A rhodamine derivative and its application in multi-ion spectral sensor

Abstract

The present invention discloses a rhodamine derivative and its application in a multi-ion spectral sensor. The present invention uses rhodamine 6G and 2-thiazole methylamine as raw materials to react and prepare the rhodamine derivative, which is a new spectral sensor RGTM based on rhodamine 6G. RGTM can respond to Fe by colorimetry and fluorescence. 3+ 、Al 3+ and Cr 3+ Etc., with high sensitivity and strong anti-interference, RGTM can also be made into a portable solid sensor, which is sensitive and eye-catching, easy to use and has good application prospects.

Description

Technical Field

[0001] The invention belongs to advanced material technology and relates to an ion sensor, in particular to a rhodamine derivative and an application thereof in a multi-ion spectrum sensor. Background Art

[0002] Rhodamine-based spectral sensors have excellent properties, such as long absorption and emission wavelengths, good photostability and high fluorescence quantum yield. The structural difference between the closed and open forms of the spiro ring is the main basis for the recognition mechanism of rhodamine-based spectral sensors. Rhodamine-based spectral sensors are usually colorless and non-fluorescent, but when they recognize and coordinate specific objects, they show obvious color and fluorescence enhancement. Rhodamine spectral sensors have been widely used in many fields such as food analysis, disease diagnosis and environmental monitoring.

[0003] For a long time, a large number of studies have focused on single ion spectral sensors. Compared with single ion spectral sensors, multi-ion spectral sensors can improve efficiency and reduce costs, so their design and synthesis have attracted more and more attention. For example, in 2018, AmitKumar Manna et al. designed and synthesized a thiourea-based spectral sensor that can detect Cu by colorimetry and fluorescence in a MeOH / H2O (1:1, v / v) system. 2+ , Hg 2+ and Ag + In 2022, Bhriguram Das et al. reported a new rhodamine-phenolphthalein derivative that can colorimetrically detect Cu in a MeOH / H2O (v / v = 9 / 1, 5 mM HEPES, pH = 7.2) system. 2+ and Fe 3+ , fluorescence detection of Al 3+ and Cr 3+ The prior art discloses a rhodamine-oxadiazole derivative that can detect Cu in acetonitrile / water (1 / 1, v / v) by colorimetry and fluorescence. 2+ , Fe was detected by fluorescence in acetonitrile / water (99 / 1, v / v) 3+ , but basically no response to other metal ions; while the fluorescent probes from rhodamine B, diethylenetriamine (or triethylenetetramine, tetraethylenepentamine) and phenyl isothiocyanate can detect mercuric ions from mercuric chloride, but basically no response to other metal ions; there is also a prior art that discloses a compound based on rhodamine B and aminoethyl sulfide that also responds to Hg 2+ It has good selectivity, but has little response to other metal ions. In addition, the literature reports that rhodamine B is first chlorinated with trichlorinated phosphorus oxychloride and then dehydrochlorinated with 2-aminothiazole to synthesize a Fe 3+ Colorimetric and fluorescent sensors, and other metal ions for Fe 3+There was no obvious interference with the detection.

[0004] Since the same sensor responds to multiple ions, the situation is relatively complex and the research on multi-ion spectral sensors is very challenging. Therefore, there are fewer varieties in general. In addition, some existing multi-ion spectral sensors require highly volatile and toxic organic solvents such as methanol as detection media, some can only be detected through a single channel of colorimetry or fluorescence, some are not sensitive enough, and their performance needs to be improved. New multi-ion spectral sensors are in urgent need of development. The biggest difficulty in developing multi-ion spectral sensors is that there is currently no clear relationship between the sensor structure and the identified ions, and similar structures can exhibit very different performances. Summary of the invention

[0005] The present invention designs and synthesizes a new spectral sensor RGTM based on rhodamine 6G. RGTM can respond to Fe by colorimetry and fluorescence. 3+ 、Al 3+ and Cr 3+ Etc., with high sensitivity and strong anti-interference, RGTM can also be made into a portable solid sensor, which is sensitive and eye-catching, easy to use and has good application prospects.

[0006] The present invention adopts the following technical scheme.

[0007] A rhodamine derivative, whose chemical structural formula is as follows:

[0008] .

[0009] The invention discloses a method for preparing the rhodamine derivatives, comprising the following steps: taking rhodamine 6G and 2-thiazolemethylamine as raw materials, and reacting to prepare the rhodamine derivatives.

[0010] Further, the molar ratio of rhodamine 6G to 2-thiazolylmethylamine is 1:(1-5); preferably, the molar ratio of rhodamine 6G to 2-thiazolylmethylamine is 1:(1.5-2.5).

[0011] Further, the reaction temperature of rhodamine 6G and 2-thiazolemethylamine is 50-100° C., and the reaction time is 1-20 h; preferably, the reaction temperature of rhodamine 6G and 2-thiazolemethylamine is 65-85° C., and the reaction time is 5-10 h.

[0012] The present invention discloses an ion spectrum sensor, comprising the above rhodamine derivative. Further, the above rhodamine derivative is used as an ion spectrum probe in the ion spectrum sensor.

[0013] The present invention discloses a method for spectral detection of ions in a system, comprising the following steps: mixing the above-mentioned rhodamine derivative with the system, and realizing the detection of ions in the system by spectrum. As common sense, the system is a solution system. The spectrum includes visible spectrum, ultraviolet spectrum, ultraviolet-visible absorption spectrum, fluorescence spectrum, etc., wherein the visible spectrum and ultraviolet spectrum can be reflected by instruments or observed by naked eyes.

[0014] In the present invention, the above-mentioned rhodamine derivatives are mixed with the system by adding the above-mentioned rhodamine derivatives into the system to achieve mixing. Under this method, the spectrum of the rhodamine derivative and the system mixed liquid is tested; or the carrier coated with the rhodamine derivatives is immersed in the system to achieve mixing. Under this method, the spectrum of the carrier coated with the rhodamine derivatives taken out is tested, which is also called RGTM solid sensor.

[0015] The present invention discloses the application of the above-mentioned rhodamine derivatives as ion spectrum probes. Furthermore, the present invention discloses the application of the above-mentioned rhodamine derivatives in the preparation of ion spectrum sensors.

[0016] In the present invention, the ion spectrum probe and the ion spectrum sensor are reversible ion spectrum probe and reversible ion spectrum sensor.

[0017] In the present invention, in the ion spectral probe and the ion spectral sensor, the number of ions is ≥1, preferably, the number of ions is 1 to 10, preferably 2 to 5; preferably, the ion spectral probe is a multi-ion spectral probe; and the ion spectral sensor is a multi-ion solid spectral sensor.

[0018] In the present invention, in the ion spectrum probe and the ion spectrum sensor, the ions include Fe 3+ 、Al 3+ Cr 3+ , Hg 2+ , Fe 2+ One or more of the .

[0019] The present invention designs and synthesizes a novel rhodamine derivative that can be used as a Fe 3+ 、Al 3+ Cr 3+ , Hg 2+ , Fe 2 + The multi-ion spectroscopy probe was further used to detect Fe 3+ 、Al 3+ Cr 3+ , Hg 2+ , Fe 2+ The target product of the present invention has a relatively simple structure and is easy to synthesize. The sensor based on the RGTM is suitable for Fe 3+ 、Al3+ Cr 3+ , Hg 2+ The detection is easy to use, has high sensitivity, eye-catching indication, strong anti-interference ability and good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The photos show the response of RGTM (10 µM) to 17 metal ions (50 µM) in CH3CN / H2O (50 / 50, v / v) solvent. RGTM concentration: 10 µM; metal ion concentration: 50 µM. Top: natural light, bottom: 365 nm UV light.

[0021] Figure 2 The UV-visible absorption spectrum (a) and fluorescence spectrum (b) of RGTM show their responsiveness to metal ions. Solvent: CH3CN / H2O (50 / 50, v / v); RGTM concentration: 10 µM; metal ion concentration: 50 µM; excitation wavelength: 530 nm; slit width: 2.5 nm.

[0022] Figure 3 The response of RGTM (10 µM) to 17 metal ions in DMF / H2O (1 / 99, v / v) solvent system. RGTM concentration: 10 µM; metal ion concentration: 50 µM. Top: natural light, bottom: 365 nm ultraviolet light.

[0023] Figure 4 The UV-visible spectra (a) and fluorescence spectra (b) of RGTM show their selectivity for metal ions. Solvent: DMF / H2O (1 / 99, v / v); RGTM concentration: 10 µM; metal ion concentration: 100 µM; excitation wavelength: 530 nm; slit width: 2.5 nm.

[0024] Figure 5 The response of RGTM (10 µM) to 17 metal ions in DMSO / H2O (10 / 90, v / v) solvent system. RGTM concentration: 10 µM, metal ion concentration: 100 µM. Top: natural light, bottom: 365 nm UV light.

[0025] Figure 6 The UV-visible spectra (a) and fluorescence spectra (b) of RGTM show their selectivity for metal ions. Solvent: DMSO / H2O (10 / 90, v / v); RGTM concentration: 10 µM; metal ion concentration: 100 µM; excitation wavelength: 530 nm; slit width: 2.5 nm.

[0026] Figure 7UV-visible absorption (a) and fluorescence intensity (b) of RGTM solution and Fe 3+ Inset: Absorbance at 530 nm / fluorescence intensity at 553 nm vs. Fe 3+ Concentration relationship. Solvent: CH3CN / H2O (50 / 50, v / v), RGTM concentration: 10 µM, metal ion concentration: 50 µM, maximum absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0027] Figure 8 UV-visible absorption (a) and fluorescence intensity (b) of RGTM solution and Al 3+ Inset: Absorbance at 530 nm / fluorescence intensity at 553 nm vs. Al 3+ Concentration relationship. Solvent: CH3CN / H2O (50 / 50, v / v), RGTM concentration: 10 µM, metal ion concentration: 50 µM, maximum absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0028] Fig. 9 UV-visible absorption (a) and fluorescence intensity (b) of RGTM solution and Cr 3+ Inset: Absorbance at 530 nm / fluorescence intensity at 553 nm vs. Cr 3+ Concentration relationship. Solvent: CH3CN / H2O (50 / 50, v / v), RGTM concentration: 10 µM, metal ion concentration: 50 µM, maximum absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0029] Fig.10 is the absorbance of the coexisting metal ion pair solution at 530 nm (a: RGTM-Fe 3+ , b:RGTM-Al 3+ 、c:RGTM-Cr 3+ ) and fluorescence intensity at 553 nm (d: RGTM-Fe 3+ 、e:RGTM-Al 3+ 、f:RGTM-Cr 3+ ) concentration: RGTM 10 µM, Fe 3+ 、Al 3+ and Cr 3+The concentration of coexisting ions is 50 µM. Solvent system: CH3CN / H2O (50 / 50, v / v). Absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0030] Fig.11 RGTM-Fe 3+ RGTM-Al 3+ and RGTM-Cr 3+ Time response of solution absorbance (a) and fluorescence intensity (b). Concentration: RGTM 10 µM, Fe 3+ 、Al 3+ and Cr 3+ is 50 µM. Solvent system: CH3CN / H2O (50 / 50, v / v). Absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0031] Fig.12 Fe was added to the CH3CN / H2O (50 / 50, v / v) solution of RGTM 3+ 、Al 3+ and Cr 3+ After adding excess EDTA, the color and fluorescence changes are shown. Concentration: RGTM is 10 µM, Fe 3+ 、Al 3+ and Cr 3+ is 50 µM, EDTA is 60 µM. Top: natural light, bottom: 365 nm UV light.

[0032] Fig.13 Colorimetric detection of Fe for RGTM 3+ (a) Al 3+ (b) and Cr 3+ (c) and fluorescence detection of Fe 3+ (d) Al 3+ (e) and Cr 3+ (f) Reversibility. Concentration: RGTM 10 µM, Fe 3+ 、Al 3+ and Cr 3+ is 50 µM, EDTA is 60 µM. Solvent system: CH3CN / H2O (50 / 50, v / v). Absorption wavelength: 530 nm, excitation wavelength: 530 nm, slit width: 2.5 nm, fluorescence wavelength: 553 nm.

[0033] Fig.14 RGTM solid sensor for Fe detection 3+RGTM concentration: 1.6 mg RGTM / g cotton swab, Fe 3+ Concentrations: 0, 0.25, 1.75, 3.75, 7.5, 11.2 mM. Left: natural light, right: 365 nm UV light.

[0034] Fig.15 RGTM solid sensor for Al detection 3+ RGTM concentration: 1.6 mg RGTM / g cotton swab, Al 3+ Concentrations: 0, 1.25, 2.5, 3.75, 6.25, 12.5 mM. Left: natural light, right: 365 nm UV light.

[0035] Fig.16 Detection of Cr for RGTM solid state sensor 3+ RGTM concentration: 1.6 mg RGTM / g cotton swab, Cr 3+ Concentrations: 0, 0.25, 2.5, 5.0, 7.5, 12.5 mM. Left: natural light, right: 365 nm UV light. DETAILED DESCRIPTION

[0036] The present invention uses rhodamine 6G and 2-thiazolemethylamine as raw materials and a one-step reaction in the presence of sodium acetate or diisopropylethylamine under the protection of an inert gas (such as nitrogen) to prepare a rhodamine derivative RGTM, which can respond to Fe by colorimetry and fluorescence. 3+ 、Al 3+ and Cr 3+ It has high sensitivity, fluorescence enhancement of 1159~555 times, linear range of 0~(30~50) μM, and detection limit as low as 1.3~2.9 nanomoles. RGTM can also be made into a portable solid sensor, which is sensitive, eye-catching, easy to use, and has good application prospects.

[0037] In the present invention, the molar ratio of rhodamine 6G, 2-thiazolemethylamine, sodium acetate or diisopropylethylamine is 1:(1.5-2.5):(1.5-2.5).

[0038] In the present invention, the reaction between rhodamine 6G and 2-thiazolemethylamine is carried out in a solvent, and the solvent includes acetonitrile or ethanol.

[0039] In the present invention, after the reaction of rhodamine 6G and 2-thiazolemethylamine is completed, the reaction solution is cooled to room temperature, the solvent is removed under reduced pressure, and the crude product is separated by silica gel column chromatography to obtain a light orange granular product RGTM.

[0040] The following is a detailed description of the technical progress of the present invention. The raw materials involved are existing products, and the specific preparation operations and performance tests are all conventional techniques. The compounds of 17 metal ions are prepared as follows:

[0041] AlCl3·6H2O, anhydrous FeCl3, FeCl2·7H2O, CrCl3·6H2O, CuSO4·5H2O, KCl, HgCl2, Pb(CH3COO)2·3H2O, CdCl2·2.5H2O, MgCl2·6H2O, CaCl2, AgNO3, ZnCl2, Ni(CH3COO)2·4H2O, NaCl, MnSO4·H2O, CoCl2·6H2O (AR, Sinopharm Chemical Reagent Co., Ltd.).

[0042] Example 1 Synthesis of RGTM

[0043]

[0044] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (38 μL, 0.4 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 70 mg of light orange granular product with a yield of 69.4%.

[0045] The molecular formula of RGTM is C 30 H 30 N4O2S, molecular weight M is 510.66. Mass spectrometry analysis [M+H] + It is 511.57. 1 H NMR (400MHz, CDCl3, δ / ppm): 7.98 (dd, J = 5.9, 1H, PhH), 7.41-7.45 (t, J = 3.5 Hz,2H, PhH, SCHCHN), 7.31 (d, J = 3.3 Hz, 1H, PhH)), 7.08-7.05 (m, 1H, SCHCHN),7.00 (d, J = 3.2 Hz, 1H, PhH), 6.32 (s, 2H, PhH), 6.09 (s, 2H, PhH), 4.64 (s,2H, NCH2), 3.46 (s, 2H, CH3CH2NH), 3.24-3.12 (m, 4H, CH3CH2NH), 1.78 (s, 6H,PhCH3), 1.30 (t,J = 7.2 Hz, 6H, CH3CH2NH). Infrared spectrum characteristic absorption peak (cm -1 ): ν (COC): 1245.86; ν (Ar-H): 1418.08, 1520.94, 743.40; ν (CN): 1376.05; ν (C=O ): 1619.19; ν (C=N): 1685.14; ν (CSC): 1057.41; ν (CH3, CH2): 2994.87, 2920.14.

[0046] Example 2 Synthesis of RGTM

[0047] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of ethanol and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (28 μL, 0.3 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 43.0 mg of light orange granular product with a yield of 42.1%.

[0048] Example 3 Synthesis of RGTM

[0049] Rhodamine 6G (0.096 g, 0.2 mmol) and N,N-diisopropylethylamine (DIPEA) (70 μL, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (28 μL, 0.3 mmol) was added, the temperature was raised to 75°C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 26.1 mg of light orange granular product with a yield of 25.5%.

[0050] Example 4 Synthesis of RGTM

[0051] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (28 μL, 0.3 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 63.1 mg of light orange granular product with a yield of 61.9%.

[0052] Example 5 Synthesis of RGTM

[0053] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (47 μL, 0.5 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 66.0 mg of light orange granular product with a yield of 64.7%.

[0054] Example 6 Synthesis of RGTM

[0055] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (38 μL, 0.4 mmol) was added, the temperature was raised to 65 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 63.8 mg of light orange granular product with a yield of 62.5%.

[0056] Example 7 Synthesis of RGTM

[0057] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (38 μL, 0.4 mmol) was added, the temperature was raised to 85 °C, and the reaction was refluxed for 7 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 68.0 mg of light orange granular product with a yield of 66.7%.

[0058] Example 8 Synthesis of RGTM

[0059] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (38 μL, 0.4 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 5 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 66.7 mg of light orange granular product with a yield of 65.3%.

[0060] Example 9 Synthesis of RGTM

[0061] Rhodamine 6G (0.096 g, 0.2 mmol) and sodium acetate (CH3COOONa) (0.033 g, 0.4 mmol) were dissolved in 8 mL of acetonitrile and stirred under N2 protection. After 5 min, 2-thiazolemethylamine (38 μL, 0.4 mmol) was added, the temperature was raised to 75 °C, and the reaction was refluxed for 10 h to stop the reaction. The reaction solution was cooled to room temperature, the solvent was removed under reduced pressure, and the crude product was separated by silica gel column chromatography using ethyl acetate / petroleum ether = 1 / 3 (v / v) as the eluent to obtain 65.4 mg of light orange granular product with a yield of 64.1%.

[0062] Example 10 Response of RGTM absorption spectrum and fluorescence spectrum to metal ions

[0063] In order to explore the response of RGTM to metal ions, RGTM was added with Fe in three solvent systems: CH3CN / H2O (50 / 50, v / v), DMF / H2O (1 / 99, v / v), and DMSO / H2O (10 / 90, v / v). 3+ , Fe 2+ Cr 3+ , Ag + , Cu 2+, Al 3+ 、Na + , K + Mg 2+ , Ca 2+ , Hg 2+ 、Zn 2+ 、Co 2+ 、Cd 2+ , Pb 2+ , Mn 2+ 、Ni 2+ The color, fluorescence, UV-visible absorption spectrum and fluorescence spectrum of the solutions before and after treatment with 17 kinds of metal ions were analyzed.

[0064] Figure 1 The color of RGTM CH3CN / H2O (50 / 50, v / v) solution before and after adding metal ions under natural light and the fluorescence under 365 nm ultraviolet light. 3+ 、Al 3+ and Cr 3+ The solution turns red and then emits yellow-green fluorescence, and the intensity decreases successively.

[0065] Figure 2 This is the UV-visible absorption spectrum of CH3CN / H2O (50 / 50, v / v) solution of RGTM before and after adding metal ions ( Figure 2 a) and fluorescence spectra ( Figure 2 b). From Figure 2 It can be found in a that Fe 3+ 、Al 3+ and Cr 3+ All of them caused RGTM to have an absorption peak at 530 nm, and the absorbance increased by 44, 11, and 9 times, respectively, and then decreased in sequence, corresponding to the color observed by the naked eye. However, other ions did not cause significant changes in the UV-visible absorption spectrum of RGTM solution. Figure 2 In b, it can be found that Fe 3+ 、Al 3+ and Cr 3+ All of them can enhance the fluorescence of RGTM at 553 nm, and the fluorescence intensity is enhanced by 1159, 624 and 555 times respectively. Other ions did not cause significant changes in the fluorescence spectrum of RGTM solution. Therefore, in the CH3CN / H2O (50 / 50, v / v) system, when the RGTM concentration is 10 µM and the metal ion concentration is 50 µM, RGTM has no significant effect on Fe 3+ 、Al 3+ and Cr 3+ All have responses.

[0066] Figure 3The color of RGTM DMF / H2O (1 / 99, v / v) solution before and after adding metal ions under natural light and the fluorescence under 365 nm ultraviolet light. 3+ Cr 3+ 、Al 3+ and Hg 2+ The solution turns red and then emits yellow-green fluorescence, and the intensity decreases successively.

[0067] Figure 4 This is the UV-visible absorption spectrum of RGTM DMF / H2O (1 / 99, v / v) solution before and after adding metal ions ( Figure 4 a) and fluorescence spectra ( Figure 4 b). From Figure 4 It can be found in a that Fe 3+ Cr 3+ 、Al 3+ and Hg 2+ All of them make RGTM have an absorption peak at 530 nm, and the absorbance enhancement factors are 50, 24, 12 and 6 times, which decrease in sequence, corresponding to the color observed by the naked eye. However, other ions do not cause obvious changes in the UV-visible absorption spectrum of RGTM solution. Figure 4 In b, it can be found that Fe 3+ Cr 3+ 、Al 3+ and Hg 2+ All of them can enhance the fluorescence of RGTM at 553 nm, and the fluorescence intensity is enhanced by 30, 20, 13 and 7 times respectively. Other ions did not cause significant changes in the fluorescence spectrum of RGTM solution. Therefore, in the DMF / H2O (1 / 99, v / v) system, when the RGTM concentration is 10 µM and the metal ion concentration is 100 µM, RGTM has no significant effect on Fe 3+ Cr 3+ 、Al 3+ and Hg 2+ All have responses.

[0068] Figure 5 The color of RGTM DMSO / H2O (10 / 90, v / v) solution before and after adding metal ions under natural light and the fluorescence under 365 nm ultraviolet light. 3+ Cr 3+ , Fe 2+ 、Al 3+ , Hg 2+ The solution turns red and then emits yellow-green fluorescence, and the intensity decreases successively.

[0069] Figure 6This is the UV-visible absorption spectrum of RGTM in DMSO / H2O (10 / 90, v / v) solution before and after adding metal ions ( Figure 6 a) and fluorescence spectra ( Figure 6 b). From Figure 6 It can be found in a that Fe 3+ Cr 3+ , Fe 2+ 、Al 3+ , Hg 2+ All of them caused RGTM to have an absorption peak at 530 nm, and the absorbance enhancement factors were 128, 71, 38, 34 and 11 times, respectively, decreasing in sequence, corresponding to the color observed by the naked eye. However, other ions did not cause significant changes in the UV-visible absorption spectrum of RGTM solution. Figure 6 In b, it can be found that Fe 3+ Cr 3+ , Fe 2+ 、Al 3+ , Hg 2+ All of them can enhance the fluorescence of RGTM at 553 nm, and the fluorescence intensity is enhanced by 40, 35, 21, 20 and 7 times respectively. Other ions did not cause significant changes in the fluorescence spectrum of RGTM solution. Therefore, in the DMSO / H2O (10 / 90, v / v) system, when the RGTM concentration is 10 µM and the metal ion concentration is 100 µM, RGTM has no significant effect on Fe 3 + Cr 3+ , Fe 2+ 、Al 3+ , Hg 2+ All have responses.

[0070] From the above results, it can be seen that in the three solvent systems, the UV-visible absorption spectrum and fluorescence spectrum of RGTM respond to multiple ions, and the common response ion is Fe 3+ 、Al 3+ and Cr 3+ , CH3CN / H2O (50 / 50, v / v) is the most commonly used solvent system in spectral probes and sensors. The fluorescence spectrum of RGTM in CH3CN / H2O (50 / 50, v / v) is 3+ 、Al 3+ and Cr 3+ The responses of the three ions are very sensitive. Therefore, the feasibility of RGTM as a spectroscopic probe and sensor in CH3CN / H2O (50 / 50, v / v) is further discussed below.

[0071] Example 11 RGTM absorption and fluorescence spectra and Fe 3+ The relationship between concentration

[0072] The UV-visible absorption and fluorescence spectra of RGTM in CH3CN / H2O (50 / 50, v / v) were investigated. 3+ The relationship between the concentrations is shown in the following table. Figure 7 As shown. 3+ As the concentration gradually increased, the absorbance of RGTM at around 530 nm and the fluorescence intensity at around 553 nm gradually increased, and in the range of 0-45 µM Fe 3+ Concentration range, with Fe 3+ The concentration showed a good linear relationship, and the linear equations of absorbance and fluorescence intensity were A=0.00699×[Fe 3+ ]–0.02724 and F=58.25597×[Fe 3+ ]–22.45004, with correlation coefficients of 0.997 and 0.997, respectively, Fe 3+ The detection limits were 2.7×10 -6 mol / L and 1.3×10 -9 mol / L, the sensitivity of fluorescence detection is very high, reaching 1.3 nanomoles.

[0073] Example 12 RGTM absorption spectrum and fluorescence spectrum and Al 3+ The relationship between concentration

[0074] The absorption and fluorescence spectra of RGTM in CH3CN / H2O (50 / 50, v / v) were investigated. 3+ The relationship between concentration and Figure 8 As shown. 3+ As the concentration gradually increased, the absorbance of RGTM at around 530 nm and the fluorescence intensity at around 553 nm gradually increased, and in the range of 0-30 µM Al 3+ Concentration range, with Al 3+ The concentration showed a good linear relationship, and the linear equations of absorbance and fluorescence intensity were A=0.00341×[Al 3+ ]–0.00254 and F=45.60517×[Al 3+ ] +3.99271, the correlation coefficients are 0.996 and 0.994, respectively. 3+ The detection limits were 5.5×10 -6 mol / L and 1.6×10 -9 mol / L, the sensitivity of fluorescence detection is very high, reaching 1.6 nanomoles.

[0075] Example 13 RGTM absorption spectrum and fluorescence spectrum and Cr 3+ The relationship between concentration

[0076] The absorption and fluorescence spectra of RGTM in CH3CN / H2O (50 / 50, v / v) were investigated in comparison with those of Cr 3+ The relationship between concentration and Fig. 9 As shown. 3+ As the concentration of RGTM gradually increased, the absorbance at around 530 nm and the fluorescence intensity at around 553 nm gradually increased, and in the range of 0-50 μM Cr 3+ Concentration range, with Cr 3+ The concentration showed a good linear relationship, and the linear equations of absorbance and fluorescence intensity were A=0.0018×[Cr 3+ ]–0.01841 and F=25.27327×[Cr 3+ ]–29.12709, the correlation coefficients are 0.995 and 0.996, respectively, Cr 3+ The detection limits were 1.05×10 -5 mol / L and 2.9×10 -9 mol / L, the sensitivity of fluorescence detection is very high, reaching 2.9 nanomoles.

[0077] Example 14 RGTM detection of Fe 3+ 、Al 3+ Cr 3+ Anti-interference

[0078] In order to investigate the detection of Fe in CH3CN / H2O (50 / 50, v / v) system, RGTM 3+ 、Al 3+ and Cr 3+ The anti-interference ability of other coexisting ions is 3+ (or Al 3+ , or Cr 3+ ) were added to the RGTM solution 2+ , Ag + , Cu 2+ 、 + , K + Mg 2+ , Ca 2+ , Hg 2+ 、Zn 2+ 、Co 2+ 、Cd 2+ , Pb 2+ , Mn 2+ 、Ni 2+ One of them is to compare the UV-visible absorption and fluorescence spectra of the solution before and after adding these ions. Fig.10As shown in the figure, after the addition of interfering ions, there was no significant change in either the absorbance at 530 nm or the fluorescence intensity near 553 nm. 3+ 、Al 3+ and Cr 3+ It has strong anti-interference ability.

[0079] Example 15 RGTM detection of Fe 3+ 、Al 3+ Cr 3+ Time responsiveness

[0080] In order to investigate the detection of Fe in CH3CN / H2O (50 / 50, v / v) system, RGTM 3+ 、Al 3+ and Cr 3+ The response speed of Fe 3+ 、Al 3+ and Cr 3+ Start and record the UV-visible absorption and fluorescence spectra of the solution at certain intervals, such as Fig.11 .Depend on Fig.11 From a, we can see that: RGTM-Fe 3+ The absorbance of the solution increased significantly within 15 minutes and reached a stable state after 25 minutes. 3+ The absorbance of the solution increased significantly within 5 minutes and reached a stable state after 10 minutes. 3+ The absorbance of the solution increased significantly within 5 minutes and reached a stable state after 15 minutes. Fig.11 From b, we can see that RGTM-Fe 3+ The fluorescence intensity of the solution increased rapidly to a maximum within 30 min and then stabilized. 3+ and RGTM-Cr 3+ The fluorescence intensity of the solution rapidly increased to a maximum within 10 min and then stabilized.

[0081] Therefore, RGTM has the ability to rapidly detect Fe in the CH3CN / H2O (50 / 50, v / v) system. 3+ 、Al 3+ and Cr 3+ ability.

[0082] Example 16 RGTM detection of Fe 3+ 、Al 3+ Cr 3+ Reversibility

[0083] Add Fe into the CH3CN / H2O (50 / 50, v / v) solution of RGTM 3+ 、Al 3+ and Cr 3+ Then, excess EDTA solution was added to investigate the detection of Fe by RGTM 3+ 、Al 3+ and Cr 3+ First, observe the color of each solution under natural light and the fluorescence under 365nm ultraviolet light and take pictures. The results are as follows Fig.12 .

[0084] Depend on Fig.12 It can be seen that the RGTM solution is colorless and non-fluorescent. 3+ 、Al 3+ and Cr 3+ After that, the solution turned red and showed yellow-green fluorescence. After adding EDTA, the solution turned back to colorless and non-fluorescent, indicating that RGTM recognized Fe 3+ 、Al 3+ and Cr 3+ The process is reversible.

[0085] The UV-visible absorption and fluorescence spectra of each solution were further measured. Fig.13 .Depend on Fig.13 From a, b, and c, we can see that the RGTM solution has almost no absorption in the visible region. 3+ 、Al 3+ and Cr 3+ After adding EDTA, the solution showed an obvious absorption peak at 530 nm. Then, the UV-visible absorption spectrum of the solution returned to almost the same as that of RGTM solution. Therefore, RGTM colorimetric detection of Fe 3+ 、Al 3+ Cr 3+ It is reversible. Fig.13 From d, e, and f, we can see that the RGTM solution emits almost no fluorescence. 3+ 、Al 3+ and Cr 3+ After addition of EDTA, the solution showed an obvious fluorescence emission peak near 553 nm. When excessive EDTA was added, the fluorescence of the solution was almost completely quenched. 3+ 、Al 3+ and Cr 3+ It is also a reversible process.

[0086] Therefore, RGTM is used as a spectroscopic sensor to detect Fe 3+ 、Al 3+ and Cr 3+ It is reversible.

[0087] Example 17 RGTM is used to detect Fe in environmental water samples 3+ 、Al 3+ Cr 3+

[0088] To investigate the practicality of RGTM, RGTM was used to analyze the pond water and tap water of Suzhou University Dushu Lake Campus. 3+ 、Al 3+ and Cr 3+ Fluorescence emission spectrum of RGTM solution. 3+ 、Al 3+ and Cr 3+ The linear relationship between the concentration of Fe 3+ 、Al 3+ and Cr 3+ Concentration, Fe 3+ 、Al 3+ and Cr 3+ The recovery rate and relative standard deviation are shown in Table 1: 3+ 、Al 3+ and Cr 3+ Concentration and added Fe 3+ 、Al 3+ and Cr 3+ The concentrations are similar, Fe 3+ 、Al 3+ and Cr 3+ The recovery rate was between 96.12% and 102.3%, and the relative standard deviation of three parallel experiments was less than 1.21%. Therefore, RGTM can be used to effectively analyze Fe in actual environmental water samples. 3+ 、Al 3+ and Cr 3+ .

[0089] Table 1 Determination of Fe in pond water and tap water by RGTM 3+ 、Al 3+ and Cr 3+ (n=3)

[0090]

[0091] Solvent system: CH3CN / H2O (50 / 50, v / v), acetonitrile added to the amount of pond water or tap water; RGTM concentration: 10 µM, RSD: relative standard deviation.

[0092] Example 18 RGTM as Fe 3+ 、Al 3+ Cr 3+ Solid state sensors

[0093] Preparation of RGTM solid sensor. Ten cotton swabs with the same visual length and uniform shape were selected as solid sensor carriers, and their masses were weighed respectively. Since the masses of the ten cotton swabs were not much different, the average value was taken as the mass of the cotton swab (accurate to 0.01 mg). The cotton swab was soaked in 200 μL of 1 mM RGTM acetonitrile solution until the cotton ball completely absorbed the RGTM solution, first dried naturally in a fume hood, and then placed in an oven to dry for 10 min to obtain a solid sensor with 1.6 mg RGTM / g cotton swab.

[0094] Preparation of test solution. Take 15 vials and divide them into three groups. Add 1, 7, 15, 30, and 45 μL of Fe 3+ In the second group of five vials, add 5, 10, 15, 25, and 50 μL of Al 3+ In the third group of five vials, add 1, 10, 20, 30, and 50 μL of Cr 3+ Then, dimethyl sulfoxide and deionized water were added to make the total volume of the solution 200 μL (solvent system: DMSO / H2O=10 / 90, v / v).

[0095] Test and result recording method: Place the RGTM solid sensor into a small bottle containing the solution to be tested until the ion solution is completely absorbed. Observe the dyeing of the cotton swab. After 30 minutes, the color of the cotton swab no longer changes. Take photos and record them with a mobile phone under natural light and ultraviolet light.

[0096] RGTM as Fe 3+ Sensor test results. Detection of Fe in DMSO / H2O=1 / 9 (v / v) solvent system using RGTM solid sensor 3+ , the results are as follows Fig.14 As shown, adding low concentration of Fe 3+ After that, the color of the cotton swab changes from white to light red. 3+ As the concentration increases, the color of the cotton swab can be seen to change from light red to red with the naked eye; under 365 nm ultraviolet light, the fluorescence of the cotton swab can be seen to change from blue to light yellow, and then from light yellow to bright yellow. RGTM can clearly indicate different concentrations of Fe 3+ .

[0097] RGTM as Al 3+ Sensor. RGTM solid sensor was used to detect Al in DMSO / H2O=1 / 9 (v / v) solvent system. 3+ , the results are as follows Fig.15 As shown, adding low concentration of Al3+ Afterwards, the color of the cotton swab changed from white to light pink. 3+ As the concentration increases, the color of the cotton swab changes from light pink to dark pink; under 365 nm ultraviolet light, the fluorescence of the cotton swab can be seen to change from blue to light yellow, and then from light yellow to bright yellow. It can be seen that RGTM can clearly indicate different concentrations of Al 3+ .

[0098] RGTM as Cr 3+ Sensor. Detection of Cr in DMSO / H2O=1 / 9 (v / v) solvent system using RGTM solid sensor 3+ , the results are as follows Fig.16 As shown, adding low concentration of Cr 3+ Afterwards, the color of the cotton swab changes from white to light red. 3+ With the increase of concentration, the color of the cotton swab changes from light red to dark red, and under 365 nm ultraviolet light, the fluorescence of the cotton swab can be seen to change from blue to light yellow, and then from light yellow to bright yellow. It can be seen that RGTM can clearly indicate different concentrations of Cr 3+ .

[0099] Therefore, RGTM can be made into a low-cost, portable solid sensor for detecting Fe 3+ 、Al 3+ Cr 3+ It is easy to use, has eye-catching instructions, and has good application prospects.

Claims

1. A rhodamine derivative, whose chemical structural formula is as follows: 。 2. The method for preparing the rhodamine derivative according to claim 1, comprising the following steps: using rhodamine 6G and 2-thiazolemethylamine as raw materials to react and prepare the above-mentioned rhodamine derivative.

3. The method for preparing the rhodamine derivative according to claim 2, characterized in that: The molar ratio of rhodamine 6G to 2-thiazolemethylamine is 1:(1-5).

4. The method for preparing the rhodamine derivative according to claim 2, characterized in that: The reaction temperature of rhodamine 6G and 2-thiazolemethylamine is 50-100° C. and the reaction time is 1-20 h.

5. An ion spectrum sensor comprising the rhodamine derivative according to claim 1.

6. The ion spectrum sensor according to claim 5, characterized in that: The ion spectrum sensor is a multi-ion spectrum sensor.

7. A method for spectrally detecting ions in a system, comprising the following steps: mixing the rhodamine derivative described in claim 1 with the system, and detecting the ions in the system by spectroscopy.

8. Use of the rhodamine derivative according to claim 1 as an ion spectroscopy probe.

9. Use of the rhodamine derivative according to claim 1 in the preparation of an ion spectrum sensor.

10. The use according to claim 8 or 9, characterized in that: In the ion spectrum probe and ion spectrum sensor, the number of ions is ≥1.

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