A liquid crystal molecular motor with dual photothermal response, its preparation method and application

Abstract

This invention provides a liquid crystal molecular motor with dual photothermal responsiveness, its preparation method, and its applications. The molecular motor has the structure shown in formula (I). This invention introduces structures containing groups such as trans-cyclohexyl groups, as shown in formulas (II) to (XIII), combining liquid crystal segments with photothermal responsiveness with chiral-reversible interferometric helicene compounds. This results in a multifunctional molecular motor capable of both photo-induced axis reversal in response to light and changes in chirality and double bond axis rotation in response to both light and heat. This molecular motor exhibits photothermal responsiveness, allowing the entire molecule to respond to both light and heat stimuli. Therefore, this molecule holds promise for the preparation of next-generation multi-responsive materials, with broad applications in smart soft materials or responsive photonic crystals.

Description

Technical Field

[0001] This invention relates to the field of multi-response functional materials technology, and in particular to a liquid crystal molecular motor with photothermal dual responsiveness, its preparation method, and its application. Background Technology

[0002] Molecular motors are molecules that respond to specific stimuli by moving their submolecular components in a defined and controllable manner to generate mechanical work. Generating mechanical work and controlled motion at the nanoscale is crucial and forward-looking. At this level, molecular motors are in equilibrium amidst the ubiquitous thermal noise from surrounding molecules and must resist the effects of this Brownian motion. Therefore, viscous forces are many orders of magnitude stronger than inertial forces, and the laws and physical methods used in macroscopic motors are inapplicable at the molecular level. Consequently, molecular motors must employ different mechanisms to absorb energy, thereby completing a mechanical cycle that drives their environment away from thermal equilibrium in a way that does work on it.

[0003] Inspired by the complexity and sophistication of biomotors, researchers have developed artificial molecular motors that can be relatively easily fabricated, manipulated and activated in different environments using various methods, and capable of performing different types of tasks. Artificial molecular motors have attracted considerable interest, offering numerous opportunities for applications in medicine, materials science, and information technology. Currently, different types of artificial molecular motors exist, such as organic motors and DNA-based motors. In addition, other types of systems are based on motors using large nanoparticles, nanotubes, or other microstructures.

[0004] Chiral over-interference helicene molecular motors were proposed by the research group of Dutch scientist BL Feringa, and derivatives with different structures were successfully synthesized. These molecules are widely used because they not only possess the photoresponsive cis-trans isomerism common to photoresponsive molecules, enabling changes in molecular structure, but also exhibit chiral inversion, a function not found in most photoresponsive molecules.

[0005] Currently, in the application of chiral interference-enhanced helicene molecular motors, the molecular host or various derivatives can only respond to light stimulation, exhibiting only a single response capability. However, the synthesis and preparation of chiral interference-enhanced helicene molecular motors with multiple responses will have a wider range of applications. Summary of the Invention

[0006] This invention provides a liquid crystal molecular motor with dual photothermal response, which solves the problem that the existing chiral interference helicene molecular motors only have a single response performance, and achieves dual photothermal response.

[0007] This invention provides a molecular motor having the structure shown in formula (I):

[0008]

[0009] Where m is 0 or 1;

[0010] Ar 1 Ar 2 Each can independently select either freely substituted or unsubstituted C3-C. 40 cycloalkyl, substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Fused aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 The group composed of heterocyclic aryl groups, Ar 1 Ar 2 They can be arbitrarily joined or fused to form substituted or unsubstituted hydrocarbon rings or aromatic rings;

[0011] R 1 ~R 7 Each is independently selected from hydrogen, deuterium, fluorine, hydroxyl, cyano, substituted or unsubstituted C1-C. 40 Alkyl, substituted or unsubstituted C1-C 40 Heteroalkyl, substituted or unsubstituted C3-C 40 cycloalkyl, substituted or unsubstituted C1-C 40 Alkoxy, substituted or unsubstituted C1-C 40 Heteroalkoxy, substituted or unsubstituted C5-C 40 Heterocyclic alkyl, substituted or unsubstituted C2-C 40 alkenyl, substituted or unsubstituted C5-C 40 Cycloalkenyl, substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 Group composed of heteroaryl groups;

[0012] And in R 1 ~R 7 Ar 1 Ar 2 At least one of them contains one of formulas (II) to (XIII):

[0013]

[0014] Z can be selected from free single bonds, -O-, -S-, -(C=O)-, and -(C≡C). y -, -(C=O)O-, -O(C=O)-, -CF2O-, -(CH2) y -、-O(CH2) y -、-(CH2)y O-, -(CH=CH) y -, -CH=CH(CH2) y -、-(CH2) y The group consisting of CH=CH-; y represents integers from 1 to 40;

[0015] R 8 ~R 10 Each is independently selected from hydrogen, deuterium, fluorine, hydroxyl, cyano, substituted or unsubstituted C1-C. 40 Alkyl, substituted or unsubstituted C1-C 40 Heteroalkyl, substituted or unsubstituted C3-C 40 cycloalkyl, substituted or unsubstituted C1-C 40 Alkoxy, substituted or unsubstituted C1-C 40 Heteroalkoxy, substituted or unsubstituted C5-C 40 Heterocyclic alkyl, substituted or unsubstituted C2-C 40 alkenyl, substituted or unsubstituted C5-C 40 Cycloalkenyl, substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 A group composed of heteroaryl groups.

[0016] This invention has discovered that by introducing structures containing groups such as trans-cyclohexyl groups, as shown in formulas (II) to (XIII), into a molecular motor, the molecular motor can change its chirality through photoisomerization, and its chirality can also change with temperature, exhibiting sensitive variations. Based on this, the liquid crystal molecular motor of this invention can respond to multiple stimuli, thereby broadening its practical application range.

[0017] It should be noted that, in this invention, the term "substituted or unsubstituted" refers to substances selected from hydrogen, deuterium, halogen, hydroxyl, cyano, nitro, amino, amido, hydrazine, hydrazone, carboxyl or their carboxylates, sulfonic acid or their sulfonates, phosphate or their phosphates, C1-C 40 Alkyl, C2-C 40 alkenyl, C2-C 40 alkynyl group, C1-C 40 Alkoxy, C3-C 40 cycloalkyl, C3-C 40 Cycloalkenyl, C6-C 60 Aryl, C6-C 60 Aryloxy group, C6-C 60 Aryl sulfide groups and C2-C 60The heterocyclic aryl group is substituted or unsubstituted by one or more substituents, or is substituted or unsubstituted by a substituent formed by linking two or more substituents of the substituents exemplified above.

[0018] The substituted or unsubstituted hydrocarbon rings or aromatic rings formed by bonding or fusion as described in this invention may contain heteroatoms or not contain heteroatoms. A condensed ring refers to a condensed aliphatic ring, a condensed aromatic ring, a condensed aliphatic heterocycle, a condensed aromatic heterocycle, or a combination thereof.

[0019] The aryl group used in this invention contains 6 to 60 carbon atoms, and the heteroaryl group contains 2 to 60 carbon atoms and at least one heteroatom, provided that the total number of carbon atoms and heteroatoms is at least 5; the heteroatom is preferably selected from N, O, or S. In this case, the two or more rings of the heteroaryl group can simply attach to each other or in a condensed form, and further, it may also include a form condensed with the aryl group. Non-limiting examples of such heteroaryl groups include six-membered monocyclic rings such as pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, and triazinyl; polycyclic rings such as phenoxathiyl, indoleazinyl, indoleyl, purine, quinolinyl, benzothiazolyl, and carbazoleyl; and 2-furanyl, N-imidazolyl, 2-isooxazolyl, 2-pyridinyl, and 2-pyrimidinyl.

[0020] Preferably, the aryl, heteroaryl, or heterocyclic aryl group described in this invention is selected from phenyl, naphthyl, anthracel, benzanthracel, phenanthryl, pyrene, etc. alkyl, perylene, fluoranyl, tetraphenyl, pentaphenyl, benzo[a]pyrene, biphenyl, amphylene, terphenyl, trimerphenyl, tetraphenyl, fluorenyl, spirodifluorenyl, dihydrophenanthrene, triphenylene, dihydropyrene, tetrahydropyrene, cis or trans indo[a]fluorenyl, cis or trans indo[a]carbazolyl, indole[a]carbazolyl, benzo[a]furan[a]carbazolyl, benzo[a]thio[a]carbazolyl, benzo[a]carbazolyl, dibenzo[a]carbazolyl, azadibenzo[g,iD]naphtho[2,1,8-cde]azine, trimerinyl, isotrimerinyl, spirotrimerinyl, spiroisotrimerinyl, furanyl, benzo[a]furanyl, isobenzo[a]furanyl Dibenzofuranyl, thiophenyl, benzothiophenyl, isobenzothiophenyl, dibenzothiophenyl, pyrroleyl, indolyl, isoindolyl, carbazoyl, pyridyl, quinolinyl, isoquinolinyl, acridineyl, phenanthridineyl, benzo[5,6]quinolinyl, benzo[6,7]quinolinyl, benzo[7,8]quinolinyl, phenothiazinyl, phenotoxazinyl, pyrazolyl, indazoleyl, imidazoyl, benzoimidazoyl, naphthiazoyl, phenanthiazoyl, pyridiniazoyl, pyraziniazoyl, quinoxoliniazoyl, oxazolyl, benzooxazolyl, naphthiazoyl, anthrazooxazolyl, phenanthiazoyl, isoxazolyl, 1,2 -Thiazolyl, 1,3-Thiazolyl, benzothiazolyl, pyridazinyl, hexaazabenzophenanthryl, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthrayl, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperyl, pyrazinyl, phenazinyl, phenoxazinyl, phenthiazinyl, fluoresceinyl, naphridinyl, azacarbazolyl, benzocarbaolinyl, carbaolinyl, phenanthrolinel, 1,2,3-triazolyl, 1,2,4-triazolyl, benzotriazolyl A group consisting of or derived from the group consisting of 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,3,5-triazinyl, 1,2,4-triazinyl, 1,2,3-triazinyl, tetrazolyl, 1,2,4,5-tetraazinyl, 1,2,3,4-tetraazinyl, 1,2,3,5-tetraazinyl, purine, pteridine, indazinyl, quinazolinyl, and benzothiadiazolyl.

[0021] The alkyl groups used in this invention contain 1 to 40 carbon atoms, and wherein a single hydrogen atom or a -CH2- group may be replaced by a straight-chain alkyl group or a branched alkyl group; the alkenyl or ynyl group contains at least two carbon atoms. As a non-limiting example, the alkyl, alkenyl or ynyl group preferably contains the following groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, cyclopentyl, n-hexyl, neohexyl, cyclohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, penynyl, hexynyl, hepynyl or ocynyl.

[0022] The alkoxy groups used in this invention have 1 to 40 carbon atoms. Preferably, the alkoxy groups are methoxy, trifluoromethoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, sec-pentoxy, 2-methylbutoxy, n-hexoxy, cyclohexoxy, n-heptoxy, cycloheptoxy, n-octoxy, cyclooctoxy, 2-ethylhexoxy, pentafluoroethoxy, or 2,2,2-trifluoroethoxy.

[0023] The heteroalkyl groups used in this invention refer to groups in which a single hydrogen atom or -CH2- group in an alkyl group is replaced by an oxygen, sulfur, or halogen atom. As non-limiting examples, these include alkoxy, alkathio, fluoroalkoxy, fluoroalkathio, particularly methyl thio, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, methylthio, ethyl thio, n-propylthio, isopropylthio, n-butylthio, isobutylthio, sec-butylthio, tert-butylthio, trifluoromethylthio, trifluoro Methoxy, pentafluoroethoxy, pentafluoroethylthio, 2,2,2-trifluoroethoxy, 2,2,2-trifluoroethylthio, ethyleneoxy, ethylenethio, propyleneoxy, propylenethio, butenthio, butenoxy, penenoxy, penenthio, cyclopentenoxy, cyclopententhio, hexenoxy, hexenthio, cyclohexenoxy, cyclohexenthio, acetylenoxy, acetylenthio, propylenoxy, propylenthio, butylenoxy, butylenthio, penylenoxy, penylenthio, hexylenoxy, hexylenthio.

[0024] Generally, the cycloalkyl and cycloalkenyl groups of the present invention can be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptyl, or cycloheptenyl, wherein one or more -CH2- groups can be replaced by O, S, or alkylsilyl groups; in addition, one or more hydrogen atoms can be replaced by deuterium atoms, halogen atoms, or cyano groups.

[0025] The heterocyclic alkyl group used in this invention refers to a monovalent functional group obtained by removing a hydrogen atom from a non-aromatic hydrocarbon with 3 to 40 atomic nuclei. In this case, one or more carbon atoms in the ring, preferably 1 to 3 carbon atoms, are replaced by heteroatoms such as N, O, or S. Non-limiting examples include tetrahydrofuran, tetrahydrothiophene, morpholine, and piperazine.

[0026] The fused-ring aryl group used in this invention refers to a monovalent functional group obtained by removing a hydrogen atom from an aromatic hydrocarbon with 6 to 60 carbon atoms that has two or more rings. In this case, the two or more rings can be simply attached to each other or attached in a condensed form. Non-limiting examples include phenanthrene, anthracene, fluoranthracene, pyrene, triphenylene, perylene, etc. Base, etc.

[0027] The aromatic amine group used in this invention refers to an amine substituted with an aryl group having 6 to 60 carbon atoms. Non-limiting examples of aromatic amine groups include diphenylamine, N-phenyl-1-naphthylamine, and N-(1-naphthyl)-2-naphthylamine. The heteroaryl amine group refers to an amine substituted with an aryl group having 6 to 60 carbon atoms or a heteroaryl group having 2 to 60 carbon atoms. Non-limiting examples of heteroaryl amine groups include N-phenylpyridin-3-amine, N-([1,1'-biphenyl]-4-yl)dibenzo[b,d]furan-2-amine, and N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-9H-fluorene-2-amine.

[0028] The aryl group used in this invention refers to R'O - The monovalent functional group represented by R' is an aryl group with 6 to 60 carbon atoms. Non-limiting examples of such aryl groups include phenoxy, naphthoxy, and biphenoxy groups.

[0029] The alkylsilyl group used in this invention refers to a silyl group substituted with an alkyl group having 1 to 40 carbon atoms, and the alkylsilyl group has at least 3 carbon atoms. Non-limiting examples of alkylsilyl groups include trimethylsilyl and triethylsilyl. Arylsilyl refers to a silyl group substituted with an aryl group having 6 to 60 carbon atoms.

[0030] According to the molecular motor provided by the present invention, in formula (I) Choose Freedom The group formed;

[0031] Where X is selected from single bond, -O-, -S-, -C(R) 13 (R) 14 )-、-Si(R 13 (R) 14 )- or -N(Ar 3 -; preferably a single bond, -O-, or -S-;

[0032] R 13 R 14 Each is independently selected from hydrogen, substituted or unsubstituted C1-C. 40 Alkyl, substituted or unsubstituted C1-C 40 Heteroalkyl, substituted or unsubstituted C3-C 40 cycloalkyl, substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 Group composed of heteroaryl groups;

[0033] Ar 3 Choose either freely substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Fused aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 Groups composed of heterocyclic aryl groups;

[0034] R 11 R 12 Each is independently selected from hydrogen, deuterium, fluorine, hydroxyl, nitrile, substituted or unsubstituted C1-C. 40 Alkyl, substituted or unsubstituted C1-C 40 Heteroalkyl, substituted or unsubstituted C3-C 40 cycloalkyl, substituted or unsubstituted C1-C 40 Alkoxy, substituted or unsubstituted C1-C 40 Heteroalkoxy, substituted or unsubstituted C5-C 40 Heterocyclic alkyl, substituted or unsubstituted C2-C 40 alkenyl, substituted or unsubstituted C5-C 40 Cycloalkenyl, substituted or unsubstituted C6-C 60 aryl, substituted or unsubstituted C6-C 60 Aromatic amino group, substituted or unsubstituted C2-C 60 Group composed of heteroaryl groups;

[0035] R 1 ~R 7 R 11 R 12 At least one of them contains one of formulas (II) to (XIII).

[0036] Preferably, R 1 ~R 5 R 11 R 12 At least one of them contains one of formulas (II) to (XIII).

[0037] According to the molecular motor provided by the present invention, R 1 ~R 7 R 11 R 12 At least one of them contains one of formulas (II), (III), (IV), (VI), (IX), and (XIII).

[0038] Preferably, R 1 ~R 7 R 11 R 12 At least one of them contains the structure shown in formula (II) or formula (IX).

[0039] According to the molecular motor provided by the present invention, Z is selected from single bonds, -O-, and -(CH2). y -、-O(CH2) y -、-(CH2) y O-, -(CH=CH) y A group consisting of -O (C = O)-, where y = 1, 2, 3, 4 or 5.

[0040] It should be noted that, provided there is no conflict, the above-mentioned preferred conditions can be combined in any way.

[0041] For example, when Selected from R 1 Containing the structure shown in formula (II), where Z is a single bond, the molecular motor structure is as follows:

[0042]

[0043] According to the molecular motor provided by the present invention, R 8 Choose C1-C with or without substitution. 40 Alkyl, substituted or unsubstituted C3-C 40 cycloalkyl, substituted or unsubstituted C1-C 40 Alkoxy, substituted or unsubstituted C2-C 40 alkenyl, substituted or unsubstituted C5-C 40 Cycloalkenyl, substituted or unsubstituted C6-C 60 A group composed of aryl groups.

[0044] Preferably, R 8Selected from fluorine, cyano, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, trifluoromethyl, trifluoroethyl, pentafluoroethyl, methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octyloxy, trifluoromethoxy, pentafluoroethoxy, tert-butoxy, substituted or unsubstituted cyclopentyl, substituted or unsubstituted cyclohexyl, substituted or unsubstituted phenyl.

[0045] According to the molecular motor provided by the present invention, R 9 R 10 Each is independently selected from the group consisting of hydrogen, deuterium, fluorine, cyano, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, methoxy, trifluoromethoxy, ethoxy, trifluoroethoxy, and pentafluoroethoxy.

[0046] According to the molecular motor provided by the present invention, when R 1 R does not contain any of the formulas (II) to (XIII). 1 It is selected from the group consisting of methyl, ethyl, propyl, trifluoromethyl, isopropyl, butyl, isobutyl, tert-butyl, and substituted or unsubstituted phenyl groups; more preferably, it is methyl.

[0047] When R 2 ~R 7 R 11 R 12 Each of R does not contain any of the formulas (II) to (XIII). 2 ~R 7 R 11 R 12 Each group is independently selected from the groups composed of hydrogen, deuterium, fluorine, and cyano groups.

[0048] In a specific embodiment of the present invention, the molecular motor is selected from the group consisting of compounds with formulas D100-D300:

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058] The molecular motor described in this invention exhibits dual photothermal responsiveness, capable of chiral reversal and unidirectional 360° rotation under light irradiation or heating conditions. Upon removal of the light or heat source, it can self-heat back to its initial state, and the rate of thermal recovery exhibits a first-order kinetic correlation with temperature.

[0059] The light source has an emission wavelength of 360nm to 720nm; preferably, the light source has an emission wavelength of 360nm to 420nm.

[0060] Secondly, the present invention provides a method for preparing the above-mentioned molecular motor.

[0061] The preparation method provided by the present invention includes: taking intermediate 1 With intermediate 2 The preparation is carried out by a McMurry coupling reaction.

[0062] Intermediate 1 can be synthesized via a route designed based on the specific compound structure.

[0063] Thirdly, the present invention also provides the application of the above-mentioned molecular motor in color photonic crystals, energy-saving smart windows, and smart soft materials.

[0064] Fourthly, the present invention provides a liquid crystal composition comprising the above-described molecular motor.

[0065] Preferably, the molecular motor accounts for 1% to 99% of the mass of the liquid crystal composition.

[0066] This invention provides a liquid crystal molecular motor with dual photothermal responsiveness, its preparation method, and its applications. By introducing structures containing groups such as trans-cyclohexyl groups, as shown in formulas (II) to (XIII), that is, combining liquid crystal segments with photothermal responsiveness with chiral-reversible interferometric helicene compounds, a multifunctional molecular motor is prepared that can undergo photo-induced axis reversal in response to light, as well as chiral changes and double bond axis rotation in response to light and heat. This molecular motor exhibits photothermal responsiveness, enabling the entire molecule to respond to both light and heat stimuli. Therefore, this molecule holds promise for the preparation of a new generation of multi-responsive materials, with broad application prospects in smart soft materials or responsive photonic crystals.

[0067] In addition, unless otherwise specified, any range described in this invention includes the endpoint, any value between the endpoints, and any subrange consisting of the endpoint or any value between the endpoints. Attached Figure Description

[0068] Figure 1This is a graph showing the trend of the torsional force of the photothermal dual-response liquid crystal molecular motor of Embodiment 1 of the present invention as a function of temperature. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0070] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials and related equipment used in the following embodiments are commercially available, and all percentages are by mass.

[0071] Example 1

[0072] This embodiment provides a liquid crystal molecular motor with dual photothermal response, namely compound D109, whose preparation method includes the following steps:

[0073] Step 1: Preparation of intermediate Int-1

[0074]

[0075] Under nitrogen protection, 20.0 mmol of methyl 2-(4'-ethyl-[1,1'-di(trans-cyclohexyl)]-4-yl)acetate was dissolved in 50 mL of dry THF. The mixture was cooled to 0 °C, and 24.0 mmol of 65% sodium hydride solid was added in portions. The mixture was stirred for 1 hour, and 24.0 mmol of 2-chloromethylnaphthalene was added dropwise. The mixture was then heated to room temperature and stirred for 2 hours. 20 mL of ice water was added dropwise, and the mixture was stirred for 30 minutes. The mixture was extracted with ethyl acetate, dried over the organic phase, filtered, concentrated under reduced pressure to dryness, and purified by silica gel column chromatography to give compound Int-1 as a white solid in 87% yield.

[0076] Step 2: Preparation of intermediate Int-2

[0077]

[0078] 20.0 mmol of Int-1 was dissolved in 60 mL of water and 20 mL of methanol. 0.1 mol of potassium hydroxide was added, and the mixture was stirred at room temperature for 12 hours. 50 mL of water was added, and dilute hydrochloric acid was added dropwise to adjust the pH to acidic. The mixture was filtered, and the filter cake was washed with water to give compound Int-2, a white solid with a yield of 92%.

[0079] Step 3: Preparation of intermediate Int-3

[0080]

[0081] Under nitrogen protection, 50 mL of concentrated sulfuric acid was cooled to 0 °C, and 40.0 mmol of Int-2 was added in portions. The mixture was stirred for 1 hour, then heated to 40 °C and stirred for 2 hours. The reaction solution was poured into 500 mL of ice-water mixture, filtered, the filter cake was washed with water, and the solid was purified by silica gel column chromatography to obtain compound Int-3, a yellow solid, with a yield of 68%.

[0082] Step 4: Preparation of compound D109

[0083]

[0084] Under nitrogen protection, titanium trichloride-aluminum chloride powder (0.1 mol, 78.5%) was mixed with 200 mL of dry THF, followed by the addition of 50.0 mmol of lithium aluminum hydride. The mixture was stirred for 10 minutes, then 49.0 mmol of triethylamine was added dropwise, and the mixture was stirred for 1 hour. Then, 10.0 mmol of Int-3 and 10.0 mmol of 9-fluorenone were added, and the mixture was heated to reflux and stirred for 24 hours. After cooling to room temperature, 150 mL of ice water was added dropwise. The mixture was filtered, and the filtrate was extracted with ethyl acetate. The organic phase was collected, washed with saturated brine, dried, filtered, and the filtrate was concentrated to dryness under reduced pressure. The filtrate was purified by silica gel column chromatography and recrystallized from ethanol to give compound D109 as a white solid in 72% yield. MS (MALDI-TOF): m / z=523.3303[M+H]+;1H NMR (δ, CDCl3): 8.32~8.31 (2H,d); 7.84~7.79 (3H,m); 7.63~7.56 (3H,m); 7.52~7.48 (2H,m); 7.38~7.32 (3H,m); 7.13~7.12 (1H,d) ;2.52~2.45(2H,m); 2.35~2.28(1H,m); 2.15~2.03(1H,m); 1.82~1.64(2H,m) ;1.58~1.36(5H,m); 1.33~1.19(6H,m); 1.16~1.03(8H,m); 0.95~0.90(3H,t).

[0085] The photo-driven process of the molecular motor D109: When D109 is irradiated with a 365nm light source, the double bond in the middle of the axis undergoes photoisomerization, resulting in an irreversible thermally induced helical flip, completing the first 180-degree rotation. At this time, the molecule is in an unstable state, and the chiral inversion of the naphthyl group is thermally induced. Similarly, under the irradiation of a 365nm light source, the second 180-degree rotation is completed. After the second rotation cycle is completed, the rotor part of the upper half of the motor molecule has completed a 360-degree unidirectional rotation relative to the stator part of the lower half.

[0086] To characterize its photothermal response performance, chirality, and helical inversion, a polarizing microscope was used to test the change in pitch of the molecule with temperature in a wedge-shaped box. A liquid crystal mixture of D109 was prepared according to the mass ratio in the table below for testing.

[0087] Table 1

[0088]

[0089]

[0090] The results are as follows Figure 1 As shown, the corresponding helical twisting force increases with increasing temperature, exhibiting a change in chirality with temperature. There is a clear phenomenon that the stripe spacing decreases with increasing temperature, proving that the chirality of the molecule has been flipped. Therefore, the molecule also has excellent thermal response properties.

[0091] Following the synthetic method described above, the compounds shown in Table 2 were prepared.

[0092] Table 2

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] As can be seen from the above examples, by incorporating liquid crystal substituents into the rotor or stator of the molecular motor, the same type of reaction can be used, and a one-step synthesis method can be employed to incorporate liquid crystal fragment substituents into different active sites, making the synthesis relatively convenient. Observations of the fringe spacing with temperature in a wedge-shaped box similar to that in Example 1, showing a clear decrease in fringe spacing with increasing temperature, demonstrate that this type of molecule also possesses excellent thermal response properties.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molecular motor, characterized in that, The molecular motor is the compound shown in D109: 。 2. The molecular motor according to claim 1, characterized in that, The molecular motor has photothermal dual responsiveness, and undergoes chiral flipping and unidirectional 360° rotation under light irradiation or heating conditions.

3. The application of the molecular motor according to claim 1 or 2 in color photonic crystals, energy-saving smart windows, and smart soft materials.

4. A liquid crystal composition, characterized in that, Includes the molecular motor as described in claim 1 or 2.

5. The liquid crystal composition according to claim 4, characterized in that, The molecular motor accounts for 1% to 99% of the mass of the liquid crystal composition.

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