Dasa molecular switch photochromic film and application thereof

Abstract

The application discloses a DASA molecular switch photochromic film and application thereof. Z ,4 E )-2-hydroxy-5-((2-hydroxybenzyl)(pyridine-2-methyl)amino)pent-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione is dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol, and a photochromic film is formed after the solvent is volatilized. The photochromic film of the application breaks the limitation of DASA molecular concentration dependence, realizes photochromism in a solid film state by means of intramolecular Michael addition and provides bicyclic isomers, and has application prospects in drug delivery, temperature sensors, chemical detectors, surface chemistry and photothermal driving.

Description

Technical Field

[0001] This invention belongs to the field of photochromic molecular switch technology, and relates to a DASA molecular switch photochromic thin film and its application in photodetector devices. Background Technology

[0002] In 2014, Read de Alanz et al. reported a novel reversible photochromic molecule in the visible and near-infrared spectral regions, namely donor-acceptor Steinhaus adducts (DASAs). Due to their excellent photochromic properties, they have attracted widespread attention and research applications [Photoswitching using visible light: a new class of organic photochromic molecules, 2014, 136, 8169-72]. Generally, research and applications of DASAs assume that below millimolecular concentrations, photoisomerization is insensitive to photopigment density, and at micromolar concentrations, effective light switching can be achieved in both solution and polymers.

[0003] In 2019, Brandon F. Lui et al. conducted a series of kinetic studies on reactants and photoproducts at different concentrations and in different chemical hosts. The results showed that photoisomerization was significantly inhibited with increasing photopigment concentration. This inhibition was a universal effect, observed in different DASA derivatives and various solid and liquid hosts [Unusual concentration dependence of the photoisomerization reaction indonor-acceptor Stenhouse adducts, 2019, 18, 1587-1595]. Therefore, the photochromism of existing DASA molecular switches is concentration-dependent, and solid-phase photochromic DASA molecular switches have not yet been reported in the literature. Summary of the Invention

[0004] This invention provides a DASA molecular switch photochromic thin film and its application in photodetector devices.

[0005] The DASA molecular switch photochromic film of the present invention is prepared by the following steps:

[0006] The DASA molecular switch was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol and coated onto a carrier surface. The 1,1,1,3,3,3-hexafluoro-2-propanol was then evaporated under hot air, forming a photochromic film on the carrier. The DASA molecular switch is 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, with the following structural formula:

[0007] .

[0008] Furthermore, the carrier can be selected according to the actual application, such as a glass slide.

[0009] Furthermore, the hot air from a hair dryer is used to evaporate 1,1,1,3,3,3-hexafluoro-2-propanol.

[0010] Furthermore, the synthesis method of the DASA molecular switch is as follows:

[0011] First, 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione was dissolved in tetrahydrofuran, and then 2-(((pyridin-2-ylmethyl)amino)methyl)phenol was added dropwise. The mixture was stirred at room temperature for 10-20 minutes, and then anhydrous diethyl ether, a poor solvent, was added to precipitate the target product. The crude product was collected by filtration, and finally the precipitate was washed with ethyl acetate to purify and obtain 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione. The structural formula of the 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione is [insert structural formula here]. The structural formula of the 2-(((pyridin-2-ylmethyl)amino)methyl)phenol is as follows: .

[0012] Preferably, the molar ratio of (2-(((pyridin-2-ylmethyl)amino)methyl)phenol and 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione is 1:1.1~1.2.

[0013] Preferably, the target product is first precipitated from the reaction solvent using anhydrous diethyl ether, and then the precipitate is washed with ethyl acetate 2-3 times.

[0014] The DASA molecular switch photochromic film of this invention is a purplish-red film. After irradiation under visible light for 40-60 minutes, the purplish-red film gradually fades. The NMR spectrum shows that the product after irradiation is a colorless compound II. The reaction route is as follows:

[0015] .

[0016] Furthermore, the present invention provides the application of the above-mentioned DASA molecular switch photochromic thin film in the fabrication of photodetector devices.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) This invention is the first to discover that when a thin film formed by coating 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridine-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione is coated, the DASA molecular switch can be isomerized from a linear structure to a piperazine-cyclopentanone (bicyclized) DASA molecule under light irradiation. This breaks the concentration-dependent constraint in the prior art and realizes photochromism under solid thin film.

[0019] (2) The present invention uses 1,1,1,3,3,3-hexafluoro-2-propanol as a solvent, which can stabilize 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pent-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione without causing it to isomerize. Furthermore, 1,1,1,3,3,3-hexafluoro-2-propanol has good solubility, low boiling point, and is easily volatile, making it easy to prepare thin films.

[0020] (3) The DASA molecular switch photochromic film of the present invention can realize photochromism in the solid film state, which broadens the application range of DASA molecules. It can be applied to photodetectors and has broad application prospects in the fields of drug delivery, temperature sensors, chemical detectors, surface chemistry and photothermal drive. Attached Figure Description

[0021] Figure 1 This is the 1H NMR spectrum of compound I.

[0022] Figure 2 This is the carbon NMR spectrum of compound I.

[0023] Figure 3 This is the two-dimensional COSY NMR spectrum of compound I.

[0024] Figure 4 This is the two-dimensional HSQC NMR spectrum of compound I.

[0025] Figure 5 This is the 1H NMR spectrum of compound II.

[0026] Figure 6 This is the carbon NMR spectrum of compound II.

[0027] Figure 7 This is the two-dimensional COSY NMR spectrum of compound II.

[0028] Figure 8 This is the two-dimensional HSQC NMR spectrum of compound II.

[0029] Figure 9 The color change diagram shows the isomerization of compound I in the thin film state to compound II under JB450 light irradiation.

[0030] Figure 10 The graph shows the change in UV-Vis absorption spectrum of compound I in thin film state after isomerization to compound II by JB450 light irradiation.

[0031] Figure 11 The curve is a kinetic fit curve of the maximum absorption wavelength change of compound I in the thin film state. Detailed Implementation

[0032] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0033] The preparation of 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione is described in reference [Photoswitching Using Visible Light: A New Class of Organic PhotochromicMolecules, 2014, 136, 8169−817]. The specific steps are as follows:

[0034] .

[0035] Cycloisopropyl malonate and deionized water were added to a round-bottom flask as solvents. Furfural was then added dropwise while stirring. The mixture was stirred at room temperature for 3-4 hours. Initially, a white solid was observed to form, which then turned into a bright yellow precipitate. The reaction progress was monitored using TLC, with a petroleum ether:ethyl acetate volume ratio of 3:1 as the developing solvent. After the reaction was complete, solid-liquid separation was performed by vacuum filtration using a Buchner funnel. The yellow precipitate was collected to obtain the crude product. The crude product was ultrasonically dissolved in dichloromethane and extracted and washed with saturated NaHSO4 solution and saturated NaHCO3 solution, respectively. After standing and separating the layers, the lower yellow organic phase was collected. Trace amounts of water were removed with anhydrous magnesium sulfate or anhydrous sodium carbonate. The product was filtered to remove the drying agent, and then concentrated by rotary evaporation under reduced pressure to obtain a bright yellow solid with a yield of 91.04%.

[0036] The preparation of 2-(((pyridin-2-ylmethyl)amino)methyl)phenol is described in reference [Syntheses, Characterization, and Crystal Structures of Two Structurally Similar SchiffBase Cobalt(III) Complexes, 2006, 36, 723–727], and the specific steps are as follows:

[0037] .

[0038] Salicylic aldehyde and methanol were first added to a round-bottom flask as solvents. Then, pyridine-2-methylamine was added dropwise while stirring. The yellow color of the solution gradually deepened with the addition of pyridine-2-methylamine. After the addition was complete, the mixture was refluxed and stirred for 4-5 h. The reaction progress was monitored using TLC, with a methanol:ethyl acetate volume ratio of 1:1. After the reaction was complete, the round-bottom flask was transferred to an ice-water bath. After complete cooling, 2.5 equivalents of sodium borohydride were slowly added. After stirring for 1-2 h and no further bubbles were generated, the mixture was refluxed overnight. The reaction progress was monitored using TLC, with a methanol:ethyl acetate volume ratio of 3:1. After the reaction was complete, the solvent was evaporated under reduced pressure to obtain a pale yellow oily liquid. This liquid was redissolved in dichloromethane and extracted and washed with saturated NaCl solution and saturated NH4Cl solution, respectively. After standing and separating the layers, the lower yellow organic phase was collected and concentrated by rotary evaporation under reduced pressure to obtain 3.56 g of the yellow oily liquid, with a yield of 83.18%.

[0039] Example 1

[0040]

[0041] Add 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione and 3-5 mL of tetrahydrofuran as solvent to a round-bottom flask. While stirring at room temperature, add 2-(((pyridin-2-ylmethyl)amino)methyl)phenol dropwise. The solution turns purple-red instantly upon addition of 2-(((pyridin-2-ylmethyl)amino)methyl)phenol. After stirring at 25 °C for 20 min, the purple-red color gradually deepens, and a small amount of purple-red precipitate forms. Monitor the reaction progress using TLC. The volume ratio of ethyl acetate to petroleum ether was chosen as the developing solvent: 3: 1. After the reaction was complete, anhydrous diethyl ether was added, the precipitate was collected after filtration, and ultrasonically washed 2-3 times with ethyl acetate. After vacuum drying, a purple-red solid was obtained, namely 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, with a yield of 84.3%. NMR characterization was performed, and the results are as follows: Figure 1-4 As shown.

[0042] Example 2

[0043] A purple-red solid, 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-dien-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol. After standing for two days under both natural light and darkness, 1H NMR spectroscopy showed no isomerization, indicating that 1,1,1,3,3,3-hexafluoro-2-propanol can stabilize compound I. However, when methanol or toluene was used as a solvent to dissolve compound I, it underwent isomerization under darkness and could not be stably preserved. The above solution was coated onto a glass slide and then dried with a hairdryer to evaporate the 1,1,1,3,3,3-hexafluoro-2-propanol, yielding a purple-red solid film, as shown below. Figure 9 As shown.

[0044] Example 3

[0045] The purplish-red solid film prepared in Example 2 was placed under a xenon lamp light source and irradiated with a wavelength of JB450. After 40 minutes of irradiation, the purplish-red color faded. Figure 9 As shown. The thin film on the slide was redissolved in a deuterated reagent and subjected to NMR characterization. The results are as follows. Figure 5-8 As shown, after the purplish-red solid film is exposed to light, compound I isomerizes into compound II.

[0046] Example 4

[0047] A purplish-red solid, 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol and coated onto the surface of a cuvette. The cuvette was then irradiated under a xenon lamp at wavelength JB450, and the absorbance changes were monitored during the irradiation process. Figure 10 As shown.

[0048] Example 5

[0049] After 120 min of JB450 illumination, the peak value of the maximum absorption peak at 540 nm gradually decreased, and the color of the originally dark film gradually faded until it disappeared. This indicates that 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione can be decolorized by light and transformed into compound II, with a conversion rate as high as 96.7%. Figure 11 The light decay kinetics curve of JB450 at room temperature conforms to the first-order reaction kinetics curve, and the linear fit is very good (R0). 2 = 0.998), the rate constant is 1.45 min -1 .

Claims

1. A DASA molecularly switched photochromic thin film, characterized in that, Prepared by the following steps: The DASA molecular switch was dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol and coated onto a carrier surface. The 1,1,1,3,3,3-hexafluoro-2-propanol was then evaporated under hot air, forming a photochromic film on the carrier. The DASA molecular switch is 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione, with the following structural formula: 。 2. The DASA molecular switch photochromic film according to claim 1, characterized in that, The carrier is a glass slide.

3. The DASA molecular switch photochromic film according to claim 1, characterized in that, The hot air from a hair dryer was used to evaporate 1,1,1,3,3,3-hexafluoro-2-propanol.

4. The DASA molecular switch photochromic film according to claim 1, characterized in that, The synthesis method of the DASA molecular switch is as follows: First, 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione was dissolved in tetrahydrofuran, and then 2-(((pyridin-2-ylmethyl)amino)methyl)phenol was added dropwise. The mixture was stirred at room temperature for 10-20 minutes, and then anhydrous diethyl ether, a poor solvent, was added to precipitate the target product. The crude product was collected by filtration, and finally the precipitate was washed with ethyl acetate to purify and obtain 5-((2Z,4E)-2-hydroxy-5-((2-hydroxybenzyl)(pyridin-2-methyl)amino)pentan-2,4-diene-1-ylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione. The structural formula of the 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione is [insert structural formula here]. The structural formula of the 2-(((pyridin-2-ylmethyl)amino)methyl)phenol is as follows: .

5. The DASA molecular switch photochromic film according to claim 4, characterized in that, The molar ratio of 2-(((pyridin-2-ylmethyl)amino)methyl)phenol to 5-(furan-2-ylmethylene)-2,2-dimethyl-1,3-dioxane-4,6-dione is 1:1.1~1.

2.

6. The DASA molecular switch photochromic film according to claim 4, characterized in that, First, precipitate the target product from the reaction solvent with anhydrous diethyl ether, then wash the precipitate 2-3 times with ethyl acetate.

7. The application of the DASA molecular switch photochromic thin film according to claim 1 in the fabrication of photodetector devices.

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