JP2022168461A - Fluorene compound and method for producing the same - Google Patents

Abstract

To provide a fluorene compound that has an emission peak in a wavelength range of 400-460 nm and can emit blue light with high emission quantum efficiency and a method for producing the same and applications therefor.SOLUTION: The present invention discloses a fluorene compound represented by a following formula (1) (where Z1a, Z1b each denote a polycyclic C16-18 arene ring, R1a, R1b each denote a substituent, k1, k2 each denote an integer of 0 or greater, m1, m2 each denote an integer of 0-4, where at least one of m1 and m2 is an integer of 1 or greater, R2a, R2b each denote a substituent, n1, n2 each denote an integer of 0-4, m1+n1, m2+n2 each denote an integer of 0-4, A1a, A1b each denote an alkylene group, Z2a, Z2b each denote an arene ring, R3a, R3b each denote a substituent, p1, p2 each denote an integer of 0 or greater).SELECTED DRAWING: None

Description

The present invention relates to novel fluorene compounds.

Inorganic or organic light emitting materials are used as light sources such as light emitting diodes (LEDs). Among these light-emitting materials, inorganic light-emitting materials tend to complicate the manufacturing process of the device, so that manufacturing facilities are costly and it is difficult to achieve large-area light-emitting devices. Therefore, an organic light-emitting material is desired because it can be produced easily or efficiently by a method such as a coating method. Compounds having a fluorene skeleton are known as such organic light-emitting materials.

Japanese Patent Application Laid-Open No. 2020-164518 (Patent Document 1) discloses a fluorene compound represented by the following formula (1) as a luminescent material capable of emitting light with high luminous quantum efficiency (quantum efficiency or quantum yield). there is

(wherein Z ^1a and Z ^1b each independently represent an arene ring, Z ^2a and Z ^2b each independently represent an arene ring, R ^1a , R ^1b , R ^2a , R ^2b , R ^3a and R ^3b each independently represents a substituent, A ^1a and A ^1b each independently represent a linear or branched alkylene group, k1 and k2 each independently represent an integer of 0 or more, m1 and m2 each independently represents an integer of 0 to 4, n1 and n2 each independently represent an integer of 0 to 4, p1 and p2 each independently represent an integer of 0 or more, m1+n1 and m2+n2 each is independently an integer of 0 to 4, and at least one of m1 and m2 is an integer of 1 or more)

JP 2020-164518 A

In Examples of Patent Document 1, 9,9-bis(2-phenylethyl) ^-2,7 -diphenylfluorene ( ^BEPF -Ph), Z ^1a and Z ^1b are biphenyl rings 9,9-bis(2-phenylethyl)-2,7-di(4-biphenylyl)fluorene (BEPF-BPh), Z ^1a and Z ^1b are naphthalene Fluorene compounds such as the ring 9,9-bis(2-phenylethyl)-2,7-di(2-naphthyl)fluorene (BEPF-Np) have been prepared and evaluated for their emission properties.

These fluorene compounds can emit ultraviolet light or visible light having an emission peak at a maximum wavelength λ _em,max of 360 to 399 nm in an emission spectrum in a solution state, which easily reflects pure emission characteristics based on their chemical structures. It is shown. Although these fluorene compounds exhibit high luminous quantum efficiency, the resulting visible light with a wavelength of less than 400 nm tends to be invisible (difficult to see) or feel dark due to the standard relative luminosity of humans. In order to make blue-based colors with low standard luminous efficiency appear brighter, it is preferable to have an emission peak on the long wavelength side of 400 nm or more, and as the wavelength increases (because the standard luminous efficiency increases up to 565 nm) Visibility can be improved. However, if the wavelength of the emission peak is too long, the base (or edge) of the emission peak extends over the light blue to bluish green wavelength range, and therefore cannot be perceived as pure blue. Therefore, as a bright blue light-emitting material, there is a demand for a material that has an emission peak in a specific wavelength region, exhibits high quantum efficiency, and strongly emits blue light.

Therefore, an object of the present invention is to provide a fluorene compound that has an emission peak in the wavelength region of 400 to 460 nm and can emit blue light with high emission quantum efficiency (quantum efficiency or quantum yield), a method for producing the same, and uses thereof. to provide.

The present inventors have made intensive studies to achieve the above objects, and as a result, have found that a specific fluorene compound has an emission peak in the wavelength region of 400 to 460 nm and exhibits extremely high emission quantum efficiency. completed.

That is, the novel fluorene compound of the present invention is represented by the following formula (1).

(wherein Z ^1a and Z ^1b each independently represent a polycyclic C _16-18 arene ring,
R ^1a and R ^1b each independently represent a substituent, k1 and k2 each independently represent an integer of 0 or more,
m1 and m2 each independently represent an integer of 0 to 4, at least one of m1 and m2 is an integer of 1 or more,
R ^2a and R ^2b each independently represent a substituent, n1 and n2 each independently represent an integer of 0 to 4,
m1+n1 and m2+n2 are each independently an integer of 0 to 4;
A ^1a and A ^1b each independently represent a linear or branched alkylene group,
^Z2a and ^Z2b each independently represent an arene ring, ^R3a and ^R3b each independently represent a substituent, p1 and p2 each independently represent an integer of 0 or more).

In the above formula (1), Z ^1a and Z ^1b are terphenylene rings or pyrene rings, m1 and m2 are integers of 0 to 2,
A ^1a and A ^1b are linear or branched C _1-6 alkylene groups,
Z ^2a and Z ^2b may be C _6-12 arene rings.

Further, in the formula (1), Z ^1a and Z ^1b are pyrene rings, m1 and m2 are 1,
A ^1a and A ^1b are linear or branched C _1-4 alkylene groups,
Z ^2a and Z ^2b may be a benzene ring, a naphthalene ring or a biphenyl ring.

Furthermore, the compound represented by the formula (1) includes at least one emission peak having a maximum wavelength λ _em,max of about 410 to 460 nm and a half width of about 70 nm or less in the emission spectrum in a dichloromethane solution state. , a blue light-emitting material having an emission quantum efficiency of about 40% or more may be used. Moreover, the compound represented by the formula (1) may be in the form of a crystal.

The present invention includes a method for producing a compound represented by the above formula (1), which includes the following step (i) or (ii).

(i) a step of coupling a compound represented by the following formula (2) with a compound represented by the following formula (3);

(Wherein, X ^1a and X ^1b each independently represent a group capable of forming a carbon-carbon bond by a coupling reaction,
X ² represents a group capable of forming a carbon-carbon bond by a coupling reaction with X ^1a and/or X ^1b ;
Z ¹ is the same as Z ^1a and/or Z ^1b in the formula (1);
R ¹ is the same as R ^1a and/or R ^1b in the formula (1), k is the same as k1 and/or k2 in the formula (1),
Z ^2a , Z ^2b , R ^2a , R ^2b , R ^3a , R ^3b , A ^1a , A ^1b , m1, m2, n1, n2, m1+n1, m2+n2, p1 and p2 are the same as in formula (1) above. )
(ii) in the above step (i), when Z ¹ of the compound represented by the above formula (3) is a ring assembly C _16-18 arene ring, the step of reacting in the presence of an ether;

Moreover, the present invention includes a method of exciting the compound represented by the formula (1) to emit light, and also includes a luminescent composition containing the compound represented by the formula (1). The luminescent composition may further contain a binder component. The binder component may contain at least one resin selected from (meth)acrylic resins, styrene resins, polycarbonate resins, and silicon resins. In the luminescent composition, the ratio of the compound represented by the formula (1) and the binder component may be about the former/latter (mass ratio)=1/0.5 to 1/1000. . The emission spectrum of the luminescent composition includes at least one emission peak having a maximum wavelength λ _em,max of about 410 to 460 nm and a half width of about 70 nm or less, and an emission quantum efficiency of about 70% or more. good.

Furthermore, the present invention includes a light-emitting device containing the compound represented by formula (1).

In the present specification and claims, the number of carbon atoms may be indicated by C ₁ , C ₆ , C ₁₀ and the like. For example, an alkyl group with 1 carbon atom is indicated by "C ₁ alkyl" and an aryl group with 6 to 10 carbon atoms is indicated by "C _6-10 aryl".

In addition, in the present specification and claims, the term "solid state" means a state in which fluidity is lost and solidified without being dispersed in a dispersion medium (binder component or matrix) such as resin.

Since the fluorene compound of the present invention has a specific chemical structure, it has an emission peak (maximum wavelength λ _em,max ) in the wavelength range of 400 to 460 nm and can emit blue light with high emission quantum efficiency. In particular, it can emit pure (monochromatic or high color purity) blue light. In addition, the fluorene compound can emit blue light with high emission quantum efficiency even in a composition (or coating state) containing a polymer (resin or binder component). Excellent organic electroluminescence (EL) [or organic light emitting diodes (OLED)] can be easily or efficiently made.

FIG. 1 shows the measurement results of the solid-state excitation spectrum (solid line) and emission spectrum (dashed line) of BEPF-TPh obtained in Example 1. FIG. FIG. 2 shows the measurement results of the solid-state excitation spectrum (solid line) and emission spectrum (dashed line) of BEPF-Py obtained in Example 2. FIG. FIG. 3 shows measurement results of excitation spectrum (solid line) and emission spectrum (broken line) of BEPF-TPh obtained in Example 1 in a dichloromethane solution state. FIG. 4 shows measurement results of excitation spectrum (solid line) and emission spectrum (dashed line) of BEPF-Py obtained in Example 2 in a dichloromethane solution state. FIG. 5 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) in the coating state of BEPF-TPh/PS (mass ratio)=1/10 obtained in Example 1. FIG. FIG. 6 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) in the state of the BEPF-TPh/PC (mass ratio)=1/10 coating film obtained in Example 1. FIG. FIG. 7 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) of the BEPF-TPh/PMMA (mass ratio)=1/10 coating film obtained in Example 1. FIG. FIG. 8 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) in the state of the BEPF-TPh/PPSQ (mass ratio)=1/10 coating film obtained in Example 1. FIG. FIG. 9 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) of the BEPF-Py/PS (mass ratio)=1/10 coating film obtained in Example 2. FIG. FIG. 10 shows measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the state of the BEPF-Py/PC (mass ratio)=1/10 coating film obtained in Example 2. FIG. FIG. 11 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) of the BEPF-Py/PMMA (mass ratio)=1/10 coating film obtained in Example 2. FIG. FIG. 12 shows measurement results of the excitation spectrum (solid line) and the emission spectrum (dashed line) in the state of the BEPF-Py/PPSQ (mass ratio)=1/10 coating film obtained in Example 2. FIG.

[Fluorene compound]
The fluorene compound of the present invention is represented by the following formula (1).

(wherein Z ^1a and Z ^1b each independently represent a polycyclic C _16-18 arene ring,
R ^1a and R ^1b each independently represent a substituent, k1 and k2 each independently represent an integer of 0 or more,
m1 and m2 each independently represent an integer of 0 to 4, at least one of m1 and m2 is an integer of 1 or more,
R ^2a and R ^2b each independently represent a substituent, n1 and n2 each independently represent an integer of 0 to 4,
m1+n1 and m2+n2 are each independently an integer of 0 to 4;
A ^1a and A ^1b each independently represent a linear or branched alkylene group,
^Z2a and ^Z2b each independently represent an arene ring, ^R3a and ^R3b each independently represent a substituent, p1 and p2 each independently represent an integer of 0 or more).

In formula (1), the polycyclic arene rings represented by Z ^1a and Z ^1b include condensed polycyclic arene rings (condensed polycyclic aromatic hydrocarbon rings), ring-assembled arene rings (ring-assembled poly cyclic aromatic hydrocarbon ring) and the like.

In the present specification and claims, the term "ring-assembled arene ring" means that two or more ring systems (arene ring systems) are directly linked by single bonds (single bonds) or double bonds, and the rings are directly linked. For example, as described later, a phenylnaphthalene ring or the like is included in a ring-assembled arene ring even if it has a condensed polycyclic arene ring skeleton. It is clearly distinguished from "fused polycyclic arene rings" such as pyrene rings (non-ring-assembled arene rings).

Condensed polycyclic C _16-18 arene rings represented by Z ^1a and Z ^1b include, for example, naphthacene ring, benzo[a]anthracene ring, chrysene ring, benzo[c]phenanthrene ring, pyrene ring, triphenylene ring, etc. fused tetracyclic C _16-18 arene rings. A preferred fused polycyclic C _16-18 arene ring is a pyrene ring.

The ring assembly C _16-18 arene ring represented by Z ^1a and Z ^1b includes, for example, 1-phenylnaphthalene ring, phenylnaphthalene ring such as 2-phenylnaphthalene ring, o-terphenyl ring, and m-terphenyl ring. , p-terphenyl ring, and the like. A preferred ring assembly C _16-18 arene ring is a p-terphenyl ring.

Preferable rings Z ^1a and Z ^1b are condensed polycyclic C _16-18 arene rings such as pyrene ring, and terphenyl rings such as p-terphenyl ring. From the viewpoint of easily improving the polycyclicity, a condensed polycyclic C _16-18 arene ring such as a pyrene ring is more preferable, and a pyrene ring is particularly preferable.

Generally, as the number of aromatic rings (benzene ring skeleton) in the chemical structure increases through condensation and/or single bonds, especially through condensation, the conjugation length increases and the emission wavelength (the wavelength at the emission peak) becomes longer. However, it is not possible to predict from the chemical structure specific emission characteristics, for example, how much the wavelength will be lengthened or what the emission quantum efficiency will be. That is, it is extremely difficult to design a highly efficient light-emitting material having an emission peak in a predetermined wavelength region. In the compound represented by the above formula (1), the polycyclic C _16-18 arene ring represented by Z ^1a and Z ^1b and the fluorene ring are bonded, and many aromatic rings are condensed or via a single bond. Even if it has a chemical structure in which it is continuous, it has an emission peak in a predetermined wavelength region without excessively lengthening the wavelength, and can emit blue light with high quantum efficiency.

The types of rings Z ^1a and Z ^1b may be different from each other, but are preferably the same. Further, when m1 and/or m2 are 2 or more, the types of the two or more rings ^Z1a and/or ^Z1b may be the same or different.

In addition, ring Z ^1a and/or Z ^1b may be substituted at any of positions 1 to 4 and 5 to 8 of the fluorene skeleton. or binding positions) are substitution positions that are in a symmetrical relationship on the paper in the above formula (1), such as 1,8-positions, 2,7-positions, 3,6-positions, 4,5-positions, and in particular, 2,7 positions are preferred.

When the rings Z ^1a and Z ^1b are pyrene rings, the bonding positions of the rings Z ^1a and Z ^1b with the fluorene skeleton are, for example, the 1-, 2-, or 4-positions of the pyrene ring, preferably the 1-position. , Z ^1a , Z ^1b is a p-terphenyl ring, for example, the 2-, 3- or 4-position, preferably the 4-position, of the p-terphenyl ring.

Substituents represented by R ^1a and R ^1b include, for example, a hydrocarbon group (or a group [-R ^A ]), a halogen atom, a hydroxyl group, a group [-OR ^A ] (wherein R ^A hydrogen group), hydroxy (poly)alkoxy group, thiol group (mercapto group), group [-SR ^A ] (wherein R ^A represents the hydrocarbon group), acyl group, carboxyl group, alkoxycarbonyl group , amino group, substituted amino group, cyano group, nitro group, trialkylsilyl group, dialkylhydrosilyl group and the like. In the present specification and claims, the term "(poly)alkoxy group" is used to include both alkoxy groups and polyalkoxy groups.

Hydrocarbon groups (or groups [-R ^A ]) include, for example, alkyl groups, cycloalkyl groups, aryl groups, groups in which two or more of these hydrocarbon groups are combined (or combined), and the like.

Examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, n-octyl group and 2-ethylhexyl. linear or branched C _1-20 alkyl groups such as groups, n-decyl groups, n-dodecyl groups, and the like. It is preferably a linear or branched C _1-12 alkyl group, more preferably a linear or branched C _1-6 alkyl group.

Cycloalkyl groups include, for example, C _5-10 cycloalkyl groups such as cyclopentyl group and cyclohexyl group. A C _5-8 cycloalkyl group is preferred.

Examples of aryl groups include naphthyl groups such as phenyl, 1-naphthyl and 2-naphthyl groups, and C _6-14 aryl groups such as biphenylyl, anthryl and phenanthryl groups. A C _6-10 aryl group is preferred.

Examples of groups in which two or more hydrocarbon groups are combined (bonded) include an alkylaryl group and an aralkyl group. Examples of alkylaryl groups include mono- or di-C _1-6 alkyl C _6-10 aryl groups such as methylphenyl group (tolyl group) and dimethylphenyl group (xylyl group). Examples of the aralkyl group include C _6-10 aryl C _1-6 alkyl groups such as a phenylmethyl group (benzyl group) and 2-phenylethyl group (phenethyl group).

Halogen atoms include, for example, fluorine, chlorine, bromine, and iodine atoms.

Examples of the group [-OR ^A ] include groups corresponding to the hydrocarbon groups represented by R ^A , such as alkoxy groups, cycloalkyloxy groups, aryloxy groups and aralkyloxy groups.

The alkoxy group includes alkoxy groups corresponding to the alkyl groups exemplified in the section of R ^A , such as linear or branched C _1-10 alkoxy groups such as methoxy group.

The cycloalkyloxy group includes cycloalkyloxy groups corresponding to the cycloalkyl groups exemplified in the section of R ^A above, such as C _5-10 cycloalkyloxy groups such as cyclohexyloxy group.

The aryloxy group includes aryloxy groups corresponding to the aryl groups exemplified in the section of R ^A above, such as C _6-10 aryloxy groups such as phenoxy group.

The aralkyloxy group includes aralkyloxy groups corresponding to the aralkyl groups exemplified in the section of R ^A above, such as C _6-10 aryl-C _1-4 alkyloxy groups such as benzyloxy group.

The hydroxy(poly)alkoxy group includes, for example, hydroxy(poly)C _2-6 alkoxy groups such as 2-hydroxyethoxy group, 2-hydroxypropoxy group and 2-(2-hydroxyethoxy)ethoxy group.

The group [-SR ^A ] includes a group corresponding to the hydrocarbon group represented by R ^A , such as an alkylthio group, a cycloalkylthio group, an arylthio group and an aralkylthio group.

The alkylthio group includes alkylthio groups corresponding to the alkyl groups exemplified in the section of R ^A above, such as C _1-10 alkylthio groups such as methylthio group.

The cycloalkylthio group includes cycloalkylthio groups corresponding to the cycloalkyl groups exemplified in the section of R ^A above, such as C _5-10 cycloalkylthio groups such as cyclohexylthio group.

The arylthio group includes arylthio groups corresponding to the aryl groups exemplified in the section of R ^A above, such as C _6-10 arylthio groups such as phenylthio group (or thiophenoxy group).

The aralkylthio group includes aralkylthio groups corresponding to the aralkyl groups exemplified in the section of R ^A above, such as C _6-10 aryl-C _1-4 alkylthio groups such as benzylthio group.

Acyl groups include, for example, C _1-6 acyl groups such as an acetyl group.

Alkoxycarbonyl groups include, for example, C _1-6 alkoxy-carbonyl groups such as methoxycarbonyl groups.

Substituted amino groups include, for example, mono- or dialkylamino groups, mono- or diacylamino groups, and the like. Mono- or di-alkylamino groups include, for example, mono- or di-C _1-4 alkylamino groups such as dimethylamino group. Mono- or diacylamino groups include, for example, mono- or di(C _1-6 acyl)amino groups such as a diacetylamino group.

Trialkylsilyl groups include, for example, triC _1-6 alkylsilyl groups such as trimethylsilyl group.

Examples of dialkylhydrosilyl groups include di-C _1-6 alkylhydrosilyl groups such as dimethylhydrosilyl groups.

These groups R ^1a and R ^1b may be used alone or in combination of two or more. When the groups R ^1a and R ^1b are cyclic hydrocarbon groups such as aryl groups, they may form a ring assembly such as a ring assembly arene ring together with the rings Z ^1a and Z ^{1b .} Preferably ^1b is not an aryl group.

When the number of substitutions k1 or k2 is 1 or more, preferable groups R ^1a or R ^1b include hydrocarbon groups such as alkyl groups, hydroxyl groups, hydroxy(poly)alkoxy groups, carboxyl groups and the like. The alkyl group is more preferably a linear or branched C _1-6 alkyl group such as a methyl group, and the hydroxy(poly)alkoxy group is more preferably a hydroxy (mono to deca) group such as a 2-hydroxyethoxy group. ) is a C _2-4 alkoxy group. Among these groups R ^1a and R ^1b , C _1-4 alkyl groups such as methyl groups, hydroxyl groups and carboxyl groups are preferred.

The substitution numbers k1 and k2 of the groups R ^1a and R ^1b may be selected according to the type of the rings Z ^1a and Z ^1b , and may be selected from, for example, integers of about 0 to 7. , an integer of 0 to 6, an integer of 0 to 5, an integer of 0 to 4, an integer of 0 to 3, an integer of 0 to 2, more preferably 0 or 1, particularly 0.

The two substitution numbers k1 and k2 may be different from each other, but are preferably identical. When the substitution number k1 or k2 is 2 or more, the types of the two or more groups R ^1a or R ^1b substituting on the ring Z ^1a or Z ^1b may be the same or different. Also, the types of the groups R ^1a and R ^1b may be different from each other, but are preferably the same. The substitution positions of the groups R ^1a and R ^1b are not particularly limited, and may be selected according to the type of rings Z ^1a and Z ^1b .

The substitution numbers m1 and m2 of the groups [-Z ^1a -(R ^1a ) _k1 ] and [-Z ^1b -(R ^1b ) _k2 ] (hereinafter also referred to as Z ¹ -containing groups) are, for example, about 1 to 3. is an integer of, preferably 1 or 2, more preferably 1. m1 and m2 may be different from each other, but are preferably the same. At least one of m1 and m2 is an integer of 1 or more, preferably both are integers of 1 or more, more preferably both are 1.

When m1 or m2 is 2 or more, the types of the two or more Z ¹ -containing groups substituted on the same benzene ring among the two benzene rings forming the fluorene skeleton may be the same or different. . The group [-Z ^1a -(R ^1a ) _k1 ] and the group [-Z ^1b -(R ^1b ) _k2 ] may be the same or different, and are preferably the same.

R ^2a and R ^2b may be substituents other than the Z ¹ -containing group, and are typically hydrocarbon groups such as alkyl groups (excluding aryl groups), fluorine atoms, chlorine atoms, bromine atoms, etc. and a cyano group. The alkyl group includes linear or branched C _1-6 alkyl groups such as methyl group, ethyl group and t-butyl group. When the number of substitutions n1 and/or n2 is 1 or more, preferred R ^2a and/or R ^2b are linear or branched C _1-4 alkyl groups such as methyl groups.

The substitution numbers n1 and n2 of R ^2a and R ^2b are, for example, each an integer of about 0 to 3, preferably an integer of 0 to 2, more preferably 0 or 1, particularly 0. n1 and n2 may be different from each other, but are preferably the same. When n1 or n2 is 2 or more, of the two benzene rings forming the fluorene skeleton, two or more R ^2a or two or more R ^2b substituted on the same benzene ring may be the same or different. good too. The types of R ^2a and R ^2b may be the same or different, preferably the same. Further, the substitution positions of R ^2a and R ^2b are not particularly limited as long as they are substituted at positions other than the substitution position of the Z ¹ -containing group.

m1+n1 and m2+n2 are for example each integers of the order of 1 to 3, preferably 1 or 2, more preferably 1. m1+n1 and m2+n2 may be different from each other, but are preferably identical.

Linear or branched alkylene groups represented by A ^1a and A ^1b include, for example, methylene group, ethylene group, methylmethylene group (ethylidene group), propylene group, 1,3-propane-diyl group, 2 , 2-propane-diyl group, 1,4-butane-diyl group, and other linear or branched C _1-6 alkylene groups. The types of the two ^alkylene groups A1a and ^A1b may be different from each other, but are preferably the same. Preferred alkylene groups A ^1a and A ^1b are linear or branched C _1-4 alkylene groups, more preferably linear or branched C _1-3 alkylene groups, especially methylene group, ethylene group A C _1-2 alkylene group such as is preferred, and an ethylene group is particularly preferred from the viewpoint of easily improving the emission quantum efficiency.

The arene rings (aromatic hydrocarbon rings) represented by ^Z2a and ^Z2b include, for example, monocyclic arene rings such as benzene ring, polycyclic arene rings, and the like. Polycyclic arene rings include condensed polycyclic arene rings (condensed polycyclic aromatic hydrocarbon rings), ring-assembled arene rings (ring-assembled polycyclic aromatic hydrocarbon rings), and the like.

Examples of condensed polycyclic arene rings include condensed bi- to tetra-cyclic arene rings such as condensed bicyclic arene rings and condensed tricyclic arene rings. The condensed bicyclic arene ring includes, for example, condensed bicyclic C _10-16 arene rings such as naphthalene ring and indene ring. Examples of condensed tricyclic arene rings include condensed tricyclic C _14-20 arene rings such as anthracene ring and phenanthrene ring.

The ring-assembled arene ring includes, for example, a biphenyl ring such as a biphenyl ring, a phenylnaphthalene ring, and a binaphthyl ring; and a tellarene ring such as a terphenyl ring.

Preferred rings Z ^2a and Z ^2b include C _6-14 arene rings, more preferably C _6-12 arene rings such as benzene ring, naphthalene ring and biphenyl ring, still more preferably benzene ring, naphthalene ring and the like. C _6-10 arene ring, especially benzene ring.

The types of rings Z ^2a and Z ^2b may be different from each other, but are preferably the same. The bonding positions of the rings ^Z2a and ^Z2b and the ^alkylene groups A1a and ^A1b are not particularly limited.

Examples of substituents represented by R ^3a and R ^3b include the same substituents as those exemplified in the section on R ^1a and R ^1b .

When the number of substitutions p1 or p2 is 1 or more, preferred groups ^{R3a or R3b include} alkyl groups, aryl groups, hydroxyl groups, hydroxy(poly)alkoxy groups, carboxyl groups, and the like. The alkyl group is more preferably a linear or branched C _1-6 alkyl group such as a methyl group, and the aryl group is more preferably a C _6-10 aryl group such as a phenyl group. The hydroxy(poly)alkoxy group is more preferably a hydroxy(mono- to deca)C _2-4 alkoxy group such as a 2-hydroxyethoxy group. Among these groups R ^3a and R ^3b , C _1-4 alkyl groups such as methyl groups, hydroxyl groups and carboxyl groups are preferred.

The substitution numbers p1 and p2 of the groups R ^3a and R ^3b may be selected according to the type of the rings Z ^2a and Z ^2b , and may be selected, for example, from integers of about 0 to 7, preferably from 0 to 0 It is an integer from 0 to 5, an integer from 0 to 4, an integer from 0 to 2, more preferably 0 or 1, especially 0.

The two substitution numbers p1 and p2 may be different from each other, but usually they are often the same. When the substitution number p1 or p2 is 2 or more, the types of the two or more groups ^R3a or two or more ^R3b substituted on the same rings ^Z2a and ^Z2b may be the same or different. Also, the types of the groups R ^3a and R ^3b may be different from each other, but are preferably the same.

The substitution positions of the groups R ^3a and R ^3b are not particularly limited, and may be selected according to the type of rings Z ^2a and Z ^2b . When Z ^2a and Z ^2b are benzene rings, the groups A ^1a and A ^1b 3-position, 4-position, 3,4-position, 3,5-position, 3,4,5-position, preferably 4-position, 3,4-position, more preferably 4-position with respect to the phenyl group that binds be. For example, when Z ^2a and Z ^2b are ^naphthalene rings, the substitution positions of the groups R ^3a and R ^3b are, for example, ¹ , 5-position, 2,6-position, preferably 2,6-position.

Typical examples of the fluorene compound represented by the formula (1) include 9,9-bis(arylalkyl)-diarylfluorene, such as 9,9-bis(arylalkyl)-2,7-di(condensed poly Cyclic C _16-18 aryl)fluorene, 9,9-bis(arylalkyl)-2,7-di(ring assembly polycyclic C _16-18 aryl)fluorene and the like.

Examples of 9,9-bis(arylalkyl)-2,7-di(fused polycyclic C _16-18 aryl)fluorene include 9,9-bis(phenylmethyl)-2,7-di(1- pyrenyl)fluorene, 9,9-bis(2-phenylethyl)-2,7-di(1-pyrenyl)fluorene, 9,9-bis(2-phenylethyl)-2,7-di(2-pyrenyl) fluorene, 9,9-bis(C _6-10 arylC _1-2 alkyl)-2,7-di (pyrenyl)fluorene and the like.

Examples of 9,9-bis(arylalkyl)-2,7-dicyclic polycyclic C _16-18 arylfluorene include 9,9-bis(phenylmethyl)-2,7-di(p-ter phenyl-4-yl)fluorene, 9,9-bis(phenylethyl)-2,7-di(p-terphenyl-4-yl)fluorene, 9,9-bis(phenylethyl)-2,7-di (p-terphenyl-3-yl)fluorene, 9,9-bis(phenylethyl)-2,7-di(p-terphenyl-2-yl)fluorene, 9,9-bis(phenylethyl)-2 ,7-di(m-terphenyl-4-yl)fluorene, 9,9-bis(phenylethyl)-2,7-di(m-terphenyl-3-yl)fluorene, 9,9-bis(phenyl 9,9-bis(C _6-10 arylC _1-2 alkyl)-2,7-di(terphenylyl)fluorene such as ethyl)-2,7-di(m-terphenyl-5′-yl)fluorene is mentioned.

Among these fluorene compounds represented by formula (1), 9,9-bis(phenylmethyl)-2,7-di(p-terphenyl-4-yl)fluorene and other 9,9-bis( C _6-10 arylC _1-2 alkyl)-2,7-di(p-terphenylyl)fluorene, 9,9-bis(C _6-10 arylC _1-2 alkyl)-2,7-di(fused poly Cyclic C _16-18 aryl)fluorene is preferable, and from the viewpoint that the quantum efficiency can be improved more effectively and the absorption coefficient can be easily improved, 9,9-bis(phenylmethyl)-2,7-di(1-pyrenyl) 9,9-bis(C _6-10 arylC _1-2 alkyl)-2,7-di(pyrenyl)fluorene such as ) fluorene are more preferred.

(Method for producing fluorene compound)
The method for producing the fluorene compound represented by the formula (1) is a conventional method, for example, according to the following reaction scheme, a compound represented by the following formula (2) and a compound represented by the following formula (3) You may manufacture through the process of carrying out a coupling reaction (or cross-coupling reaction) (henceforth a 1st method).

(Wherein, X ^1a and X ^1b each independently represent a group capable of forming a carbon-carbon bond by a coupling reaction,
X ² represents a group capable of forming a carbon-carbon bond by a coupling reaction with X ^1a and/or X ^1b ;
Z ¹ is the same as Z ^1a and/or Z ^1b in the formula (1) including preferred embodiments,
R ¹ is the same as R ^1a and / or R ^1b in the formula (1) including preferred embodiments, k is the same as k1 and / or k2 in the formula (1) including preferred embodiments,
Z ^2a , Z ^2b , R ^2a , R ^2b , R ^3a , R ^3b , A ^1a , A ^1b , m1, m2, n1, n2, m1+n1, m2+n2, p1 and p2 are represented by the formula (1 ). )

Coupling reactions include conventional coupling reactions such as Suzuki-Miyaura coupling reaction, Migita-Kosugi-Stille coupling reaction, Negishi coupling reaction, Hiyama coupling reaction, and the like using a palladium catalyst (or palladium ( 0) catalyst), a coupling reaction with a nickel catalyst (or a nickel (0) catalyst) such as the Kumada-Tamao-Corriu coupling reaction, and the like, and the Suzuki-Miyaura coupling reaction is preferred. .

^The reactive groups ^{X1a and X1b and} X2 can be appropriately selected according to the type of the coupling reaction. When synthesized by the Suzuki-Miyaura coupling reaction, one of the reactive groups X ^1a and X ^1b includes, for example, a halogen atom or a fluorinated alkanesulfonyloxy group. Halogen atoms include, for example, iodine, bromine, and chlorine atoms. The fluorinated alkanesulfonyloxy group includes, for example, a fluorinated C _1-4 alkanesulfonyloxy group such as a trifluoromethanesulfonyloxy group (or group [-OTf]).

One of these reactive groups ^{X1a and X1b may} be used alone or in combination of two or more. Of these one reactive groups, a halogen atom is preferred, an iodine atom and a bromine atom are more preferred, and a bromine atom is preferred.

In the Suzuki-Miyaura coupling reaction, examples of the other reactive group X ² that can be coupled with one of the reactive groups X ^1a and X ^1b include a boronic acid group (a dihydroxyboryl group or a group [-B(OH ) ₂ ]), a boronate ester group, and the like. Boronate ester groups include, for example, dialkoxyboryl groups such as dimethoxyboryl, diisopropoxyboryl and dibutoxyboryl; pinacolatoboryl (or group [-Bpin]), 1,3,2-dioxaborinane-2 -yl group, cyclic boronate ester groups such as 5,5-dimethyl-1,3,2-dioxabolinan-2-yl group, and the like.

These other reactive groups X2 may be used alone or in combination of ^two or more. Of the other reactive groups, the group [-B(OH) ₂ ] and the group [-Bpin] are preferred.

The groups X ^1a and X ^1b and the group X ² may be any pair of reactive groups capable of coupling reaction with each other regardless of the above examples. ^1a and ^X1b may be said other reactive group such as a boronic acid group and the group X2 may be said one reactive group such as a halogen atom, but the groups ^X1a and ^{X1b may} be a halogen atom etc. and the group X2 is the other reactive group, such as a boronic ^acid group.

Examples of the compound represented by formula (2) include 9,9-bis(phenylmethyl)-2,7-dibromofluorene and 9,9-bis(2-phenylethyl)-2,7-dibromofluorene. 9,9-bis(C _6-10 arylC _1-2 alkyl)-dihalofluorene and the like.

The compound represented by the formula (2) can be prepared, for example, by the method described in JP-A-2009-96782, that is, 9H-fluorenes unsubstituted at the 9-position such as 2,7-dibromofluorene and potassium t- It can also be prepared by reacting with a basic catalyst such as butoxide to generate a fluorene anion having an anion at the 9-position of the fluorene skeleton, and reacting this fluorene anion with a haloalkylarene such as (2-bromoethyl)benzene. good.

Examples of the compound represented by the formula (3) include boronic acid compounds or boronic acid ester compounds corresponding to Z ^1a and/or Z ^1b in the formula (1), such as 2-([1,1 ': Terphenyl having a cyclic boronic acid ester group such as 4',1''-terphenyl]-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane; 1-pyrene boron Acids such as pyreneboronic acid, etc. Commercially available products can be used as the compound represented by the formula (3).

The ratio of the compound represented by the formula (2) and the compound represented by the formula (3) may be, for example, the former/latter (molar ratio) = about 1/2 to 1/10. , preferably 1/2.05 to 1/3, more preferably 1/2.1 to 1/2.5.

When synthesized by the Suzuki-Miyaura coupling reaction, the reaction is usually carried out in the presence of a palladium catalyst. Palladium catalysts include conventional coupling catalysts such as palladium (0) catalysts, palladium (II) catalysts, and the like.

Palladium(0) catalysts include, for example, tetrakis(triphenylphosphine)palladium(0) [or Pd(PPh ₃ ) ₄ ], bis(tri-t-butylphosphine)palladium(0) [or Pd(P(t palladium(0)-phosphine complexes such as -Bu) ₃ ) ₂ ].

Palladium(II) catalysts include, for example, [1,2-bis(diphenylphosphino)ethane]palladium(II) dichloride [or PdCl ₂ (dppe)], [1,3-bis(diphenylphosphino)propane] palladium (II) dichloride [or PdCl ₂ (dppp)], [1,1′-bis(diphenylphosphino)ferrocene] palladium (II) dichloride [or PdCl ₂ (dppf)], bis(triphenylphosphine) palladium ( II) Palladium(II) dichloride [or PdCl ₂ (PPh ₃ ) ₂ ], bis(tri-o-tolylphosphine)palladium(II) dichloride [or PdCl ₂ (P(o-tolyl) ₃ ) ₂ ], etc.- phosphine complexes and the like. When a palladium (II) catalyst is used, the reaction is initiated by reduction to a zero-valent complex by a reducing compound in the reaction system such as phosphine, amine, or organometallic reagent.

The palladium catalyst includes, for example, a catalyst precursor such as tris(dibenzylideneacetone) dipalladium(0) chloroform complex [or Pd ₂ (dba) ₃ CHCl ₃ ] and a coordination catalyst such as phosphines and carbenes. may be prepared in the reaction system by adding

These catalysts can be used alone or in combination of two or more. Of these catalysts, palladium(0)-phosphine complexes such as Pd(PPh ₃ ) ₄ are preferred. The ratio of the catalyst may be, for example, about 0.005 to 0.1 mol, preferably 0.01 to 0.03, in terms of metal per 1 mol of the compound represented by the formula (2). Mole.

The Suzuki-Miyaura coupling reaction may be performed in the presence of a base. Examples of bases include metal carbonates or hydrogen carbonates, metal hydroxides, metal fluorides, metal phosphates, metal organic acid salts, metal alkoxides, and the like.

Examples of metal carbonates or hydrogen carbonates include alkali metal carbonates or hydrogen carbonates such as sodium carbonate, potassium carbonate, cesium carbonate, sodium hydrogen carbonate, thallium (I) carbonate, and the like.

Examples of metal hydroxides include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and cesium hydroxide, alkaline earth metal hydroxides such as barium hydroxide, and thallium (I) hydroxide. be done.

Examples of metal fluorides include alkali metal fluorides such as potassium fluoride and cesium fluoride.

Examples of metal phosphates include alkali metal phosphates such as tripotassium phosphate.

Examples of metal organic acid salts include alkali metal acetates such as potassium acetate.

Examples of metal alkoxides include alkali metal alkoxides such as sodium methoxide, sodium ethoxide and potassium t-butoxide.

These bases can be used alone or in combination of two or more. Of these bases, metal carbonates such as potassium carbonate are preferred. The ratio of the base may be, for example, about 0.01 to 100 mol, preferably 1 to 80 mol, more preferably 10 to 60 mol, per 1 mol of the compound represented by the formula (2). be.

The coupling reaction may be performed in the presence or absence of a phase transfer catalyst. Examples of phase transfer catalysts include tetraalkylammonium halides such as tetrabutylammonium bromide (TBAB) and trioctylmethylammonium chloride. These phase transfer catalysts may be used alone or in combination of two or more. Of these phase transfer catalysts, TBAB is preferred.

The coupling reaction may be carried out in the absence or presence of a solvent inert to the reaction. Examples of solvents include water; alcohols such as methanol and ethanol; ethers such as cyclic ethers and chain ethers; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate; amides such as N,N-dimethylformamide, dimethylacetamide and N-methyl-2-pyrrolidone; sulfoxides such as dimethylsulfoxide; aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and the like Hydrogens and the like can be mentioned.

Cyclic ethers include, for example, dioxane and tetrahydrofuran (THF). Examples of chain ethers include diethyl ether and diisopropyl ether.

Examples of aliphatic hydrocarbons include hexane and dodecane. Cyclohexane etc. are mentioned as alicyclic hydrocarbons. Examples of aromatic hydrocarbons include toluene and xylene.

These solvents can be used alone or in combination of two or more. In the above formula (3), when using a compound in which Z ¹ (Z ^1a and Z ^1b ) is a C _16-18 arene ring in the ring assembly, the reaction does not proceed unless at least an ether is present. It appears that the compound of formula (1) cannot be prepared. Therefore, when using a compound in which Z ¹ (Z ^1a and Z ^1b ) in the above formula (3) is a ring assembly C _16-18 arene ring, among the solvents, water and ethers, particularly water and a cyclic solvent such as THF A mixed solvent of ethers is preferable; in the case of using a compound in which Z ¹ (Z ^1a and Z ^1b ) is a condensed polycyclic C _16-18 arene ring in the above formula (3), among the above solvents, water and toluene It is preferable to use a mixed solvent of aromatic hydrocarbons such as

The coupling reaction may be carried out under an inert gas atmosphere, for example, under an atmosphere of nitrogen; a rare gas such as helium or argon. The reaction temperature is, for example, 50 to 200°C, preferably 60 to 150°C, more preferably 70 to 130°C. The reaction time may be, for example, about 1 to 48 hours, specifically about 12 to 36 hours.

After completion of the reaction, if necessary, the reaction mixture is subjected to a conventional separation and purification method, such as washing, extraction, dehydration, concentration, decantation, crystallization, recrystallization, reprecipitation, column chromatography, a combination of these methods, and the like. It may be separated and purified.

Moreover, the fluorene compound represented by the formula (1) may be produced by the second method shown by the following reaction formula.

(Wherein, X ³ represents a halogen atom,
A ¹ is the same as A ^1a and/or A ^1b in the formula (1) including preferred embodiments,
Z ² is the same as Z ^2a and/or Z ^2b in the formula (1) including preferred embodiments,
R ³ is the same as R ^3a and / or R ^3b in the formula (1) including preferred embodiments, p is the same as p1 and / or p2 in the formula (1) including preferred embodiments,
Z ^1a , Z ^1b , R ^1a , R ^1b , R ^2a , R ^2b , k1, k2, m1, m2, n1, n2, m1+n1 and m2+n2 are respectively the same as the above formula (1) including preferred embodiments. ).

In the ^second method, the compound [-A ^1a -Z ^2a- (R ^3a ) _p1 ] and the group [-A ^1b -Z ^2b -(R ^3b ) _p2 ] (hereinafter these are also referred to as Z ² -containing groups). The order of introduction of the Z1 ^- containing group and the Z2 ^- containing group is different from that of the first method.

The halogen atom represented by X3 includes ^, for example, a chlorine atom, a bromine atom, an iodine atom and the like.

Examples of the compound represented by the formula (4) include 9H-fluorenes having a Z ¹ -containing group such as 2,7-diphenylfluorene and unsubstituted at the 9-position. The compound represented by the formula (4) may be prepared by a method such as using a compound in which the 9-position of the fluorene skeleton is unsubstituted in place of the compound represented by the formula (2) in the first method. It is the same as the description of the first method including preferred aspects such as reaction conditions.

The second method corresponds to using the compound represented by the above formula (4) as the 9H-fluorenes unsubstituted at the 9-position in the method for preparing the compound represented by the above formula (2). It can be prepared according to the method described in JP-A-2009-96782.

(Characteristics of fluorene compound)
Since the fluorene compound represented by the formula (1) has a specific molecular structure, it has at least one emission peak in a specific wavelength region when excited by external energy such as light energy or electrical energy (specific It has a maximum emission peak wavelength λ _em,max in the wavelength region, and can emit blue light with extremely high emission quantum efficiency. Therefore, the present invention also includes a method of exciting the fluorene compound represented by the formula (1) with the external energy or the like to cause the fluorene compound to emit light in a specific wavelength region.

The luminescence quantum efficiency of the fluorene compound represented by the formula (1) is, for example, about 20% or more, preferably 25 to 50% at a temperature of 25° C. in a solid state, and Z ^1a and Z ^1b are condensed polycyclic in the case of a C _16-18 arene ring, preferably 30-45%, more preferably 35-40%; when Z ^1a and Z ^1b are a ring assembly C _16-18 arene ring, preferably 20-35%; More preferably 25 to 30%.

The fluorene compound represented by the formula (1) has a maximum wavelength λ _{em, max} in the range of, for example, about 400 to 460 nm, preferably 410 to 460 nm, in the solid-state emission (fluorescence or phosphorescence) spectrum at a temperature of 25°C. and when Z ^1a and Z ^1b are fused polycyclic C _16-18 arene rings, preferably stepwise from 420 to 460 nm, 435 ∼455 nm, containing at least one emission peak with a maximum wavelength λ _em,max in the range of 445-455 nm, when Z ^1a and Z ^1b are ring aggregates C _16-18 arene rings, preferably in steps of 410 It contains at least one emission peak with a maximum wavelength λ _em,max in the range of ˜450 nm, 410-435 nm, 415-425 nm.

In the solid-state emission spectrum, the half width of the emission peak (or emission band) having the maximum wavelength λ _em,max is, for example, 100 nm or less, preferably 1 to 70 nm, and Z ^1a and Z ^1b are condensed polycyclic In the case of a C _16-18 ^arene ring, preferably ^stepwise : 10 to 65 nm, 40 to 60 nm, 50 to 60 nm _; Stepwise, 10-60 nm, 25-50 nm, 35-45 nm.

Further, the fluorene compound represented by the formula (1) has an emission peak having a maximum wavelength λ _{ex, max} in a range of, for example, about 250 to 450 nm in a solid-state excitation spectrum (or absorption spectrum) at a temperature of 25°C ( or absorption peak), and when Z ^1a and Z ^1b are condensed polycyclic C _16-18 arene rings, the maximum wavelength is preferably in the range of 260 to 350 nm, more preferably 270 to 300 nm. containing at least one emission (absorption) peak with λ _ex,max , preferably in the range of 350-430 nm, more preferably 380-420 nm when Z ^1a and Z ^1b are ring assembly C _16-18 arene rings It contains at least one emission (absorption) peak with wavelength λ _ex,max .

The solid state includes, for example, crystalline forms such as single crystals and polycrystals, and non-crystalline forms (amorphous), and crystalline forms such as polycrystals are preferred.

In addition, the fluorene compound represented by the formula (1) can emit light with high quantum efficiency in a specific wavelength region even in an emission spectrum in a solution state where pure emission characteristics based on the chemical structure are likely to be reflected.

The luminescence quantum efficiency of the fluorene compound represented by the formula (1) may be, for example, about 30% or more, preferably 50 to 100%, at a temperature of 25° C. in a dichloromethane solution state, and Z ^1a and Z ^1b may be In the case of fused polycyclic C _16-18 arene rings, preferably from 70 to 100%, 80 to 100%, 85 to 95%, stepwise, Z ^1a and Z ^1b are the ring assembly C _16-18 arene In the case of rings, it is preferably 50-60%.

The fluorene compound represented by the formula (1) has an emission (fluorescence or phosphorescence) spectrum at a temperature of 25° C. in a dichloromethane solution state, for example, about 400 to 460 nm, preferably 410 to 460 nm, more preferably 410 to 450 nm. The range may include at least one emission peak (or emission band) having a maximum wavelength λ _em,max , and when Z ^1a and Z ^1b are fused polycyclic C _16-18 arene rings, preferably the following steps Specifically, it contains at least one emission peak with a maximum wavelength λ _em,max in the range of 415-440 nm, 420-430 nm, and when Z ^1a and Z ^1b are ring aggregates C _16-18 arene rings, preferably the following steps Specifically, it may contain at least one emission peak having a maximum wavelength λ _em,max in the range of 410-435 nm and 415-425 nm. In the emission spectrum of the solution state, the fluorene compound may have one or more emission peaks, preferably only one emission peak, and all emission peaks (maximum wavelength λ _em,max ) is preferably contained within said wavelength range.

In the emission spectrum in a dichloromethane solution state, the half width of the emission peak (or emission band) having the maximum wavelength λ _em,max may be selected from the range of, for example, 1 to 100 nm, preferably 30 to 70 nm. , Z ^1a and Z ^1b are condensed polycyclic C _16-18 arene rings, preferably from 40 to 65 nm, 50 to 60 nm in steps below, and Z ^1a and Z ^1b are ring assembly C _16-18 arene In the case of a ring, it is preferably from 30 to 60 nm and from 40 to 50 nm in stages.

The fluorene compound represented by the formula (1) has a maximum wavelength λ _ex, for example, in the range of about 270 to 400 nm, preferably 300 to 380 nm, in the excitation spectrum (or absorption spectrum) in a dichloromethane solution state at a temperature of 25 ° C. may contain at least one emission ^peak (or absorption peak) with a _{maximum wavelength} ^λ containing at least one emission (absorption) peak with _ex,max and preferably having a maximum wavelength λ _ex,max in the range of 320-350 nm when Z ^1a and Z ^1b are ring assemblies C _16-18 arene rings Contains at least one (absorption) peak.

In the measurement of the emission quantum efficiency, the emission spectrum, and the excitation spectrum in the dichloromethane solution state, the concentration of the fluorene compound is particularly limited as long as it is sufficiently diluted to the extent that the effects of concentration quenching and the like are not significantly observed. may be about 1×10 ⁻³ to 5×10 ⁻³ g/L, or about 1×10 ⁻⁶ to 10×10 ⁻⁶ mol/L.

In the present specification and claims, the emission spectrum, excitation spectrum, and emission quantum efficiency can be measured by the methods described in Examples below.

In addition, since the fluorene compound represented by the formula (1) exhibits high luminous quantum efficiency, a photosensitive substance (or a sensitive substance) that is responsive to light, such as a photopolymerization initiator, a luminescent material ( or a luminescent compound) may act as a sensitizer capable of sensitization. The luminescent material (other luminescent material) as the photosensitive substance may be a fluorescent material or a phosphorescent material, as long as it can impart energy from an excited sensitizer (exciter or excited species), i.e. As long as the excitation energy (bandgap) is lower than the energy that can be transferred from the exciter, there is no particular limitation, and conventional luminescent materials such as green to red luminescent materials can be used.

(Luminescent composition)
The luminescent composition (or blue luminescent composition) contains at least the fluorene compound represented by the formula (1) as a luminescent material and/or a sensitizer. When the fluorene compound represented by the formula (1) is contained as a sensitizer, it is preferable to contain another light-emitting material. The fluorene compounds represented by formula (1) may be used alone or in combination of two or more.

In addition to the fluorene compound represented by formula (1), the luminescent composition may or may not contain a binder component, if necessary. By containing the binder component, the fluorene compound represented by the formula (1) is diluted, and there is a tendency that the effect of concentration quenching can be suppressed compared to the solid state. Therefore, it is preferable to use a coating film (light-emitting composition) containing a binder as the light-emitting layer of an organic EL from the viewpoint of high emission quantum efficiency and easy or efficient production.

As described above, if the conjugation length is extended by bonding the rings ^Z1a and ^Z1b to the fluorene ring, it is expected that the emission wavelength will be lengthened. Compounds containing a ring skeleton) generally tend to have lower dispersibility (compatibility or solubility). Therefore, even in a coating film containing a binder component, the fluorene compound represented by the formula (1) aggregates and cannot be sufficiently diluted, and it is expected that the emission quantum efficiency will decrease due to concentration quenching as in the solid state. be. However, although the fluorene compound has many benzene ring skeletons, it can suppress aggregation in the binder component and exhibits unexpectedly high quantum efficiency. Especially useful as a material.

As the binder component, for example, commonly used resins (or polymer compounds) can be used, and thermoplastic resins, curable resins (thermally or photocurable resins), and the like can be mentioned.

Examples of thermoplastic resins include olefin-based resins; (meth)acrylic-based resins; styrene-based resins; vinyl-based resins such as vinyl chloride resins and vinyl alcohol-based resins; Resins such as polyalkylene arylates, polyarylates, liquid crystal polyesters; polyamide resins such as aliphatic polyamides, alicyclic polyamides, semi-aromatic polyamides, wholly aromatic polyamides (aramid); polyacetal resins; polyphenylene ethers Polyphenylene sulfide-based resin; Polysulfone-based resin, such as polysulfone, polyethersulfone, etc.; Polyetherketone-based resin, such as polyetherketone, polyetheretherketone, polyetherketoneetherketoneketone, etc.; Thermoplastic polyimide system resins such as polyetherimide resins and polyamideimide resins; thermoplastic elastomers; cellulose resins such as cellulose ester resins such as triacetyl cellulose, and cellulose ether resins such as ethyl cellulose.

Curable resins (thermally or photocurable resins) include, for example, epoxy resins; urethane resins; thermosetting polyester resins such as alkyd resins, unsaturated polyester resins, diallyl phthalate resins, vinyl ester resins; Phenolic resins; amino resins such as melamine resins, urea resins, guanamine resins; furan resins; thermosetting polyimide resins such as bismaleimide resins, bismaleimide triazine resins; oxane and the like.

These binder components can also be used individually or in combination of 2 or more types. Among these binder components, (meth)acrylic resins, styrene resins, polycarbonate resins, and silicon resins are preferable from the viewpoint of facilitating uniform dispersion of the fluorene compound represented by the formula (1).

(Meth)acrylic resins include, for example, (meth)acrylic acid, (meth)acrylic acid C _1-18 alkyl ester, hydroxy C _2-18 alkyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylic acid ) homopolymers or copolymers of (meth)acrylic monomers such as acrylonitrile; and copolymers of the above (meth)acrylic monomers with other copolymerizable monomers.

Examples of (meth)acrylic monomer homo- or copolymers include poly(meth)acrylic acid esters such as polymethyl(meth)acrylate, methyl methacrylate-(meth)acrylic acid copolymers, methacrylic Examples thereof include methyl acid-acrylic acid ester-(meth)acrylic acid copolymer and methyl methacrylate-(meth)acrylic acid ester copolymer.

In copolymers of (meth)acrylic monomers and other copolymerizable monomers, examples of the copolymerizable monomers include styrene-based monomers such as styrene and α-methylstyrene, maleic anhydride and the like.

Among these (meth)acrylic resins, poly(meth)acrylic acid C _1-8 alkyl esters such as polymethyl methacrylate are preferred.

Styrene-based resins include, for example, homo- or copolymers of styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene; copolymers of the above styrene-based monomers and copolymerizable monomers; impact-resistant styrenic resins [that is, graft copolymers and/or blends (mixtures) with rubber components];

Examples of homo- or copolymers of styrene-based monomers include polystyrenes such as atactic polystyrene, isotactic polystyrene (IPS), syndiotactic polystyrene (SPS), styrene-vinyltoluene copolymers, and styrene-α. -Methylstyrene copolymer and the like.

Examples of copolymers of styrene-based monomers and copolymerizable monomers include styrene-acrylonitrile copolymers (AS resins), styrene-(meth)acrylic acid copolymers, styrene-(meth)acryl Examples include acid ester copolymers (MS resin, etc.), styrene-maleic anhydride copolymers, styrene-phenylmaleimide copolymers, styrene-butadiene block copolymers, styrene-butadiene-styrene block copolymers, and the like.

Examples of high-impact styrene resins include high-impact polystyrene (HIPS); acrylonitrile-butadiene-styrene copolymer (ABS resin); acrylic rubber A and chlorinated polyethylene instead of butadiene rubber B in the ABS resin. C, AXS resin using a rubber component such as ethylene propylene rubber (or ethylene propylene diene rubber) E, specifically, AAS resin, ACS resin, AES resin, etc.; (meth) acrylic acid ester-butadiene-styrene copolymer Coalescing, such as methyl methacrylate-butadiene-styrene copolymer (MBS resin).

Among these styrenic resins, homopolymers or copolymers of styrenic monomers, particularly homopolymers, are preferred.

Examples of polycarbonate-based resins include aromatic polycarbonate resins, specifically bisphenol-type polycarbonate resins containing bi- or bisphenols as polymerization components such as bisphenol A-type polycarbonate resins and bisphenol F-type polycarbonate resins.

Examples of the bi- or bisphenols include bis(hydroxyaryl)alkanes, bis(hydroxyaryl)-arylalkanes, bis(hydroxyaryl)cycloalkanes, bis(hydroxyaryl)ethers, bis(hydroxyaryl) Bisphenols such as ketones, bis(hydroxyaryl)sulfides, bis(hydroxyaryl)sulfoxides and bis(hydroxyaryl)sulfones;

Examples of bis(hydroxyaryl)alkanes include bis(4-hydroxyphenyl)methane (bisphenol F), 1,1-bis(4-hydroxyphenyl)ethane (bisphenol AD), 2,2-bis(4- hydroxyphenyl)propane (bisphenol A), 1,1-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)butane (bisphenol B), 2,2-bis(4-hydroxyphenyl) -3-methylbutane, 2,2-bis(4-hydroxy-3-phenylphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C), 2,2-bis(4 -hydroxy-3-isopropylphenyl)propane (bisphenol G) and the like.

Examples of bis(hydroxyaryl)-arylalkanes include 1,1-bis(4-hydroxyphenyl)-1-phenylethane (bisphenol AP) and bis(4-hydroxyphenyl)-diphenylmethane (bisphenol BP). mentioned.

Examples of bis(hydroxyaryl)cycloalkanes include 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z), 1,1-bis( 4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC) and the like.

Bis(hydroxyaryl) ethers include, for example, bis(4-hydroxyphenyl) ether.

Bis(hydroxyaryl)ketones include, for example, bis(4-hydroxyphenyl)ketone.

Bis(hydroxyaryl)sulfides include, for example, bis(4-hydroxyphenyl)sulfide.

Bis(hydroxyaryl)sulfoxides include, for example, bis(4-hydroxyphenyl)sulfoxide.

Examples of bis(hydroxyaryl)sulfones include bis(4-hydroxyphenyl)sulfone (bisphenol S).

Examples of biphenols include o,o'-biphenol, m,m'-biphenol and p,p'-biphenol.

These bi- or bisphenols can be used alone or in combination of two or more.

Among these polycarbonate-based resins, bisphenol-type polycarbonate resins containing bis(hydroxyaryl)alkanes such as bisphenol A as polymerization components are preferred.

In silicon-based resins, the polyorganosiloxane (silicone) skeleton includes monofunctional M units (generally represented by R ₃ SiO _1/2 ), bifunctional D units (generally R ₂ SiO _2/2 ), trifunctional T units (commonly represented by RSiO _3/2 ), and tetrafunctional Q units (commonly represented by SiO _4/2 units).

The group R in the formulas representing the M, D and T units is a substituent. Examples of this substituent include an alkyl group, an aryl group, a cycloalkyl group, and a vinyl group.

Examples of alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-hexyl group, n-octyl group, 2 C _1-12 alkyl groups such as -ethylhexyl group and n-decyl group.

Examples of the aryl group include C _6-14 aryl groups such as a phenyl group, a methylphenyl group (tolyl group), a dimethylphenyl group (xylyl group), a biphenylyl group and a naphthyl group.

Cycloalkyl groups include C _5-10 cycloalkyl groups such as cyclopentyl, cyclohexyl and methylcyclohexyl groups.

These substituents can be used alone or in combination of two or more. Among these substituents, a C _1-4 alkyl group such as a methyl group and a C _6-12 aryl group such as a phenyl group are preferable, and a C _{6- 10} aryl groups are particularly preferred.

Examples of terminal groups (groups bonded to terminal silicon (Si) atoms) include hydroxyl groups, alkoxy groups, and halogen atoms such as chlorine atoms. Examples of the alkoxy group include C _1-4 alkoxy groups such as methoxy and ethoxy groups, preferably C _1-2 alkoxy groups.

These terminal groups can be used alone or in combination of two or more. Among these terminal groups, they are usually hydroxyl groups, C _1-2 alkoxy groups and the like in many cases.

The silicon-based resin preferably contains at least one type of unit selected from the T unit and the Q unit, and particularly preferably contains the T unit, from the viewpoint of facilitating the formation of a coating film. The proportion of T units in the entire silicon-based resin is, for example, 50 mol% or more, preferably in a stepwise range of 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, and 95 mol%. above, in particular a silsesquioxane (or polysilsesquioxane) that is substantially 100 mol %. Also, the proportion of T units in the silicon-based resin as a whole can be selected, for example, from a range of about 60 to 100 mol %, preferably 80 to 99.9 mol %.

The silsesquioxane (or polysilsesquioxane) may be ladder-shaped (or ladder-shaped) or cage-shaped (or cage-shaped). It is preferably in the form of (network-like or random structure). Such silsesquioxanes include, for example, polyalkylsilsesquioxanes formed of T units (alkylsilsesquioxane units) in which the substituent R is an alkyl group, such as polymethylsilsesquioxane. such as polyC _1-4 alkylsilsesquioxanes of; _{Polysilsesquioxanes} formed of T units where R is an alkyl group and T units where R is an aryl group, and the like.

These silsesquioxanes may be used alone or in combination of two or more. Among these silsesquioxanes, polyarylsilsesquioxanes formed of T units in which R is an aryl group are preferred, especially _{polyC 6-10 arylsilsesquioxanes} such as polyphenylsilsesquioxanes. Sun is preferred.

When Z ^1a and Z ^1b are condensed polycyclic C _16-18 arene rings, preferred binder components are (meth)acrylic resins, styrene resins and polycarbonate resins, more preferably styrene resins and polycarbonates. When Z ^1a and Z ^1b are ring aggregate C _16-18 arene rings, (meth)acrylic resins and polycarbonate resins are preferred, and (meth)acrylic resins are also acceptable. Combining these binder components with the fluorene compound seems to facilitate effective improvement of the luminescence quantum efficiency.

The ratio of the binder component may be selected from the range of, for example, about 1 to 99.99% by mass, about 10 to 99.9% by mass, preferably from 20 to 90% by weight, based on the total solid content. % by mass, 30 to 70% by mass, or 40 to 60% by mass, more preferably 30 to 99% by mass, 50 to 95% by mass, and 80 to 93% by mass in a stepwise manner. In addition, the ratio of the fluorene compound represented by the formula (1) and the binder component may be selected from the range of, for example, the former/latter (mass ratio) = about 1/0.5 to 1/1000, It is preferably from 1/0.7 to 1/200 and from 1/0.8 to 1/100 in the following steps, and from the viewpoint of effectively suppressing the decrease in emission quantum efficiency, the following steps are more preferable. Typically 1/1 to 1/50, 1/1 to 1/40, 1/2 to 1/30, 1/4 to 1/20, 1/6 to 1/15. If the proportion of the binder component is too low, the emission quantum efficiency may decrease due to concentration quenching.

In addition, the luminescent composition (or coating agent) may further contain a solvent in order to adjust the viscosity and improve the coatability (or handleability). good too. Examples of solvents include hydrocarbons, halogenated hydrocarbons, alcohols, glycols, ethers, glycol ethers, glycol ether acetates, ketones, carboxylic acids, esters, carbonates, nitriles, amides, sulfoxides, water, mixed solvents thereof, and the like.

Examples of hydrocarbons include aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as toluene and xylene.

Examples of halogenated hydrocarbons include dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene and the like.

Examples of alcohols include C _1-6 alkanols such as methanol, ethanol, 1-propanol, 2-propanol, n-butanol, isobutanol, s-butanol and t-butanol.

Examples of glycols include (poly)C _2-4 alkylene glycols such as ethylene glycol, propylene glycol and diethylene glycol.

Examples of ethers include chain ethers such as diethyl ether, and cyclic ethers such as tetrahydrofuran and 1,4-dioxane.

Glycol ethers include, for example, cellosolves, carbitols, (poly)C _2-4 alkylene glycol mono C _1-4 alkyl ethers such as triethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether; and (poly)C _2-4 alkylene glycol di-C _1-4 alkyl ethers such as ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether and dipropylene glycol dimethyl ether.

Examples of the cellosolves include C _1-4 alkyl cellosolves such as methyl cellosolve and ethyl cellosolve. Examples of the carbitols include C _1-4 alkyl carbitols such as methyl carbitol and ethyl carbitol.

Examples of glycol ether acetates include (poly)C _2-4 alkylene glycol mono-C _1-4 alkyl ether acetates such as cellosolve acetates, carbitol acetates, propylene glycol monomethyl ether acetate, and dipropylene glycol monobutyl ether acetate. is mentioned.

Examples of the cellosolve acetates include C _1-4 alkyl cellosolve acetates such as methyl cellosolve acetate. Examples of the carbitol acetates include C _1-4 alkyl carbitol acetates such as methyl carbitol acetate.

Examples of ketones include chain ketones such as acetone and methyl ethyl ketone, and cyclic ketones such as cyclohexanone.

Examples of carboxylic acids include acetic acid and propionic acid.

Examples of esters include acetic acid esters such as methyl acetate, ethyl acetate and butyl acetate, and lactic acid esters such as methyl lactate.

Examples of carbonates include chain carbonates such as dimethyl carbonate and cyclic carbonates such as propylene carbonate.

Nitriles include, for example, acetonitrile, propionitrile, benzonitrile and the like.

Examples of amides include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone and the like.

Examples of sulfoxides include dimethylsulfoxide and the like.

These solvents can be used alone or in combination of two or more. Among these solvents, halogenated hydrocarbons such as dichloromethane and chloroform are preferred.

The ratio of the solvent can be appropriately selected according to the viscosity of the luminescent composition, etc., and is not particularly limited. The solid content concentration of the luminescent composition is, for example, 0.01 to 50% by mass, preferably 0.1 to 10% by mass, more preferably 0.5 to 10% by mass, particularly 0.5 to 2% by mass. be.

The luminescent composition may contain conventional additives. Usual additives include, for example, dyes, pigments, pigment dispersants, wetting agents, thickeners, coupling agents, antifoaming agents, anti-settling agents, anti-skinning agents, polymerization inhibitors, polymerization initiators, curing agents. , leveling agents, thixotropic agents, anti-color separation agents, matting agents, flame retardants, stabilizers, plasticizers, softeners, lubricants, release agents, antistatic agents, and the like. Examples of the stabilizer include antioxidants, ultraviolet absorbers, light stabilizers, and antiozonants.

Since the additive may absorb the excitation light for exciting the fluorene compound (luminescent material) and the light emitted by the excited luminescent material, the coating agent may be substantially free of additives. . Therefore, the luminescent composition contains at least the fluorene compound represented by the formula (1), and optionally contains only a binder component and/or a solvent, that is, does not contain substantially any additives. configuration is preferred.

The luminescent properties of the luminescent composition containing the binder component or the coating film (or coating film) formed using this composition may be appropriately adjusted according to the types and concentrations of the fluorene compound and the binder component.

The luminescence quantum efficiency of the luminescent composition (or coating film) containing a binder component may be selected from a range of, for example, about 30% or higher at a temperature of 25° C., preferably 50 to 100%, more preferably 70 to 70%. 100%, and when Z ^1a and Z ^1b are fused polycyclic C _16-18 arene rings, preferably stepwise: 75-100%, 80-100%, 85-95%, Z ^1a and when Z ^1b is a ring assembly C _16-18 arene ring, preferably 75-90%, 75-85%, stepwise below.

The luminescent composition (or coating film) has a maximum wavelength λ _{em , max} , and when Z ^1a and Z ^1b are fused polycyclic C _16-18 arene rings, preferably stepwise below 415-440 nm , containing at least one emission peak with a maximum wavelength λ _em,max in the range of 420-430 nm, and when Z ^1a and Z ^1b are ring assemblies C _16-18 arene rings, preferably stepwise below 415-440 nm , at least one emission peak having a maximum wavelength λ _em,max in the range of 420-435 nm. In the emission spectrum of the luminescent composition (or coating film) containing the binder component, the fluorene compound may have one or more emission peaks, and preferably has only one emission peak. Also, all emission peaks (maximum wavelength λ _em,max ) are preferably contained within said wavelength range.

In the emission spectrum of the luminescent composition (or coating film), the half width of the emission peak (or emission band) having the maximum wavelength λ _em,max may be selected from a range of, for example, about 1 to 100 nm. , preferably from 30 to 70 nm, and when Z ^1a and Z ^1b are condensed polycyclic C _16-18 arene rings, preferably from 40 to 65 nm, from 50 to 60 nm, in steps below, Z ^1a and Z ^1b is a ring assembly C _16-18 arene ring, preferably from 40 to 60 nm and from 45 to 55 nm in steps below.

The luminescent composition (or coating film) has a maximum wavelength λ _{ex , max} and when Z ^1a and Z ^1b are fused polycyclic C _16-18 arene rings, the maximum wavelength is preferably in the range of 350-360 nm. contains at least one emission (absorption) peak with λ _ex,max and preferably has a maximum wavelength λ _ex,max in the range of 345 to 360 nm when Z ^1a and Z ^1b are ring assemblies C _16-18 arene rings It contains at least one emission (absorption) peak.

Such luminescent compositions can be used in various forms or applications, such as coating agents such as paints and ink compositions. Further, the luminescent composition may be used, for example, as an invisible ink such as a security ink (or security marker) described in JP-A-2020-164518.

(Light emitting element or photoelectric conversion element)
The light-emitting device (or photoelectric conversion device) may contain at least the fluorene compound represented by the formula (1) as a light-emitting material and/or a sensitizer. may be included in the form When the fluorene compound represented by the formula (1) is contained as a sensitizer, it is preferable to contain another light-emitting material.

Typical light-emitting elements include current-injection light-emitting elements such as inorganic light-emitting diodes (LEDs) and organic EL elements (or organic light-emitting diodes (OLED)), with organic EL elements being preferred. A current-injection type light emitting device such as an organic EL device is formed of an anode (transparent electrode), a cathode (metal electrode), and an organic layer (organic thin film) or an organic-inorganic hybrid layer interposed between the electrodes. As a representative structure, each layer is preferably formed in the order of transparent substrate/anode/hole transport layer/light emitting layer/electron transport layer/cathode. In addition, when the light emitting layer functions as a hole transport layer or an electron transport layer, the hole transport layer or the electron transport layer is not necessarily required.

Examples of transparent substrates include substrates made of inorganic materials such as glass; substrates made of organic materials such as (meth)acrylic resins, styrene resins, polycarbonate resins, and polyester resins. Polyester-based resins include polyalkylene arylate-based resins such as polyethylene terephthalate. Further, the substrate may be plate-like, but may be sheet-like or film-like.

The anode may be a transparent electrode, preferably a conductive metal oxide such as ITO (Indium Tin Oxide), FTO (Fluorine-doped Tin Oxide), ZnO (Zinc Oxide).

Examples of hole transport materials that form the hole (hole) transport layer include aromatic amines, phthalocyanines such as copper phthalocyanine, and conductive polymers such as polythiophenes. It may be a hole transport material described in Japanese Patent Application Laid-Open No. 2020-164518 (Patent Document 1). These hole transport materials may be used alone or in combination of two or more. Among these, conductive polymers such as PEDOT:PSS are preferred.

The light-emitting layer may contain the fluorene compound represented by the formula (1) as a light-emitting material, or may contain other commonly used light-emitting materials. These luminescent materials may be used alone or in combination of two or more. The light-emitting layer may be composed only of a light-emitting material, or may contain the light-emitting material as a guest material (or dopant) and a host material. As the host material, for example, the host material described in JP-A-2020-164518 (Patent Document 1) such as biphenyls; Examples include the binder component exemplified in the item of the item. These host materials may be used alone or in combination of two or more.

Examples of electron-transporting materials that form the electron-transporting layer include light metal organic complexes such as aluminum complexes and beryllium complexes, bisstyrylarene derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, silole derivatives, and the like. It may also be an electron-transporting material described in Japanese Patent Application Laid-Open No. 2020-164518 (Patent Document 1). These electron transport materials can be used alone or in combination of two or more.

The cathode (metal electrode) is often made of, for example, a single metal such as aluminum (Al), magnesium (Mg), silver (Ag), or an alloy thereof.

An anode buffer layer (hole injection layer) such as a copper phthalocyanine thin film may be formed between the anode and the hole transport layer, and a cathode buffer layer (hole injection layer) may be formed between the cathode and the electron transport layer. A buffer layer (electron injection layer), for example, an inorganic thin film such as a lithium fluoride (LiF) thin film, a lithium oxide (Li ₂ O) thin film, an organic thin film doped with a metal such as lithium (Li), etc. good.

The thickness of each layer (organic phase) interposed between the anode and cathode is, for example, 0.1 to 500 nm, preferably 1 to 200 nm, and the thickness of the entire organic phase may be about 1 μm or less.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited by these examples. Moreover, the evaluation method is shown below.

[Evaluation method]
(NMR)
It was measured using "ULTRASHIELD300" manufactured by BRUKER.

(HPLC)
It was measured using "LC-20A" manufactured by Shimadzu Corporation.

(Luminous properties)
Using a spectrofluorophotometer ("F-4500" manufactured by Hitachi High-Technologies Corporation, light source: xenon lamp, detector: photomultiplier tube, spectrometer: diffraction grating), the excitation spectrum and emission (fluorescence or phosphorescence) spectrum is measured at room temperature (25° C.), and the maximum wavelength λ _ex,max of the excitation spectrum, the maximum wavelength λ _em,max of the emission spectrum, and the peak (or emission band) containing this λ _em,max Find the half width.

(Luminous Quantum Efficiency)
A fluorescence spectrophotometer equipped with a fluorescence integrating sphere unit ("ILF-533" manufactured by JASCO Corporation, diameter 100 mmφ) ("FP-6500" manufactured by JASCO Corporation, light source: xenon lamp, detector: photoelectron multiplier Multiplier tube, spectrometer: diffraction grating) is corrected using the instrument function obtained using the attached standard light source for calibration. Calculated. The excitation light is measured with no sample installed to determine the spectral area of the irradiated excitation light, and then the excitation light is measured with the sample installed to determine the spectral area of the irradiated excitation light that is not absorbed by the sample. , the number of photons absorbed by the sample was calculated by obtaining the difference between them. At the same time, the emission spectrum of the sample was also observed, and the number of emitted photons was calculated from the spectral area. The emission quantum efficiency was calculated from the number of photons emitted with respect to the number of photons finally absorbed.

[Preparation of fluorene compound]
(Example 1) Preparation of BEPF-TPh

9,9-bis(2-phenylethyl) represented by the above formula (2-1) prepared according to Synthesis Example 1 of JP-A-2020-164518 (Patent Document 1) was placed in a 100 mL three-neck eggplant flask. -2,7-dibromofluorene [or BEPF-Br] (0.266 g, 0.50 mmol) and 2-([1,1′:4′,1 "-Terphenyl]-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.392 g, 1.1 mmol), 2 M potassium carbonate aqueous solution (5 mL), Tetrahydrofuran (THF, 20 mL) was added, Pd(PPh ₃ ) ₄ (0.0116 g, 0.010 mmol) was added under a nitrogen atmosphere, and the mixture was heated and stirred at 80° C. for 24 hours.

After cooling to room temperature, dichloromethane (10 mL) and distilled water (20 mL) were added for extraction. Further, the organic layer was washed with distilled water (20 mL×2 times), dehydrated with magnesium sulfate, and then the solvent was removed to obtain a yellow solid.

After purification by silica gel chromatography (solvent: hexane/dichloromethane = 10/1 (volume ratio)), recrystallization (solvent: toluene) yielded 9,9-bis represented by the above formula (1-2). (2-Phenylethyl)-2,7-di(p-terphenyl-4-yl)fluorene (also referred to as BEPF-TPh) was obtained as pale yellow crystals (0.172 g, yield 41%). The results of ¹ H NMR spectrum of the obtained BEPF-TPh are shown below.

¹ H NMR (600 MHz, CDCl ₃ ): δ (ppm) 2.07-2.10 (m, 4H), 2.46-2.48 (m, 4H), 6.96-6.97 (m, 4H), 7.07-7.17 (m, 6H), 7.36-7.39 (m, 2H), 7.46-7.49 (m, 4H), 7.66-7.79 ( m, 24H), 7.89-7.90 (m, 2H).

(Reference example 1)
A coupling reaction was attempted in the same manner as in Example 1, except that 20 mL of toluene was used instead of THF as the reaction solvent. rate 0%).

(Example 2) Preparation of BEPF-Py

BEPF-Br (0.106 g, 0.20 mmol) represented by the above formula (2-1) and 1-pyreneboronic acid (0.20 mmol) represented by the above formula (3-2) were placed in a 100 mL three-neck eggplant flask. 108 g, 0.44 mmol), 2M potassium carbonate aqueous solution (2 mL), and toluene (5 mL) were added. Pd(PPh ₃ ) ₄ (0.0046 g, 0.0040 mmol) was added under a nitrogen atmosphere, and the mixture was heated and stirred at 120° C. for 24 hours.

After cooling to room temperature, dichloromethane (10 mL) and distilled water (20 mL) were added for extraction. Further, the organic layer was washed with distilled water (20 mL×2 times), dehydrated with magnesium sulfate, and then the solvent was removed to obtain a yellow solid.

After purification by silica gel chromatography (solvent: hexane/dichloromethane = 10/1 (volume ratio)), recrystallization (solvent: toluene) yields 9,9-bis represented by the above formula (1-2). (2-Phenylethyl)-2,7-di(1-pyrenyl)fluorene (also referred to as BEPF-Py) was obtained as white crystals (0.102 g, yield 66%). The results of ¹ H NMR spectrum of the obtained BEPF-Py are shown below.

¹ H NMR (600 MHz, CDCl ₃ ): δ (ppm) 2.27-2.28 (m, 4H), 2.48-2.50 (m, 4H), 7.05-7.13 (m, 6H), 7.19-7.22 (m, 4H), 7.74-7.79 (m, 4H), 8.03-8.34 (m, 20H).

(Comparative Example 1) Preparation of BEPF According to Reference Example 1 of JP-A-2020-164518 (Patent Document 1), 9,9-bis(2-phenylethyl)fluorene (also referred to as BEPF) represented by the following formula ) was prepared.

(Comparative Example 2) Preparation of BEPF-Ph According to Example 1 of JP-A-2020-164518 (Patent Document 1), 9,9-bis(2-phenylethyl)-2, represented by the following formula, 7-diphenylfluorene (also called BEPF-Ph) was prepared.

(Comparative Example 3) Preparation of BEPF-BPh According to Example 4 of JP-A-2020-164518 (Patent Document 1), 9,9-bis(2-phenylethyl)-2, represented by the following formula, 7-di(4-biphenylyl)fluorene (also called BEPF-BPh) was prepared.

(Comparative Example 4) Preparation of BEPF-Np According to Example 3 of JP-A-2020-164518 (Patent Document 1), 9,9-bis(2-phenylethyl)-2, represented by the following formula, 7-di(2-naphthyl)fluorene (also called BEPF-Np) was prepared.

[Light Emitting Properties of Fluorene Compound]
(Emission characteristics in solid state)
The solid-state excitation spectra, emission spectra, and emission quantum efficiencies of the fluorene compounds prepared in Examples and Comparative Examples were measured. Table 1 shows the correspondence between the samples and the obtained spectra and the spectrum measurement conditions, and Table 2 and FIGS. 1 and 2 show the measurement results. In Table 1, "emission wavelength" indicates the wavelength obtained by monitoring the emission intensity in the excitation spectrum, and "excitation wavelength" indicates the wavelength of the excitation light in the emission spectrum (same below).

(Luminescence properties in solution state)
The fluorene compounds prepared in Examples and Comparative Examples were dissolved in dichloromethane at the concentrations shown in Table 3, and the excitation spectrum, emission spectrum, and emission quantum efficiency in the solution state were measured. Table 3 shows the correspondence between the samples and the obtained spectra and the spectrum measurement conditions, and Table 4 and FIGS. 3 and 4 show the measurement results.

In addition, in the measurement of the solution state, all the examples and comparative examples were sufficiently diluted, and no significant influence such as concentration quenching was confirmed.

As is clear from Tables 2 and 4 and FIGS. 1 to 4, unlike the comparative example, the example emitted blue light having a maximum wavelength λ _em,max in the wavelength region of 410 to 460 nm in the emission spectrum.

As mentioned above, when the number of aromatic rings in a chemical structure increases through condensation or a single bond, it is expected that the conjugation length will increase and the emission wavelength will increase. cannot be predicted. For example, pentacene, which has five benzene ring skeletons, has maximum wavelengths λ _em,max at 537 nm and 582 nm in solution and emits green to yellow light. Although they each have a structure in which terphenyl rings or pyrene rings are bonded and more benzene ring skeletons are linked than pentacene, they emit blue light without elongating the wavelength to the green wavelength region. In addition, in the examples, not only does it emit blue light in the above-mentioned specific wavelength region, but it also emits light with a high quantum efficiency and a relatively narrow half-value width, but these emission characteristics are also difficult to predict from the chemical structure. be.

The luminescence properties based on the compound (or chemical structure) are particularly reflected in the results in the solution state (Table 4), but the fluorene compounds of the examples are in the wavelength region of 410 to 460 nm (more pure blue and brighter ). In particular, the quantum efficiency of BEPF-Py of Example 2 was not only remarkably high, but also unexpectedly exhibited a single emission peak and high monochromaticity as visible light (blue emission). In particular, pyrene, which is a compound corresponding to Z ^1a and Z ^1b of BEPF-Py, exhibits a single emission peak on the longer wavelength side in the excimer (excited dimer) state, but has a short emission peak in the monomer state (solution state). It is known that a plurality of emission peaks are exhibited on the wavelength side (the peaks are divided finely). Therefore, it was unexpected that BEPF-Py exhibited a single emission peak in the wavelength region of 410 to 460 nm.

(Luminous properties in coating film state)
As shown in Table 6, 0.001 g of each fluorene compound prepared in Examples or Comparative Examples and 0.01 g of each binder component described later were added to chloroform at a predetermined solid content concentration (Example: 1% by mass, Comparative Example: 5% by mass) to prepare a mixture (coating agent).

Each of the obtained coating agents was applied onto a quartz substrate (“Labo-USQ” manufactured by Taiko Seisakusho Co., Ltd.) using a spin coater (“1H-D7” manufactured by Mikasa Co., Ltd., 1000 rpm) and heated to 90° C. on a hot plate. and dried for 30 minutes to form a coating film. Excitation spectra, emission spectra, and emission quantum efficiencies were measured using each of the formed coating films. Table 5 shows the correspondence between the samples and the obtained spectra and the spectrum measurement conditions, and Table 6 and FIGS. 5 to 12 show the measurement results. Moreover, the resin used as a binder component is shown below.

PS: Polystyrene, manufactured by PS Japan Co., Ltd. PC: Polycarbonate, manufactured by Mitsubishi Engineering-Plastics Co., Ltd. PMMA: Polymethyl methacrylate, manufactured by Mitsubishi Rayon Co., Ltd. PPSQ: Polyphenylsilsesquioxane, prepared by the method described below. thing.

Preparation of PPSQ 1 mmol of trimethoxyphenylsilane, 1.5 mL of tetrahydrofuran as a solvent, 60 μL of formic acid as an acid catalyst, and 60 μL of water are mixed and heated and stirred at 90° C. for 3 hours to initiate a hydrolysis reaction. and the condensation reaction was carried out and dried. After allowing to cool, the remaining acid was washed away with pure water, then 1.5 mL of tetrahydrofuran was added to form a solution again, heated and stirred at 110°C for 2 hours, and dried to dryness to synthesize PPSQ represented by the following formula. .

As is clear from Table 6 and FIGS. 5 to 12, even in the state of the coating film containing the binder component, the maximum wavelength λ _em,max in the emission spectrum in the wavelength region of 410 to 460 nm was observed in the example, unlike the comparative example. and emitted light with a relatively narrow half-width. Also, high quantum efficiency was exhibited in any binder component. As in Patent Document 1, in the case of organic EL applications that emit ultraviolet light, energy transfer from the light-emitting material to the binder component is likely to occur. While the luminous properties of the state are important, in organic EL applications that emit visible light (blue) in which the energy transfer is difficult to occur, the luminous properties of the coating film state are important. Therefore, the fluorene compounds of Examples that exhibit excellent quantum efficiency in the above wavelength region can be suitably used for organic EL applications that emit blue light.

In addition, as mentioned above, if the conjugation length is extended, the emission wavelength is expected to be longer. Molecules (light-emitting materials) tend to aggregate with each other, so concentration quenching is expected to reduce the emission quantum efficiency. However, although the fluorene compounds of Examples have a considerable number of benzene ring skeletons, they exhibit unexpectedly high quantum efficiency in the state of coating, making them particularly useful as blue light-emitting materials for organic EL (OLED). is. The quantum efficiency of BEPF-TPh of Example 1 was unexpectedly significantly improved in the coating state compared to the solution state.

In addition, in BEPF-Py of Example 2, when the solid content concentration of the coating agent was set to 5% by mass (that is, a thick coating film was prepared) during the preparation of the coating film, the light emission characteristics were evaluated. There was too much absorption of , resulting in saturation of the measurement result (all the light was absorbed by the film, and the change in the extinction coefficient with wavelength could not be confirmed, and the excitation spectrum was trapezoidal instead of peaked). Saturation was not observed in any of the fluorene compounds in the comparative example (solid content concentration 5% by mass), indicating that BEPF-Py has a higher absorption coefficient than conventional fluorene compounds. Since the intensity (or brightness) of luminescence increases in proportion to the extinction coefficient (ability to absorb light) and luminescence quantum efficiency (efficiency of conversion from absorbed excitation light), BEPF-Py with both high It is thought that it can emit light brightly.

The fluorene compound of the present invention can be effectively used as a luminescent material and/or a sensitizer, especially a blue luminescent material. In particular, the fluorene compound can be dissolved in an organic solvent, unlike an inorganic light-emitting body made of an inorganic material. Since a coating layer or coating film can be formed easily or efficiently, it can be effectively used as, for example, a coating agent such as invisible ink, a light-emitting material and/or a sensitizer in applications such as light-emitting devices (or photoelectric conversion devices).

Examples of light emitting elements (or photoelectric conversion elements) include current injection type light emitting elements such as organic EL elements. Typically, it can be effectively used in various applications such as display applications and light sources such as lighting applications.

Claims (12)

A compound represented by the following formula (1).

(wherein Z ^1a and Z ^1b each independently represent a polycyclic C _16-18 arene ring,
R ^1a and R ^1b each independently represent a substituent, k1 and k2 each independently represent an integer of 0 or more,
m1 and m2 each independently represent an integer of 0 to 4, at least one of m1 and m2 is an integer of 1 or more,
R ^2a and R ^2b each independently represent a substituent, n1 and n2 each independently represent an integer of 0 to 4,
m1+n1 and m2+n2 are each independently an integer of 0 to 4;
A ^1a and A ^1b each independently represent a linear or branched alkylene group,
^Z2a and ^Z2b each independently represent an arene ring, ^R3a and ^R3b each independently represent a substituent, and p1 and p2 each independently represent an integer of 0 or more. ) In the above formula (1), Z ^1a and Z ^1b are terphenylene rings or pyrene rings, m1 and m2 are integers of 0 to 2,
A ^1a and A ^1b are linear or branched C _1-6 alkylene groups,
The compound according to claim 1, wherein Z ^2a and Z ^2b are C _6-12 arene rings. In the formula (1), Z ^1a and Z ^1b are pyrene rings, m1 and m2 are 1,
A ^1a and A ^1b are linear or branched C _1-4 alkylene groups,
3. The compound according to claim 1 or ² , wherein Z2a and ^Z2b are a benzene ring, a naphthalene ring or a biphenyl ring. A blue light emitting material having at least one emission peak with a maximum wavelength λ _em,max of 410 to 460 nm and a half width of 70 nm or less in an emission spectrum in a dichloromethane solution state, and an emission quantum efficiency of 40% or more. A compound according to any one of 1 to 3. 5. A method for producing the compound according to any one of claims 1 to 4, comprising the step (i) or (ii) below.
(i) a step of coupling a compound represented by the following formula (2) with a compound represented by the following formula (3);

(Wherein, X ^1a and X ^1b each independently represent a group capable of forming a carbon-carbon bond by a coupling reaction,
X ² represents a group capable of forming a carbon-carbon bond by a coupling reaction with X ^1a and/or X ^1b ;
Z ¹ is the same as Z ^1a and/or Z ^1b in the formula (1);
R ¹ is the same as R ^1a and/or R ^1b in the formula (1), k is the same as k1 and/or k2 in the formula (1),
Z ^2a , Z ^2b , R ^2a , R ^2b , R ^3a , R ^3b , A ^1a , A ^1b , m1, m2, n1, n2, m1+n1, m2+n2, p1 and p2 are the same as in formula (1) above. )
(ii) in the above step (i), when Z ¹ of the compound represented by the above formula (3) is a ring assembly C _16-18 arene ring, the step of reacting in the presence of an ether; A method of exciting the compound according to any one of claims 1 to 4 to emit light. A luminescent composition comprising a compound according to any one of claims 1-4. 8. The luminescent composition according to claim 7, further comprising a binder component. 9. The luminescent composition according to claim 8, wherein the binder component contains at least one resin selected from (meth)acrylic resins, styrene resins, polycarbonate resins and silicon resins. The luminescent composition according to claim 8 or 9, wherein the ratio of the compound represented by formula (1) and the binder component is the former/latter (mass ratio) = 1/0.5 to 1/1000. . The emission spectrum includes at least one emission peak having a maximum wavelength λ _em,max of 410 to 460 nm and a half width of 70 nm or less, and an emission quantum efficiency of 70% or more. A luminescent composition as described. A light-emitting device comprising the compound according to any one of claims 1 to 4.

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