-15 Alkyl, C 3-20 cycloalkyl, -C 1-15 Alkyl-C 6-20 Aryl, -C 1-15 Alkyl-5-20 heteroaryl, -C 6-20 Aryl-C 1-15 Alkyl, deuterated C 1-15 Alkyl; R C R1' may be the same or different, and are independently selected from =O, nitro, C 1-15 Alkyl, C 1-15 Alkyl group; m is selected from integers from 0 to 5; Y is selected from CH2, O, S, C(O).

3. The compound according to claim 2, characterized in that: The R 1a and the R 1b Choose one of the following structures: in, Indicates a connection key.

4. The compound according to any one of claims 1-3, characterized in that: The structure of the compound is shown in Formulas I-1 to I-6:

5. A method for preparing the compound according to any one of claims 1-4, comprising the following step a) or b): a) Combine the compound shown in Formula II with compound R S1 -L and MX are mixed and reacted to give the compound shown in formula (I); in, R1 ’ R2 ’ R3 ’ R4 ’ R5 ’ R6 ’ R7 ’ R8 ’ R9 ’ R 10 ’ R 11 ’ R 12 ’ R 13 ’ R 14 ’ R 15 ’ R 16 ’ R 17 ’ R 18 ’ R 19 ’ R 20 ’ The group Z or -SR in the compound shown in formula (I) S2 L represents a leaving group; MX is a metal salt of X, where M is selected from silver, and X is defined as the compound shown in formula (I). b) The compound shown in formula II' was mixed with diphenyl sulfoxide and trifluoromethanesulfonic anhydride to obtain the compound shown in formula (I); Where n and X - The definition is the same as that of the compound shown in formula (I).

6. The use of the compound according to any one of claims 1-4 as a fluorescent probe for detecting polymer conformation in solution.

7. The application according to claim 6, characterized in that: The compound is added as an additive to the polymer solution.

8. The application according to claim 6 or 7, characterized in that: The polymers include, but are not limited to: polyurethane, polyacrylic acid, polymethacrylic acid, acrylic resin, poly(N-isopropylacrylamide), polyvinyl alcohol, and polyethyleneimine.

9. The application according to claim 7 or 8, characterized in that: The polymer solution was prepared using the following solvents: One, two, or more of the following: tetrahydrofuran, N,N-dimethylformamide, dimethylformamide, dichloromethane, cyclohexanone, water, ethanol, acetonitrile, isopropanol, and acetone; In the solution of the polymer, the concentration of the polymer is 0.1-10 g / L, and the concentration of the compound is 0.1-100 mmol / L.

10. The application according to any one of claims 7-9, characterized in that: The compound was tested for polymer conformational changes induced by temperature, pH, light, metal ions in solution, and externally applied magnetic field or voltage. Changes in polymer conformation can be detected by detecting changes in the fluorescence intensity of the solution or the shift in the position of the fluorescence peak.

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