KR102592738B1 - Novel mechanofluorochromic organic material and use thereof - Google Patents

Abstract

The present invention relates to a mechanofluorochromic (MFC) organic material, which includes an electron donor unit that donates electrons and an electron acceptor that is bonded to the electron donor unit and accepts electrons. It has a molecular structure including an acceptor unit, the electron acceptor unit includes pyrene, and the electron donor unit is bonded to the 2 and 7 positions of the pyrene. Do it as
According to one embodiment of the present invention, the mechanically discolorable organic material is capable of controlling intramolecular charge transfer.

Description

Novel mechanofluorochromic organic material and use thereof}

The present invention relates to a novel mechanofluorochromic (MFC) organic material, and more specifically, is based on a pyrene acceptor and contains an electron acceptor group (EDG) contained in the donor molecular structure. ) or a novel MFC organic material that enables induction of MFC properties and control of MFC efficiency by controlling photophysical and photochemical properties through electron withdrawing groups (EWG).

Recently, among organic solid emitting materials, MFC organic materials have been in the spotlight as smart materials due to their endless application possibilities. These properties of MFC organic materials are effective in fields such as sensors, security systems, strain detectors, data storage devices, memory devices, and optical displays, so efforts are being made to develop MFC organic materials.

MFC properties mainly appear in metal complexes or polymers such as gold (Au) and platinum (Pt). MFC materials using metal complexes have excellent interactions between molecules and easily induce MFC characteristics. In particular, they induce unique MFC characteristics such as simple color changes as well as phosphorescence due to external physical stimuli and forces. However, MFC metal complex materials have problems with high manufacturing costs and mass production in that they use rare metals. On the other hand, MFC polymer materials are inexpensive because they do not use rare metals, and can be mass-produced because they are easily synthesized. However, because MFC polymer materials have large molecules, it is very difficult to selectively control MFC properties to suit the field to which they are applied. Therefore, recently, MFC organic materials whose MFC properties are controlled through modification of the molecular structure without using rare metals have been attracting attention.

The properties of MFC organic materials are mainly determined by the interaction between molecules according to the molecular structure. At this time, the variables of interaction between molecules are many and the packing between molecules is complicated, so MFC organic materials are still limited. In addition, luminescent organic molecules generally exhibit high radioactivity in a solution state, but when aggregated, such as in a solid state, a phenomenon called Aggregation Caused Quenching (ACQ) occurs, in which weak luminescence or light disappears, which reduces MFC efficiency. Therefore, it is difficult to develop MFC organic materials.

One object of the present invention is to provide a novel MFC organic material made of pure organic compounds that have mechanofluorochromic (MFC) properties and can selectively control MFC efficiency.

Another object of the present invention is to provide a security ink composition comprising a novel MFC organic material.

The technical problems to be achieved by the novel MFC organic material according to the technical idea of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below. .

This is explained in detail as follows. Meanwhile, each description and embodiment disclosed in the present application may also be applied to each other description and embodiment. That is, all combinations of the various elements disclosed in this application fall within the scope of this application. Additionally, the scope of the present application cannot be considered limited by the specific description described below.

In order to achieve the above object, according to one embodiment of the present invention, a molecule comprising an electron donor unit that donates electrons and an electron acceptor unit that is bonded to the electron donor unit and accepts electrons. Mechanofluorochromic structure, wherein the electron acceptor unit includes pyrene, and the electron donor unit is bonded to the 2 and 7 positions of the pyrene. ; MFC) provides organic materials.

According to one embodiment of the present invention, there is provided a mechanically discolorable organic material represented by Formula 1:

[Formula 1]

According to one embodiment, in Formula 1, D represents an electron donor unit, and may each independently be any one selected from compounds represented by the following Formulas 2 to 6:

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

According to one embodiment, in Formulas 2 to 6, R is each independently a diphenylamine group, a dimethylamine group, a substituted or unsubstituted C1-C4 alkyl group, a C1-C4 alkoxy group, H, a halogen group, CN, and It may be any one selected from NO ₂ .

According to one embodiment, the substituted or unsubstituted C1-C4 alkyl group may be a methyl (Me) group or a trifluoromethyl (CF ₃ ) group.

According to one embodiment, the C1-C4 alkoxy group may be a methoxy (OMe) group.

According to one embodiment, the halogen group may be a fluoro (F) group.

According to one embodiment, the mechanically discolorable organic material may be capable of controlling intramolecular charge transfer.

According to one embodiment, the photoluminescence peak wavelength (PL peak wavelength) of the mechanically discolorable organic material may range from 400 to 600 nm.

According to one embodiment of the present invention, a color-changing composition including the mechanically color-changing organic material is provided.

According to one embodiment of the present invention, a security ink composition including the mechanically discolorable organic material is provided.

The mechanically discolorable organic material according to the present invention is inexpensive because it does not use rare metals, and can be mass-produced because it is easily synthesized. In addition, it has the advantage of high mechanical discoloration efficiency because Aggregation Caused Quenching (ACQ), which causes weak light emission or light extinction during aggregation, does not occur.

In addition, according to the present invention, the mechanical color change efficiency of the mechanical color change organic material can be selectively controlled by electron donating groups and electron withdrawing groups.

However, the effects that can be achieved by the mechanically discolorable organic material according to an embodiment of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. It could be.

In order to more fully understand the drawings cited in this specification, a brief description of each drawing is provided.
Figure 1 shows the UV spectrum of a mechanically changeable organic material according to an embodiment of the present invention.
Figure 2 shows the PL spectrum (a) of a mechanically discoloring organic material according to an embodiment of the present invention, and a photograph (b) of the luminescence phenomenon.
Figure 3 shows PL spectra [(a) to (e) of the mechanically changeable organic material in pure powder state (pristine), ground state (grinded state), and fumed state (fumed) according to an embodiment of the present invention. )] represents a photograph (f) of the luminescence phenomenon.
Figure 4 shows the reproducibility of mechanically discolorable organic materials [(a):CN, (b):F, (c):H, (d):Me, (e):OMe] according to an embodiment of the present invention. Shows the experimental results.
Figure 5 shows a film using a security ink composition containing a mechanically discolorable organic material according to an embodiment of the present invention.

The invention disclosed in this specification can be subject to various changes and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail through detailed description. However, this is not intended to limit the technology disclosed in this specification to specific embodiments, and the technology disclosed in this specification should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

In describing the invention disclosed in this specification, if it is determined that a detailed description of related known technology may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, numbers (eg, first, second, etc.) used in the description of this specification are merely identifiers to distinguish one component from another component.

In the disclosure of this specification, when a part “includes” a certain element, this means that it may further include other elements rather than excluding other elements unless otherwise stated.

As used herein, the terms “about,” “substantially,” and the like are used to mean at or close to a numerical value when manufacturing and material tolerances inherent in the stated meaning are given, and are used to convey the meaning of the present disclosure. Precise or absolute figures are used to assist in preventing unscrupulous infringers from taking unfair advantage of stated disclosures.

Additionally, when a component, such as a layer, membrane, region, plate, etc., is said to be "on" or "on" another component, it means not only that it is "directly above" the other component, but also that there is another component in between. It should be understood that it can also include cases. Conversely, when an element is said to be "right on top" of another part, it should be understood to mean that there is no other part in between.

As used in the present disclosure, the terms “step of” or “step of” do not mean “step for.”

In the present disclosure, the term "substitution" means changing a hydrogen atom bonded to a carbon atom of a compound to another substituent, and the position to be substituted is not limited as long as it is the position where the hydrogen atom is substituted, that is, a position where the substituent can be substituted, 2 In the case of more than one substitution, two or more substituents may be the same or different from each other.

In the present disclosure, the term “substituted or unsubstituted” refers to deuterium (-D); halogen group; Nitrile group; nitro group; hydroxyl group; silyl group; boron group; Alkoxy group; Alkyl group; Cycloalkyl group; Aryl group; and a heterocyclic group, or is substituted with a substituent in which two or more of the above-exemplified substituents are linked, or does not have any substituent. For example, “a substituent group in which two or more substituents are connected” may be a biphenyl group. That is, the biphenyl group may be an aryl group, or it may be interpreted as a substituent in which two phenyl groups are connected.

In the present disclosure, “halo” or “halogen” refers to bromo (Br), chloro (Cl), fluoro (F), or iodo (I), and the preferred halogen as a substituent is fluoro or It could be chloro.

In the disclosure of this specification, “alkyl group” refers to a saturated aliphatic hydrocarbon group such as, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, and tert-butyl group, which is a substituent You don't have to have it even if you have it. There is no particular limitation on the additional substituent when substituted, and examples include alkyl group, halogen, aryl group, heteroaryl group, etc. This point is also common to the description below. Additionally, the number of carbon atoms in the alkyl group is not particularly limited, but is preferably in the range of 1 to 10, more preferably 1 to 4, from the viewpoint of availability and cost.

In the disclosure of this specification, “alkoxy group” refers to a functional group to which an aliphatic hydrocarbon group is bonded through an ether bond, such as a methoxy group, ethoxy group, or propoxy group, and this aliphatic hydrocarbon group may or may not have a substituent. . The number of carbon atoms in the alkoxy group is not particularly limited, but is preferably in the range of 1 to 10, more preferably in the range of 1 to 4.

In the present disclosure, “UV” refers to light with a wavelength of approximately 200 nm to 400 nm.

In the disclosure of this specification, “photoluminescence peak wavelength” refers to the wavelength representing the maximum photoluminescence intensity, and “range of photoluminescence peak wavelength” refers to selecting the photoluminescence peak wavelength in consideration of luminance and color coordinates. refers to the possible range.

As used herein, “maximum absorption wavelength” refers to the wavelength that exhibits maximum absorption, and “range of maximum absorption wavelength” refers to the normalized absorption intensity of 20% or more (or 30% or more in the curve including the maximum absorption wavelength). ) refers to the range of wavelengths.

As used herein, a “normalized UV absorption spectrum” means normalizing the absorption intensity by dividing the absorption at each wavelength (intensityλ) by the absorption intensity at the wavelength exhibiting the highest absorption (Intensityλmax), and normalizing this over all wavelengths. The absorption intensity is graphed.

In the present disclosure, “layer” refers to a film resulting from a composition containing one or more film-forming polymeric resins and a substantially dry liquid carrier.

In the present disclosure, “liquid carrier” includes any liquid that acts as a carrier for a material dispersed in a solid state and/or dissolved therein.

In the present disclosure, “security ink composition” refers to any composition that can form a layer on a solid substrate and that can be applied preferentially, but not exclusively, by a printing method.

In the disclosure of this specification, the term "combination thereof" included in the Markushi format expression means a mixture or combination of one or more components selected from the group consisting of the components described in the Markushi format expression, It means including one or more selected from the group consisting of.

In addition, each of the components described below may additionally perform some or all of the functions of other components in addition to the main functions that each component is responsible for, and some of the main functions of each component may be different from other components. Of course, it can also be performed exclusively by a component.

Expressions such as “first,” “second,” “first,” or “second” used in various embodiments may modify various elements regardless of order and/or importance, and describe the elements. It is not limited. For example, a first component may be renamed to a second component without departing from the scope of the present invention, and similarly, the second component may also be renamed to the first component.

According to one embodiment of the present invention, a mechanofluorochromic device having a molecular structure including an electron donor unit that donates electrons and an electron acceptor unit that is bonded to the electron donor unit and accepts electrons. ; MFC) provides organic materials.

Mechanical discoloration means that the color emitted is changed by physical external stimulation and force such as pressing, grinding, or grinding without changing the molecular structure, and is converted to its original state through heating, cooling, or solvent vapor, and this phenomenon can be repeatedly converted. As a property that can be achieved, the organic material with mechanical discoloration according to the present invention refers to a material that has mechanical discoloration and is made of pure organic compounds. The organic material with mechanical discoloration according to the present invention can secure economic efficiency and reproducibility by not using rare metals, and the mechanical discoloration can be adjusted through modification of the molecular structure.

According to one embodiment, the mechanically discolorable organic material has a molecular structure comprising at least one electron donor unit that donates electrons and an electron acceptor unit that is bonded to the electron donor unit and accepts electrons. Includes compounds having

According to one embodiment, the electron acceptor unit may be an organic compound having acceptor properties, for example, pyrene, phenanthroimidazole, tetraphenylimidazole, Examples include benzoxazole and benzoylmethyleneindol, but are not limited thereto. In a preferred embodiment, the electron acceptor unit includes pyrene. Pyrene effectively improves absorption and release properties through site-selective functional group substitution in the active site at positions 1, 3, 6, and 8 and the K-region at positions 4, 5, 9, and 10. Control. Additionally, the planar pyrene geometry induces intermolecular π-π interactions and leads to aggregation, emission quenching, broad emission band and red-shift properties.

According to one embodiment, the electron donor unit may be bonded to positions 2 and 7 of the pyrene. The mechanically discolorable organic material may be a compound having a donor-acceptor-donor molecular structure in which electron donor units are bonded. The pyrene acts as an electron acceptor unit, and weakly induces intramolecular interactions by using positions 2 and 7 of pyrene, where planar nodes exist, as the basic skeleton. When intramolecular interactions become weak, intermolecular interactions increase, mechanical discoloration appears, and mechanical discoloration efficiency also increases.

According to one embodiment of the present invention, there is provided a mechanically discolorable organic material represented by the following formula (1):

[Formula 1]

In Formula 1,

D represents an electron donor unit, and may each independently be any one selected from compounds represented by the following formulas 2 to 6:

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

The molecular structure of the electron donor unit may be relatively non-planar than that of pyrene, which is the electron acceptor unit. Accordingly, the efficiency of mechanically discolorable organic materials can be improved by preventing the Aggregation Caused Quenching (ACQ) phenomenon caused by π-π stacking between molecules.

In the above formulas 2 to 6, R is a substituent that can be introduced into the electron donor unit and may include an electron donating group or a withdrawing group. The introduction of electron donating and withdrawing groups allows tuning of charge transfer properties within the same moiety comprising a donor, acceptor and π-linker. It is possible to control charge transfer within a molecule by controlling the electron-donating group in the electron-withdrawing group.

The R may each independently be selected from a diphenylamine group, a dimethylamine group, a substituted or unsubstituted C1-C4 alkyl group, a C1-C4 alkoxy group, H, a halogen group, CN, and NO ₂ . For example, the substituted or unsubstituted C1-C4 alkyl group may be a methyl (Me) group or a trifluoromethyl (CF ₃ ) group. In another example, the C1-C4 alkoxy group may be a methoxy (OMe) group. In another example, the halogen group may be a fluoro (F) group.

According to one embodiment, the mechanically discolorable organic material may have a UV spectrum with an absorption peak at any one of 270 to 280 nm, 345 to 355 nm, and 357 to 365 nm, referring to Figure 1. Not limited. Referring to FIG. 2(a), the mechanically discolorable organic material may have a photoluminescence peak wavelength (PL peak wavelength) of 400 to 600 nm by using excitation light with a wavelength of 365 nm or less. It is not limited to this. For example, when the peak wavelength ranges from 500 nm to 550 nm, green light may be emitted. Generally, the greater the energy of the excitation light, the more likely it is to cause decomposition of the material, but since the excitation light in the wavelength range of 365 nm or less has a relatively small excitation energy, green light emission with good color purity can be obtained without causing decomposition of the material. there is. As another example, when the peak wavelength range is 550 nm to 600 nm, red light may be emitted.

According to the UV and PL spectrum of the mechanically discolorable organic material, the spectrum of the R group introduced into the donor unit may shift to a red wavelength as it moves from an electron withdrawing group to an electron donating group. This is due to the transition of charge transfer within the molecule, that is, it is possible to control charge transfer within the molecule by controlling the electron withdrawing group to the electron donating group.

According to one embodiment of the present invention, a color-changing composition including the mechanically color-changing organic material is provided. The color changing composition may include at least one type of organic light-emitting material. The light-emitting material refers to an organic material that emits light of a different wavelength from that of the light when irradiated with certain light. Exemplarily, the light-emitting material may include a mechanically discolorable organic material according to an embodiment of the present invention. The higher the electron-withdrawing ability of the mechanically discolorable organic material, the higher the mechanical discoloration efficiency.

According to one embodiment, the composition may be a composition containing a mechanically discoloring organic material and a solvent.

The solvent is not particularly limited as long as it can dissolve the organic material and does not excessively affect the light emission and durability of the organic material. Illustrative examples include water, 2-propanol, ethanol, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, hexane, acetone, methyl acetate, ethyl acetate, butyl acetate, propyl acetate, and isopropyl acetate. , terpineol, texanol, methyl cellosolve, ethyl cellosolve, butylcarbitol, butylcarbitol acetate, 1-methoxy-2-propanol, propylene glycol monomethyl ether acetate, tetrahydrofuran, tetrahydropyran. , 1,4-dioxane, etc., and it is also possible to use a mixture of two or more types of these solvents.

According to one embodiment of the present invention, a security ink composition including the mechanically discolorable organic material is provided. These security ink compositions can be used to induce and detect photoluminescence using their mechanical discoloration properties. The security ink composition may be excited by light to convert at least part of the light into light of a different wavelength. For example, in the case of blue light, the wavelength may be converted through a mechanically discoloring organic material included in the security ink composition and emitted as white light.

The security ink composition may further include one or more machine-readable materials selected from the group consisting of magnetic materials, electrically conductive materials, and combinations or mixtures thereof. The “machine-readable material” means that the material exhibits one or more unique properties detectable by a device or machine and may be included in a layer, thereby allowing the use of specific equipment for authentication to identify the layer or an article comprising the layer. It refers to a material that can provide an authentication method.

According to one embodiment, when the security ink composition includes a mechanically discoloring organic material, the pyrene 2,7 position-based compound, which is a pure organic compound, exhibits mechanical discoloration, and the mechanical discoloration is achieved by an electron donating group and an electron withdrawing group. The mechanical discoloration efficiency of organic materials can be selectively adjusted. Mechanical color change efficiency refers to how many times a material can be reversibly used when its color changes due to mechanical stimulation. In other words, the higher the electron-withdrawing ability, the more times mechanical discoloration (phenomenon) can occur. According to the present invention, the higher the electron-withdrawing ability of the mechanochromic organic material, the higher the mechanochromic efficiency.

According to one embodiment, the security ink composition may further include one or more forensic markers and/or one or more taggants.

According to one embodiment of the present invention, discoloration of the security ink composition comprising the mechanically discolorable organic material may be detected by an optical sensor, a magnetic sensor, a mechanical sensor, and/or a conductivity detection sensor.

Hereinafter, the present invention will be described in more detail with reference to examples. The examples below are for illustrative purposes only, and it is clear to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, and such changes or modifications also fall within the scope of the appended patent claims. It's natural.

(Example)

Preparation of mechanically discolorable organic materials

[Scheme 1]

Scheme 1 exemplarily shows a procedure for synthesizing a mechanically discolorable organic material according to an embodiment of the present invention.

(1) Synthesis of compound 2,7-Bis[4’-[bis(4’’-cyanophenyl)amino]phenyl]pyrene

2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (0.5 g, 1.1 mmol) and 4,4' in a two neck flask. -((4-bromophenyl)azanediyl)dibenzonitrile (0.91 g, 2.42 mmol) was mixed in an aqueous solution of tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), toluene, and potassium carbonate (K ₂ CO ₃ ). It was stirred at 110°C for 24 hours. After completion of the reaction, it was cooled to room temperature, the metal salt was extracted through reduced pressure filtration, and the organic layer was separated using water-dichloromethane. The obtained organic layer was dried over anhydrous sodium hydrogen sulfate, and the solvent was distilled off under reduced pressure to obtain compound (1).

Compound (1)

¹ H-NMR (500 MHz, CDCl ₃ , ppm) δ 8.43 (s, 1H), 8.20 (s, 1H), 7.94 (d, J = 8.5 Hz, 1H), 7.62 (d, J = 9.0 Hz, 2H ), 7.34 (d, J = 8.5 Hz, 1H), 7.25 (d, J = 9.0 Hz, 2H).

¹³ C{ ¹ H} (125MHz, CDCl ₃ , ppm) δ 150.15, 144.52, 139.45, 137.74, 133.68, 131.68, 129.77, 128.10, 127.22, 123.89, 123.73, 123.18, 118.89, 106.17.

(2) Synthesis of compound 2,7-Bis[4’-[bis(4’’-fluorophenyl)amino]phenyl]pyrene

2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (0.5 g, 1.1 mmol) and 4-bromo- in a two neck flask. N , N -bis(4-fluorophenyl)aniline (0.87 g, 2.42 mmol) was mixed with tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), toluene, and potassium carbonate (K ₂ CO ₃ ) aqueous solution. Afterwards, it was stirred at 110°C for 24 hours. After completion of the reaction, it was cooled to room temperature, the metal salt was extracted through reduced pressure filtration, and the organic layer was separated using water-dichloromethane. The obtained organic layer was dried over anhydrous sodium hydrogen sulfate, and the solvent was distilled off under reduced pressure to obtain compound (2).

Compound (2)

¹ H-NMR (500 MHz, CDCl ₃ , ppm) δ 8.38 (s, 1H), 8.14 (s, 1H), 7.79 (d, J = 8.5 Hz, 1H), 7.20-7.15 (m, 3H), 7.04 (t, J = 8.0 Hz, 2H).

¹³ C{ ¹ H} (125MHz, CDCl ₃ , ppm) δ 147.53, 143.73, 135.06, 131.52, 128.73, 127.91, 126.25, 126.18, 123.62, 123.37, 122.85, 116.36, 116.18.

(3) Synthesis of compound 2,7-Bis(triphenylamino)pyrene

2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (0.5 g, 1.1 mmol) and 4-bromo- in a two neck flask. N , N -diphenylaniline (0.78 g, 2.42 mmol) was mixed in an aqueous solution of tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), toluene, and potassium carbonate (K ₂ CO ₃ ) and incubated at 110°C for 24 hours. It was stirred. After completion of the reaction, it was cooled to room temperature, the metal salt was extracted through reduced pressure filtration, and the organic layer was separated using water-dichloromethane. The obtained organic layer was dried over anhydrous sodium hydrogen sulfate, and the solvent was distilled off under reduced pressure to obtain compound (3).

Compound (3)

¹ H-NMR (500 MHz, CDCl ₃ , ppm) δ 8.40 (s, 1H), 8.15 (s, 1H), 7.80 (d, J = 9.0 Hz, 1H), 7.33 (t, J = 8.5 Hz, 2H ), 7.29-7.28 (m, 1H), 7.22 (d, J = 8.5 Hz, 2H), 7.09 (t, J = 7.0 Hz, 1H).

¹³ C{ ¹ H} (125 MHz, CDCl ₃ , ppm) δ 147.71, 131.51, 129.34, 128.65, 127.90, 124.52, 124.12, 123.41, 123.04.

(4) Synthesis of compound 2,7-Bis[4’-[bis(4’’-methylphenyl)amino]phenyl]pyrene

2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (0.5 g, 1.1 mmol) and 4-bromo- in a two neck flask. N , N -di- p -tolylaniline (0.85 g, 2.42 mmol) was mixed in an aqueous solution of tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), toluene, and potassium carbonate (K ₂ CO ₃ ) and then mixed at 110 °C. It was stirred at ℃ for 24 hours. After completion of the reaction, it was cooled to room temperature, the metal salt was extracted through reduced pressure filtration, and the organic layer was separated using water-dichloromethane. The obtained organic layer was dried over anhydrous sodium hydrogen sulfate, and the solvent was distilled off under reduced pressure to obtain compound (4).

Compound (4)

¹ H-NMR (500 MHz, CDCl ₃ , ppm) δ 8.28 (s, 1H), 8.03 (s, 1H), 7.66 (d, J = 8.5 Hz, 1H), 7.13 (d, J = 8.5 Hz, 1H ), 7.05-7.01 (m, 4H).

¹³ C{ ¹ H} (125 MHz, CDCl ₃ , ppm) δ 145.26, 134.38, 132.71, 131.47 129.97, 128.47, 127.85, 124.78, 123.32, 122.90, 20.87.

(5) Synthesis of compound 2,7-Bis[4’-[bis(4’’-methoxyphenyl)amino]phenyl]pyrene

2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrene (0.5 g, 1.1 mmol) and 4-bromo- in a two neck flask. N , N -bis(4-methoxyphenyl)aniline (0.93 g, 2.42 mmol) was mixed with tetrakis(triphenylphosphine)palladium (Pd(PPh ₃ ) ₄ ), toluene, and potassium carbonate (K ₂ CO ₃ ) aqueous solution. Afterwards, it was stirred at 110°C for 24 hours. After completion of the reaction, it was cooled to room temperature, the metal salt was extracted through reduced pressure filtration, and the organic layer was separated using water-dichloromethane. The obtained organic layer was dried over anhydrous sodium hydrogen sulfate, and the solvent was distilled off under reduced pressure to obtain compound (5).

Compound (5)

¹ H-NMR (500 MHz, CDCl ₃ , ppm) δ 8.36 (s, 1H), 8.12 (s, 1H), 7.74 (d, J = 8.5 Hz, 1H), 7.18-7.12 (m, 3H), 6.90 (d, J = 9.0 Hz, 2H).

¹³ C{ ¹ H} (125 MHz, CDCl ₃ , ppm) δ 131.45, 127.83, 126.68, 123.20, 121.23, 114.77, 55.54.

(Experimental example)

Luminescent properties of MFC organic material compounds

Figure 1 shows the UV spectrum (DCM solvent) of compounds (1) to (5), and Figure 2(a) shows the PL spectrum (DCM solvent).

UV and PL spectra were recorded using a Sinco Mega-2100 spectrophotometer in dual beam mode, and fluorescence cystometry was performed using a Shimadzu fluorometer (RF-6000) with a wavelength resolution of ~1 nm. Fluorescence lifetime was measured with a PicoQuant FluoTime 200 utilizing a time-correlated single photon counting method. A pulsed diode laser operating at a repetition rate of 20 MHz was used as the excitation source. The FWHM of the laser pulse was typically 45 ps and the instrument response function was ~190 ps using a Hamamatzu photomultiplier tube (H5783-01). Emission quantum yield (ΦPL) was calculated using William's comparison method for samples at five different concentrations of (1–5) μM using 9,10-diphenyl anthracene (ΤPL = 0.95, ethanol) as reference standard. It has been done.

According to the UV and PL spectra, the spectrum shifted to a red wavelength as the R group introduced into the donor went from an electron-withdrawing group to an electron-donating group. It was confirmed that this is due to the transition of intramolecular charge transfer, that is, it is possible to control intramolecular charge transfer by controlling the electron withdrawing group to the electron donating group.

Figure 3(a) shows compound (1); (b) is compound (2); (c) is compound (3); (d) is compound (4); (e) shows the PL spectrum of compound (5) in pure powder state (pristine), ground state (grinded), and fumed state. Referring to FIG. 3, it was confirmed that there was no ACQ phenomenon through the pure powder PL spectra of compounds (1) to (5). In addition, when the powder of the compound was ground, the PL spectrum shifted to a redder wavelength than that of the original powder, and when fumed with acetone vapor, the PL spectrum became more similar to the PL spectrum of the original powder as the electron withdrawing group increased. As a result, it was confirmed that the compound according to an embodiment of the present invention is an MFC organic material with MFC properties in pure organic molecules. In addition, it can be confirmed that the charge transfer within the molecule was controlled by controlling the electron donating group and the electron withdrawing group, and that this affected the interaction between molecules, thereby controlling the MFC efficiency. Therefore, it was confirmed that the pyrene 2,7 position-based donor-acceptor-donor compound according to an embodiment of the present invention exhibits MFC characteristics, and that MFC efficiency can be selectively controlled by controlling the electron withdrawing group and the electron donating group.

Reproducibility of MFC

An efficiency test was conducted to determine how repeatedly the MFC organic materials of compounds (1) to (5) synthesized in the above examples could be reused. Repeated use of organic materials means that when the original material (pristine) is mechanically stimulated (grinded), the luminescent color changes, and when vapor of a volatile solvent is injected (fumed), it returns to its original state. This process ( In other words, this means that the phenomenon of mechanical discoloration can be reversibly repeated many times.

Referring to Figure 4, it can be seen that the efficiency is controlled depending on the substituent effect, and increases as the electron-withdrawing ability becomes stronger.

Films using security ink compositions containing MFC organic materials

A fluorescent image paper film was produced using the MFC organic materials of compounds (1) to (5) synthesized in the above examples, and the MFC efficiency was visually compared. The powder of the MFC organic material of compounds (1) to (5) synthesized under a UV lamp at a wavelength of 365 nm was applied on filter paper, and then the letter “D” was drawn using a metal bar as a pen. Referring to Figure 5, CN emitted light purple, F emitted blue, H emitted light blue, Me emitted light blue, and OMe emitted cyan. For CN, F, H and Me (compounds (1) to (4)), when viewed with the naked eye, the letters emit bluish fluorescence compared to the background color, emphasizing the red shift in the PL spectrum due to polishing. In contrast, in the case of OMe (compound (5)), the letters emitted blue-green fluorescence similar to the background color. That is, with increasing electron-withdrawing ability from Me to CN, the letter “D” was quickly and easily erased using acetone vapor as an eraser. In the case of OMe, there was no change such as the letter “D” being erased. Afterwards, the letter “U” was redrawn on the film, and an increase in electron-withdrawing ability, which was influenced by the degree to which the letter “D” was erased, was clearly observed. Therefore, it can be seen that the higher the electron-withdrawing ability, the higher the MFC efficiency. In other words, it can be seen that the substituents can be selectively adjusted to suit the field to be applied.

Above, the technology disclosed in this specification has been described in detail with preferred embodiments, but the technical idea of the present invention is not limited to the above embodiments, and is within the scope of the technical idea of the present invention. Various modifications and changes are possible depending on the user.

Claims (12)

delete delete A mechanically discolorable organic material represented by the formula (1):
[Formula 1]

In Formula 1,
D represents an electron donor unit, each independently selected from compounds represented by the following formulas 2 to 6,
[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 2 to 6,
R is each independently selected from diphenylamine group, dimethylamine group, substituted or unsubstituted C1-C4 alkyl group, C1-C4 alkoxy group, H, halogen group, CN and NO ₂ . According to claim 3,
The substituted or unsubstituted C1-C4 alkyl group is a methyl (Me) group or a trifluoromethyl (CF ₃ ) group. According to claim 3,
The C1-C4 alkoxy group is a methoxy (OMe) group, and the mechanically discoloring organic material. According to claim 3,
A mechanically discolorable organic material, wherein the halogen group is a fluoro (F) group. According to claim 3,
The mechanically discolorable organic material is characterized in that it is capable of controlling intramolecular charge transfer. According to claim 3,
The mechanically discolorable organic material has a photoluminescence peak wavelength (PL peak wavelength) in the range of 400 to 600 nm. A discoloring composition comprising the mechanically discoloring organic material of any one of claims 3 to 8. According to clause 9,
A color-changing composition, characterized in that the higher the electron-withdrawing ability of the mechanically changing organic material, the higher the mechanically changing efficiency. A security ink composition comprising the mechanically discolorable organic material of any one of claims 3 to 8. According to claim 11,
A security ink composition for inducing and detecting photoluminescence using mechanical photochromic properties.