Triarylamine-based dual recognition method for fluorine ions by chiral photosensitive molecules

Abstract

The invention provides a dual recognition method for fluorine ions by chiral photosensitive molecules based on triarylamine. A unique supramolecular assembly and an achiral inorganic anionic material are co-assembled, so that circular dichroism absorption spectrum (CD) signal amplification and F ion recessive recognition are realized. Meanwhile, under the condition of ultraviolet irradiation, the supermolecule system containing the F ions shows color development which is completely different from that of other anions, and dominant recognition is carried out on the F ions.

Description

Technical Field

[0001] The invention belongs to the field of inorganic anion detection, and specifically relates to a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, and is suitable for a fluoride ion detection material system. Background Art

[0002] The field of supramolecular chemistry, especially the self-assembly of chiral molecules, shows great potential for applications in sensing, nanotechnology and materials science. However, achieving precise control over the expression of chirality within these systems, especially when subjected to specific stimuli, remains a major challenge. Fluorine, as the element with the smallest atomic weight and the highest electronegativity in the halogen family, usually exists in the form of fluoride ions in the natural environment. Adequate fluoride intake is essential for dental health, not only preventing tooth decay but also promoting the deposition of minerals in bones. However, excessive fluoride intake may cause dental fluorosis and may interfere with the normal development of bones, leading to skeletal fluorosis. In addition, excessive fluoride may also cause damage to kidney and liver function and affect the health of the nervous system and blood system. At high concentrations, fluoride ions can interfere with the normal metabolism of the immune system and may cause abnormal immune function by inhibiting the synthesis of proteins and DNA. In addition to its impact on human health, fluoride pollution also enters the environment through human activities such as coal burning, fertilizer application, aluminum smelting, and the production of ceramics, bricks and glass, posing a threat to the health of humans and ecosystems. Excessive fluorine content in the soil can also inhibit plant metabolism and photosynthesis, thereby reducing crop yields. Given the importance of fluorine ions to human health and ecological balance, developing a highly selective, highly sensitive and easy-to-operate fluorine ion detection method is of great significance for scientific research and environmental monitoring. Summary of the invention

[0003] The purpose of the present invention is to provide a method for dual recognition of fluoride ions by chiral photosensitive molecules based on triarylamine, and the detection method is simple and highly operable.

[0004] The dual recognition method of fluoride ions by triarylamine-based chiral photosensitive molecules provided by the present invention is: using circular dichroism spectroscopy to detect the intensity change of the chiral triarylamine derivative molecular self-assembly before and after the addition of fluoride ions, thereby realizing implicit recognition of F ions; or using ultraviolet light to distinguish the color change of the chiral triarylamine derivative molecular self-assembly before and after the addition of fluoride ions, thereby realizing explicit recognition of F ions.

[0005] Specifically, the dual recognition method of fluoride ions by chiral photosensitive molecules based on triarylamine comprises the following steps: 1) detecting the circular dichroism (CD) intensity CD0 of the chiral triarylamine derivative molecular self-assembly, and detecting the circular dichroism (CD) intensity CD1 of the chiral triarylamine derivative molecular self-assembly system containing anions, and if CD1 is significantly enhanced compared to CD0, it is determined that the anions are fluoride ions or include fluoride ions; 2) irradiating the chiral triarylamine derivative molecular self-assembly system containing anions with ultraviolet light. If the system appears red under ultraviolet light, it is determined that the anions are fluoride ions or include fluoride ions.

[0006] When the anion detection material system is tested for the presence of fluoride ions, either or both of the above steps 1) and 2) can be performed in any order.

[0007] In the above method, the chiral triarylamine derivative molecular self-assembly is present in a mixed solvent, the mixed solvent is DMF / DCM, and the volume ratio of DMF to DCM can be 0.02-0.5:1, specifically 0.02-0.25:1, 0.25:1; The obvious enhancement is an enhancement of more than 10 times; The chiral triarylamine derivative molecular self-assembly is prepared by a method comprising the following steps: The chiral triarylamine derivative molecules are assembled supramolecularly in a mixed solvent to obtain the product. The anion-containing chiral triarylamine derivative molecular self-assembly system is prepared by a method comprising the following steps: The anionic compound and the chiral triarylamine derivative molecules are subjected to supramolecular assembly in a mixed solvent to obtain the product; Wherein, the mixed solvent is DMF / DCM, and the volume ratio of DMF to DCM can be 0.02-0.5:1, specifically 0.02-0.25:1, 0.25:1; The concentration of the chiral triarylamine derivative molecule in the mixed solvent is 0.088-1.0 mg / mL, specifically 0.88 mg / mL; The chiral triarylamine derivative molecule is S or R-UNTA, and its structural formula is as follows:

[0008] The chiral triarylamine derivative molecule (S / R-UNTA) is prepared by reacting 4,4',4'-triaminotriphenylamine and (S) / (R)-(+)-1-(1-naphthyl)ethyl isocyanate as raw materials.

[0009] Specifically, the chiral triarylamine derivative molecule (S-UNTA) is Figure 1The synthetic route shown was prepared by a method comprising the following steps: 4,4',4'-triaminotriphenylamine (580 mg, 2 mmol) and (S)-(+)-1-(1-naphthyl)ethyl isocyanate (1305.5 mg, 6.6 mmol) were added to a round-bottom flask, and then tetrahydrofuran (THF) was added, and the mixture was heated to reflux for 24 hours with stirring in an oil bath. After the reaction was completed, the precipitate was filtered and collected, and then the filter cake was recrystallized from DMF and DCM, and then dried under vacuum for 24 hours to obtain a white solid in 65.2% S-UNTA.

[0010] R-UNTA was synthesized following the same procedure as S-UNTA.

[0011] This molecule has been reported in previous literature: DOI:10.1002 / smtd.202400538.

[0012] The molar ratio of the self-assembly to the F ion (detected unit) may be 1:1-3, and may be 1:3.

[0013] The application of chiral triarylamine derivative molecules or chiral triarylamine derivative molecular self-assemblies in F ion detection also falls within the protection scope of the present invention.

[0014] The invention also provides a F ion recognition material.

[0015] The F ion recognition material provided by the present invention is the chiral triarylamine derivative molecule or the self-assembly of the chiral triarylamine derivative molecule, wherein the chiral triarylamine derivative molecule can be specifically S / R-UNTA.

[0016] The triarylamine-based chiral photosensitive molecule of the present invention avoids the tedious enantiomer synthesis and the response to external stimuli, is a unique controllable chiral optical material, and has significant application in the recognition of fluoride ions.

[0017] The present invention has the following advantages: (1) The present invention prepares nanofibers by supramolecular assembly ( Fig. 9 ), which can show a significantly enhanced circular dichroism absorption spectrum signal after the addition of F ions.

[0018] (2) The present invention combines chiral materials with non-chiral inorganic anions, which can form a distinct helical fiber structure after adding F ions ( Fig. 9 ), becoming a new type of controllable F ion recognition material.

[0019] (3) The present invention co-assembles chiral materials with F ions, which can show completely different color reactions after ultraviolet light irradiation and can be used as a new type of visual F ion recognition material.

[0020] (4) The adjustable F ion recognition material prepared by the present invention has a simple preparation method, which provides a new idea for studying F ion recognition materials and a new choice for optical materials in the field of anion recognition.

[0021] The present invention studies the ability of triarylamine derivative molecule UNTA to specifically recognize fluoride ions in a DMF-DCM mixed solvent, and the circular dichroism absorption spectrum intensity of the UNTA system with fluoride ions added is enhanced by more than 15 times. In addition, UNTA turns green after ultraviolet light exposure in a DMF-DCM mixed solvent, while UNTA+fluoride ions turn red after ultraviolet light exposure in an organic solvent, realizing naked eye recognition of F ions. The present invention realizes dual recognition of F ions by chiral supramolecular in an organic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the synthetic route of chiral triarylamine derivative molecule (S / R-UNTA).

[0023] Figure 2 The CD absorption spectra of the assembly UNTA prepared in Example 1 of the present invention and the assembly UNTA+F - CD absorption spectrum.

[0024] Figure 3 This is the CD spectrum obtained by adding different equivalents of F ions into the assembly UNTA in Example 2 of the present invention.

[0025] Figure 4 g is obtained by adding different equivalents of F ions to the assembly UNTA in Example 2 of the present invention. abs statistics.

[0026] Figure 5 The assembly prepared in Example 3 of the present invention is added with different anions (F - ,Cl - ,Br - ,NO3 - ,CH3SO3 - ) and the difference in macroscopic color after UV light exposure for a period of time. The anions added from left to right are: blank, F - , Cl - , Br - , NO3 - , CH3SO3 - .

[0027] Figure 6 The figure shows the changes in the ultraviolet absorption spectrum of the assembly prepared in Example 4 of the present invention after adding 3 equivalents of F ions and irradiating it with ultraviolet light for different time periods.

[0028] Figure 7 It is a fitting curve of the change of the absorption peak at 500 nm in the ultraviolet absorption spectrum of the assembly prepared in Example 4 of the present invention after adding 3 equivalents of F ions and irradiating with ultraviolet light for different time conditions.

[0029] Figure 8 The difference is the circular dichroism absorption spectra of the assembly prepared in Example 5 of the present invention after adding 3 equivalents of different anions.

[0030] Fig. 9 is the microscopic morphology of the assembly formed by R / S-UNTA assembly, where a is the nanofiber structure formed by self-assembly of R-UNTA in a mixed solvent (DMF:DCM=1:4), b is the nanohelical fiber structure formed by co-assembly of R-UNTA and F ions in a mixed solvent (DMF:DCM=1:4) (the molar ratio of F ions to UNTA is 3:1), and c is the nanohelical fiber structure formed by co-assembly of S-UNTA and F ions in a mixed solvent (DMF:DCM=1:4) (the molar ratio of F ions to UNTA is 3:1). DETAILED DESCRIPTION

[0031] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0032] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0033] In the following examples, the chiral triarylamine derivative molecule (S-UNTA) is prepared according to Figure 1 The synthetic route shown was prepared by a method comprising the following steps: 4,4',4'-triaminotriphenylamine (580 mg, 2 mmol) and (S)-(+)-1-(1-naphthyl)ethyl isocyanate (1305.5 mg, 6.6 mmol) were added to a round-bottom flask, and then tetrahydrofuran (THF) was added, and the mixture was heated to reflux for 24 hours with stirring in an oil bath. After the reaction was completed, the precipitate was filtered and collected, and then the filter cake was recrystallized from DMF and DCM, and then dried under vacuum for 24 hours to obtain a white solid in 65.2% S-UNTA.

[0034] The preparation method of R-UNTA is the same as above, except that the (S)-(+)-1-(1-naphthyl)ethyl isocyanate is replaced by (R)-(+)-1-(1-naphthyl)ethyl isocyanate.

[0035] Example 1 This embodiment provides a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, comprising the following steps: (1) Disperse 4.4 mg of R / S-UNTA molecules in 1 mL of DMF, heat to form a transparent solution, and then cool to 25°C. After 10 minutes, obtain 0.2 mL of a fixed concentration (4.4 mg / mL) UNTA solution. Prepare a DMF solution of UNTA according to the calculated ratio, add 0.8 mL of a poor solvent (DCM), and after 30 minutes, obtain a self-assembled body of UNTA.

[0036] (2) The preparation method of F ion co-assembly is similar to the above method. First, F ion (tetrabutylammonium fluoride (F - )) was dissolved in DCM and then co-assembled with UNTA according to the calculated ratio (the molar ratio of F ion to UNTA was 3:1). Some assemblies were taken from the sample tube and placed in a 0.1 mm cuvette for spectral testing.

[0037] (3) In the DMF / DCM solvent mixture, UNTA assembled alone to form self-assemblies. - )) After the introduction of the system, a significant enhancement of the chirality of UNTA was observed, especially when co-assembled with F ions. The CD spectrum of the R-UNTA assembly is the opposite of the CD spectrum of S-UNTA. Three equivalents of F ions were added to the R-UNTA and S-UNTA system, and the CD spectrum of the resulting co-assembly was analyzed. S-UNTA showed a significant positive CD signal from 250nm to 400nm, which intersected at 333nm. After co-assembly with ions, R-UNTA exhibited a CD spectrum that was a mirror image of S-UNTA, characterized by the appearance of negative CD signals in the same wavelength range (see Figure 2 ).

[0038] Among them, the tetrabutylammonium fluoride (F - ), purchased from Inokai Reagent Co., Ltd.

[0039] Example 2 This embodiment provides a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, comprising the following steps: (1) Disperse 4.4 mg of R / S-UNTA molecules in 1 mL of DMF, heat to form a transparent solution, and then cool to 25°C. After 10 minutes, obtain 0.2 mL of a fixed concentration (4.4 mg / mL) UNTA solution. Prepare a DMF solution of UNTA according to the calculated ratio, add 0.8 mL of a poor solvent (DCM), and after 30 minutes, obtain a self-assembled body of UNTA.

[0040] (2) The preparation method of F ion co-assembly is similar to the above method. First, F ion (tetrabutylammonium fluoride (F - )) was dissolved in DCM and then co-assembled with UNTA according to the calculated ratio. Some of the assembly was taken out of the sample tube and placed in a 0.1 mm cuvette for spectral testing.

[0041] (3) F ion titration experiments were performed on UNTA at a constant concentration. Different equivalents of F ions were added to the R-UNTA solution, and then its CD spectrum was analyzed. The addition of F ions led to an enhancement of the R-UNTA CD signal (see Figure 3 ). For the mixed system with different F ion concentrations, g abs Further analysis showed that with the increase of F ion content, the g of R-UNTA at 310 nm increased. abs Gradually increase (see Figure 4 ). This indicates that the addition of F ions into the system can significantly enhance the CD absorption spectrum intensity of UNTA, and the F ions in the system can be implicitly identified through CD spectrum.

[0042] Among them, the tetrabutylammonium fluoride (F - ), purchased from Inokai Reagent Co., Ltd.

[0043] Example 3 This embodiment provides a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, comprising the following steps: (1) Disperse 4.4 mg of R / S-UNTA molecules in 1 mL of DMF, heat to form a transparent solution, and then cool to 25°C. After 10 minutes, obtain 0.2 mL of a fixed concentration (4.4 mg / mL) UNTA solution. Prepare a DMF solution of UNTA according to the calculated ratio, add 0.8 mL of a poor solvent (DCM), and after 30 minutes, obtain the UNTA assembly.

[0044] (2) The preparation method of anion co-assembly is similar to the above method. First, various inorganic anions (F - , Cl - Br - 、NO3 - 、CH3SO3 -) (Tetrabutylammonium fluoride (F - ), tetrabutylammonium chloride (Cl - ), Tetrabutylammonium bromide (Br - ), Tetrabutylammonium nitrate (NO3 - ), Tetrabutylammonium methanesulfonate (CH3SO3 - )) was dissolved in DCM and then co-assembled with UNTA according to the calculated ratio (the molar ratio of anion to UNTA was 3:1). Some of the assembly was taken out of the sample tube and placed in a 0.1 mm cuvette for spectral testing.

[0045] (3) Recognition experiments of different anions were carried out at a constant concentration of UNTA. R-UNTA was combined with various inorganic anions (F - , Cl - Br - 、NO3 - 、CH3SO3 - The resulting solution was initially colorless and transparent. After irradiation with 365 nm UV light for 10 min, a clear visual difference emerged: - Systems containing ions show a distinct red color, while systems containing other anions show a green color (see Figure 5 ). This clearly shows that R-UNTA - The specific selectivity is manifested as a macroscopic color change observable to the naked eye.

[0046] Among them, the tetrabutylammonium fluoride (F - ), tetrabutylammonium chloride (Cl - ), Tetrabutylammonium bromide (Br - ), Tetrabutylammonium nitrate (NO3 - ), Tetrabutylammonium methanesulfonate (CH3SO3 - ) was purchased from Inokai Reagent Co., Ltd.

[0047] Example 4 This embodiment provides a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, comprising the following steps: (1) Disperse 4.4 mg of R / S-UNTA molecules in 1 mL of DMF, heat to form a transparent solution, and then cool to 25°C. After 10 minutes, obtain 0.2 mL of a fixed concentration (4.4 mg / mL) UNTA solution. Prepare a DMF solution of UNTA according to the calculated ratio, add 0.8 mL of a poor solvent (DCM), and after 30 minutes, obtain the UNTA assembly.

[0048] (2) The preparation method of F ion co-assembly is similar to the above method. First, F ion (tetrabutylammonium fluoride (F- ) was dissolved in DCM and then co-assembled with UNTA according to the calculated ratio. Some of the assemblies were taken out of the sample tube and placed in a 0.1 mm cuvette for spectral testing.

[0049] (3) Conduct an experiment to measure the change of UV absorption spectrum of the UNTA+F ion assembly with constant concentration as a function of illumination time.

[0050] Three equivalents of F ions were added to the R-UNTA solution, and then the system containing F ions was irradiated with 365nm ultraviolet light. As the illumination time changed, an absorption peak appeared at 500nm in the system, which increased with time. The intensity of the ultraviolet absorption peak at 500nm was analyzed, and its intensity change curve was first rapidly increased, and then slowly strengthened (see Figure 6 and Figure 7 ). This indicates that after adding F ions to the system and irradiating with ultraviolet light, the ultraviolet absorption spectrum of UNTA shows a strong absorption peak at 500nm, which corresponds to its color change after ultraviolet light irradiation. At the same time, it is also very sensitive to F ions and can respond quickly under ultraviolet light irradiation, producing changes in color and spectrum.

[0051] Among them, the tetrabutylammonium fluoride (F - ), purchased from Inokai Reagent Co., Ltd.

[0052] Example 5 This embodiment provides a dual recognition method for fluoride ions by chiral photosensitive molecules based on triarylamine, comprising the following steps: (1) Disperse 4.4 mg of R / S-UNTA molecules in 1 mL of DMF, heat to form a transparent solution, and then cool to 25°C. After 10 minutes, obtain 0.2 mL of a fixed concentration (4.4 mg / mL) UNTA solution. Prepare a DMF solution of UNTA according to the calculated ratio, add 0.8 mL of a poor solvent (DCM), and after 30 minutes, obtain the UNTA assembly.

[0053] (2) The preparation method of anion co-assembly is similar to the above method. First, various inorganic anions (F - , Cl - Br - 、NO3 - 、CH3SO3 - ) (Tetrabutylammonium fluoride (F - ), tetrabutylammonium chloride (Cl - ), Tetrabutylammonium bromide (Br - ), Tetrabutylammonium nitrate (NO3 - ), Tetrabutylammonium methanesulfonate (CH3SO3 -)) was dissolved in DCM and then co-assembled with UNTA according to the calculated ratio. Some of the assembly was taken out of the sample tube and placed in a 0.1 mm cuvette for spectral testing.

[0054] (3) Recognition experiments of different anions were carried out at a constant concentration of UNTA. R-UNTA was combined with various inorganic anions (F - , Cl - Br - 、NO3 - 、CH3SO3 - ) co-assembly was compared. The CD spectra were analyzed. The addition of F ions led to an enhancement of the R-UNTA CD signal. However, there was no significant change in the CD intensity of the mixed system containing different anions other than F ions (see Figure 8 ). This indicates that the addition of F ions into the system can significantly enhance the CD absorption spectrum intensity of UNTA, while other anions cannot achieve this effect. Therefore, the F ions in the system can be implicitly identified through CD spectroscopy.

[0055] Among them, the tetrabutylammonium fluoride (F - ), tetrabutylammonium chloride (Cl - ), Tetrabutylammonium bromide (Br - ), Tetrabutylammonium nitrate (NO3 - ), Tetrabutylammonium methanesulfonate (CH3SO3 - ) was purchased from Inokai Reagent Co., Ltd. The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. A dual recognition method for fluoride ions based on chiral photosensitive molecules of triarylamine, which comprises: using circular dichroism spectroscopy to detect the intensity change of the chiral triarylamine derivative molecular self-assembly before and after the addition of fluoride ions, thereby realizing implicit recognition of F ions; or using ultraviolet light to distinguish the color change of the chiral triarylamine derivative molecular self-assembly before and after the addition of fluoride ions, thereby realizing explicit recognition of F ions.

2. The method according to claim 1, characterized in that The dual recognition method of fluoride ions by chiral photosensitive molecules based on triarylamine comprises the following steps: 1) detecting the circular dichroism intensity CD0 of the chiral triarylamine derivative molecular self-assembly, and detecting the circular dichroism intensity CD1 of the chiral triarylamine derivative molecular self-assembly system containing anions, and if CD1 is significantly enhanced compared with CD0, it is determined that the anion is a fluoride ion or includes a fluoride ion; 2) irradiating the chiral triarylamine derivative molecular self-assembly system containing anions with ultraviolet light. If the system appears red under ultraviolet light, it is determined that the anions are fluoride ions or include fluoride ions.

3. The method according to claim 2, characterized in that The chiral triarylamine derivative molecular self-assembly exists in a mixed solvent, and the mixed solvent is DMF / DCM, and the volume ratio of DMF to DCM is 0.02-0.5:

1.

4. The method according to claim 2, characterized in that: In step 1), the significant enhancement is an enhancement of more than 10 times.

5. The method according to claim 2, characterized in that: The chiral triarylamine derivative molecular self-assembly is prepared by a method comprising the following steps: The chiral triarylamine derivative molecules are subjected to supramolecular assembly in a mixed solvent to obtain the product; The anion-containing chiral triarylamine derivative molecular self-assembly system is prepared by a method comprising the following steps: The supermolecule is assembled by carrying out supramolecular assembly of anion-containing compounds and chiral triarylamine derivative molecules in a mixed solvent; Wherein, the mixed solvent is DMF / DCM, and the volume ratio of DMF to DCM is 0.02-0.5:1; The concentration of the chiral triarylamine derivative molecules in the mixed solvent is 0.088-1.0 mg / mL.

6. The method according to claim 2, characterized in that The chiral triarylamine derivative molecule is S or R-UNTA, and its structural formula is as follows: 。 7. The method according to claim 2, characterized in that The molar ratio of the self-assembly to the F ion is 1:1-3.

8. Application of chiral triarylamine derivative molecules or chiral triarylamine derivative molecular self-assemblies in F ion detection.

9. A F ion recognition material, which is a chiral triarylamine derivative molecule or a self-assembly of chiral triarylamine derivative molecules.

10. The F ion recognition material according to claim 9, characterized in that: The chiral triarylamine derivative molecule is S / R-UNTA.

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