Dithienylethene-imine compound as well as preparation method and application thereof

Abstract

The invention provides a dithienylethene-imine compound as well as a preparation method and application thereof. Specifically, the invention discloses a compound shown as a formula I or a formula I. R1 is NO2, NMe2 or Me. The compound provided by the invention has the properties of rapid light response property, high closed-loop body conversion rate, light stability and the like, and is a very good novel dithienylethene optical switch # imgabs 0 # imgabs 1 #.

Description

Technical Field

[0001] The invention relates to a dithienylethylene-imine compound and a preparation method and application thereof. Background Art

[0002] Dithienylethylene photoresponsive molecules have good thermal bistability, fatigue resistance, fast photoresponsivity and high ring opening and closing conversion rate. Its open and closed ring bodies have great differences in color, spectrum, conductivity, reactivity and other physical and chemical properties. These characteristics have made it attract much attention in recent years and widely used in light-controlled molecular switches, information encryption, molecular probes, materials and biology.

[0003] Due to the inherent "proofreading" and "error checking" functions of the many reversible covalent reactions contained in dynamic covalent chemistry, dynamic covalent chemistry has been widely used to construct unique molecules and extended structures, and has been used to construct a variety of stimulus-responsive intelligent systems. Among them, the imine bond has become a popular dynamic bond with multiple functions. The imine bond can participate in three different dynamic covalent reactions: condensation, exchange and metathesis reactions. The open and closed ring forms of the dithienylethylene group have completely different thermodynamic properties, which can be used to regulate the balance of dynamic reactions. Molecular design combines dithienylethylene and imine bonds to give molecules more application potential. Molecules can be used to design light-regulated dynamic covalent chemical systems, providing a theoretical basis for the construction of new intelligent materials.

[0004] However, the photoreaction conversion rate of existing dithienylethylene photoresponsive molecules is not high enough and the response speed is slow, so it is necessary to develop better dithienylethylene photoswitches. Summary of the invention

[0005] In order to overcome the technical problems of low photoreaction conversion rate and slow response speed of dithiophene ethylene optical switches in the prior art, the present invention provides a novel dithiophene ethylene optical switch with fast photoresponse properties, high closed-loop conversion rate, photostability and the like, which is an excellent novel dithiophene ethylene optical switch.

[0006] The present invention solves the above technical problems through the following technical solutions:

[0007] The present invention provides a compound as shown in Formula I or Formula I':

[0008] or ;

[0009] R 1 NO 2 、NMe 2 or Me.

[0010] In some embodiments, the compound as shown in Formula I is:

[0011] , or ;

[0012] The compound shown in formula I' is:

[0013] , or .

[0014] The present invention also provides a method for preparing the compound shown in formula I.

[0015] ;

[0016] The method comprises the following steps: in the presence of a solvent, reacting a compound as shown in formula II with benzylamine to generate a compound as shown in formula I; wherein R 1 is as defined in the preceding item.

[0017] The solvent is a conventional solvent for this type of reaction in the art, such as one or more of methanol, ethanol, and n-hexane, and another example is ethanol.

[0018] In some embodiments, in the method for preparing the compound of Formula I, the reaction temperature is 65°C to 80°C; for example, 75°C.

[0019] In some embodiments, in the method for preparing the compound of Formula I, the reaction progress can be detected using conventional methods in the art (such as HPLC, TLC, NMR, etc.), and the reaction time is 8 to 16 hours; for example, 12 hours.

[0020] In some embodiments, in the method for preparing the compound of formula I, the molar ratio of the compound of formula II to the benzylamine is 1:(0.5-2); for example, 1:1.

[0021] The present invention also provides a compound as shown in Formula II:

[0022] ;

[0023] Among them, R 1 is as defined in the preceding item.

[0024] The present invention also provides a method for preparing the compound as shown in Formula II, which comprises the following steps:

[0025] ;

[0026] In the presence of a solvent, a catalyst and a base, the compound represented by formula III and the compound represented by formula IV react to generate the compound represented by formula II;

[0027] Among them, R 1 The definition of is as described in the previous item, and X is halogen.

[0028] In some embodiments, X is I or Br; for example, I.

[0029] In the method for preparing the compound shown in Formula II, the solvent is a conventional solvent for this type of reaction in the art, and it only needs to be able to dissolve the reaction system; for example, THF.

[0030] In some embodiments, in the method for preparing the compound of Formula II, the catalyst is tetrakistriphenylphosphine palladium.

[0031] In the method for preparing the compound of formula II, the base is a conventional base for this type of reaction in the art; for example, an alkali metal carbonate; for example, potassium carbonate.

[0032] In some embodiments, in the method for preparing the compound of Formula II, the reaction temperature of the reaction is 70-90°C; for example, 70°C.

[0033] In some embodiments, in the method for preparing the compound of formula II, the molar ratio of the compound of formula III to the compound of formula IV is (0.5~2):1; for example, 1:1.

[0034] In some embodiments, in the method for preparing the compound of formula II, the molar ratio of the compound of formula III to the base is 1:(4-8); for example, 1:4.

[0035] In some embodiments, in the method for preparing the compound of formula II, the molar ratio of the compound of formula III to the catalyst is 1:(0.05-0.1); for example, 1:0.1.

[0036] The present invention also provides the use of any of the aforementioned compounds represented by Formula I or Formula I' as a photoswitch molecule.

[0037] In some embodiments, the photoswitch molecule is a photochromic molecule.

[0038] In some embodiments, the compound of Formula I is ring-closed under 254nm-405nm light; for example, under 365nm light or 405nm light.

[0039] In some embodiments, the compound represented by Formula I' opens the ring under 500nm-750nm light; for example, opens the ring under 535nm light.

[0040] In some embodiments, in the application, the compound represented by Formula I or Formula I' undergoes any of the following reactions under light:

[0041] ,

[0042] or

[0043] .

[0044] In some embodiments, the compound of Formula I is ring-closed within 10 to 50 minutes under light irradiation; for example, within 19 minutes, 20 minutes, or 40 minutes under light irradiation.

[0045] In some embodiments, the compound of Formula I' opens the ring under light for 1 to 3 hours; for example, opens the ring under light for 1 hour, 2 hours, or 2.25 hours.

[0046] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0047] The reagents and raw materials used in the present invention are commercially available.

[0048] The term "halogen" refers to fluorine, chlorine, bromine or iodine.

[0049] The term "photoswitch molecule" refers to a molecule that can undergo reversible structural changes between two or more stable states through light excitation of a specific wavelength. This light-driven isomerization reaction (such as cis-trans isomerization, cyclization / ring opening, etc.) will significantly change the physical or chemical properties of the molecule (such as absorption spectrum, geometric configuration, polarity, conductivity, etc.), and different states can be switched by light of different wavelengths (such as ultraviolet light / visible light) or thermal relaxation. Such molecules have important application value in the fields of optical information storage, molecular devices, smart materials, light-controlled drug release and bioimaging.

[0050] The term "photochromic" is defined as a chemical that undergoes a reversible transformation between two isomers with different absorption spectra in one or both directions when exposed to light. Common photochromic molecules include azobenzene, dithienylethylene, spiropyran, etc.

[0051] The positive and progressive effect of the present invention is that the compound provided by the present invention has the properties of rapid light response, high closed-ring conversion rate, light stability and the like, and is a very good new type of dithienylethylene optical switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is the deuterated dichloromethane of compound 6 of the present invention 1 H NMR spectrum;

[0053] Figure 2 Single crystal structure diagram of Compound 6 of the present invention;

[0054] Figure 3 UV-visible spectrogram of Compound 6 of the present invention before and after 365 nm light irradiation in dichloromethane onto PSS;

[0055] Figure 4 For Compound 6 of the present invention in deuterated dichloromethane without light irradiation, irradiated with 365 nm light for 10 min and then irradiated with 535 nm light for 1 h 1 1H NMR spectrum. Detailed implementation manners

[0056] The present invention will be further illustrated below by way of examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0057] Example 1 Preparation of Compounds 6, 8 and 10

[0058] ;

[0059] ;

[0060] Step S1: Synthesis of Compound 1: Add 3,5-dibromo-2-methylthiophene (5 g, 19.5 mmol) into a 250 mL Schlenk flask. Repeat the vacuum evacuation and argon replacement three times. Add 40 mL of anhydrous THF with a long needle. Place the solution in a -80 °C low-temperature reactor and stir. Slowly drop n-BuLi (13 mL, 1.6 M hexane solution) into the above solution. The reaction solution reacts at -80 °C for 1 h. Then slowly drop a THF (40 mL) solution of trimethylchlorosilane (2.1 g, 19.5 mol) into the solution with a needle. The reaction solution continues to react at -80 °C for 1 h. Then stir at room temperature overnight. Add a large amount of water to quench the reaction. Extract with dichloromethane. Dry the organic phase with anhydrous sodium sulfate. Rotavapor to remove the solvent. Use petroleum ether as the mobile phase for silica gel column chromatography. Compound 1 is obtained, which is a light yellow liquid, 3.9 g, with a yield of 80%.

[0061] 1H NMR spectrum of Compound 1: 1 1H NMR (400 MHz, Chloroform-d) δ 7.01 (s, 1H), 2.42 (s, 3H), 0.29 (s, 9H).

[0062] Step S2: Synthesis of compound 2: Compound 1 (1.4 g, 5.6 mmol) was added to a 250 mL Shrek bottle, and the vacuum was repeated three times to replace the argon gas. 20 mL of anhydrous THF was added with a long needle, and the solution was placed in a -80°C low-temperature reactor and stirred. n-BuLi (3.5 mL, 1.6 M) was slowly added dropwise to the above solution. The reaction solution was reacted at -80°C for 1 h. Then a solution of octafluorocyclopentene (0.6 g, 2.8 mol) in THF (40 mL) was slowly added dropwise to the solution with a needle. The reaction solution continued to react at -80°C for 1 h. Then it was stirred at room temperature overnight. A large amount of water was added to quench the reaction, and the dichloromethane was extracted. The organic phase was dried over anhydrous sodium sulfate, the solvent was removed by rotary evaporation, and petroleum ether was used as the mobile phase for silica gel column chromatography. Compound 2 was obtained as a white solid, 1.3 g, with a yield of 92%.

[0063] H NMR spectrum of compound 2: 1 H NMR (400 MHz, Chloroform-d) δ 7.05 (s, 1H), 1.90 (s, 3H), 0.27 (s, 9H).

[0064] Step S3: Synthesis of compound 3: Compound 2 (200 mg, 0.4 mmol) was dissolved in 20 mL DCM and stirred in a low-temperature reactor at 0°C. ICl (253 mg, 1.6 mmol) dissolved in DCM was added in batches, and the reaction solution was stirred at 0°C for 2 h. The product 3 was obtained by rotary evaporation and PE column chromatography to obtain a white solid product 3, 186 mg, with a yield of 75%.

[0065] H NMR spectrum of compound 3: 1 H NMR (400 MHz, Chloroform-d) δ 7.18 (s, 2H), 1.89 (s, 6H).

[0066] Step S4: Synthesis of compound 4: Add compound 3 (500 mg, 0.8 mmol) and tetrakistriphenylphosphine palladium (93 mg, 0.08 mmol) to a three-necked flask, and repeat the vacuum and argon gas replacement three times. Use a long needle to add THF (55 mL) and 30 mL of potassium carbonate (7.5 g) aqueous solution. Slowly drop a solution of p-formylphenylboronic acid (121 mg, 0.8 mmol) in THF (30 mL). React at 90°C for 24 h. Add ammonium chloride solution to neutralize, remove THF by rotary evaporation, and extract with EA. Dry the organic phase with anhydrous sodium sulfate, filter, and column chromatography with eluent (PE / EA = 5:1) to obtain 325 mg of a yellow solid product with a yield of 68%.

[0067] H NMR spectrum of compound 4: 1 H NMR (400 MHz, Chloroform-d) δ 10.01 (s, 1H), 7.90 (d, J = 8.4 Hz, 2H), 7.69 (d, J = 8.4 Hz, 2H), 7.38 (s, 1H), 7.23 (s,1H), 1.98 (s, 3H), 1.93 (s, 3H).

[0068] Step S5: Synthesis of compound 5: Add compound 4 (160 mg, 0.3 mmol), p-nitrophenylboronic acid (49 mg, 0.3 mmol) and tetrakistriphenylphosphine palladium (31 mg, 0.03 mmol) to a three-necked flask, and repeat the vacuum and argon gas replacement three times. Use a long needle to add THF (30 mL) and 5 mL of potassium carbonate (1.2 mmol, 148 mg) aqueous solution. Heat to reflux at 70°C for 12h. Add ammonium chloride solution to neutralize, remove THF by rotary evaporation, and extract with EA. Dry the organic phase with anhydrous sodium sulfate, filter, and use eluent (PE / EA = 2:1) column chromatography to obtain 141 mg of green solid product with a yield of 89%.

[0069] H NMR spectrum of compound 5: 1 H NMR (600 MHz, Chloroform-d) δ 10.02 (s, 1H), 8.25 (d, J = 8.8 Hz, 2H), 7.90 (d, J = 8.1 Hz, 2H), 7.69 (dd, J = 11.3, 8.4Hz, 4H), 7.44 (d, J = 8.0 Hz, 2H), 2.02 (d, J = 7.2 Hz, 6H).

[0070] Step S6: Synthesis of compound 6: In a 25 mL round-bottom flask, compound 5 (55 mg, 0.09 mmol) and benzylamine (10 mg, 0.09 mmol) were added, dissolved with EtOH (10 mL), and heated to reflux at 75°C for 12 h. The solvent was removed by rotary evaporation, and recrystallized from n-hexane to obtain 60 mg of light cyan solid powder with a yield of 95%.

[0071] The H NMR spectrum of compound 6 (such as Figure 1 shown): 1 H NMR (400 MHz, Methylene Chloride-d 2) δ 8.40 (s, 1H), 8.23 ​​(d, J = 8.8 Hz, 2H), 7.81 (d, J = 7.9 Hz, 2H), 7.71(d, J = 8.9 Hz, 2H), 7.62 (d, J = 8.1 Hz, 2H), 7.48 (s, 1H), 7.38 (s, 1H), 7.35 (d, J = 4.4 Hz, 4H), 7.28 (h, J = 4.2 Hz, 1H), 4.81 (s, 2H), 2.02 (d, J = 10.7 Hz, 6H).

[0072] Step S7: Synthesis of compound 7: Add compound 4 (211 mg, 0.4 mmol), 4-N,N-dimethylphenylboronic acid (58 mg, 0.4 mmol) and tetrakistriphenylphosphine palladium (41 mg, 0.04 mmol) to a three-necked flask, and repeat the vacuum and argon gas replacement three times. Use a long needle to add THF (30 mL) and 5 mL of potassium carbonate (1.6 mmol, 195 mg) aqueous solution. Heat to reflux at 90°C for 12h. Add ammonium chloride solution to neutralize, remove THF by rotary evaporation, and extract with EA. Dry the organic phase with anhydrous sodium sulfate, filter, and use eluent (PE / EA = 2:1) column chromatography to obtain 146 mg of green solid product with a yield of 70%.

[0073] H NMR spectrum of compound 7: 1 H NMR (400 MHz, Chloroform-d) δ 10.00 (s, 1H),7.89 (d, J = 8.3 Hz, 2H), 7.69 (d, J = 8.2 Hz, 2H), 7.46 – 7.37 (t, 3H), 7.09(s, 1H), 6.71 (d, J = 8.8 Hz, 2H), 2.99 (s, 6H), 2.00 (s, 3H), 1.93 (s, 3H).

[0074] Step S8: Synthesis of compound 8: Compound 7 (60 mg, 0.1 mmol) and benzylamine (11 mg, 0.1 mmol) were added to a 25 mL round-bottom flask, dissolved with EtOH (10 mL), and heated under reflux at 75°C for 12 h. The solvent was removed by rotary evaporation, and recrystallized from n-hexane to obtain 65 mg of a green solid powder with a yield of 94%.

[0075] H NMR spectrum of compound 8: 1H NMR (400 MHz, Chloroform-d) δ 8.38 (s, 1H),7.80 (d, J = 8.0 Hz, 2H), 7.58 (d, J = 8.1 Hz, 2H), 7.48 – 7.32 (m, 8H), 7.09(s, 1H), 6.71 (d, J = 8.6 Hz, 2H), 4.85 (s, 2H), 2.99 (s, 6H), 1.96 (d, J =15.7 Hz, 6H).

[0076] Step S9: Synthesis of compound 9: Add compound 4 (276 mg, 0.5 mmol), p-methylphenylboronic acid (63 mg, 0.5 mmol) and tetrakistriphenylphosphine palladium (53 mg, 0.05 mmol) to a three-necked flask, and repeat the vacuum and argon gas replacement three times. Use a long needle to add THF (30 mL) and 5 mL of potassium carbonate (2 mmol, 255 mg) aqueous solution. Heat to reflux at 70°C for 12h. Add ammonium chloride solution to neutralize, remove THF by rotary evaporation, and extract with EA. Dry the organic phase with anhydrous sodium sulfate, filter, and use eluent (PE / EA = 2:1) column chromatography to obtain 233 mg of light blue solid product with a yield of 90%.

[0077] H NMR spectrum of compound 9: 1 H NMR (400 MHz, Chloroform-d) δ 10.01 (s, 1H), 7.89 (d, J = 8.2 Hz, 2H), 7.69 (d, J = 8.1 Hz, 2H), 7.46 – 7.40 (m, 3H), 7.24– 7.16 (m, 3H), 2.37 (s, 3H), 1.98 (d, J = 14.1 Hz, 6H).

[0078] Step S10: Synthesis of compound 10: Compound 9 (40 mg, 0.07 mmol) and benzylamine (8 mg, 0.07 mmol) were added to a 25 mL round-bottom flask, dissolved with EtOH (10 mL), and heated under reflux at 75°C for 12 h. The solvent was removed by rotary evaporation, and recrystallized from n-hexane to obtain 44 mg of a colorless solid powder with a yield of 96%.

[0079] H NMR spectrum of compound 10: 1H NMR (400 MHz, Chloroform-d) δ 8.39 (s, 1H), 7.79 (d, J = 8.1 Hz, 2H), 7.58 (d, J = 8.1 Hz, 2H), 7.43 (d, J = 8.0 Hz, 2H), 7.35 (d, J = 5.5 Hz, 5H), 7.28 (d, J = 6.9 Hz, 1H), 7.24 – 7.15 (m, 3H), 4.84(s, 2H), 2.37 (s, 3H), 1.97 (d, J = 4.9 Hz, 6H).

[0080] Example 2 Characterization of the crystal structure of compound 6

[0081] 5 mg of compound 6 was dissolved in 1 mL of chloroform, and a single crystal of compound 6 was obtained by a solvent exchange method using chloroform as a good solvent and n-hexane as a poor solvent.

[0082] Its crystal structure was characterized by X-ray diffraction (e.g. Figure 2 As shown). In solution, dithienylethylene has two conformations: parallel and antiparallel. In the crystal, the molecule exists in only one conformation. The cis conformation cannot undergo photochromic reaction. From the single crystal structure, the single crystal of compound 6 is antiparallel, and the distance between the two methyl ortho carbons involved in the ring-closing reaction is 3.594 Å (less than the distance ≤ 4.2 Å that can undergo photoinduced ring-closing reaction), indicating that the single crystal can undergo ring-closing reaction.

[0083] Example 3 Property Testing of Compounds 6, 8 and 10

[0084] ;

[0085] ;

[0086] ;

[0087] The UV absorption spectrum of compound 6 was obtained by Shimadzu UV-3600 Plus UV-vis spectrophotometer. -5 The absorption spectrum of M, DCM) has a maximum absorption wavelength of 327 nm in the ultraviolet region. After irradiation with 365 nm light, a new absorption peak is generated in the visible light region with a maximum absorption wavelength of 635 nm (e.g. Figure 3 This is because the ultraviolet light causes the compound to undergo a photochromic reaction, producing a closed ring body, leading to the formation of a large π electron delocalization system.

[0088] The compound 6 (5 mM, CD 2 Cl 2 ) photoreaction process, after 365 nm light irradiation for 10 min, it reaches the photostable state (PSS), and the ring-closing conversion rate is 97%. Then, after 535 nm light irradiation for 1 h, the ring-closed body undergoes a ring-opening reaction and returns to the initial ring-opening state, and the ring-opening conversion rate is 100% (such as Figure 4 The ring-closing conversion rate was 96% after irradiation with visible light at 405 nm for 20 min, and then the ring-opening conversion rate was 100% after irradiation with 535 nm for 1 h.

[0089] The same method was used to monitor the photoreaction process of compound 8: the ring-closing conversion rate was 96% when irradiated with 365 nm for 20 min, and the ring-opening conversion rate was 98% when irradiated with 535 nm for 2 h. The ring-closing conversion rate was 77% when irradiated with visible light at 405 nm for 40 min, and the ring-opening conversion rate was 98% when irradiated with 535 nm for 2 h15 min.

[0090] The same method was used to monitor the photoreaction process of compound 10: the ring-closing conversion rate was 78% under 365 nm illumination for 19 min, and the ring-opening conversion rate was 99% under 535 nm illumination for 1 h.

[0091] The structures and photoresponse properties of compounds 6, 8, and 10 were characterized by nuclear magnetic resonance, single crystal X-ray diffraction, and UV-visible absorption spectroscopy. The results showed that compounds 6, 8, and 10 have fast photoresponse properties, high closed-ring conversion rates, and photostability. They are excellent new dithienylethylene optical switches with potential for application in dynamic chemistry, intelligent gating, and other fields.

Claims

1. A compound as shown in formula I or formula I': or ; R 1 It is NO2, NMe2 or Me.

2. The compound as shown in formula I or formula I' according to claim 1, characterized in that: The compound shown in formula I is , or ; The compound shown in formula I' is , or .

3. A method for preparing a compound as shown in formula I, characterized in that: It includes the following steps: ； In the presence of a solvent, the compound shown in formula II reacts with benzylamine to generate a compound shown in formula I; wherein R 1 The definition as claimed in claim 1 or 2.

4. The method for preparing the compound of formula I as claimed in claim 3, characterized in that: It meets one or more of the following conditions: (1) The solvent is one or more of methanol, ethanol, and n-hexane; (2) The reaction temperature of the reaction is 65°C to 80°C, for example 75°C; (3) The reaction time of the reaction is 8 to 16 hours, for example 12 hours; (4) The molar ratio of the compound represented by formula II to the benzylamine is 1:(0.5-2); for example, 1:

1.

5. A compound as shown in formula II: ； in, R 1 The definition as claimed in claim 1 or 2.

6. A method for preparing a compound as shown in formula II, characterized in that: It includes the following steps: ； In the presence of a solvent, a catalyst and a base, the compound represented by formula III and the compound represented by formula IV react to generate the compound represented by formula II; Among them, R 1 As defined in claim 1 or 2, X is halogen.

7. The method for preparing the compound of formula II as claimed in claim 6, characterized in that: It meets one or more of the following conditions: (1) X is I or Br; for example, I; (2) The solvent is THF; (3) The catalyst is tetrakistriphenylphosphine palladium; (4) The base is an alkali metal carbonate; for example, potassium carbonate; (5) The reaction temperature of the reaction is 70-90°C, for example 70°C; (6) The molar ratio of the compound represented by formula III to the compound represented by formula IV is (0.5-2):1; for example, 1:1; (7) The molar ratio of the compound represented by formula III to the base is 1:(4-8); for example 1:4; and, (8) The molar ratio of the compound represented by formula III to the catalyst is 1:(0.05-0.1); for example, 1:0.

1.

8. Use of the compound of formula I or formula I' as claimed in claim 1 or 2 as a photoswitch molecule.

9. Use of the compound represented by formula I or formula I' as claimed in claim 8 as a photoswitch molecule, characterized in that: It meets one or more of the following conditions: (1) The photoswitch molecule is a photochromic molecule; (2) The compound as shown in Formula I is ring-closed under light at 254 nm to 405 nm; (3) The compound represented by formula I' is ring-opened under 500nm~750nm light; (4) the compound of formula I is ring-closed under light for 10 to 50 minutes; and, (5) The compound represented by formula I' undergoes ring opening under light for 1 to 3 hours.

10. Use of the compound represented by formula I or formula I' as claimed in claim 8 as a photoswitch molecule, characterized in that: It meets one or both of the following conditions: (1) The compound of formula I is ring-closed under 365 nm light or 405 nm light; (2) The compound represented by formula I' is ring-opened under 535 nm light; (3) the compound of formula I is ring-closed under light for 19 minutes, 20 minutes or 40 minutes; and, (4) The compound represented by formula I' is ring-opened under light for 1 hour, 2 hours or 2.25 hours; (5) The compound represented by Formula I or Formula I' undergoes any of the following reactions under light: 、 or 。

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