JP2021063169A - Light up-conversion material - Google Patents

Abstract

To provide a novel solid light up-conversion material that can achieve high light up-conversion yields.SOLUTION: A light up-conversion material contains a light up-conversion emission body and a photosensitizer and is solid. The photosensitizer has a chemical structure in which a triplet photosensitized part and a molecule anchor part are coupled.SELECTED DRAWING: None

Description

The present invention relates to an optical up-conversion material.

Conventionally, an optical up-conversion light emitter that converts long-wavelength light into short-wavelength light has been known. As an optical up-conversion illuminant, an inorganic optical up-conversion illuminant using a rare earth element or the like is known. Inorganic light up-conversion light emitters have been applied to IR cards and the like that convert infrared laser light into visible light, and have already been put into practical use.

On the other hand, the organic light up-conversion illuminant using an organic compound uses the strong and wide absorption spectrum of the organic compound to increase the light with a wider wavelength and lower incident power than the inorganic light up-conversion illuminant. It is known that conversion is possible. Applications of the organic optical up-conversion illuminant include, for example, organic thin-film solar cells, perovskite solar cells, and photocatalysts. In these applications, it is visible light in the short wavelength region of the sunlight spectrum that generates charge from sunlight, and ultraviolet light and blue light are particularly used in photocatalysts and the like. Therefore, it is expected that by using an organic optical up-conversion illuminant for these devices, the long wavelength component thereof is converted into a short wavelength component, and the photoelectric conversion efficiency of the solar cell and the reaction efficiency of the photocatalyst are improved. It is also expected to be used to promote the growth of plants by converting the green component, which is most strongly contained in sunlight, into a short-wavelength blue component that is efficiently absorbed by the chloroplasts of plants. Furthermore, by using a low-power (less than 1 mW) laser pointer that can be used in general without restrictions, it is possible to obtain characteristic short-wavelength light emission that does not normally occur, so it can be used as an ink material for special purposes such as anti-counterfeiting. The application of is also considered. As described above, in recent years, organic light up-conversion illuminants have been attracting attention (see, for example, Patent Document 1, Non-Patent Documents 1 and 2).

The organic light up-conversion illuminant is generally used together with a photosensitizer and is used as an organic light up-conversion material. Examples of the optical up-conversion mechanism in the currently known organic optical up-conversion materials include the following mechanisms. First, the photosensitizer molecule ( ¹ A) in the ground state absorbs light energy and transitions to the excited singlet state ( ¹ A ^{* ) (1} A + hν → ¹ A ^* ). Next, intersystem crossing occurs rapidly to the excited triplet state ( ³ A ^{* ) (1} A ^* → ³ A ^* ), and energy is transferred from the excited triplet state of the photosensitizer molecule to the illuminant molecule. Is done. This causes the photosensitizer molecule to lose energy and return to its ground state. On the other hand, the luminescent molecule ( ¹ E) in the ground state changes to an excited triplet ( ³ E ^* ) (triplet-triplet energy transfer: ³ A ^* + ¹ E → ¹ A + ³ E ^* ). .. When the concentration of the luminescent molecule changed to the excited triplet state increases, the interaction between the luminescent molecules changed to the excited triplet state becomes efficient, and one of the luminescent molecules changed to the excited triplet state occurs. Energy is transferred from the other illuminant molecule. At this time, one luminescent molecule that has changed to the excited triplet state returns to the ground state, and the other changes to the excited singlet state (triplet-triplet annihilation process: ³ E ^* + ³ E ^* → ¹ E +. ¹ E ^* ). ^{Then, up-converted luminescence (1} E ^* → ¹ E + hν _f ) is generated as fluorescence from the illuminant molecule changed to the excited singlet state. Such a mechanism is called "triplet-triplet up-conversion" or the like.

Considering the above mechanism, in the organic optical up-conversion material, the energy of the excited triplet state of the illuminant needs to be about half the energy of the excited singlet state. Therefore, as the luminescent material, a molecule having an aromatic ring skeleton or the like is used. Further, as the photosensitizer, an organometallic complex or the like that generates an excited triplet state with high efficiency is used.

For example, anthracene, 9,10-diphenylanthracene and the like are known as light up-conversion light emitters in the blue light emitting region. Further, as a sensitizer that operates in response to them, metal porphyrin compounds, particularly Pt-octaethylporphyrin, Pd-octaethylporphyrin, Pt-tetraphenylporphyrin, Pd-tetraphenylporphyrin and the like are known. ..

Further, most of the conventional organic optical up-conversion materials are liquids as described later, and from the viewpoint of practical use, the development of solid organic optical up-conversion materials is also required.

Special Table 2008-506798 International Publication 2014/136619 JP-A-2017-171888

Ceroni, P.M. , Energy up-conversion by low-power extraction: new applications of an old concept. Chemistry (Weinheim and der Bergstrasse, Germany) 2011, 17, 9560-4. Tupke, T.M. Shalav, a. Richards, B.I. S. Wurfer, P.M. Green, M. et al. , Efficiency enhancement of solar cells by luminescence up-conversion of sunlight. Solar Energy Materials and Solar Cells 2006, 90, 3327-3338.

In organic light up-conversion materials, due to the principle of operation, energy transfer between the sensitizer and the illuminant and pair annihilation between the triplet illuminants are performed between the sensitizer and the illuminant or the triplet illuminant. Molecular collisions between each other are required. For this reason, conventionally, as a high-efficiency material having an emission quantum yield of more than 10%, there has been a gel-like medium in which the molecules in the triplet state are movable, or a gel-like medium containing substantially the liquid. However, there were difficulties in handling and deviceization.

Furthermore, since the transfer of energy between the sensitizer and the luminescent material and the triplet luminescent material are hindered by oxygen in the atmosphere, it is necessary to seal the sensitizer and the luminescent material in an inert gas to remove oxygen. In these respects, the same applies to the prior art of the present inventors (Patent Document 2).

Therefore, in order to realize a solid high-efficiency material, the present inventors have investigated a method that enables high-efficiency energy transfer between the sensitizer and the luminescent material even in a solid. As a result, it is necessary to overcome the problem that the sensitizer and the illuminant are separately aggregated and crystallized, and the sensitizers are solidified when the solvent is evaporated from the mixed solution of the sensitizer and the illuminant. By setting the condition that the crystallization of the luminescent material proceeds faster than the crystallization of the luminescent material, the sensitizer can be incorporated into the luminescent material crystal to realize a solid that enables highly efficient energy transfer. Inspired by. Therefore, the concentration of the sensitizer to the luminescent material is lowered, the concentration of the luminescent material is increased to about the saturation concentration, the type of solvent and the volatilization conditions are adjusted, and the luminescent material is rapidly crystallized. As shown in 3, the above-mentioned problems have been solved. Patent Document 3 provides an optical up-conversion material which is a solid containing a specific optical up-conversion illuminant and a photosensitizer, which is produced by a casting method from this mixed saturated solution, and the emission quantum yield of the solid is provided. The maximum rate exceeds 10%. This is a very high light up-conversion emission yield compared to the solid materials before that, and it is clarified that even a solid can achieve a high light up-conversion emission yield comparable to that of a liquid.

However, the solid obtained by the casting method from the mixed saturated solution disclosed in Patent Document 3 is formed from microcrystal grains, and the characteristics of the microcrystal grains are not uniform among the particles and are contained in the microcrystal grains. There are also many microcrystal grains that do not show up-conversion luminescence. Therefore, there is a problem that the overall up-conversion yield is lower than the maximum value, and it is desired to develop a method for further improving the optical up-conversion yield of the material as a whole.

Under such circumstances, the present invention is a novel solid-state optical up-conversion material capable of achieving a high optical up-conversion yield by eliminating variations in microcrystal grains and uniformly obtaining strong light emission. The main purpose is to provide. It is also an object of the present invention to provide a novel compound that can be suitably used as a photosensitizer for a light up-conversion material.

The present inventors have made diligent studies to solve the above problems. As a result, in a solid optical up-conversion material containing a photo-upconversion illuminant and a photosensitizer, the chemistry in which the triplet photosensitizer and the molecular anchor portion are linked as the photosensitizer. It was found that strong photo-up-conversion light emission can be obtained with almost all microcrystal grains by using the one having a structure. Here, the triplet photosensitizer can generate the triplet state by photoexcitation and transfer the energy to the optical up-conversion illuminant to generate the triplet state of the optical up-conversion illuminant. It refers to partial chemical structures responsible for corresponding to the photosensitiser molecule ⁽¹ a). Further, the molecular anchor portion has high compatibility with the optical up-conversion illuminant, and refers to a partial chemical structure that can be mixed in the crystal of the optical up-conversion illuminant. The present invention is an invention completed by further studying based on such findings.

［一般式（Ｂ１）中、
基Ｘは、それぞれ独立して、ベンゼン環に結合した炭素数が１以上の化学構造を有する連結部であり、
ｍは、それぞれ独立して、１又は２であり、
基Ｙは、それぞれ、波線が付された結合手によって基Ｘと結合しており、
前記結合手は、前記基Ｙの縮合環、及び当該縮合環に結合している両端のベンゼン環の任意の位置に結合しており、
前記基ＹのＲａ¹、Ｒａ²、Ｒａ³、及びＲａ⁴は、それぞれ独立して、水素原子、アルキル基、アルコキシ基であるか、又は、Ｒａ¹とＲａ²、Ｒａ³とＲａ⁴が、それぞれ互いに連結して、エーテル結合、エステル結合、アミド結合及びスルフィド結合からなる群より選択された少なくとも一種の結合を有することがある炭素数が５〜１０の直鎖のアルキレン基であり、
Ｒａ_n1（ここで０≦ｎ１≦８）は、０個以上８個以下の置換基であって、それぞれ芳香環に結合した水素原子と置換しており、それぞれ独立に、アルキル基、アルコキシ基、フェニル基、水酸基、またはアミノ基であり、
Ｒｂ_n2（ここで０≦ｎ２≦８）は、０個以上８個以下の置換基であって、それぞれ芳香環に結合した水素原子と置換しており、それぞれ独立に、アルキル基、アルコキシ基、フェニル基、水酸基、またはアミノ基であり、
Ｍは金属である。］ That is, the present invention provides the inventions of the following aspects.
Item 1. An optical up-conversion material that contains an optical up-conversion illuminant and a photosensitizer and is a solid.
The photosensitizer is a photo-up-conversion material having a chemical structure in which a triplet photosensitizer portion and a molecular anchor portion are connected.
Item 2. Item 2. The optical up-conversion material according to Item 1, wherein the optical up-conversion illuminant and the molecular anchor portion of the photosensitizer have a common chemical structure.
Item 3. Item 2. The optical up-conversion material according to Item 2, wherein the common chemical structure is a structure in which a plurality of benzene rings are condensed.
Item 4. The optical up-conversion material according to Item 1 to 3, wherein the structure of the molecular anchor portion of the photosensitizer is the same chemical structure as the optical up-conversion illuminant except for a connecting portion.
Item 5. Item 2. The photo-up-conversion material according to any one of Items 1 to 4, wherein the triplet photosensitizer of the photosensitizer contains a porphyrin skeleton.
Item 6. Item 2. The optical up-conversion according to any one of Items 1 to 5, wherein the triplet photosensitizer portion and the molecular anchor portion of the photosensitizer are bonded by a chemical structure having one or more carbon atoms. material.
Item 7. Items 1 to 6 in which the total ratio of the light up-conversion illuminant and the photosensitizer in the solid containing the light up-conversion illuminant and the photosensitizer is 60% by mass or more. Or the optical up-conversion material according to item 1.
Item 8. The solid containing the light up-conversion illuminant and the photosensitizer is fine particles having a particle size of 1 nm or more and 100 μm or less.
Item 2. The optical up-conversion material according to any one of Items 1 to 7, which has a structure in which the fine particles are dispersed in a medium.
Item 9. Item 2. The optical up-conversion material according to any one of Items 1 to 8, wherein the solid containing the optical up-conversion illuminant and the photosensitizer is a crystal.
Item 10. A method for converting an optical wavelength, which comprises irradiating the light up-conversion material according to any one of Items 1 to 9 with light to emit light having a wavelength shorter than that of the irradiated light.
Item 11. It is provided with a step of drying a solution containing a light up-conversion illuminant and a photosensitizer.
The photosensitizer is a method for producing a photo-up-conversion material, which has a chemical structure in which a triplet photosensitizer portion and a molecular anchor portion are connected.
Item 12. A compound represented by the following general formula (B1).

[In the general formula (B1),
The group X is a connecting portion having a chemical structure having one or more carbon atoms bonded to the benzene ring independently of each other.
m is 1 or 2 independently of each other.
Each group Y is bonded to the group X by a wavy bond.
The bond is bonded to the fused ring of the group Y and the benzene rings at both ends bonded to the condensed ring at arbitrary positions.
The groups Y Ra ¹ , Ra ² , Ra ³ and Ra ⁴ are independently hydrogen atoms, alkyl groups and alkoxy groups, or Ra ¹ and Ra ² , Ra ³ and Ra ⁴ are A linear alkylene group having 5 to 10 carbon atoms, each linked to each other, which may have at least one bond selected from the group consisting of ether bonds, ester bonds, amide bonds and sulfide bonds.
_Ran1 (here, 0 ≦ n1 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and is independently an alkyl group, an alkoxy group, and the like. It is a phenyl group, a hydroxyl group, or an amino group,
Rb _n2 (here, 0 ≦ n2 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and is independently an alkyl group, an alkoxy group, and the like. It is a phenyl group, a hydroxyl group, or an amino group,
M is a metal. ]

According to the present invention, it is possible to provide a novel solid-state optical up-conversion material capable of achieving a high optical up-conversion yield. Furthermore, according to the present invention, it is also possible to provide a novel compound that can be suitably used as a photosensitizer for a light up-conversion material.

In Example 1, a DPA (Chemical Formula (1a)) crystal doped with a sensitizer having a connecting portion having 6 carbon atoms (a sensitizer of the chemical formula (S1) (k = 4)) obtained by the casting method. It is a microscopic transmission image. The left and right are images in the same sample but in different locations. The circular part is the field of view of the microscope. The objective lens is 20x. The scale bar is 50 μm. It is an up-conversion emission image hyperimage of the same place on the left and right in the same sample as in FIG. The incident wavelength is 532 nm. The scale bar is 50 μm. It is a spectrum of the up-conversion emission of the crystal obtained in Example 1. The excitation wavelength is 532 nm. It is the sum of the histograms for the emission intensities of the two emission images shown in FIG. 2 and the histograms of the other two emission images in the same sample, for a total of four locations. In Example 2, a DPA (Chemical Formula (1a)) crystal doped with a sensitizer having a connecting portion having 3 carbon atoms (a sensitizer of chemical formula (S1) (k = 4)) obtained by the casting method. It is a microscopic transmission image. The left and right images are images in the same sample but in different locations. The circular part is the field of view of the microscope. The objective lens is 20x. The scale bar is 50 μm. It is an up-conversion emission image hyperimage of the same place on the left and right in the same sample as in FIG. The incident wavelength is 532 nm. The scale bar is 50 μm It is a spectrum of the up-conversion emission of the crystal obtained in Example 2. The excitation wavelength is 532 nm. It is the sum of the histograms for the emission intensities of the two emission images shown in FIG. 6 and the histograms of the other two emission images in the same sample, for a total of four locations. In Comparative Example 1, it is a microscopic transmission image of a DPA (Chemical formula (A1)) crystal obtained by a casting method and doped with a photosensitizer (Chemical formula (S2)) having no molecular anchor portion. The left and right images are images in the same sample but in different locations. The circular part is the field of view of the microscope. The objective lens is 20x. The scale bar is 50 μm. It is an up-conversion emission image hyperimage of the same place on the left and right in the same sample as in FIG. The incident wavelength is 532 nm. The scale bar is 50 μm. It is a spectrum of the up-conversion emission of the crystal obtained in Comparative Example 1. The excitation wavelength is 532 nm. It is the sum of the histograms for the emission intensities of the two emission images shown in FIG. 10 and the histograms of the other two emission images in the same sample, for a total of four locations. In Example 3, a C7-sDPA (chemical formula (1b)) doped with a sensitizer having a connecting portion having 6 carbon atoms (a sensitizer of the chemical formula (S1) (k = 4)) obtained by the casting method. It is a microscopic transmission image of a crystal. The left and right are images in the same sample but in different locations. The circular part is the field of view of the microscope. The objective lens is 20x. The scale bar is 50 μm. It is an up-conversion emission image hyperimage of the same place on the left and right in the same sample as in FIG. The incident wavelength is 532 nm. The scale bar is 50 μm. It is a spectrum of the up-conversion emission of the crystal obtained in Example 3. The excitation wavelength is 532 nm.

The optical up-conversion material of the present invention is a solid optical up-conversion material containing an optical up-conversion illuminant and a photosensitizer, and the photosensitizer is a triple term photosensitizer and a molecule. It is characterized by having a chemical structure in which an anchor portion is connected. Here, the triplet photosensitizer can generate the triplet state by photoexcitation and transfer the energy to the optical up-conversion illuminant to generate the triplet state of the optical up-conversion illuminant. It refers to partial chemical structures responsible for corresponding to the photosensitiser molecule ⁽¹ a). Further, the molecular anchor portion has high compatibility with the optical up-conversion illuminant, and refers to a partial chemical structure that can be mixed in the crystal of the optical up-conversion illuminant. By providing such a configuration, the optical up-conversion material of the present invention is a novel solid optical up-conversion material and can realize a high optical up-conversion yield. Specifically, since the main component is an optical up-conversion illuminant, the transfer of triplet energy between the optical up-conversion illuminants effectively occurs in the solid, and the triplet-triplet annihilation causes optical up-conversion emission. A large number of contributing portions are present at high density, and a high optical up-conversion yield can be achieved. Hereinafter, the optical up-conversion material of the present invention and a novel compound that can be suitably used as a photosensitizer for the optical up-conversion material will be described in detail.

In this specification, the numerical values connected by "-" mean a numerical range including the numerical values before and after "-" as the lower limit value and the upper limit value. When a plurality of lower limit values and a plurality of upper limit values are described separately, any lower limit value and upper limit value can be selected and connected by "~".

[Light up-conversion illuminant]
The optical up-conversion illuminant can receive the triplet energy of the photosensitizer of the present invention, and has a function of emitting light having a shorter wavelength than the light absorbed by the photosensitizer due to the triplet-triplet annihilation. As long as it is a compound, it is not particularly limited and may be a known light emitter. Examples of the optical up-conversion illuminant include polycyclic aromatic compounds. Examples of the polycyclic aromatic compound include a polycyclic aromatic compound having a fused ring number of 3 to 5, which may have a substituent. Examples of the aromatic ring constituting the fused ring include a benzene ring and a cyclopentadi. Examples thereof include an enyl ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a furan ring, a thiophene ring, and a silol ring, and among these, a benzene ring is preferable.

Among the preferable light up-conversion light emitters contained in the light up-conversion material of the present invention, the compounds in which the aromatic ring constituting the fused ring is a benzene ring are specifically described in the following general formulas (A1) to (A16). Examples thereof include compounds represented by.

In the general formulas (A1) to (A16), Ra ¹ , Ra ² , Ra ³ , and Ra ⁴ are independently hydrogen atoms, alkyl groups, and alkoxy groups, or Ra ¹ and Ra ² , respectively. Ra ³ and Ra ⁴ may each be linked to each other and have at least one bond selected from the group consisting of ether bonds, ester bonds, amide bonds and sulfide bonds. It is an alkylene group. Among these, Ra ¹ , Ra ² , Ra ³ , and Ra ⁴ are all preferably hydrogen atoms or either of the above-mentioned alkylene groups.

When Ra ¹ and Ra ² are linked to each other to form a linear alkylene group having 5 to 10 carbon atoms, Ra ¹ and Ra ² form a ring structure. Similarly, when Ra ³ and Ra ⁴ are linked to each other to form a linear alkylene group having 5 to 10 carbon atoms, Ra ³ and Ra ⁴ form a ring structure. In the general formulas (A1) to (A16), when these ring structures are provided, the ring structure surrounds the central fused ring, the interaction between the illuminants is likely to occur, and the optical up-conversion yield. (For example, R. Sato, H. Kitoh-Nishioka, K. Kamada, T. Mizokuro, K. Kobayashi, Y. Shigeta, J. Phys. Chem. C 2018, 122, 5334 -5340.). Further, the ^{two benzene rings having Ra 1} , Ra ² , Ra ³ , and Ra ⁴ are bonded at positions where radicals are likely to be generated when these benzene rings are not bonded to the central fused ring. .. That is, in these structures, two benzene rings bonded to the fused ring prevent radicals from being generated at these positions (eg, Y. Fujiwara, R. Ozawa, D. Onuma, K. Suzuki). , K. Yoza and K. Kobayashi, J. Org. Chem., 2013, 78, 2206.). Therefore, it can be said that it is effectively suppressed that the illuminants react with each other to form a dimer due to the radical reaction and the light up-conversion yield is lowered.

Further, in the general formulas (A1) to (A16), _Ran1 (where n1 is an integer of 0 or more) represents n1 substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring. Independently, it is an alkyl group, an alkoxy group, a phenyl group, a hydroxyl group, or an amino group. The maximum number of the substituents (that is, the upper limit of n1) varies depending on the structure, but the range of n1 includes, for example, n1 = 0 to 8, preferably n1 = 0 (that is, the substituent Ra _n1 does not exist). ..

Further, as the optical up-conversion illuminant, the following general formulas (1a-1) to (1a-3), (1b-1) to (1b-3), (1c-1) to (1c-3), ( The compounds represented by 1d-1) to (1d-3) are particularly preferable.

In the general formulas (1a-1) to (1a-3), (1b-1) to (1b-3), (1c-1) to (1c-3), (1d-1) to (1d-3). , R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, a hydroxyl group, or an amino group. When R ¹¹ and R ¹² are alkyl groups or alkoxy groups, respectively, the number of carbon atoms is not particularly limited, but from the viewpoint of facilitating the interaction between the illuminants, it is preferably about 1 to 10, more preferably. Is about 5 to 10. Further, R ²¹ and R ²² independently represent a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, a hydroxyl group, or an amino group. When R ²¹ and R ²² are alkyl groups or alkoxy groups, respectively, the number of carbon atoms is not particularly limited, but from the viewpoint of facilitating the interaction between the illuminants, it is preferably about 1 to 10, more preferably. Is about 5 to 10.

Specific examples of the optical up-conversion illuminant include compounds represented by the following formulas (1a), (1b), (1c), and (1d).

The method for producing the optical up-conversion illuminant is not particularly limited, and for example, it can be produced by a known synthesis method described in Japanese Patent No. 6455884, JP-A-2017-171888, and the like.

In the optical up-conversion material described later, the optical up-conversion light emitter of the present invention may be used alone or in combination of two or more.

[Photosensitizer]
The optical up-conversion material of the present invention contains a photosensitizer in addition to the optical up-conversion illuminant. In the light up-conversion material of the present invention, the light up-conversion illuminant is usually the main component in quantity, and the photosensitizer is in a small amount. The photosensitizer can absorb light energy and transfer the light energy to the light up-conversion illuminant of the present invention. In this way, by forming a solid with a composition containing a small amount of photosensitizer together with the light up-conversion illuminant as the main component, the portion that contributes to the accumulation of absorbed energy and the light up-conversion light emission due to the triplet state can be obtained. Many can be present and high optical up-conversion yields can be achieved. Further, in order to transfer the energy from the photosensitizer to the light up-conversion illuminant, it is necessary to combine the two with the same triplet energy order or the former having a higher energy order. In the present invention, the sensitizer is characterized by having a chemical structure in which a triplet photosensitizer portion and a molecular anchor portion are connected. A chemical structure in which a triple-term photosensitizer, in which the photosensitizer functions as a photosensitizer, and a molecular anchor, which is molecularly designed to have a high affinity with the photo-up-conversion illuminant, are linked. By having it, when the photo-up-conversion illuminant crystallizes, the molecular anchor portion is easily incorporated into the crystal, and the sensitizer portion connected to the molecular anchor portion is also incorporated into the crystal at the same time. Is expected. As a result, the light up-conversion illuminant and the sensitizer portion of the photosensitizer are located close to each other in the crystal, and the transfer of energy from the sensitizer to the light up-conversion illuminant is not hindered. It can be done efficiently. Compared with the conventional method described in Patent Document 3, the structure of the triplet sensitizer portion is formed by having the molecular anchor portion which is highly compatible with the photo-up-conversion illuminant of the main component as a matrix in the sensitizer. The probability of being incorporated into the crystal structure without agglomeration of sensitizers increases. As a result, it is considered that the energy transfer from the sensitizer to the luminescent material can be promoted in the solid, so that many of the microcrystal grains generated at the time of solidification have up-conversion characteristics.

The photosensitizer of the present invention may have a chemical structure in which the triplet photosensitizer and the molecular anchor portion are connected, but the photosensitizer is contained in the crystal of the photo-up-conversion illuminant. In order to make it easier to take in, it is preferable that the molecular anchor portion of the photosensitizer has a molecular structure having high compatibility with the photo-up-conversion illuminant. It is preferable that the molecular anchor portion of the photosensitizer contains a chemical structure common to that of the photo-up-conversion illuminant, because the higher the similarity of the molecular structures, the higher the compatibility. More preferably, it is desirable that the molecular structure of the molecular anchor portion of the photosensitizer contains the same structure as the molecular structure of the optical up-conversion illuminant. Specifically, the structure of the molecular anchor portion of the photosensitizer is preferably the same chemical structure except for the connecting portion between the optical up-conversion illuminant and the triplet photosensitizer portion of the molecular anchor portion. The "connecting portion" of the molecular anchor portion here is represented by a group Y, for example, in the case where the photosensitizer is a compound represented by the following general formula (B) described later. Of the molecular anchor portions, the portion connected to the group X, which is the connecting portion with the triplet photosensitizer portion, is the connecting portion of the group Y, and the group Y (molecular anchor portion) is the connecting portion. Since it is bonded to the group X, it has a structure different from that of the photo-up-conversion illuminant existing as one molecule. Further, the common chemical structure preferably includes a structure in which a plurality of benzene rings are condensed because the energy of the excited triplet state needs to be about half the energy of the excited singlet state. The number of condensations of the benzene ring is preferably 3 to 5.

Further, the triplet photosensitizer portion of the photosensitizer is preferably composed of an organometallic complex. The metal constituting the organometallic complex is not particularly limited, but for example, Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Pd, Ag, Re, Os. , Ir, Pt, Pb and the like, preferably Pt and Pd. Specific examples of the organometallic complex include a metal complex of porphyrin or a substitute thereof, a metal complex of phthalocyanine or a substitute thereof, and among these, a metal complex of porphyrin or a substitute thereof is preferably mentioned. It is particularly preferable that the triplet photosensitizer of the photosensitizer contains a porphyrin skeleton.

Specific examples of the photosensitizer include compounds represented by the following general formula (B).

In the general formula (B), each group X is a connecting portion having a chemical structure having one or more carbon atoms bonded to a benzene ring (four benzene rings represented by the general formula (B)) independently of each other. .. m is 1 or 2 independently of each other. The carbon number of the group X is preferably 3 or more, preferably 3 to 10 and 3 to 8 because the photosensitizer is more easily incorporated into the crystal of the photo-up-conversion illuminant. More preferably, it is more preferably 3 to 6. Further, the group X preferably has 1 to 2 ether bonds from the viewpoint of ease of synthesis and the like. Further, in the general formula (B), the m groups XY bonded to the benzene ring may be bonded to any of the ortho-position, meta-position, and para-position on the benzene ring, respectively, but the meta-position Alternatively, it is preferably bonded to the para position, and more preferably bonded to the para position. Further, in the general formula (B), two m groups XY bonded to the benzene ring are bonded to the ortho-position or the meta-position of one benzene ring, respectively (that is, the general formula (B). ), The general formulas (Bb) and (Bc) described later, in which a total of eight groups XY exist, can also be mentioned. Preferred embodiments of the general formula (B) include, for example, the following general formulas (Ba), (Bb), (Bc) and the like.

Rb _n2 (here, 0 ≦ n2 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and is independently an alkyl group and an alkoxy group, respectively. , Phenyl group, hydroxyl group, or amino group. The range of the number of substituents (ie, the range of n2) is preferably n2 = 0 (ie, the substituent Rb _n2 is absent). M is a metal. Preferred M includes Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Pd, Ag, Re, Os, Ir, Pt, Pb and the like. Pt and Pd are preferable.

In the photosensitizer represented by the general formula (B), the group Y constitutes the molecular anchor portion, the group X constitutes the connecting portion, and is bonded to the group Y via the group X. The porphyrin skeleton constitutes the triplet photosensitizer.

In the general formula (B), the group Y constituting the molecular anchor portion preferably has a structure represented by the following general formulas (A1-1) to (A16-1).

The general formulas (A1-1) to (A1-16) as the group Y are respectively bonded to the group X of the general formula (B) by a bond with a wavy line. In the group Y, the bond is bonded to the condensed ring of the group Y and the hydrogen of the benzene ring at both ends bonded to the condensed ring (the bond is the hydrogen of the condensed ring or the benzene ring at both ends). Replaced with an atom). ^{Ra 1} , Ra ² , Ra ³ and Ra ⁴ of the group Y are independently hydrogen atoms, alkyl groups and alkoxy groups, or Ra ¹ and Ra ² , Ra ³ and Ra ⁴ are respectively. A linear alkylene group having 5 to 10 carbon atoms which may be linked to each other and have at least one bond selected from the group consisting of ether bonds, ester bonds, amide bonds and sulfide bonds. Among these, Ra ¹ , Ra ² , Ra ³ , and Ra ⁴ are all preferably hydrogen atoms or either of the above-mentioned alkylene groups.

Further, _Ran1 (here, 0 ≦ n1 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and each of them is independently an alkyl group. It is an alkoxy group, a phenyl group, a hydroxyl group, or an amino group. The range of the number of substituents (ie, the range of n1) is preferably n1 = 0 (ie, the substituent Ra _n1 is absent).

When a compound represented by the general formula (A-1) is used for the optical up-conversion illuminant, the photosensitizer is more easily incorporated into the crystals of the optical up-conversion illuminant. Of these, those in which the group Y is represented by the general formula (A1-1) are preferable. That is, the optical up-conversion light emitting material of the present invention is an optical up-conversion light emitter represented by the general formula (A-1) and a photosensitizer represented by the general formula (B), wherein the base Y is It is particularly preferable to include a photosensitizer represented by the general formula (A1-1).

In the optical up-conversion material of the present invention, one type of photosensitizer may be used alone, or two or more types may be used in combination.

The compound represented by the general formula (B) can be synthesized according to Synthesis Examples 1 and 2 described in Examples.

Among the photosensitizers used in the photo-up-conversion material of the present invention, the compound represented by the following general formula (B1) is a novel compound. As described above, the compound preferably functions as a photosensitizer for an optical up-conversion material when used in combination with an optical up-conversion illuminant. At that time, it is more preferable to use an optical up-conversion light emitter having the general formula (A-1).

In the general formula (B1), the groups X, m, Rb _n2 , and M are the same as the general formula (B), respectively, and the group Y is the general formula among the groups Y of the general formula (B). It is represented by (A1-1). Ra 1, Ra ² , Ra ³ , and Ra ⁴ , Ra _n ^{1 of} the group Y are as described above, respectively.

The compound represented by the general formula (B1) can be synthesized according to Synthesis Examples 1 and 2 described in Examples.

In the optical up-conversion material of the present invention, the compounding ratio (molar ratio) of the optical up-conversion illuminant and the photosensitizer is not particularly limited, but from the viewpoint of effectively increasing the up-conversion emission quantum yield, light is used. The amount of the light up-conversion illuminant is preferably about 10 to 100,000 mol, more preferably about 1,000 to 30,000 mol, and even more preferably about 3,000 to 10,000 mol with respect to 1 mol of the sensitizer.

In the optical up-conversion material of the present invention, the total ratio of the optical up-conversion illuminant and the photosensitizer in the solid containing the optical up-conversion illuminant and the photosensitizer is not particularly limited. However, from the viewpoint of effectively increasing the up-conversion emission quantum yield, 60% by mass or more, more preferably 90% by mass or more can be mentioned.

Further, the optical up-conversion material of the present invention preferably contains crystals formed by the optical up-conversion illuminant and the photosensitizer from the viewpoint of effectively increasing the up-conversion emission quantum yield. This is because, in the optical up-conversion material of the present invention, the luminous efficiency of the crystalline portion is particularly high.

In the present invention, the up-conversion emission quantum yield (Φuc) is calculated by the following mathematical formula (A).
Φuc ＝ 2 × Φstd × (Astd / Auc) × (Iuc / Istd) × (Nuc / Nstd) ² (A)

In the above equation, the coefficient 2 is a coefficient introduced to set the maximum emission quantum yield to 1. Φstd is the emission yield of the standard substance, and its value is known. Astd and Auc are the absorbances of the standard substance and the sample under test at the excitation wavelength, respectively. In addition, Istd and Iuc are integrated emission intensities obtained by integrating the emission intensities of the standard substance and the sample to be measured at wavelengths over the entire light emitter, respectively. In particular, for the sample to be measured for up-conversion, the integrated emission intensity for the up-conversion emission band having a wavelength shorter than that of the excitation light. Further, Nstd and Nuc are the refractive indexes of the solvent or the ambient medium at the emission wavelengths of the standard substance and the sample to be measured, respectively.

As a standard substance, any substance that can be excited at the same wavelength and optical arrangement as the sample to be measured and whose reliable fluorescence quantum yield has been reported can be used. For example, in the examples described later, an ethylene glycol solution (100 μM) of rhodamine 101 was used as a standard substance, and its fluorescence quantum yield of 0.94 was used as Φstd. This fluorescence quantum yield value is based on the article "C. Wurth, C. Lochmann, M. Spieles, J. Pauli, K. Hoffmann, T. Schuttrigkeit, T. Schuttrigkeit, T. Franzl, U. Resch-Genger, Appl. Spectroscop. 2010, 64, 733. ”, The fluorescence quantum yield of the dilute solution is 0.89, which is a value determined by using Φstd in the following formula (B).
Φfl ＝ Φstd × (Astd / Auc) × (Iuc / Istd) × (Nuc / Nstd) ² (B)

In addition, by directly measuring the ethylene glycol solution (100 μM) of Rhodamine 101 by the method described in the paper “Shiina, S. Oishi, S. Tobita, Phys. Chem. Chem. Phys. 2009, 11, 9850.” It also matched the obtained values within an error of 3%.

The temperature at which the optical up-conversion material of the present invention is solid is not particularly limited as long as it is solid at the time of use, and is solid at at least 125 ° C.

The method for producing the optical up-conversion material of the present invention is not particularly limited, but it can be produced by a method including a step of drying a solution containing the optical up-conversion illuminant and a photosensitizer. By adopting such a manufacturing method, an optical up-conversion material having particularly excellent luminous efficiency can be obtained.

Specifically, it contains the above-mentioned photosensitizer, and the light up-conversion illuminant has a high concentration, specifically, a concentration of 1/10 or more of the saturation concentration, and further sensitizes. By preparing a solution in which 1000 mol or more, more preferably 3000 mol or more, of the luminescent substance molecule is prepared with respect to 1 mol of the agent molecule, and rapidly volatilizing the solvent from the solution, the photo-up-conversion material in the solid form can be rapidly prepared. Can be manufactured. As a method for rapidly volatilizing, a method such as using a highly volatile polar solvent such as tetrahydrofuran to drop dry on the surface of a glass substrate having good wettability can be exemplified. By producing the optical up-conversion material in this way, it is possible to quickly shift to the solid form in a state where the mutual dispersibility between the light emitter and the photosensitizer is high. As a result, aggregation of the light emitters or the photosensitizers during the transition from the liquid to the solid is suppressed, and the light emitters and the photosensitizers adjacent to each other are dispersed in the solid. Conceivable. Therefore, it is considered that the triplet energy transfer from the photosensitizer to the adjacent illuminant is efficiently performed in the solid, and as a result, a high up-conversion emission quantum yield is obtained. In Patent Document 2, a solution in which a photosensitizer and a light up-conversion illuminant are dissolved in a solvent is prepared, but the solution is used as a light up-conversion material without drying the solvent. .. Patent Document 2 assumes a solution as a material system that achieves the highest up-conversion efficiency, and volatilization from the solution causes the sensitizer and the illuminant to crystallize separately, as shown in Non-Patent Document 3. It was known that this did not cause up-conversion.

The solvent is not particularly limited, and for example, an organic solvent, water, or the like can be used. Specific examples of the organic solvent include nitrile solvents such as acetonitrile and benzonitrile, halogen solvents such as chloroform, dichloromethane, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene and o-dichlorobenzene; tetrahydrofuran, Ether-based solvents such as dioxane; aromatic hydrocarbon-based solvents such as benzene, toluene, and xylene; cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptan, n-octane, n-nonane, n-decane. Other aliphatic hydrocarbon solvents; ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone; ester solvents such as ethyl acetate, butyl acetate, ethyl cell solve acetate; ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, Polyhydric alcohols such as ethylene glycol monomethyl ether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin, 1,2-hexanediol and derivatives thereof; methanol, ethanol, propanol, isopropanol, cyclohexanol, etc. Alcohol-based solvent; sulfoxide-based solvent such as dimethyl sulfoxide; amide-based solvent such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, etc. Among these, diacetone is preferable because of its high volatile nature. , Tetrahydrofuran, chloroform, dichloromethane, cyclohexane, but this is not the case depending on the volatile conditions. The solution can be dried by, for example, an inkjet method, a spray-drying method, or the like.

The optical up-conversion material of the present invention may be contained in a resin, glass, or the like as the obtained fine crystal grains as they are or after being pulverized. The resin is not particularly limited and can be appropriately set according to the intended use. For example, (meth) acrylic resin, polyester resin, polyurethane resin, epoxy resin, polyolefin resin, polyamide resin, polystyrene resin, cellulose resin, imide Known resins such as resins, polyvinyl chloride resins, fluororesins, silicone resins, polycarbonate resins, polysulfone resins, cyclic polyolefin resins, polylactic acid resins, and vinyl ester resins can be used. The shape of the resin is not particularly limited and can be appropriately set according to the intended use, and examples thereof include a film shape, a sheet shape, and a fibrous shape.

The glass is not particularly limited and can be appropriately set according to the intended use. For example, quartz glass, borosilicate glass, soda glass, alumina silicate glass, soda lime glass, non-alkali glass and the like can be used. it can. The shape of the glass is not particularly limited and can be appropriately set according to the intended use, and examples thereof include a film shape, a sheet shape, and a fibrous shape.

Furthermore, the photo-up-conversion material of the present invention is not crystallized by volatilization of the solvent, but a solution containing the up-conversion illuminant and the sensitizer is contained in a solvent having low solubility in the sensitizer and the up-conversion illuminant. It may be obtained by a method of rapidly discharging and crystallizing. The solvent used for the former is a good solvent having high solubility in both, and the solvent used for the latter is a poor solvent having low solubility. Examples of the good solvent include tetrahydrofuran, acetone, dimethyl sulfoxide, dimethylformamide, benzene, toluene, hexane and the like, and examples of the poor solvent include water. By this method, the optical up-conversion material of the present invention can be obtained as a solution dispersed in a poor solvent as solid fine particles having a particle size of 1 nm or more and less than 1 μm. After that, it may be used as a solid material dispersed in a medium made of polymer or glass. That is, in the optical up-conversion material of the present invention, the solid containing the optical up-conversion illuminant and the photosensitizer is fine particles having a particle size of 1 nm to 1 μm, preferably 5 nm to 500 nm, and more preferably 10 nm to 200 nm. , The fine particles may be provided with a structure in which the fine particles are dispersed in a medium (solvent, polymer material, glass, etc.).

In the optical up-conversion material of the present invention, when the structure of the general formula (B1) is used, the wavelength of the absorbed light is usually about 480 to 560 nm, preferably about 490 to 510 nm and the absorption intensity peaks at about 525 to 540 nm. There is. In the optical up-conversion material of the present invention, the emission intensity peaks at a position where the wavelength of the emitted light is usually about 400 to 550 nm, preferably about 400 to 480 nm. ^{Further, the light irradiation intensity (W / cm 2} ) of the light irradiating the light up-conversion material of the present invention can be appropriately set according to the use of the light up-conversion material, for example, 0.001 to 10 W / cm. There are about ^two.

Since the optical up-conversion material of the present invention can efficiently convert the wavelength incident on the optical up-conversion material into a short wavelength, solar cells such as organic solar cells, natural light illumination, LEDs, organic EL elements, biomarkers, etc. It can be suitably used for applications such as displays, printing, security certification, optical data storage devices, and sensors. The optical up-conversion material of the present invention can be suitably used as a light wavelength conversion method that emits light having a wavelength shorter than that of the irradiated light by irradiating the light.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

[Synthesis Example 1]
According to the synthetic route shown in the following formula, a photosensitizer having 6 carbon atoms in the connecting portion used in Example 1 described later (a photosensitizer having k = 4 in the chemical formula (S1) (Pd-TPP-OC6O-DPA). )) Was synthesized.

ここで、

である。

here,

Is.

The details of each reaction in the synthetic pathway of Synthesis Example 1 are as follows.

(Synthesis of 2)
1 (3.00 g, 7.33 mmol), bis (pinacolat) diboron (B ₂ pin ₂ ) (2.22 g, 8.80 mmol), PdCl ₂ (dppf), CH ₂ Cl ₂ (305 mg,) in a 200 mL reaction eggplant flask. 0.37 mmol) and KOAc (2.16 g, 21.99 mmol) were added and replaced with Ar, dry-1,4-dioxane (80 mL) was added, and the mixture was stirred at 80 ° C. for 24 hours under shading. After returning to room temperature, CH ₂ Cl ₂ is added to the reaction solution, the insoluble material is filtered through Celite, CH ₂ Cl ₂ and water are added _{to the filtrate and extracted with CH 2} Cl ₂ , and the organic layer is water and saturated brine. Washed with and dried with sodium sulfate. After the organic layer is evaporated, the residue is purified by silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1: 3, CH ₂ Cl ₂ only, CH ₂ Cl ₂ : EtOAc = 3: 1). It was obtained as a pale yellowish greenish white solid (2.92 g, yield 87%).
Mp = 228 to 232 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 8.27 (s, 1H), 7.72-7.57 (m, 10H), 7.52-7.47 (m, 4H), 7.36-7.32 (m, 2H), 1.31 (s, 12H) ).

(Synthesis of 3)
2 (4.00 g, 8.76 mmol) and Oxone (10.79 g, 17.55 mmol) were placed in a 1 L reaction flask, replaced with Ar, and Ar-bubbled THF (240 mL), Acetone (48 mL), H ₂ O (24 mL). ) Was added, and the mixture was stirred at room temperature for 2 hours under shading. The reaction solution was made open and ice-cooled, and _{300 mL of water containing about 5 tablespoons of Na 2} S ₂ O ₄ was added to quench the excess Oxone. The reaction mixture was then extracted with EtOAc, the organic layer was washed with water, saturated brine and dried over sodium sulfate. After the organic layer was evaporated, the residue was purified by adsorption silica gel column chromatography (elution: EtOAc: hexane = 1:10) to give 3 as a yellow solid (2.86 g, 94% yield).
Mp = 225 to 226 ° C.
^{1 1} H NMR (400 MHz, DMSO-d ₆ ) δ 9.83 (d, 1H), 7.67-7.42 (m, 13H), 7.41-7.26 (m, 2H), 7.04 (dd, J = 2.4 and 9.3 Hz, 1H ), 6.79 (d, J = 2.4 Hz, 1H).

(Synthesis of 4a)
3 (301 mg, 0.869 mmol) and K ₂ CO ₃ (365 mg, 2.641 mmol) were placed in a 50 mL reaction flask and substituted with Ar, and Ar bubbling THF (20 mL) and 1,6-diiodohexane (0.90 mL, 0.90 mL,) were added. 5.5 mmol) was added, and the mixture was stirred at 50 ° C. for 45 hours under shading, and then further stirred at 70 ° C. for 24 hours. After returning to room temperature, EtOAc and water were added to the reaction solution and extracted with EtOAc. The organic layer was washed with water and saturated brine, and dried over sodium sulfate. After the organic layer was evaporated, the residue was purified by silica gel column chromatography (elution: EtOAc: hexane = 1: 40, 1: 20) and further purified by recycling preparative HPLC to give 4a as a yellow-green solid (5a). 355 mg, yield 73%).
Mp = 138-140 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 7.67-7.54 (m, 9H), 7.50-7.47 (m, 4H), 7.33-7.29 (m, 2H), 7.03 (dd, J = 2.4 and 9.8 Hz, 1H ), 6.85 (d, J = 2.4 Hz, 1H), 3.83 (t, J = 6.3 Hz, 2H), 3.19 (t, J = 6.8 Hz, 2H), 1.86-1.81 (m, 2H), 1.78-1.71 (m, 2H), 1,47-1.41 (m, 4H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 156.19, 139.61, 139.29, 139.28, 137.36, 135.04, 131.42, 131.41, 131.16, 130.53, 128.89, 128.72, 128.52, 127.59, 127.54, 127.19, 126.56, 125.26, 124.20, 120. , 103.73, 67.50, 33.49, 30.36, 28.92, 25.22, 7.12.

(Synthesis of TPP-OC6O-DPA)
Tetrakis (4-hydroxyphenyl) porphyrin (TPP-OH) (69.5 mg, 0.102 mmol), 4a (285 _{mg, 0.512 mmol), K 2} CO ₃ (112 mg, 0.816 mmol) was placed in a 50 mL reaction flask. After Ar substitution, dry-DMF (10 mL) was added, and the mixture was stirred at 40 ° C for 48 hours, 60 ° C for 68 hours, and 80 ° C for 6 hours under shading. After returning to room temperature, DMF was distilled off from the reaction solution, CH ₂ Cl ₂ was added to the residue, and the mixture was filtered. _{CH 2} Cl ₂ and water were added to the filtrate _{, extracted with CH 2} Cl ₂ , the organic layer was washed with water and saturated brine, and dried over sodium sulfate. After evaporating the organic layer, silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1.5: 1,2: 1,3: 1,5: 1, CH ₂ Cl ₂ only, CH ₂ Cl ₂ : Purification with EtOAc = 4: 1) was further thermally recrystallized from toluene-hexane to give TPP-OC6O-DPA as a reddish brown solid (226 mg, 87% yield).
Mp = 141-144 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 8.86 (s, 8H), 8.11 (d, J = 8.3 Hz, 8H), 7.66-7.46 (m, 60H), 7.32-7.29 (m, 8H), 7.09 ( dd, J = 2.4 and 9.3 Hz, 4H), 6.91 (d, J = 2.4 Hz, 4H), 4.26 (t, J = 6.3 Hz, 8H), 3.93 (t, J = 6.3 Hz, 8H), 2.02- 1.97 (m, 8H), 1.89-1.86 (m, 8H), 1.68-1.61 (m, 16H), -2.75 (s, 2H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 159.03, 156.26, 139.62, 139.28, 137.36, 135.74, 135.04, 134.65, 131.42, 131.41, 131.19, 130.53, 128.91, 128.74, 128.70, 128.50, 127.56, 127.17, 126.59, 126.56 , 125.26, 124.18, 120.20, 119.92, 112.82, 103.75, 68.25, 67.65, 29.57, 29.18, 26.21, 26.17.

(Synthesis of Pd-TPP-OC6O-DPA)
TPP-OC6O-DPA (50.2 mg, 0.0210 mmol) and PdCl ₂ (8.32 mg, 0.0469 mmol) were placed in a 100 mL reaction flask, replaced with Ar, dry-benzonitrile (50 mL) was added, and 170 under shading. The mixture was stirred at ° C for 2 hours. After returning to room temperature, benzonitrile was distilled off from the reaction solution, the residue was washed with hexane, CH ₂ Cl ₂ and water were added _{to the residue, extracted with CH 2} Cl ₂ , and the organic layer was made of water and saturated brine. It was washed with water and dried over sodium sulfate. After the organic layer is evaporated, the residue is purified by adsorption silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1: 1, CH ₂ Cl ₂ only), and further _{reprecipitated from CH 2} Cl ₂ -hexane. , Pd-TPP-OC6O-DPA was obtained as an orange solid (47.9 mg, yield 91%).
Mp = 161-164 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 8.83 (s, 8H), 8.05 (d, J = 8.8 Hz, 8H), 7.66-7.46 (m, 60H), 7.34-7.30 (m, 8H), 7.08 ( dd, J = 2.4 and 9.8 Hz, 4H), 6.91 (d, J = 2.4 Hz, 4H), 4.25 (t, J = 6.3 Hz, 8H), 3.93 (t, J = 6.3 Hz, 8H), 2.02- 1.97 (m, 8H), 1.89-1.85 (m, 8H), 1.69-1.59 (m, 16H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 158.70, 155.94, 141.70, 139.31, 138.95, 137.04, 134.95, 134.73, 133.89, 131.09, 130.88s, 130.71, 130.22, 128.60, 128.42, 128.39, 128.19, 127.25, 126.86, 126.27, 126.25, 124.93, 123.86, 121.25, 119.88, 112.52, 103.45, 67.93, 67.34, 29.25, 28.86, 25.88, 25.85.

[Synthesis Example 2]
According to the synthetic route shown in the following formula, a photosensitizer having 3 carbon atoms in the connecting portion used in Example 2 described later (a photosensitizer (Pd-TPP-OC3O-DPA) having k = 1 in the chemical formula (S1)). )) Was synthesized.

ここで、

である。

here,

Is.

The details of each reaction in the synthetic route of Synthesis Example 2 are as follows.

(Synthesis of 4b)
_{Put 3 (1.00 g, 2.89 mmol) and K 2} CO ₃ (1.20 g, 8.67 mmol) in a 200 mL reaction eggplant flask and replace them with Ar, and dry-THF (10 mL) and 1,3-dibromopropane (1). .80 mL, 17.70 mmol) was added, and the mixture was stirred at 70 ° C. for 88 hours under shading. After returning to room temperature, CH ₂ Cl ₂ and water were added _{to the reaction solution, extracted with CH 2} Cl ₂ , the organic layer was washed with water and saturated brine, and dried over sodium sulfate. After evaporation of the organic layer, the residue was purified by adsorption silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1:10, 1: 7) to give 4b as a yellow-green solid (1.17 g, yield). Rate 87%).
Mp = 129 to 133 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 7.67-7.53 (m, 9H), 7.50-7.47 (m, 4H), 7.33-7.29 (m, 2H), 7.02 (dd, J = 2.4 and 9.8 Hz, 1H ), 6.88 (d, J = 2.4 Hz, 1H), 3.98 (t, J = 6.3 Hz, 2H), 3.57 (t, J = 6.3 Hz, 2H), 2.27 (quint, J = 6.3 Hz, 2H).

(Synthesis of TPP-OC3O-DPA)
4b (116 mg, 0.248 mmol), TPP-OH (33.8 mg, 0.0498 mmol) and K ₂ CO ₃ (56.5 mg, 0.409 mmol) were placed in a 50 mL reaction flask and replaced with Ar, and dry-DMF (10 mL) was added. ) Was added, and the mixture was stirred at 40 ° C for 48 hours, at 60 ° C for 44 hours, and at 80 ° C for 24 hours under shading. After returning to room temperature, DMF was distilled off from the reaction solution, CH ₂ Cl ₂ was added to the residue, and the mixture was filtered. _{CH 2} Cl ₂ and water were added to the filtrate _{, extracted with CH 2} Cl ₂ , the organic layer was washed with water and saturated brine, and dried over sodium sulfate. After the organic layer is evaporated, it is purified by adsorption silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1: 3, 1: 1, CH ₂ Cl ₂ : EtOAc = 3: 1) and purified by TPP-OC3O-DPA. Was obtained as a reddish brown solid (84.3 mg, yield 76%).
Mp = 315 to 318 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 8.81 (s, 8H), 8.09 (d, J = 8.8 Hz, 8H), 7.68-7.48 (m, 60H), 7.34-7.30 (m, 8H), 7.14 ( dd, J = 2.4 and 9.3 Hz, 4H) 7.00 (d, J = 2.4 Hz, 4H), 4.43 (t, J = 6.3 Hz, 8H), 4.20 (t, J = 6.3 Hz, 8H), 2.42 (quint) , J = 6.3 Hz, 8H), -2.79 (s, 2H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 159.13, 156.42, 139.92, 139.61, 137.75, 136.03, 135.53, 135.17, 131.78, 131.48, 130.94, 129.37, 129.12, 128.86, 127.96, 127.93, 127.53, 127.01, 126.93, 125.65 , 124.61, 120.38, 120.18, 113.22, 104.32, 65.23, 64.59, 29.78.

(Synthesis of Pd-TPP-OC3O-DPA)
TPP-OC3O-DPA (90.3 mg, 0.0406 mmol) and PdCl ₂ (17.0 mg, 0.096 mmol) were placed in a 100 mL reaction flask, replaced with Ar, dry-benzonitrile (60 mL) was added, and 170 ° C. under shading. The mixture was stirred with C for 1 h. After returning to room temperature, benzonitrile is distilled off from the reaction solution, CH ₂ Cl ₂ and water are added _{to the residue, extracted with CH 2} Cl ₂ , the organic layer is washed with water and saturated brine, and dried over sodium sulfate. I let you. After evaporating the organic layer, adsorption silica gel column chromatography (elution: CH ₂ Cl ₂ : hexane = 1: 1, 3: 2, 2: 1, CH ₂ Cl ₂ only, CH ₂ Cl ₂ : EtOAc = 3: 1 ), And further _{reprecipitated from CH 2} Cl ₂ -hexane to give Pd-TPP-OC3O-DPA as an orange solid (70.1 mg, 74% yield).
Mp = 334 to 337 ° C.
^{1 1} H NMR (400 MHz, CDCl ₃ ) δ 8.78 (s, 8H), 8.03 (d, J = 8.8 Hz, 8H), 7.68-7.48 (m, 60H), 7.34-7.31 (m, 8H), 7.13 ( dd, J = 2.4 and 9.3 Hz, 4H), 7.00 (d, J = 2.4 Hz, 4H), 4.42 (t, J = 6.3 Hz, 8H), 4.20 (t, J = 6.3 Hz, 8H), 2.41 ( quint, J = 6.3 Hz, 8H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 158.81, 156.10, 142.00, 139.60, 139.28, 137.42, 135.23, 134.41, 131.45, 131.16, 131.00, 130.61, 129.05, 128.80, 128.54, 127.63, 127.61, 127.21, 126.69, 126.61 , 125.32, 124.28, 121.48, 120.06, 112.91, 104.00, 64.90, 64.27, 29.45.

[Example 1]
The photosensitizer synthesized in Synthesis Example 1 (the one having a chemical structure represented by k = 4 (the number of carbon atoms in the linking chain is 6) of the following formula (S1)) is added to a medium made of tetrahydrofuran (THF). A predetermined concentration solution was prepared. Next, a powder of a compound (DPA: diphenylanthracene) represented by the chemical formula (1a) was added to this predetermined concentration solution as a light up-conversion illuminant, and the solution was uniformly dissolved to obtain a solution. This corresponds to the case where the molecular structure of the molecular anchor portion of the photosensitizer contains the same structure as the molecular structure of the optical up-conversion illuminant except for the connecting portion of the molecular anchor portion. At this time, the molar ratio of the luminescent material to the photosensitizer was 1000 mol of the light up-conversion illuminant with respect to 1 mol of the photosensitizer, and the concentration of the light up-conversion illuminant was room temperature (23 ° C.). Was the saturation concentration in. Next, the obtained solution was taken in a dropper, dropped on the surface of a slide glass, and left as it was at room temperature (23 ° C.) for 1 minute in the air to dry, thereby obtaining a solid sample spread in a circle. .. The diameter of the circularly expanding portion was about 2 cm.

Next, the obtained solid sample was observed as a transmission image under an optical microscope (objective lens 20 times). As a result, it was shown that the solid sample consisted of granular crystals of various shapes (Fig. 1). Further, through the same objective lens, green laser light (continuous light) having a wavelength of 532 nm was irradiated to the crystal grains of the solid sample in the center of the field of view under the microscope (light intensity 6.0 W / cm ² at the irradiated site). In this state, the light emitted from the solid sample was observed through a notch filter with a CCD camera fixed at a predetermined exposure time and sensitivity, and the light emission spectrum was observed with a fiber spectroscope. As a result, it was confirmed that the crystal grains emitted bright blue light (Fig. 2). Although the observed images at two locations are illustrated in FIG. 2, it was confirmed that almost all the observed crystals emit blue light by comparing with the transmitted optical images at the corresponding locations (FIG. 1). This was the same at other points in the sample not shown. Further, it was confirmed that the spectrum of the blue light emitting portion (FIG. 3) had a peak of 455 nm and was up-conversion light emission having a wavelength shorter than that of the incident light of 532 nm.

In order to show on a more quantitative scale the fact that a large number of crystal grains showing up-conversion luminescence shown in FIG. 2 are obtained, it is further the same as the luminescence images at two locations in the sample shown in FIG. For the other two emission images in the sample, the brightness (Brightness) of each pixel of the image is classified into 16 stages with respect to a common predetermined maximum emission intensity, and the number of pixels belonging to each stage of brightness (the number of pixels belonging to each stage of brightness (Brightness). A histogram was created in which the frequency of appearance and Occurrence) were counted. The four histograms obtained to average the results of these four locations are taken as the average value of the number of appearances in each stage based on the brightness stage, and the average emission intensity histogram of the four locations is taken (FIG. 4). ) Was obtained. At this time, the weakest brightness stage (0 to 1) included pixels in which no light emission was obtained due to the absence of crystal grains, and thus was excluded from the histogram. The obtained histogram showed a considerable number of appearance frequencies even in the region where the emission intensity stage was strong (brightness stages 6 to 14), and it was shown that a large number of crystal grains that strongly emit light were present. Moreover, when one of the crystallized grains emitting light was selected under a microscope and the up-conversion emission quantum yield was measured, it was 2.1%.

[Example 2]
A solid sample was prepared under exactly the same conditions as in Example 1 except that the chemical formula of the photosensitizer was k = 1 (3 carbon atoms in the connecting chain), and the obtained solid sample was observed as a transmission image. did. This case also corresponds to the case where the molecular structure of the molecular anchor portion of the photosensitizer contains the same structure as the molecular structure of the optical up-conversion illuminant except for the connecting portion of the molecular anchor portion. As a result, it was shown that the solid sample consisted of granular crystals of various shapes (Fig. 5). Further, when the luminescence from the solid sample was observed under the same conditions as in Example 1, it was confirmed that blue luminescence was obtained from almost all the observed crystals (Fig. 6). Further, it was confirmed that the spectrum of the blue emission point (FIG. 7) had a peak of 445 nm and was up-conversion emission having a wavelength shorter than that of the incident light of 532 nm. By the same procedure as in Example 1, an average emission intensity histogram (FIG. 8) of four locations was obtained for the two emission images in the sample shown in FIG. 6 and the other two emission images in the same sample. Obtained. The obtained histogram showed a considerable number of appearance frequencies even in the region where the emission intensity stage was strong (brightness stages 6 to 14), and it was shown that a large number of crystal grains that strongly emit light were present. Moreover, when one of the crystallized grains emitting light was selected under a microscope and the up-conversion emission quantum yield was measured, it was 3.0%.

[Comparative Example 1]
As the photosensitizer, a solid sample spread in a circle by the same method as in Example 1 except that a compound having no connecting portion represented by the following chemical formula (S2) was used instead of the chemical formula (S1). Obtained. The diameter of the circularly expanding portion was about 2 cm.

The obtained solid sample was observed as a transmission image. As a result, it was shown that the solid sample consisted of granular crystals of various shapes (Fig. 9). Further, the luminescence from the solid sample was observed under the same conditions as in Example 1. As a result, the number of crystal grains emitting blue light was small, and most of the crystal grains did not emit light (Fig. 10). Further, it was confirmed that the spectrum of the blue emission point (FIG. 11) had a peak of 445 nm and was up-conversion emission having a wavelength shorter than that of the incident light of 532 nm.

By the same procedure as in Example 1, an average emission intensity histogram (FIG. 12) of four locations was obtained for the two emission images in the sample shown in FIG. 9 and the other two emission images in the same sample. Obtained. The obtained histogram showed almost no frequency of appearance in the region where the emission intensity stage was strong (brightness stages 6 to 14), and most of the appearance frequency was shown in the stage where the emission intensity was weak (brightness stages 1 to 6). This means that there are almost no crystal grains that emit strong light. As the results of these images and histograms show, Comparative Example 1 is clearly inferior to Example 1 under the same conditions, indicating that the present invention can uniformly obtain a solid that emits up-conversion light. Moreover, when one of the crystallized grains emitting light was selected under a microscope and the up-conversion emission quantum yield was measured, it was 0.3%.

[Example 3]
A solid sample was prepared under exactly the same conditions as in Example 1 except that the optical up-conversion illuminant was a DPA derivative having a cyclic alkoxy chain of the chemical formula (1b), and the obtained solid sample was used as a transmission image. Observed. That is, the photosensitizer has a structural formula (S1) (k = 4). In this case, it corresponds to the case where the molecular structure of the molecular anchor portion of the photosensitizer is not the same as the molecular structure of the optical up-conversion illuminant but contains a common structure. As a result, it was shown that the solid sample consisted of granular crystals of various shapes (Fig. 13). Further, when the luminescence from the solid sample was observed under the same conditions as in Example 1, it was confirmed that blue luminescence was obtained from almost all the observed crystals (FIG. 14). Further, it was confirmed that the spectrum of the blue light emitting portion (FIG. 15) had a peak of 430 nm and was up-conversion light emission having a wavelength shorter than that of the incident light of 532 nm. Moreover, when one of the crystallized grains emitting light was selected under a microscope and the up-conversion emission quantum yield was measured, it was 1.3%. In Example 3, up-conversion emission was obtained in almost all the crystal grains as in Example 1, but the emission quantum yield was lower than that in Example 1. This means that the effect of the present invention can be obtained even when the molecular structure of the molecular anchor portion of the photosensitizer is not the same as the molecular structure of the optical up-conversion illuminant but contains a common structure, but the molecular anchor It is shown that a better effect can be obtained in the case of the same structure except for the connecting portion of the portions.

The present invention is a field in which the utility is produced by using light having a wavelength shorter than the wavelength currently used in industry, that is, fuel substance production by a photocatalyst, promotion of plant growth, improvement of solar cell efficiency, security ink, photocuring agent. Although it can be used for wavelength expansion, etc., it is not limited to these examples.

Claims (12)

An optical up-conversion material that contains an optical up-conversion illuminant and a photosensitizer and is a solid.
The photosensitizer is a photo-up-conversion material having a chemical structure in which a triplet photosensitizer portion and a molecular anchor portion are connected. The optical up-conversion material according to claim 1, wherein the optical up-conversion illuminant and the molecular anchor portion of the photosensitizer have a common chemical structure. The optical up-conversion material according to claim 2, wherein the common chemical structure is a structure in which a plurality of benzene rings are condensed. The optical up-conversion material according to any one of claims 1 to 3, wherein the structure of the molecular anchor portion of the photosensitizer is the same chemical structure as the optical up-conversion illuminant except for a connecting portion. The photo-up-conversion material according to any one of claims 1 to 4, wherein the triplet photosensitizer of the photosensitizer contains a porphyrin skeleton. The photosensitizer according to any one of claims 1 to 5, wherein the triplet photosensitizer portion and the molecular anchor portion of the photosensitizer are bonded by a chemical structure having one or more carbon atoms. Conversion material. Claims 1 to 6, wherein the total ratio of the light up-conversion illuminant and the photosensitizer in the solid containing the light up-conversion illuminant and the photosensitizer is 60% by mass or more. The optical up-conversion material according to any one of the following items. The solid containing the light up-conversion illuminant and the photosensitizer is fine particles having a particle size of 1 nm or more and 100 μm or less.
The optical up-conversion material according to any one of claims 1 to 7, further comprising a structure in which the fine particles are dispersed in a medium. The light up-conversion material according to any one of claims 1 to 8, wherein the solid containing the light up-conversion illuminant and the photosensitizer is a crystal. A method for converting an optical wavelength, which comprises irradiating the light up-conversion material according to any one of claims 1 to 9 with light to emit light having a wavelength shorter than that of the irradiated light. It is provided with a step of drying a solution containing a light up-conversion illuminant and a photosensitizer.
The photosensitizer is a method for producing a photo-up-conversion material, which has a chemical structure in which a triplet photosensitizer portion and a molecular anchor portion are connected. A compound represented by the following general formula (B1).

[In the general formula (B1),
The group X is a connecting portion having a chemical structure having one or more carbon atoms bonded to the benzene ring independently of each other.
m is 1 or 2 independently of each other.
Each group Y is bonded to the group X by a wavy bond.
The bond is bonded to the fused ring of the group Y and the benzene rings at both ends bonded to the condensed ring at arbitrary positions.
The groups Y Ra ¹ , Ra ² , Ra ³ and Ra ⁴ are independently hydrogen atoms, alkyl groups and alkoxy groups, or Ra ¹ and Ra ² , Ra ³ and Ra ⁴ are A linear alkylene group having 5 to 10 carbon atoms, each linked to each other, which may have at least one bond selected from the group consisting of ether bonds, ester bonds, amide bonds and sulfide bonds.
_Ran1 (here, 0 ≦ n1 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and is independently an alkyl group and an alkoxy group, respectively. , Phenyl group, hydroxyl group, or amino group,
Rb _n2 (here, 0 ≦ n2 ≦ 8) is 0 or more and 8 or less substituents, each of which is substituted with a hydrogen atom bonded to an aromatic ring, and is independently an alkyl group, an alkoxy group, and the like. It is a phenyl group, a hydroxyl group, or an amino group,
M is a metal. ]

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