Fluorescent surfactant, process for its preparation and use as a tracer

Abstract

The present application provides a fluorescent surfactant shown in formula I, a preparation method and application as a tracer. The preparation method of the fluorescent surfactant is simple, and after being combined with an anionic or cationic surfactant, the fluorescent surfactant can trace the absorption and conduction process of the anionic or cationic surfactant in a plant body. Further, the absorption and conduction process of a pesticide wrapped by the anionic or cationic surfactant in the plant body can also be traced, and scientific guidance is provided for reasonably designing and selecting an efficient, low-toxic and environment-friendly pesticide adjuvant (surfactant).

Description

Technical Field

[0001] This invention belongs to the field of tracer technology, and mainly relates to a fluorescent surfactant, its preparation method, and its application as a tracer. Background Technology

[0002] Surfactants are a crucial component of pesticide adjuvants, typically comprising 1-10% of pesticide formulations. They play a vital role in pesticide storage, foliar deposition and spread, and subsequent absorption and translocation. Surfactants can form abundant self-assembled structures in solution, such as spherical micelles, worm-like micelles, and vesicles. It is generally believed that surfactants promote the penetration and absorption of pesticides on and within crops. When spraying pesticides on leaves, surfactants can disrupt the structure of the waxy layer and alter the permeability of epidermal cell membranes to some extent, thereby facilitating the entry of pesticide molecules into the crop. However, the damage to the leaf surface caused by surfactants also affects the leaf's ability to resist external pathogens and prevent water loss. Currently, the mechanisms of surfactant absorption and translocation within the plant itself, as well as the interactions between surfactants, crops, and pesticides, are not fully understood. A thorough understanding of these processes is essential for the rational design and selection of highly efficient, low-toxicity, and environmentally friendly surfactants as pesticide adjuvants to improve pesticide utilization.

[0003] Patent (CN115191430A) discloses the application of a biomass-based surfactant system as an adjuvant in improving the effective utilization rate of pesticides. The system requires a small amount and has a good effect on inhibiting pesticide splashing and bouncing. However, the patent lacks research on the subsequent absorption and translocation of the surfactant on the leaf surface.

[0004] Patent (CN118285380A) discloses a surfactant assembly for regulating pesticide absorption and conduction on leaves. It compares the effects of three assemblies—micelles, vesicles, and liquid-liquid condensates—on pesticide delivery on leaves. However, this patent only observes the distribution of Nile Red and does not directly observe the distribution of surfactant molecules.

[0005] In summary, the existing technology has the following technical problems:

[0006] 1. There is a lack of effective technical means to track the migration and transformation of surfactant molecules in plants (such as wheat and other crops);

[0007] 2. Current research mainly focuses on the foliar spraying process, lacking research on the absorption and translocation process of surfactants from the roots of plants (such as wheat) from bottom to top;

[0008] 3. The influence of the structure and properties of surfactant assemblies on pesticide delivery remains unclear. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a naphthalimide fluorescent surfactant that possesses both fluorescent and surfactant properties. This invention utilizes a fluorescent surfactant and laser confocal fluorescence microscopy to observe the absorption and conduction processes of the surfactant in plants from top to bottom and from bottom to top.

[0010] By analyzing the results of confocal imaging of systems such as NIC12-DTAB and NIC12-SDS, the effects of the charged properties and morphology of surfactant assemblies on pesticide delivery and crop growth can be investigated.

[0011] The technical solution of the present invention is as follows:

[0012] The compound represented by Formula I:

[0013]

[0014] Among them, R1, R2, and R3 may be the same or different, and are independently selected from C. 1-12 alkyl;

[0015] m and n may be the same or different, and are independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12;

[0016] X is a halogen.

[0017] According to an embodiment of the present invention, R1, R2, and R3 may be the same or different, and are independently selected from C. 1-6 alkyl;

[0018] m and n may be the same or different, and are independently selected from 0, 1, 2, 3, 4, 5, 6, 7 or 8;

[0019] X is iodine, chlorine, or bromine.

[0020] According to embodiments of the present invention, R1, R2, and R3 are the same and are selected from methyl, ethyl, or propyl; m is 0, 1, or 2; and n is selected from 6, 7, 8, or 9.

[0021] X is iodine, chlorine, or bromine.

[0022] The present invention also provides a method for preparing the compound represented by Formula I as described above, comprising:

[0023]

[0024] Among them, R1, R2, R3, m, n and X have the definitions described above;

[0025] Compound I-2 was reacted with compound R3X to prepare the compound shown in Formula I.

[0026] According to an embodiment of the present invention, compound I-2 is prepared by the following method:

[0027]

[0028] Among them, R1, R2, m and n have the definitions described above;

[0029] 1) Compound I-1 was prepared by reacting compound Ia with compound Ib;

[0030] 2) Compound I-1 was reacted with compound Ic to prepare compound I-2.

[0031] The present invention also provides the use of the compounds shown in Formula I for preparing surfactant tracers or pesticide tracers;

[0032] The surfactant is used to trace the absorption and translocation process of the surfactant in the plant.

[0033] The pesticide tracer is used to trace the absorption and translocation process of pesticides within plants.

[0034] According to an embodiment of the present invention, the surfactant is an anionic or cationic surfactant, such as SDS or DTAB.

[0035] According to an embodiment of the present invention, the pesticide is a hydrophobic pesticide.

[0036] The present invention also provides a method for tracing surfactants or pesticides using compounds represented by Formula I as described above, comprising:

[0037] The compound shown in Formula I was mixed and dissolved with a surfactant in water to prepare a solution. Plants were cultured in the resulting solution, and the fluorescence of the surfactant in the plant was observed using a laser confocal fluorescence microscope to understand the absorption and conduction process of the surfactant.

[0038] Alternatively, the compound shown in Formula I can be mixed and dissolved with a surfactant in water to prepare a solution, and then a hydrophobic dye can be added to the solution. Plants can be cultured in the resulting solution, and then the fluorescence of the hydrophobic dye in the plant can be observed using a laser confocal fluorescence microscope to obtain the absorption and conduction process of the hydrophobic dye, and further to obtain the absorption and conduction process of the pesticide.

[0039] According to an embodiment of the present invention, in the method for tracing surfactants, the laser wavelength of the laser confocal fluorescence microscope is 488 nm.

[0040] According to an embodiment of the present invention, in the method for tracing pesticides, the hydrophobic dye is one of Nile Red, Methylene Blue, and Crystal Violet; when the hydrophobic dye is Nile Red, the laser wavelength of the laser confocal fluorescence microscope is 559 nm.

[0041] According to an embodiment of the present invention, since most pesticides are hydrophobic substances, the hydrophobic dye can be used as a reference to simulate the absorption and conduction process of pesticides in plants.

[0042] Beneficial effects

[0043] The method for preparing the fluorescent surfactant of this invention is simple. When combined with anionic or cationic surfactants, it can trace the absorption and translocation process of the anionic or cationic surfactants within plants. Furthermore, it can also trace the absorption and translocation process of pesticides encapsulated by the anionic or cationic surfactants within plants, providing scientific guidance for the rational design and selection of highly efficient, low-toxicity, and environmentally friendly pesticide adjuvants (surfactants). Attached Figure Description

[0044] Figure 1 The synthetic route for the fluorescent surfactant NIC12 is shown.

[0045] Figure 2 The UV absorption and fluorescence emission spectra of NIC12 are shown.

[0046] Figure 3 The surface tension and zeta potential of the binary systems NIC12, NIC12-DTAB and NIC12-SDS are given.

[0047] Figure 4 Cryo-transmission electron microscopy image of the NIC12-DTAB and NIC12-SDS binary system assembly.

[0048] Figure 5 Confocal images and fluorescence intensities of wheat roots after treatment with the NIC12-DTAB ternary system for different time periods (NIC12 represents the fluorescence observed in NIC12; Nile Red represents the fluorescence observed in Nile Red).

[0049] Figure 6 The results of root imaging of wheat after culturing wheat in ternary systems of different concentrations of NIC12-DTAB and NIC12-SDS for 48 h (NIC12 represents the fluorescence of NIC12 observed; Nile Red represents the fluorescence of Nile Red observed).

[0050] Figure 7 Images of wheat stems after culturing the NIC12-DTAB and NIC12-SDS ternary systems for 3-6 days (NIC12 represents the fluorescence observed in NIC12; Nile Red represents the fluorescence observed in Nile Red).

[0051] Figure 8Appearance of wheat after culturing the NIC12-DTAB and NIC12-SDS ternary systems for 3-6 days.

[0052] Figure 9 Wheat leaf images after culturing wheat leaves in the NIC12-DTAB and NIC12-SDS ternary systems for 1 hour (NIC12 represents the fluorescence observed in NIC12; Nile Red represents the fluorescence observed in Nile Red). Detailed Implementation

[0053] To further understand the present invention, the solutions provided by the present invention will be specifically described below with reference to comparative examples and embodiments. However, the present invention is not limited to these embodiments. Any changes, substitutions, or simplifications made under the core idea of ​​the present invention are within the scope of protection of the present invention.

[0054] This application Figure 5-7 In Figure 9, the green fluorescence is the result of the test at a laser wavelength of 488 nm; the red fluorescence is the result of the test at a laser wavelength of 559 nm.

[0055] Example 1

[0056] The preparation method of the fluorescent surfactant NIC12 used in this invention is as follows (synthetic route diagram is shown below). Figure 1 As shown in the diagram: 2.0 g (7.22 mmol) of 4-bromo-1,8-naphthalenedicarboxylic anhydride was added to a 250 mL two-necked flask, followed by 90 mL of anhydrous ethanol. The mixture was heated to reflux (1100 rpm, 85 °C) with magnetic stirring. Then, 867 μL (7.94 mmol, 1.1 eq) of N,N-dimethylethylenediamine was added, and the mixture was heated to reflux again. After reacting for 5 h, heating was stopped, and the mixture was cooled to room temperature. A solid precipitated out. The solid was filtered, washed three times with water and ice-cold ethanol, and dried under vacuum to give product 1 as a pale yellow solid, 2.310 g, with a yield of 91%.

[0057] 2.0 g (5.76 mmol) of product 1 and 3.45 mL (17.28 mmol, 3 eq.) of n-decylamine were added to a 100 mL two-necked flask, followed by 25 mL of ethylene glycol monomethyl ether, yielding a pale yellow, clear solution. The solution was heated to reflux (125 °C, 1100 rpm) with magnetic stirring. The reaction was monitored by TLC. After the reaction was complete, the solvent was removed by rotary evaporation. The solution was extracted with chloroform, and the organic layer was dried over anhydrous MgSO4 and then rotary evaporated to obtain the crude product. The crude product was purified by silica gel column chromatography to give 1.529 g of an orange-yellow solid, with a yield of 62%.

[0058] Add 35 mL of dichloromethane and 1110 μL (17.97 mmol, 5 eq.) of iodomethane to the above product, stir overnight at room temperature, stop the reaction, filter, wash with ethyl acetate, dry, and recrystallize the obtained solid with methanol-ethyl acetate to give 0.748 g of yellow solid NIC12, yield 72%. 1 H NMR (400MHz, DMSO-d6) δ8.76(d,J=8.5Hz,1H),8.47(d,J=7.3Hz,1H),8.30(d,J=8.6Hz,1H),7.89(t,J=5.5Hz,1H),7.72(t,J=7.9Hz,1H),6.81 (d,J=8.7Hz,1H),4.44(t,J=7.1Hz,2H),3.61(t,J=7.1Hz,2H),3.39(q,J=6.5Hz,2H),1.71(p,J=7.2Hz,2H),1.45–1.19(m,15H),0.87(t,3H). 13 C NMR (101MHz, DMSO-d6) δ 163.89, 162.79, 151.20, 134.75, 131.05, 129.75, 129.24, 124.37, 121.49, 120.19, 106.84, 104.03, 62.29, 52.48, 42.93, 39.50, 33.42, 31.35, 29.08, 29.02, 28.88, 28.77, 27.84, 26.67, 22.16, 14.02. ESI-MS: 438.37. Elemental analysis results: C 27 H 40 IN3O2: calcd, C, 57.34%; H, 7.07%; N, 7.42%; found: calcd, C, 57.08%; H, 7.06%; N, 7.45%.

[0059] Preparation method of NIC12-DTAB and NIC12-SDS systems: Weigh a certain mass of NIC12 powder into an aqueous solution of DTAB or SDS, heat until completely dissolved, and use the resulting clear solution as the mother liquor. Then, dilute the mother liquor (X) with water three times at a specific molar fraction. NIC12 =C NIC12 / (C NIC12 +C DTAB或SDS Different total concentrations (C) were obtained by dilution. T(Total concentration refers to the total concentration of NIC12 and DTAB, or NIC12 and SDS; a total of 5 concentrations of 0, 1.0, 5.0, 10.0 and 25.0 mM were prepared. Among them, the molar percentage of NIC12 was 30%) NIC12-DTAB or NIC12-SDS mixed solutions were prepared.

[0060] in, Figure 2 The images show the UV absorption and fluorescence emission spectra of NIC12. Figure 2 It can be seen that the maximum absorption wavelength of NIC12 is 457nm, the fluorescence emission wavelength is 567nm, and the fluorescence intensity shows a trend of first increasing and then decreasing with increasing concentration.

[0061] Figure 3 The surface tension and zeta potential of the binary systems NIC12, NIC12-DTAB, and NIC12-SDS are given. Figure 3 It can be seen that the critical micelle concentration (CMC) of the NIC12-DTAB system is 209 μM, and γ cmc =34mN / m, all higher than NIC12 itself (CMC=108μM, γ cmc =32mN / m). Conversely, the CMC and γ of the NIC12-SDS system cmc (CMC = 18 μM, γ) cmc =27mN / m) is relatively low. The NIC12-DTAB system is generally positively charged, while the NIC12-SDS system is generally negatively charged.

[0062] Figure 4 Cryo-transmission electron microscopy images of assemblies formed from the binary systems of NIC12-DTAB and NIC12-SDS. Figure 4 It is known that the NIC12-DTAB system mainly forms nanowires and worm-like micelles, while the NIC12-SDS system mainly forms vesicles and rod-shaped micelles.

[0063] In addition, a ternary system was prepared by completely dissolving the hydrophobic dye Nile Red in NIC12-DTAB or NIC12-SDS through stirring, in order to conduct further testing.

[0064] Example 2

[0065] The method for observing the distribution of surfactants and Nile red in wheat using laser confocal fluorescence microscopy is as follows:

[0066] Wheat seeds were induced to germinate in the dark at 25°C. Germinated wheat seeds were then cultured in Hoagland's nutrient solution for 7 days (culture temperature 25°C, relative humidity 55%, light intensity 7000 Lx). After 7 days of culture, the wheat seedlings were transferred to different concentrations of NIC12-DTAB or NIC12-SDS ternary systems (C12-DTAB or NIC12-SDS) containing the hydrophobic dye Nile Red prepared in Example 1. T =0, 1.0, 5.0, 10.0 and 25.0 mM; when C T When the concentration of Nile Red in the solution is 0, the solution contains only Nile Red. After culturing for different times, the samples are removed and washed three times with water to remove residual solution from the roots. The roots, stems, and leaves of wheat are wrapped in 10% agarose and sliced ​​into thin sections using a vibratory microtome. The sliced ​​samples are placed on coverslips, and a drop of PBS buffer solution is added. The coverslips are then covered, and the samples are observed using a laser confocal fluorescence microscope with laser wavelengths of 488 nm and 559 nm.

[0067] Images of wheat roots after treatment with the NIC12-DTAB ternary system for different time periods are shown below. Figure 5 As shown, the fluorescence intensity corresponding to each fluorescence image was statistically analyzed using ImageJ. Figure 5 It can be seen that the Nile red fluorescence intensity of wheat roots treated with the NIC12-DTAB ternary system was much higher than that of the control group (C T =0mM), and the fluorescence intensity of both the surfactant and Nile Red increased continuously with the extension of treatment time and then tended to stabilize.

[0068] After culturing wheat with NIC12-DTAB and NIC12-SDS ternary systems at different concentrations for 48 hours, the effects of the system on wheat roots were compared. Figure 6 As shown in the image, comparing the imaging results of the two systems reveals that in the NIC12-DTAB system, more surfactant molecules enter the wheat roots more quickly and have already reached the central column of the root. In contrast, in the NIC12-SDS system, only a very small amount of surfactant enters the wheat roots.

[0069] After culturing wheat with 10.0 mM NIC12-DTAB and NIC12-SDS for 3-6 days, the results of laser confocal imaging of wheat stem sections and the overall growth status of wheat are as follows: Figure 7 and Figure 8 As shown, both the surfactant and Nile Red are transported from bottom to top through the phloem of wheat. The NIC12-SDS system can still deliver Nile Red even with less surfactant entering the wheat interior. Furthermore, in the NIC12-DTAB system, a large amount of surfactant enters the wheat interior, which adversely affects the normal growth of wheat after prolonged cultivation.

[0070] Therefore, the fluorescent surfactant NIC12 of this application can trace the absorption and transduction pathways of conventional anionic or cationic surfactants in plants, and even the absorption of pesticides in plants or crops, providing guidance for the rational design and selection of highly efficient, low-toxicity, and environmentally friendly pesticide adjuvants (surfactants).

[0071] For the top-down absorption and conduction process: 30 μL of different concentrations of NIC12-DTAB or NIC12-SDS surfactant solutions containing the aqueous dye Nile Red, prepared in Example 1, were dropped onto wheat leaves. After standing for 1 hour, the leaves were rinsed three times with water, and the liquid on the leaf surface was gently wiped dry with paper. The leaves were then placed on a glass slide, covered with a coverslip, and observed under a laser confocal microscope. The test results are as follows: Figure 9 As shown, by Figure 9 It can be seen that stomata are the main pathway for surfactants (DTAB and SDS) and Nile Red to enter the leaf surface.

[0072] 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 use of the compound shown in Formula I in the preparation of pesticide tracers; I in, R1, R2, and R3 may be the same or different, and are independently selected from C. 1-6 alkyl; m is selected from 0, 1, 2, 3, 4, 5 or 6; n is selected from 6, 7, 8, 9, 10, or 11; X is iodine, chlorine, or bromine; The pesticide tracer is used to trace the absorption and translocation process of pesticides within plants; The pesticide in question is a hydrophobic pesticide.

2. The use according to claim 1, wherein, In Equation I, R1, R2, and R3 are the same and are selected from C. 1-6 alkyl; m is selected from 0, 1, 2, 3, 4 or 5; n is selected from 6, 7, 8, 9, or 10; X is iodine, chlorine, or bromine.

3. The use according to claim 1, wherein, In Formula I, R1, R2, and R3 are the same and are selected from methyl, ethyl, or propyl; m is 0, 1, or 2; and n is selected from 6, 7, 8, or 9. X is iodine, chlorine, or bromine.

4. The use according to claim 1, wherein, The compound represented by Formula I was prepared by the following method: Wherein, R1, R2, R3, m, n and X have the definitions described in any one of claims 1-3; Compound I-2 was reacted with compound R3X to prepare the compound shown in Formula I.

5. The use according to claim 4, wherein, Compound I-2 was prepared using the following method: Wherein, R1, R2, m and n have the definitions described in any one of claims 1-3; 1) Compound I-1 is prepared by reacting compound Ia with compound Ib; 2) Compound I-1 was reacted with compound Ic to prepare compound I-2.

6. A method for tracing pesticides using the compound shown in Formula I, wherein, include: I Among them, R1, R2, and R3 may be the same or different, and are independently selected from C. 1-6 alkyl; m is selected from 0, 1, 2, 3, 4, 5 or 6; n is selected from 6, 7, 8, 9, 10, or 11; X is iodine, chlorine, or bromine; The compound shown in Formula I was mixed and dissolved with a surfactant in water to prepare a solution. Then, a hydrophobic dye was added to the solution. Plants were cultured in the resulting solution, and the fluorescence of the hydrophobic dye in the plant was observed using a laser confocal fluorescence microscope to understand the absorption and conduction process of the hydrophobic dye, and further to understand the absorption and conduction process of pesticides. The pesticide in question is a hydrophobic pesticide.

7. The method according to claim 6, wherein, In the method for tracing surfactants, the laser wavelength of the laser confocal fluorescence microscope is 488 nm.

8. The method according to claim 6, wherein, In the method for tracing pesticides, the hydrophobic dye is one of Nile Red, Methylene Blue, and Crystal Violet.

9. The method according to claim 8, wherein, When the hydrophobic dye is Nile Red, the laser wavelength of the laser confocal fluorescence microscope is 559 nm.

10. The method according to claim 6, wherein, In Equation I, R1, R2, and R3 are the same and are selected from C. 1-6 alkyl; m is selected from 0, 1, 2, 3, 4 or 5; n is selected from 6, 7, 8, 9, or 10; X is iodine, chlorine, or bromine.

11. The method according to claim 6, wherein, In Formula I, R1, R2, and R3 are the same and are selected from methyl, ethyl, or propyl; m is 0, 1, or 2; and n is selected from 6, 7, 8, or 9. X is iodine, chlorine, or bromine.

Images