Fluorene compound and method for producing the same

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

[Technical Field]

[0001] The present invention relates to novel fluorene compounds. [Background technology]

[0002] Inorganic and organic light-emitting materials are used as light sources for devices such as light-emitting diodes (LEDs). Among these light-emitting materials, inorganic light-emitting materials tend to require complicated manufacturing processes, which increases the cost of manufacturing equipment and makes it difficult to achieve large-area light emission. Therefore, organic light-emitting materials are in demand because they can be easily and efficiently prepared by methods such as coating. Compounds with a fluorene skeleton are known as such organic light-emitting materials.

[0003] Japanese Patent Application Laid-Open No. 2020-164518 (Patent Document 1) discloses a fluorene compound represented by the following formula (1) as a light-emitting material capable of emitting light with high luminescence quantum efficiency (quantum efficiency or quantum yield).

[0004] [ka]

[0005] (In the formula, Z 1a and Z 1b each independently represents an arene ring, and Z 2a and Z 2b each independently represents an arene ring, and R 1a , R 1b , R 2a , R 2b , R 3a and R 3b each independently represents a substituent, A 1a and A 1beach independently represent a linear or branched alkylene group, k1 and k2 each independently represent an integer of 0 or greater, m1 and m2 each independently represent 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 greater, m1+n1 and m2+n2 each independently represent an integer of 0 to 4, and at least one of m1 and m2 is an integer of 1 or greater. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-164518 Summary of the Invention [Problem to be solved by the invention]

[0007] In the examples of Patent Document 1, the compound represented by the formula (1) is Z 1a and Z 1b 9,9-bis(2-phenylethyl)-2,7-diphenylfluorene (BEPF-Ph) where Z is a benzene ring. 1a and Z 1b is a biphenyl ring, 9,9-bis(2-phenylethyl)-2,7-di(4-biphenylyl)fluorene (BEPF-BPh), Z 1a and Z 1b Fluorene compounds such as 9,9-bis(2-phenylethyl)-2,7-di(2-naphthyl)fluorene (BEPF-Np), in which the ring is a naphthalene ring, have been prepared and their luminescent properties have been evaluated.

[0008] These fluorene compounds have a maximum wavelength λ in the emission spectrum in a solution state, which is likely to reflect the pure emission characteristics based on the chemical structure. em,maxIt has been shown that fluorene compounds can emit ultraviolet or visible light with an emission peak in the 360-399 nm range. Although these fluorene compounds exhibit high luminous quantum efficiency, the resulting visible light with wavelengths less than 400 nm tends to be invisible (difficult to see) or perceived as dim due to the standard luminous efficiency of humans. To perceive blue colors with low standard luminous efficiency as brighter, it is preferable for the emission peak to be on the long wavelength side of 400 nm or more. Visibility improves as the wavelength increases (because the standard luminous efficiency increases up to 565 nm). However, if the wavelength of the emission peak is too long, the base (or edge) of the emission peak extends into the light blue to blue-green wavelength range, making it impossible to perceive as pure blue. Therefore, there is a demand for bright blue-emitting materials that have an emission peak in a specific wavelength range, exhibit high quantum efficiency, and emit strong blue light.

[0009] 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 is capable of emitting blue light with high emission quantum efficiency (quantum efficiency or quantum yield), a method for producing the same, and uses thereof. [Means for solving the problem]

[0010] As a result of extensive research to achieve the above object, the inventors have discovered 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, thereby completing the present invention.

[0011] That is, the novel fluorene compound of the present invention is represented by the following formula (1).

[0012] [ka]

[0013] (In the formula, Z 1a and Z 1b are each independently a polycyclic C 16-18 represents an arene ring, R 1a and R1b each independently represents 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, and at least one of m1 and m2 is an integer of 1 or more; R 2a and R 2b each independently represents a substituent, n1 and n2 each independently represents an integer of 0 to 4, m1+n1 and m2+n2 each independently represent an integer of 0 to 4, A 1a and A 1b each independently represents a linear or branched alkylene group, Z 2a and Z 2b each independently represents an arene ring, and R 3a and R 3b each independently represents a substituent, and p1 and p2 each independently represent an integer of 0 or more).

[0014] In the formula (1), Z 1a and Z 1b is a terphenylene ring or a pyrene ring, m1 and m2 are integers of 0 to 2, A 1a and A 1b is linear or branched C 1-6 is an alkylene group, Z 2a and Z 2b C 6-12 It may also be an arene ring.

[0015] In addition, in the formula (1), Z 1a and Z 1b is a pyrene ring, m1 and m2 are 1, A 1a and A 1b is linear or branched C 1-4 is an alkylene group, Z 2a and Z 2b may be a benzene ring, a naphthalene ring or a biphenyl ring.

[0016] Furthermore, the compound represented by the formula (1) has an emission spectrum with a maximum wavelength λ em,max The compound represented by formula (1) may be a blue light-emitting material having at least one emission peak with a wavelength of about 410 to 460 nm and a half-width of about 70 nm or less, and having a luminescence quantum efficiency of about 40% or more. The compound represented by formula (1) may be in the form of a crystal.

[0017] The present invention encompasses a method for producing a compound represented by formula (1) above, which comprises either the following step (i) or (ii):

[0018] (i) a step of subjecting a compound represented by the following formula (2) to a coupling reaction with a compound represented by the following formula (3):

[0019] [ka]

[0020] (In the formula, X 1a and X 1b each independently represents a group capable of forming a carbon-carbon bond by a coupling reaction, X 2 is the X 1a and / or X 1b represents a group capable of forming a carbon-carbon bond by a coupling reaction together with Z 1 is Z in the formula (1). 1a and / or Z 1b is the same as R 1 is R in the formula (1) 1a and / or R 1b and k is the same as k1 and / or k2 in 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). (ii) In the step (i), Z of the compound represented by the formula (3) 1 is a ring set C 16-18 When the ring is an arene ring, a step of reacting the ring in the presence of an ether

[0021] The present invention also encompasses a method for exciting a compound represented by formula (1) to emit light, and also encompasses a luminescent composition containing the compound represented by formula (1). The luminescent composition may further contain a binder component. The binder component may contain at least one resin selected from a (meth)acrylic resin, a styrene resin, a polycarbonate resin, and a silicon resin. In the luminescent composition, the ratio of the compound represented by formula (1) to the binder component may be such that the former / the latter (mass ratio) is approximately 1 / 0.5 to 1 / 1000. In the emission spectrum of the luminescent composition, the maximum wavelength λ em,max The wavelength may be about 410 to 460 nm, and the half width may be about 70 nm or less, and the luminescence quantum efficiency may be about 70% or more.

[0022] Furthermore, the present invention includes a light-emitting device containing the compound represented by the formula (1).

[0023] In this specification and claims, the number of carbon atoms is represented by C1, C6, C 10 For example, an alkyl group with 1 carbon atom is represented as "C1 alkyl," and an aryl group with 6 to 10 carbon atoms is represented as "C 6-10 It is indicated as "aryl".

[0024] In addition, in this specification and claims, the term "solid state" refers to a solidified state in which the fluidity is lost and the substance is not dispersed in a dispersion medium (binder component or matrix) such as a resin. [Effects of the Invention]

[0025] The fluorene compound of the present invention has a specific chemical structure, and therefore has an emission peak (maximum wavelength λ ) in the wavelength region of 400 to 460 nm. em,max ) and can emit blue light with high luminescence quantum efficiency. In particular, they can emit pure (monochromatic or highly color-pure) blue light. Furthermore, since the fluorene compounds can emit blue light with high luminescence quantum efficiency even when they are in the form of a composition (or coating film) containing a polymer (resin or binder component), their use as blue-emitting materials allows for the easy and efficient production of excellent organic electroluminescence (EL) devices [or organic light-emitting diodes (OLED)]. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) of the solid-state BEPF-TPh obtained in Example 1. [Figure 2] FIG. 2 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) of the solid-state BEPF-Py obtained in Example 2. [Figure 3] FIG. 3 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) of BEPF-TPh obtained in Example 1 in a dichloromethane solution state. [Figure 4] FIG. 4 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) of BEPF-Py obtained in Example 2 in a dichloromethane solution state. [Figure 5] FIG. 5 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-TPh / PS (mass ratio) = 1 / 10 obtained in Example 1. [Figure 6] FIG. 6 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-TPh / PC (mass ratio) = 1 / 10 obtained in Example 1. [Figure 7]FIG. 7 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-TPh / PMMA (mass ratio) = 1 / 10 obtained in Example 1. [Figure 8] FIG. 8 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-TPh / PPSQ (mass ratio) = 1 / 10 obtained in Example 1. [Figure 9] FIG. 9 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-Py / PS (mass ratio) = 1 / 10 obtained in Example 2. [Figure 10] FIG. 10 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-Py / PC (mass ratio) = 1 / 10 obtained in Example 2. [Figure 11] FIG. 11 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-Py / PMMA (mass ratio) = 1 / 10 obtained in Example 2. [Figure 12] FIG. 12 shows the measurement results of the excitation spectrum (solid line) and emission spectrum (dashed line) in the coating film state of BEPF-Py / PPSQ (mass ratio) = 1 / 10 obtained in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0027] [Fluorene compounds] The fluorene compound of the present invention is represented by the following formula (1).

[0028] [ka]

[0029] (In the formula, Z 1a and Z 1b are each independently a polycyclic C 16-18 represents an arene ring, R 1a and R 1beach independently represents 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, and at least one of m1 and m2 is an integer of 1 or more; R 2a and R 2b each independently represents a substituent, n1 and n2 each independently represents an integer of 0 to 4, m1+n1 and m2+n2 each independently represent an integer of 0 to 4, A 1a and A 1b each independently represents a linear or branched alkylene group, Z 2a and Z 2b each independently represents an arene ring, and R 3a and R 3b each independently represents a substituent, and p1 and p2 each independently represent an integer of 0 or more).

[0030] In the formula (1), Z 1a and Z 1b Examples of the polycyclic arene ring represented by the formula (I) include a fused polycyclic arene ring (fused polycyclic aromatic hydrocarbon ring) and a ring-assembled arene ring (ring-assembled polycyclic aromatic hydrocarbon ring).

[0031] In this specification and claims, the term "ring assembly arene ring" refers to two or more ring systems (arene ring systems) directly connected by single bonds or double bonds, and the number of bonds directly connecting the rings is one less than the number of ring systems. For example, as will be described later, a phenylnaphthalene ring is included in the ring assembly arene ring even though it has a fused polycyclic arene ring skeleton, and is clearly distinguished from "fused polycyclic arene rings" such as pyrene rings (non-ring assembly arene rings).

[0032] Z 1a and Z 1b A fused polycyclic ring C represented by 16-18Examples of the arene ring include fused tetracyclic C rings such as naphthacene ring, benzo[a]anthracene ring, chrysene ring, benzo[c]phenanthrene ring, pyrene ring, and triphenylene ring. 16-18 A preferred fused polycyclic C 16-18 The arene ring is a pyrene ring.

[0033] Z 1a and Z 1b A ring set C represented by 16-18 Examples of the arene ring include phenylnaphthalene rings such as 1-phenylnaphthalene ring and 2-phenylnaphthalene ring, and terphenyl rings such as o-terphenyl ring, m-terphenyl ring and p-terphenyl ring. 16-18 The arene ring is a p-terphenyl ring.

[0034] Preferred Ring Z 1a and Z 1b As examples, fused polycyclic C rings such as pyrene rings 16-18 arene rings and terphenyl rings such as p-terphenyl rings, and from the viewpoint of more effectively improving quantum efficiency and facilitating improvement of the absorption coefficient, fused polycyclic C rings such as pyrene rings are more preferred. 16-18 An arene ring is preferred, and a pyrene ring is particularly preferred.

[0035] Generally, as the number of aromatic rings (benzene ring skeletons) in a chemical structure increases through condensation and / or single bonds, particularly through condensation, it is expected that the conjugation length will increase and the emission wavelength (wavelength at the emission peak) will become longer. However, it is not possible to predict specific emission characteristics, such as how much the wavelength will become longer and what the emission quantum efficiency will be, from the chemical structure. In other words, it is extremely difficult to design a highly efficient light-emitting material that has an emission peak in a predetermined wavelength region. The compound represented by the formula (1) is Z 1a and Z 1b Polycyclic C represented by 16-18Even though the compound has a chemical structure in which an arene ring and a fluorene ring are bonded and many aromatic rings are connected via condensation or single bonds, it has an emission peak in a predetermined wavelength region without excessively long wavelengths and can emit blue light with high quantum efficiency.

[0036] Ring Z 1a and Z 1b The types of m1 and / or m2 may be different from each other, but are preferably the same. 1a and / or Z 1b The types may be the same or different from each other.

[0037] Also, ring Z 1a and / or Z 1b may be substituted at any of the 1- to 4-positions and the 5- to 8-positions of the fluorene skeleton, but when m1 and m2 are 1, preferred substitution positions (or bonding positions) are those which are symmetrical on the paper in formula (1) such as the 1,8-positions, the 2,7-positions, the 3,6-positions, and the 4,5-positions, and the 2,7-positions are particularly preferred.

[0038] In addition, ring Z 1a , Z 1b The bonding position with the fluorene skeleton is ring Z 1a , Z 1b is a pyrene ring, for example, the 1-, 2- or 4-position of the pyrene ring, preferably the 1-position, and the ring Z 1a , Z 1b When is a p-terphenyl ring, it is, for example, the 2-, 3- or 4-position of the p-terphenyl ring, preferably the 4-position.

[0039] R 1a and R 1b Examples of the substituent represented by the formula (I) include a hydrocarbon group (or a group [-R A ]), halogen atoms, hydroxyl groups, groups [-OR A ](where R A represents the hydrocarbon group), a hydroxy(poly)alkoxy group, a thiol group (mercapto group), a group [—SR A ](where R Arepresents the hydrocarbon group), acyl group, carboxyl group, alkoxycarbonyl group, amino group, substituted amino group, cyano group, nitro group, trialkylsilyl group, dialkylhydrosilyl group, etc. In the present specification and claims, the term "(poly)alkoxy group" is used to include both alkoxy groups and polyalkoxy groups.

[0040] Hydrocarbon group (or group [-R A ]) includes, for example, an alkyl group, a cycloalkyl group, an aryl group, and a group in which two or more of these hydrocarbon groups are combined (or bonded) with each other.

[0041] Examples of the alkyl group include linear or branched C alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-hexyl, n-octyl, 2-ethylhexyl, n-decyl, and n-dodecyl groups. 1-20 Preferably, the alkyl group is a linear or branched C 1-12 Alkyl groups, more preferably linear or branched C 1-6 It is an alkyl group.

[0042] Examples of the cycloalkyl group include C cyclopentyl and cyclohexyl groups. 5-10 cycloalkyl groups. Preferably, C 5-8 It is a cycloalkyl group.

[0043] Examples of the aryl group include C aryl groups such as phenyl, naphthyl groups such as 1-naphthyl and 2-naphthyl, biphenylyl, anthryl, and phenanthryl. 6-14 An aryl group is preferably C 6-10 It is an aryl group.

[0044] Examples of groups in which two or more hydrocarbon groups are combined (bonded) include alkylaryl groups, aralkyl groups, etc. Examples of alkylaryl groups include mono- or di-C alkylaryl groups such as methylphenyl groups (tolyl groups) and dimethylphenyl groups (xylyl groups). 1-6 Alkyl C 6-10 Examples of the aralkyl group include C aryl groups such as phenylmethyl groups (benzyl groups) and 2-phenylethyl groups (phenethyl groups). 6-10 Aryl C 1-6 Examples include alkyl groups.

[0045] Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

[0046] Group [-OR A ] is the above-mentioned R A Examples of the hydrocarbon groups include groups corresponding to the hydrocarbon groups represented by the following formula:

[0047] The alkoxy group includes the above-mentioned R A Alkoxy groups corresponding to the alkyl groups exemplified in the above section, for example, linear or branched C groups such as methoxy groups 1-10 Examples thereof include an alkoxy group.

[0048] The cycloalkyloxy group includes the above-mentioned R A cycloalkyloxy groups corresponding to the cycloalkyl groups exemplified in the above section, for example, C such as cyclohexyloxy groups 5-10 Examples thereof include a cycloalkyloxy group.

[0049] The aryloxy group includes the above-mentioned R A aryloxy groups corresponding to the aryl groups exemplified in the above section, for example, C such as phenoxy groups 6-10 Examples thereof include an aryloxy group.

[0050] The aralkyloxy group is the same as the R AAralkyloxy groups corresponding to the aralkyl groups exemplified in the above section, for example, C such as benzyloxy groups 6-10 Aryl-C 1-4 Examples thereof include an alkyloxy group.

[0051] Examples of the hydroxy(poly)alkoxy group include hydroxy(poly)C groups such as a 2-hydroxyethoxy group, a 2-hydroxypropoxy group, and a 2-(2-hydroxyethoxy)ethoxy group. 2-6 Examples thereof include an alkoxy group.

[0052] The group [-SR A ] is the above-mentioned R A Examples of the hydrocarbon group include an alkylthio group, a cycloalkylthio group, an arylthio group, and an aralkylthio group.

[0053] The alkylthio group includes the above-mentioned R A alkylthio groups corresponding to the alkyl groups exemplified in the above section, for example, C such as methylthio groups 1-10 Examples include an alkylthio group.

[0054] The cycloalkylthio group includes the above-mentioned R A a cycloalkylthio group corresponding to the cycloalkyl group exemplified in the above section, for example, a C such as a cyclohexylthio group; 5-10 Examples include a cycloalkylthio group.

[0055] The arylthio group includes the above-mentioned R A An arylthio group corresponding to the aryl group exemplified in the above section, for example, a C such as a phenylthio group (or a thiophenoxy group) 6-10 Examples include an arylthio group.

[0056] The aralkylthio group is the same as the R A Aralkylthio groups corresponding to the aralkyl groups exemplified in the above section, for example, C such as benzylthio groups 6-10 Aryl-C 1-4 Examples include an alkylthio group.

[0057] Examples of the acyl group include C acetyl groups. 1-6 Examples include an acyl group.

[0058] Examples of the alkoxycarbonyl group include C alkoxycarbonyl groups such as methoxycarbonyl groups. 1-6 Examples include alkoxy-carbonyl.

[0059] Examples of the substituted amino group include mono- or di-alkylamino groups, mono- or di-acylamino groups, etc. Examples of the mono- or di-alkylamino group include mono- or di-C groups such as dimethylamino groups. 1-4 Examples of the mono- or diacylamino group include a mono- or di(C)amino group such as a diacetylamino group. 1-6 acyl)amino group.

[0060] Examples of the trialkylsilyl group include tri-C groups such as trimethylsilyl groups. 1-6 Examples include alkylsilyl groups.

[0061] Examples of the dialkylhydrosilyl group include di-C groups such as dimethylhydrosilyl groups. 1-6 Examples include alkylhydrosilyl groups.

[0062] These groups R 1a and R 1b may be used alone or in combination of two or more. 1a and R 1b When is a cyclic hydrocarbon group such as an aryl group, the ring Z 1a and Z 1b may form an assembled ring such as a ring-assembled arene ring together with the group R 1a and R 1b is preferably not an aryl group.

[0063] When the number of substitutions k1 or k2 is 1 or more, the preferred group R 1a or R 1bExamples of the alkyl group include a hydrocarbon group such as an alkyl group, a hydroxyl group, a hydroxy(poly)alkoxy group, and a carboxyl group. The alkyl group is more preferably a linear or branched C group such as a methyl group. 1-6 The hydroxy(poly)alkoxy group is preferably a hydroxy(mono to deca) C group such as a 2-hydroxyethoxy group. 2-4 These groups R 1a and R 1b Among them, C such as methyl group 1-4 Alkyl groups, hydroxyl groups and carboxyl groups are preferred.

[0064] base R 1a and R 1b The substitution numbers k1 and k2 of the ring Z 1a and Z 1b For example, it can be selected from integers of about 0 to 7, and preferred ranges are the following stepwise integers of 0 to 6, 0 to 5, 0 to 4, 0 to 3, and 0 to 2, more preferably 0 or 1, and particularly preferably 0.

[0065] The two substitution numbers k1 and k2 may be different from each other, but are preferably the same. When the substitution number k1 or k2 is 2 or more, the ring Z 1a or Z 1b Two or more groups R 1a or R 1b The types of groups R may be the same or different. 1a and R 1b The types of groups R may be different from each other, but are preferably the same. 1a and R 1b The substitution position of ring Z is not particularly limited. 1a and Z 1b The selection may be made depending on the type of

[0066] group [-Z 1a -(R 1a ) k1 ] and the group [-Z 1b -(R 1b ) k2] (Hereafter, these are referred to as Z 1 The numbers of substitutions m1 and m2 of the groups (also referred to as "containing groups") are, for example, integers of about 1 to 3, preferably 1 or 2, and 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, and more preferably both are 1.

[0067] When m1 or m2 is 2 or more, two or more Z groups substituted on the same benzene ring among the two benzene rings forming the fluorene skeleton are 1 The types of the contained groups may be the same or different. 1a -(R 1a ) k1 ] and the group [-Z 1b -(R 1b ) k2 ] may be the same or different, and are preferably the same.

[0068] R 2a and R 2b is the Z 1 Any substituent other than the containing group may be used, and representative examples include hydrocarbon groups such as alkyl groups (excluding aryl groups), halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, and cyano groups. Examples of alkyl groups include linear or branched C groups such as methyl groups, ethyl groups, and t-butyl groups. 1-6 When the number of substitutions n1 and / or n2 is 1 or more, preferred R 2a and / or R 2b As the alkyl group, linear or branched C 1-4 It is an alkyl group.

[0069] R 2a and R 2bThe substitution numbers n1 and n2 are, for example, integers of about 0 to 3, preferably integers of 0 to 2, more preferably 0 or 1, and particularly preferably 0. n1 and n2 may be different from each other, but are preferably the same. When n1 or n2 is 2 or more, two or more R groups substituted on the same benzene ring among the two benzene rings forming the fluorene skeleton are 2a or 2 or more R 2b The types of R may be the same or different. 2a and R 2b The types of R may be the same or different, and are preferably the same. 2a and R 2b The substitution position of Z is not particularly limited. 1 It is sufficient that the substituent is at a position other than the substitution position of the containing group.

[0070] m1+n1 and m2+n2 are, for example, each an integer of about 1 to 3, preferably 1 or 2, and more preferably 1. m1+n1 and m2+n2 may be different from each other, but are preferably the same.

[0071] A 1a and A 1b Examples of the linear or branched alkylene group represented by the formula (I) include linear or branched C alkylene groups such as methylene, ethylene, methylmethylene (ethylidene), propylene, 1,3-propanediyl, 2,2-propanediyl, and 1,4-butanediyl. 1-6 alkylene groups. 1a and A 1b The alkylene groups A may be different from each other, but are preferably the same. 1a and A 1b is linear or branched chain C 1-4 alkylene group, more preferably a linear or branched C 1-3 Alkylene groups, especially methylene and ethylene groups 1-2 An alkylene group is preferred, and an ethylene group is particularly preferred because it is easy to improve the luminescence quantum efficiency.

[0072] Z 2a and Z 2b Examples of the arene ring (aromatic hydrocarbon ring) represented by the formula (I) include a monocyclic arene ring such as a benzene ring, a polycyclic arene ring, etc. Examples of the polycyclic arene ring include a fused polycyclic arene ring (fused polycyclic aromatic hydrocarbon ring), a ring-assembled arene ring (ring-assembled polycyclic aromatic hydrocarbon ring), etc.

[0073] Examples of the fused polycyclic arene ring include fused bicyclic arene rings, fused tricyclic arene rings, and other fused bicyclic to tetracyclic arene rings. Examples of the fused bicyclic arene ring include fused bicyclic C rings such as naphthalene rings and indene rings. 10-16 Examples of the fused tricyclic arene ring include fused tricyclic C arene rings such as anthracene rings and phenanthrene rings. 14-20 arene rings.

[0074] Examples of the ring-assembled arene ring include biarene rings such as biphenyl ring, phenylnaphthalene ring, and binaphthyl ring; and terarene rings such as terphenyl ring.

[0075] Preferred Ring Z 2a and Z 2b As for C 6-14 arene rings, and more preferably C rings such as benzene rings, naphthalene rings, and biphenyl rings. 6-12 C rings such as arene rings, more preferably benzene rings and naphthalene rings 6-10 An arene ring, especially a benzene ring.

[0076] Also, ring Z 2a and Z 2b The types of rings Z may be different from each other, but are preferably the same. 2a and Z 2b and an alkylene group A 1a and A 1b The bonding position is not particularly limited.

[0077] R 3a and R 3bThe substituent represented by the formula (I) is the same as that of the above-mentioned R 1a and R 1b Examples of the substituents include the same groups as those exemplified in the section 1.

[0078] When the number of substitutions p1 or p2 is 1 or more, the preferred group R 3a or R 3b Examples of the alkyl group include an alkyl group, an aryl group, a hydroxyl group, a hydroxy(poly)alkoxy group, and a carboxyl group. The alkyl group is more preferably a linear or branched C group such as a methyl group. 1-6 The aryl group is preferably a C alkyl group such as a phenyl group. 6-10 The hydroxy(poly)alkoxy group is preferably a hydroxy(mono to deca) C group such as a 2-hydroxyethoxy group. 2-4 These groups R 3a and R 3b Among them, C such as methyl group 1-4 Alkyl groups, hydroxyl groups and carboxyl groups are preferred.

[0079] base R 3a and R 3b The substitution numbers p1 and p2 of the ring Z 2a and Z 2b For example, it can be selected from integers of about 0 to 7, preferably integers of 0 to 5, integers of 0 to 4, integers of 0 to 2, more preferably 0 or 1, and particularly preferably 0.

[0080] The two substitution numbers p1 and p2 may be different from each other, but are usually the same. When the substitution number p1 or p2 is 2 or more, the same ring Z 2a and Z 2b Two or more groups R 3a or 2 or more R 3b The types of groups R may be the same or different. 3a and R 3b The types may be different from each other, but are preferably the same.

[0081] base R 3a and R 3b The substitution position of ring Z is not particularly limited. 2a and Z 2b may be selected according to the type of Z 2a and Z 2b is a benzene ring, the group A 1a and A 1b For example, the positions are 3, 4, 3,4, 3,5, and 3,4,5, preferably 4 and 3,4, and more preferably 4, relative to the phenyl group bonded to Z. 2a and Z 2b is a naphthalene ring, the group R 3a and R 3b The substitution position of group A 1a and A 1b The substituent is, for example, at the 1,5-positions, or the 2,6-positions, preferably the 2,6-positions, relative to the 1-naphthyl group or 2-naphthyl group bonded to the group.

[0082] Representative examples of the fluorene compound represented by the formula (1) include 9,9-bis(arylalkyl)-diarylfluorene, for example, 9,9-bis(arylalkyl)-2,7-di(fused polycyclic C 16-18 aryl)fluorene, 9,9-bis(arylalkyl)-2,7-di(cyclic assembly polycyclic C 16-18 aryl)fluorene and the like.

[0083] 9,9-bis(arylalkyl)-2,7-di(fused polycyclic C 16-18 Examples of aryl)fluorenes include 9,9-bis(C aryl)fluorenes such as 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, and 9,9-bis(2-phenylethyl)-2,7-di(4-pyrenyl)fluorene. 6-10 Aryl C 1-2 alkyl)-2,7-di(pyrenyl)fluorene, and the like.

[0084] 9,9-bis(arylalkyl)-2,7-dicyclic assemblies of polycyclic C 16-18 Examples of arylfluorenes include 9,9-bis(C fluorene)s such as 9,9-bis(phenylmethyl)-2,7-di(p-terphenyl-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, and 9,9-bis(phenylethyl)-2,7-di(m-terphenyl-5′-yl)fluorene. 6-10 Aryl C 1-2 alkyl)-2,7-di(terphenylyl)fluorene.

[0085] Among these fluorene compounds represented by the formula (1), 9,9-bis(C 6-10 Aryl C 1-2 alkyl)-2,7-di(p-terphenylyl)fluorene, 9,9-bis(C 6-10 Aryl C 1-2 Alkyl)-2,7-di(fused polycyclic C 16-18 aryl)fluorene is preferred, and 9,9-bis(C aryl)fluorene such as 9,9-bis(phenylmethyl)-2,7-di(1-pyrenyl)fluorene is preferred from the viewpoint of more effectively improving the quantum efficiency and facilitating an improvement in the absorption coefficient. 6-10 Aryl C 1-2 More preferred is 2,7-di(pyrenyl)fluorene.

[0086] (Method of producing fluorene compound) The fluorene compound represented by formula (1) may be produced by a conventional method, for example, by subjecting a compound represented by formula (2) below and a compound represented by formula (3) below to a coupling reaction (or cross-coupling reaction) according to the following reaction scheme (hereinafter also referred to as method 1).

[0087] [ka]

[0088] (In the formula, X 1a and X 1b each independently represents a group capable of forming a carbon-carbon bond by a coupling reaction, X 2 is the X 1a and / or X 1b represents a group capable of forming a carbon-carbon bond by a coupling reaction together with Z 1 is Z in the formula (1). 1a and / or Z 1b and the same as, including preferred embodiments thereof, R 1 is R in the formula (1) 1a and / or R 1b and k is the same as k1 and / or k2 in the formula (1), including preferred embodiments thereof; 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 the formula (1) above, including preferred embodiments.)

[0089] Examples of the coupling reaction include conventional coupling reactions, for example, coupling reactions using a palladium catalyst (or a palladium(0) catalyst) such as the Suzuki-Miyaura coupling reaction, the Migita-Kosugi-Stille coupling reaction, the Negishi coupling reaction, and the Hiyama coupling reaction, and coupling reactions using a nickel catalyst (or a nickel(0) catalyst) such as the Kumada-Tamao-Corriu coupling reaction, with the Suzuki-Miyaura coupling reaction being preferred.

[0090] Reactive Group X 1a and X 1b and X 2 can be appropriately selected depending on the type of the coupling reaction. When the synthesis is carried out by the Suzuki-Miyaura coupling reaction, one of the reactive groups X 1a and X 1b Examples of the fluorinated alkanesulfonyloxy group include a halogen atom or a fluorinated alkanesulfonyloxy group. Examples of the halogen atom include an iodine atom, a bromine atom, and a chlorine atom. Examples of the fluorinated alkanesulfonyloxy group include a fluorinated C such as a trifluoromethanesulfonyloxy group (or group [-OTf]). 1-4 Examples include an alkanesulfonyloxy group.

[0091] One of these reactive groups X 1a and X 1b may be used alone or in combination of two or more. Of these reactive groups, a halogen atom is preferred, an iodine atom or a bromine atom is more preferred, and a bromine atom is more preferred.

[0092] In the Suzuki-Miyaura coupling reaction, one of the reactive groups X 1a and X 1b and another reactive group X that can be coupled with 2Examples of the boronic acid group include a boronic acid group (dihydroxyboryl group or group [-B(OH)2]), a boronate ester group, etc. Examples of the boronic acid ester group include a dialkoxyboryl group such as a dimethoxyboryl group, a diisopropoxyboryl group, and a dibutoxyboryl group; a pinacolatoboryl group (or group [-Bpin]), a 1,3,2-dioxaborinan-2-yl group, and a 5,5-dimethyl-1,3,2-dioxaborinan-2-yl group, etc.

[0093] The other reactive group X 2 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.

[0094] In addition, the group X 1a and X 1b and group X 2 The reactive groups may be any reactive groups, regardless of the examples given above, as long as they are a pair of reactive groups capable of coupling reaction with each other. For example, the group X 1a and X 1b is the other reactive group such as a boronic acid group, and group X 2 may be one of the reactive groups such as a halogen atom, but the group X 1a and X 1b is one of the reactive groups such as a halogen atom, and the group X 2 is preferably the other reactive group such as a boronic acid group.

[0095] The compound represented by the formula (2) includes 9,9-bis(C fluorene) such as 9,9-bis(phenylmethyl)-2,7-dibromofluorene and 9,9-bis(2-phenylethyl)-2,7-dibromofluorene. 6-10 Aryl C 1-2 alkyl)-dihalofluorene.

[0096] The compound represented by formula (2) may be prepared, for example, by the method described in JP 2009-96782 A, that is, by reacting a 9H-fluorene that is unsubstituted at the 9-position, such as 2,7-dibromofluorene, with a base catalyst such as potassium t-butoxide to generate a fluorene anion having an anion at the 9-position of the fluorene skeleton, and then reacting this fluorene anion with a haloalkylarenes such as (2-bromoethyl)benzene.

[0097] The compound represented by the formula (3) includes compounds represented by the formula (1) 1a and / or Z 1b Examples include boronic acid compounds or boronate ester compounds corresponding to the formula (3), for example, terphenyls having a cyclic boronic ester group such as 2-([1,1':4',1"-terphenyl]-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane; and pyreneboronic acids such as 1-pyreneboronic acid. As the compound represented by formula (3), commercially available products can be used.

[0098] The ratio of the compound represented by the formula (2) to 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, and more preferably 1 / 2.1 to 1 / 2.5.

[0099] When synthesis is carried out by the Suzuki-Miyaura coupling reaction, the reaction is usually carried out in the presence of a palladium catalyst, such as a conventional coupling catalyst, for example, a palladium(0) catalyst or a palladium(II) catalyst.

[0100] Examples of palladium(0) catalysts include palladium(0)-phosphine complexes such as tetrakis(triphenylphosphine)palladium(0) [or Pd(PPh3)4] and bis(tri-t-butylphosphine)palladium(0) [or Pd(P(t-Bu)3)2].

[0101] Examples of palladium(II) catalysts include palladium(II)-phosphine complexes such as [1,2-bis(diphenylphosphino)ethane]palladium(II) dichloride (or PdCl(dppe)], [1,3-bis(diphenylphosphino)propane]palladium(II) dichloride (or PdCl(dppp)], [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (or PdCl(dppf)], bis(triphenylphosphine)palladium(II) dichloride (or PdCl(PPh)), and bis(tri-o-tolylphosphine)palladium(II) dichloride (or PdCl(P(o-tolyl))). When a palladium(II) catalyst is used, the reaction begins by reduction to a zero-valent complex with a reducing compound in the reaction system, such as a phosphine, amine, or organometallic reagent.

[0102] The palladium catalyst may be prepared in situ by adding a catalyst precursor such as tris(dibenzylideneacetone)dipalladium(0) chloroform complex [or Pd2(dba)3·CHCl3] to a ligand such as a phosphine or carbene.

[0103] These catalysts can be used alone or in combination of two or more. Among these catalysts, palladium(0)-phosphine complexes such as Pd(PPh3)4 are preferred. The proportion of the catalyst, calculated as metal, may be, for example, about 0.005 to 0.1 moles, preferably 0.01 to 0.03 moles, per mole of the compound represented by formula (2).

[0104] The Suzuki-Miyaura coupling reaction may be carried out in the presence of a base, such as a metal carbonate or hydrogen carbonate, a metal hydroxide, a metal fluoride, a metal phosphate, a metal organic acid salt, or a metal alkoxide.

[0105] Examples of metal carbonates or hydrogen carbonates include alkali metal carbonates or hydrogen carbonates such as sodium carbonate, potassium carbonate, cesium carbonate, and sodium hydrogen carbonate, and thallium (I) carbonate.

[0106] 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.

[0107] Examples of metal fluorides include alkali metal fluorides such as potassium fluoride and cesium fluoride.

[0108] Examples of metal phosphates include alkali metal phosphates such as tripotassium phosphate.

[0109] Examples of metal organic acid salts include alkali metal acetates such as potassium acetate.

[0110] Examples of metal alkoxides include alkali metal alkoxides such as sodium methoxide, sodium ethoxide, and potassium t-butoxide.

[0111] These bases can be used alone or in combination of two or more. Among these bases, metal carbonates such as potassium carbonate are preferred. The proportion of the base may be, for example, about 0.01 to 100 mol, preferably 1 to 80 mol, and more preferably 10 to 60 mol, per mol of the compound represented by formula (2).

[0112] The coupling reaction may be carried out in the presence or absence of a phase transfer catalyst. Examples of the phase transfer catalyst include tetraalkylammonium halides such as tetrabutylammonium bromide (TBAB) and trioctylmethylammonium chloride. These phase transfer catalysts can be used alone or in combination. Among these phase transfer catalysts, TBAB is preferred.

[0113] The coupling reaction may be carried out in the absence or presence of an inert solvent. Examples of the solvent 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; nitriles such as acetonitrile and benzonitrile; amides such as N,N-dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxides such as dimethyl sulfoxide; and hydrocarbons such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons.

[0114] Examples of cyclic ethers include dioxane, tetrahydrofuran (THF), etc. Examples of chain ethers include diethyl ether, diisopropyl ether, etc.

[0115] Examples of aliphatic hydrocarbons include hexane and dodecane. Examples of alicyclic hydrocarbons include cyclohexane. Examples of aromatic hydrocarbons include toluene and xylene.

[0116] These solvents may be used alone or in combination of two or more. 1 (Z 1a and Z 1b ) is a ring set C 16-18 When using a compound having an arene ring, the reaction does not proceed unless at least an ether is present, and it seems that the compound represented by the formula (1) cannot be prepared. 1 (Z1a and Z 1b ) is a ring set C 16-18 When a compound having an arene ring is used, among the above-mentioned solvents, a mixed solvent of water and ethers, particularly a mixed solvent of water and cyclic ethers such as THF, is preferred; 1 (Z 1a and Z 1b ) is a fused polycyclic C 16-18 When a compound having an arene ring is used, it is preferable to use a mixed solvent of water and an aromatic hydrocarbon such as toluene among the above solvents.

[0117] The coupling reaction may be carried out under an inert gas atmosphere, for example, under an atmosphere of nitrogen or a rare gas such as helium or argon. The reaction temperature is, for example, 50 to 200° C., preferably 60 to 150° C., and more preferably 70 to 130° C. The reaction time may be, for example, about 1 to 48 hours, specifically about 12 to 36 hours.

[0118] After completion of the reaction, the reaction mixture may be separated and purified, if necessary, by a conventional separation and purification method, such as washing, extraction, dehydration, concentration, decantation, crystallization, recrystallization, reprecipitation, column chromatography, or a combination thereof.

[0119] The fluorene compound represented by the formula (1) may also be produced by a second method shown in the following reaction scheme.

[0120] [ka]

[0121] (In the formula, X 3 represents a halogen atom, A 1 is A in the above formula (1) 1a and / or A 1b and the same as, including preferred embodiments thereof, Z 2 is Z in the formula (1). 2a and / or Z 2band the same as, including preferred embodiments thereof, R 3 is R in the formula (1) 3a and / or R 3b and p is the same as p1 and / or p2 in the formula (1), including preferred embodiments thereof; Z 1a , Z 1b , R 1a , R 1b , R 2a , R 2b , k1, k2, m1, m2, n1, n2, m1+n1 and m2+n2 are the same as those in the formula (1) above, including preferred embodiments.

[0122] In the second method, a compound represented by the formula (4) (or Z 1 9H-fluorenes which have a group containing a fluorene group and are unsubstituted at the 9-position) 1a -Z 2a -(R 3a ) p1 ] and the group [-A 1b -Z 2b -(R 3b ) p2 ] (Hereafter, these are referred to as Z 2 In other words, the first method is to react a compound represented by the formula (5) corresponding to Z 1 Containing groups and Z 2 The order of introduction of the containing groups is different.

[0123] X 3 Examples of the halogen atom represented by the formula (I) include a chlorine atom, a bromine atom, and an iodine atom.

[0124] The compound represented by the formula (4) includes Z compounds such as 2,7-diphenylfluorene. 1and 9H-fluorenes having a fluorene-containing group and no substitution at the 9-position. The compound represented by formula (4) may be prepared by a method in which a compound having no substitution at the 9-position of the fluorene skeleton is used instead of the compound represented by formula (2) in the first method, and the method is the same as that described for the first method, including preferred embodiments such as reaction conditions.

[0125] The second method corresponds to using a compound represented by formula (4) as a 9H-fluorene unsubstituted at the 9-position in the method for preparing a compound represented by formula (2), and can be prepared in accordance with the method described in JP 2009-96782 A.

[0126] (Characteristics of fluorene compounds) The fluorene compound represented by the formula (1) has a specific molecular structure, and therefore, when excited by external energy such as light energy or electrical energy, it has at least one emission peak in a specific wavelength region (the maximum wavelength λ of the emission peak in the specific wavelength region). em,max and can emit blue light with extremely high luminescence quantum efficiency. Therefore, the present invention also encompasses a method in which the fluorene compound represented by formula (1) is excited by the external energy or the like to cause the fluorene compound to emit light in a specific wavelength region.

[0127] The luminescence quantum efficiency of the fluorene compound represented by the formula (1) is, for example, about 20% or more, preferably 25 to 50%, in a solid state at a temperature of 25°C. 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, Z is preferably 30 to 45%, more preferably 35 to 40%. 1a and Z 1b is a ring set C 16-18 In the case of arene rings, it is preferably 20 to 35%, more preferably 25 to 30%.

[0128] The fluorene compound represented by the formula (1) has a maximum wavelength λ in the range of, for example, about 400 to 460 nm, preferably 410 to 460 nm, in the emission (fluorescence or phosphorescence) spectrum in a solid state at a temperature of 25°C. em,max and Z 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the ranges of 420 to 460 nm, 435 to 455 nm, and 445 to 455 nm in the following stepwise manner. em,max and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the ranges of 410 to 450 nm, 410 to 435 nm, and 415 to 425 nm in the following stepwise manner. em,max The compound has at least one emission peak having the formula:

[0129] In the solid-state emission spectrum, the maximum wavelength λ em,max The half width of the emission peak (or emission band) having Z is, for example, 100 nm or less, preferably 1 to 70 nm, 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the thickness is preferably 10 to 65 nm, 40 to 60 nm, and 50 to 60 nm in the following stepwise manner. 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the thickness is preferably 10 to 60 nm, 25 to 50 nm, and 35 to 45 nm in the following stepwise manner.

[0130] The fluorene compound represented by the formula (1) has a maximum wavelength λ in the range of, for example, about 250 to 450 nm in the excitation spectrum (or absorption spectrum) in the solid state at a temperature of 25°C. ex,max and Z 1a and Z 1b is a fused polycyclic C 16-18In the case of an arene ring, the maximum wavelength λ is preferably in the range of 260 to 350 nm, more preferably 270 to 300 nm. ex,max and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 350 to 430 nm, more preferably 380 to 420 nm. ex,max It contains at least one emission (absorption) peak having the following structure:

[0131] The solid state may be, for example, a crystalline form such as a single crystal or polycrystal, or an amorphous form, with a crystalline form such as a polycrystal being preferred.

[0132] Furthermore, the fluorene compound represented by the formula (1) can emit light with high quantum efficiency in a specific wavelength range even in the emission spectrum in a solution state, which tends to reflect the pure luminescence characteristics based on the chemical structure.

[0133] 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%, in a dichloromethane solution state at a temperature of 25°C. 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the ratio is preferably 70 to 100%, 80 to 100%, and 85 to 95% in the following stepwise manner: Z 1a and Z 1b is a ring set C 16-18 In the case of arene rings, it is preferably 50 to 60%.

[0134] The fluorene compound represented by the formula (1) has an emission (fluorescence or phosphorescence) spectrum in a dichloromethane solution at a temperature of 25° C., with a maximum wavelength λ in the range of, for example, about 400 to 460 nm, preferably 410 to 460 nm, and more preferably 410 to 450 nm. em,max and Z 1a and Z 1b is a fused polycyclic C16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 415 to 440 nm and 420 to 430 nm in the following stepwise manner. em,max and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 410 to 435 nm and 415 to 425 nm in the following stepwise manner. em,max In the emission spectrum in the solution state, the fluorene compound may have one or more emission peaks, preferably only one emission peak, and more preferably all emission peaks (maximum wavelength λ em,max ) is preferably included in the wavelength range.

[0135] In the emission spectrum in a dichloromethane solution, the maximum wavelength λ em,max The half width of the emission peak (or emission band) having Z may be selected, for example, from the range of 1 to 100 nm, preferably from the range of about 30 to 70 nm. 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the thickness is preferably 40 to 65 nm, 50 to 60 nm, and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the thickness is preferably 30 to 60 nm and 40 to 50 nm in the following stepwise manner.

[0136] The fluorene compound represented by the formula (1) has an excitation spectrum (or absorption spectrum) in a dichloromethane solution at a temperature of 25° C., with a maximum wavelength λ in the range of, for example, about 270 to 400 nm, preferably 300 to 380 nm. ex,max and Z 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 340 to 370 nm. ex,max and Z1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 320 to 350 nm. ex,max It contains at least one emission (absorption) peak having the following structure:

[0137] In measuring the luminescence quantum efficiency, emission spectrum, and excitation spectrum of the dichloromethane solution, the concentration of the fluorene compound is not particularly limited as long as it is sufficiently diluted to a degree that the influence of concentration quenching and the like is not significantly observed. For example, 1×10 -3 ~5×10 -3 g / L or 1 x 10 -6 ~10×10 -6 It may be on the order of mol / L.

[0138] In the present specification and claims, the emission spectrum, excitation spectrum, and luminescence quantum efficiency can be measured by the methods described in the examples below.

[0139] Since the fluorene compound represented by formula (1) exhibits high luminescence quantum efficiency, it may be used as a sensitizer that can sensitize a photosensitive substance (or responsive substance) responsive to light, such as a photopolymerization initiator, a luminescent material (or luminescent compound), etc. The luminescent material (other luminescent material) as the photosensitive substance may be a fluorescent material or a phosphorescent material, and is not particularly limited as long as it can transfer energy from the excited sensitizer (exciton or excited species), i.e., as long as it has a lower excitation energy (band gap) than the energy transferable from the exciton, and conventional luminescent materials such as green to red luminescent materials can be used.

[0140] (Luminescent composition) The luminescent composition (or blue luminescent composition) contains at least the fluorene compound represented by formula (1) as a luminescent material and / or a sensitizer. When the fluorene compound represented by formula (1) is contained as a sensitizer, it is preferable that another luminescent material is contained. The fluorene compound represented by formula (1) can be used alone or in combination of two or more kinds.

[0141] The luminescent composition may or may not further contain a binder component, as necessary, in addition to the fluorene compound represented by formula (1). The inclusion of a binder component tends to dilute the fluorene compound represented by formula (1), thereby suppressing the effect of concentration quenching compared to the solid state. Therefore, using a coating film (luminescent composition) containing a binder as the luminescent layer of an organic electroluminescent device is preferable in terms of high luminescence quantum efficiency and ease or efficiency of production.

[0142] As mentioned above, the ring Z is 1a and Z 1b When the conjugation length increases due to the bonding of , the emission wavelength is expected to become longer. However, compounds containing a large number of aromatic rings (benzene ring skeletons) in their chemical structure generally tend to have reduced dispersibility (compatibility or solubility). Therefore, even in coating films containing binder components, the fluorene compound represented by formula (1) aggregates and cannot be sufficiently diluted, which is expected to result in a decrease in emission quantum efficiency due to concentration quenching, as in the solid state. However, despite having many benzene ring skeletons, the fluorene compound surprisingly can suppress aggregation in the binder component and exhibits unexpectedly high quantum efficiency, making it particularly useful as a blue-emitting material for organic light-emitting diodes (OLEDs).

[0143] As the binder component, for example, a commonly used resin (or polymer compound) can be used, and examples thereof include a thermoplastic resin and a curable resin (thermo- or photo-curable resin).

[0144] Examples of thermoplastic resins include olefin-based resins; (meth)acrylic resins; styrene-based resins; vinyl-based resins, such as vinyl chloride resins and vinyl alcohol-based resins; fluororesins; polycarbonate-based resins; thermoplastic polyester-based resins, such as polyalkylene arylates, polyarylates, and liquid crystal polyesters; polyamide-based resins, such as aliphatic polyamides, alicyclic polyamides, semi-aromatic polyamides, and wholly aromatic polyamides (aramids); polyacetal-based resins; polyphenylene ether-based resins; polyphenylene sulfide-based resins; polysulfone-based resins, such as polysulfone and polyethersulfone; polyetherketone-based resins, such as polyetherketone, polyetheretherketone, and polyetherketoneetherketoneketone; thermoplastic polyimide-based resins, such as polyetherimide-based resins and polyamideimide-based resins; thermoplastic elastomers; and cellulose-based resins, such as cellulose ester-based resins such as triacetyl cellulose and cellulose ether-based resins such as ethyl cellulose.

[0145] Examples of curable resins (thermo- or photo-curable resins) include epoxy resins; urethane-based resins; thermosetting polyester-based resins, such as alkyd resins, unsaturated polyester-based resins, diallyl phthalate resins, and vinyl ester resins; phenolic resins; amino resins, such as melamine resins, urea resins, and guanamine resins; furan resins; thermosetting polyimide-based resins, such as bismaleimide-based resins and bismaleimide triazine resins; and silicon-based resins, such as polysilsesquioxanes.

[0146] These binder components can be used alone or in combination of two or more. Among these binder components, (meth)acrylic resins, styrene resins, polycarbonate resins, and silicon resins are preferred from the viewpoint of facilitating uniform dispersion of the fluorene compound represented by formula (1).

[0147] Examples of the (meth)acrylic resin include (meth)acrylic acid and (meth)acrylic acid C 1-18Alkyl ester, (meth)acrylic acid hydroxy C 2-18 Examples thereof include homopolymers or copolymers of (meth)acrylic monomers such as alkyl, glycidyl (meth)acrylate, and (meth)acrylonitrile; and copolymers of the above-mentioned (meth)acrylic monomers with other copolymerizable monomers.

[0148] Examples of homopolymers or copolymers of (meth)acrylic monomers include poly(meth)acrylic acid esters such as polymethyl(meth)acrylate, methyl methacrylate-(meth)acrylic acid copolymers, methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymers, and methyl methacrylate-(meth)acrylic acid ester copolymers.

[0149] In the copolymer of a (meth)acrylic monomer and another copolymerizable monomer, examples of the copolymerizable monomer include styrene monomers such as styrene and α-methylstyrene, and maleic anhydride.

[0150] Among these (meth)acrylic resins, poly(meth)acrylic acid C such as polymethyl methacrylate 1-8 Alkyl esters are preferred.

[0151] Examples of styrene-based resins include homopolymers or copolymers of styrene-based monomers such as styrene, α-methylstyrene, and vinyltoluene; copolymers of the above-mentioned styrene-based monomers with copolymerizable monomers; and impact-resistant styrene-based resins (i.e., graft copolymers and / or blends (mixtures) with rubber components).

[0152] Examples of homopolymers or copolymers of styrene-based monomers include polystyrenes such as atactic polystyrene, isotactic polystyrene (IPS), and syndiotactic polystyrene (SPS), styrene-vinyltoluene copolymers, and styrene-α-methylstyrene copolymers.

[0153] Examples of copolymers of styrene-based monomers and copolymerizable monomers include styrene-acrylonitrile copolymers (AS resins), styrene-(meth)acrylic acid copolymers, styrene-(meth)acrylic acid ester copolymers (such as MS resins), styrene-maleic anhydride copolymers, styrene-phenylmaleimide copolymers, styrene-butadiene block copolymers, and styrene-butadiene-styrene block copolymers.

[0154] Examples of impact-resistant styrene resins include high impact polystyrene (HIPS); acrylonitrile-butadiene-styrene copolymer (ABS resin); AXS resin, specifically AAS resin, ACS resin, AES resin, etc., in which a rubber component such as acrylic rubber A, chlorinated polyethylene C, or ethylene propylene rubber (or ethylene propylene diene rubber) E is used instead of the butadiene rubber B of the ABS resin; and (meth)acrylic acid ester-butadiene-styrene copolymer, for example, methyl methacrylate-butadiene-styrene copolymer (MBS resin).

[0155] Among these styrene-based resins, homopolymers or copolymers of styrene-based monomers, particularly homopolymers, are preferred.

[0156] Examples of polycarbonate resins include aromatic polycarbonate resins, specifically bisphenol-type polycarbonate resins containing bisphenols or bisphenols as polymerization components, such as bisphenol A-type polycarbonate resins and bisphenol F-type polycarbonate resins.

[0157] Examples of the bi- or bisphenols include bisphenols such as bis(hydroxyaryl)alkanes, bis(hydroxyaryl)-arylalkanes, bis(hydroxyaryl)cycloalkanes, bis(hydroxyaryl)ethers, bis(hydroxyaryl)ketones, bis(hydroxyaryl)sulfides, bis(hydroxyaryl)sulfoxides, and bis(hydroxyaryl)sulfones; and biphenols.

[0158] 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), and 2,2-bis(4-hydroxy-3-isopropylphenyl)propane (bisphenol G).

[0159] Examples of bis(hydroxyaryl)-arylalkanes include 1,1-bis(4-hydroxyphenyl)-1-phenylethane (bisphenol AP) and bis(4-hydroxyphenyl)-diphenylmethane (bisphenol BP).

[0160] Examples of bis(hydroxyaryl)cycloalkanes include 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol Z), and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC).

[0161] Examples of bis(hydroxyaryl) ethers include bis(4-hydroxyphenyl) ether.

[0162] Examples of bis(hydroxyaryl)ketones include bis(4-hydroxyphenyl)ketone.

[0163] Examples of bis(hydroxyaryl)sulfides include bis(4-hydroxyphenyl)sulfide.

[0164] Examples of the bis(hydroxyaryl) sulfoxides include bis(4-hydroxyphenyl) sulfoxide.

[0165] Examples of bis(hydroxyaryl)sulfones include bis(4-hydroxyphenyl)sulfone (bisphenol S).

[0166] Examples of biphenols include o,o'-biphenol, m,m'-biphenol, and p,p'-biphenol.

[0167] These biphenols or bisphenols may be used alone or in combination.

[0168] Among these polycarbonate resins, bisphenol-type polycarbonate resins containing bis(hydroxyaryl)alkanes such as bisphenol A as polymerization components are preferred.

[0169] In silicon-based resins, the polyorganosiloxane (silicone) backbone is composed of monofunctional M units (generally RSiO 1 / 2 (units represented by RSiO 2 / 2 (units represented by the formula (RSiO)), trifunctional T units (generally RSiO 3 / 2 and tetrafunctional Q units (generally SiO 4 / 2 The unit may contain at least one unit selected from the group consisting of units represented by the following formula:

[0170] The group R in the formulae representing the M unit, D unit, and T unit is a substituent, such as an alkyl group, an aryl group, a cycloalkyl group, or a vinyl group.

[0171] Examples of the alkyl group include C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, n-hexyl, n-octyl, 2-ethylhexyl, and n-decyl. 1-12 Examples include alkyl groups.

[0172] Examples of the aryl group include C aryl groups such as phenyl, methylphenyl (tolyl), dimethylphenyl (xylyl), biphenylyl, and naphthyl. 6-14 Examples include an aryl group.

[0173] Examples of cycloalkyl groups include C cyclopentyl, cyclohexyl, and methylcyclohexyl groups. 5-10 Examples include a cycloalkyl group.

[0174] These substituents may be used alone or in combination of two or more. Among these substituents, C 1-4 C such as alkyl group and phenyl group 6-12 An aryl group is preferred, and a C group such as a phenyl group is preferred in terms of facilitating uniform dispersion of the fluorene compound. 6-10 Aryl groups are particularly preferred.

[0175] Examples of the terminal group (a group bonded to the terminal silicon (Si) atom) include a hydroxyl group, an alkoxy group, and a halogen atom such as a chlorine atom. Examples of the alkoxy group include C groups such as a methoxy group and an ethoxy group. 1-4 Alkoxy groups are preferred, and C 1-2 It is an alkoxy group.

[0176] These terminal groups can be used alone or in combination of two or more. Among these terminal groups, hydroxyl groups, C 1-2 In many cases, it is an alkoxy group.

[0177] The silicon-based resin preferably contains at least one unit selected from the T unit and the Q unit, particularly preferably the T unit, in order to facilitate the formation of a coating film. The proportion of T units in the entire silicon-based resin is, for example, 50 mol% or more, with preferred ranges being 60 mol% or more, 70 mol% or more, 80 mol% or more, 90 mol% or more, and 95 mol% or more, in the following stepwise order. In particular, the silicon-based resin is a silsesquioxane (or polysilsesquioxane) that is substantially 100 mol%. The proportion of T units in the entire silicon-based resin can be selected from the range of, for example, about 60 to 100 mol%, and may preferably be 80 to 99.9 mol%.

[0178] Silsesquioxane (or polysilsesquioxane) may be ladder-shaped or cage-shaped, but a three-dimensional network structure (network or random structure) is preferred from the viewpoint of ease of forming a coating film. Examples of such silsesquioxane include polyalkylsilsesquioxanes formed from T units (alkylsilsesquioxane units) in which the substituent R is an alkyl group, such as polyC such as polymethylsilsesquioxane. 1-4 alkylsilsesquioxanes, etc.; polyarylsilsesquioxanes formed with T units (arylsilsesquioxane units) where R is an aryl group, for example, polyC such as polyphenylsilsesquioxanes; 6-12 aryl silsesquioxanes; polysilsesquioxanes formed from T units where R is an alkyl group and T units where R is an aryl group; and the like.

[0179] These silsesquioxanes can be used alone or in combination of two or more. Among these silsesquioxanes, polyarylsilsesquioxanes formed by T units in which R is an aryl group are preferred, and polyC such as polyphenylsilsesquioxane is particularly preferred. 6-10 Aryl silsesquioxanes are preferred.

[0180] Preferred binder components include Z 1a and Z1b is a fused polycyclic C 16-18 In the case of an arene ring, a (meth)acrylic resin, a styrene resin, or a polycarbonate resin is preferred, and a styrene resin or a polycarbonate resin is more preferred. 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, a (meth)acrylic resin or a polycarbonate resin is preferred, and a (meth)acrylic resin may also be used. Combining these binder components with the fluorene compound appears to facilitate effective improvement of the luminescence quantum efficiency.

[0181] The proportion of the binder component may be selected from the range of, for example, about 1 to 99.99% by mass, or about 10 to 99.9% by mass, based on the total solid content, and may be preferably 20 to 90% by mass, 30 to 70% by mass, or 40 to 60% by mass in the following stepwise manner, and more preferably 30 to 99% by mass, 50 to 95% by mass, or 80 to 93% by mass in the following stepwise manner. The ratio of the fluorene compound represented by formula (1) to the binder component may be selected, for example, from a range of about 1 / 0.5 to 1 / 1000 (mass ratio) of the former to the latter, preferably 1 / 0.7 to 1 / 200, 1 / 0.8 to 1 / 100, and more preferably 1 / 1 to 1 / 50, 1 / 1 to 1 / 40, 1 / 2 to 1 / 30, 1 / 4 to 1 / 20, and 1 / 6 to 1 / 15, in order to effectively suppress a decrease in luminescence quantum efficiency. If the ratio of the binder component is too low, luminescence quantum efficiency may decrease due to concentration quenching, and if the ratio of the binder component is too high, luminescence intensity may decrease (or bright light may not be emitted).

[0182] The luminescent composition (or coating agent) may further contain a solvent to adjust the viscosity and improve application (or handling) properties, and the solvent may be dried and removed from the coating film after application. Examples of the solvent include hydrocarbons, halogenated hydrocarbons, alcohols, glycols, ethers, glycol ethers, glycol ether acetates, ketones, carboxylic acids, esters, carbonates, nitriles, amides, sulfoxides, water, and mixed solvents thereof.

[0183] Examples of hydrocarbons include aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as toluene and xylene.

[0184] Examples of halogenated hydrocarbons include dichloromethane, chloroform, 1,2-dichloroethane, and chlorobenzene.

[0185] Examples of alcohols include C 1, C 2, C 3, C 4, C 5, C 6, C 7, C 8, C 9, C 10, C 11, C 12, C 13, C 14, C 15, C 16, C 17, C 18, C 19, C 20, C 21, C 22, C 23, C 24, C 25, C 36, C 1-6 Alkanols and the like.

[0186] Examples of glycols include (poly)C such as ethylene glycol, propylene glycol, and diethylene glycol. 2-4 alkylene glycols and the like.

[0187] Examples of the ethers include chain ethers such as diethyl ether, and cyclic ethers such as tetrahydrofuran and 1,4-dioxane.

[0188] Examples of glycol ethers include (poly)C such as cellosolves, carbitols, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. 2-4 Alkylene glycol mono C1-4 Alkyl ethers; (poly)C such as ethylene glycol dimethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, and dipropylene glycol dimethyl ether 2-4 Alkylene glycol di C 1-4 Alkyl ethers and the like.

[0189] Examples of the cellosolves include C methyl cellosolve, ethyl cellosolve, etc. 1-4 Examples of the carbitols include C carbitols such as methyl carbitol and ethyl carbitol. 1-4 Alkyl carbitol and the like.

[0190] Examples of glycol ether acetates include (poly)C such as cellosolve acetates, carbitol acetates, propylene glycol monomethyl ether acetate, and dipropylene glycol monobutyl ether acetate. 2-4 Alkylene glycol mono C 1-4 Alkyl ether acetates and the like.

[0191] Examples of the cellosolve acetates include C methyl cellosolve acetate. 1-4 Examples of the carbitol acetates include C carbitol acetates such as methyl carbitol acetate. 1-4 Alkyl carbitol acetates and the like.

[0192] Examples of ketones include chain ketones such as acetone and methyl ethyl ketone, and cyclic ketones such as cyclohexanone.

[0193] Examples of carboxylic acids include acetic acid and propionic acid.

[0194] Examples of esters include acetate esters such as methyl acetate, ethyl acetate, and butyl acetate, and lactate esters such as methyl lactate.

[0195] Examples of carbonates include chain carbonates such as dimethyl carbonate, and cyclic carbonates such as propylene carbonate.

[0196] Examples of nitriles include acetonitrile, propionitrile, and benzonitrile.

[0197] Examples of amides include N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone.

[0198] The sulfoxides include, for example, dimethyl sulfoxide.

[0199] 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.

[0200] The proportion of the solvent is not particularly limited and can be appropriately selected depending on the viscosity of the luminescent composition, etc. The solids concentration of the luminescent composition is, for example, 0.01 to 50 mass%, preferably 0.1 to 10 mass%, more preferably 0.5 to 10 mass%, and particularly preferably 0.5 to 2 mass%.

[0201] The luminescent composition may contain conventional additives. Examples of conventional additives include dyes, pigments, pigment dispersants, wetting agents, thickeners, coupling agents, antifoaming agents, antisettling agents, antiskinning agents, polymerization inhibitors, polymerization initiators, curing agents, leveling agents, thixotropic agents, color separation inhibitors, matting agents, flame retardants, stabilizers, plasticizers, softeners, lubricants, release agents, and antistatic agents. Examples of the stabilizers include antioxidants, ultraviolet absorbers, light stabilizers, and antiozonants.

[0202] In addition, the coating agent may be substantially free of additives because the additives may absorb the excitation light for exciting the fluorene compound (light-emitting material) and the light emitted by the excited light-emitting material. Therefore, the light-emitting composition preferably contains at least the fluorene compound represented by formula (1) and, if necessary, only a binder component and / or a solvent, i.e., a composition substantially free of additives.

[0203] The luminescent properties of a luminescent composition containing a binder component or a coating film formed using this composition may be adjusted appropriately depending on the type and concentration of the fluorene compound, binder component, etc.

[0204] The luminous quantum efficiency of the luminous composition (or coating film) containing the binder component may be selected from a range of, for example, about 30% or more at a temperature of 25°C, preferably 50 to 100%, more preferably 70 to 100%, and Z 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the ratio is preferably 75 to 100%, 80 to 100%, and 85 to 95% in the following stepwise manner: Z 1a and Z 1b is a ring set C 16-18 In the case of arene rings, the proportions are preferably 75 to 90% and 75 to 85% in the following stepwise manner.

[0205] The luminescent composition (or coating film) has an emission (fluorescence or phosphorescence) spectrum at a temperature of 25° C. with a maximum wavelength λ in the range of, for example, about 400 to 460 nm, preferably 410 to 460 nm, and more preferably 410 to 450 nm. em,max and Z 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 415 to 440 nm and 420 to 430 nm in the following stepwise manner. em,max and Z 1a and Z 1b is a ring set C16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 415 to 440 nm and 420 to 435 nm in the following stepwise manner. em,max 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, preferably only one emission peak, and more preferably all emission peaks (maximum wavelength λ em,max ) is preferably included in the wavelength range.

[0206] In the emission spectrum of the luminescent composition (or coating film), the maximum wavelength λ em,max The half-value width of the emission peak (or emission band) having Z may be selected, for example, from the range of about 1 to 100 nm, and is preferably 30 to 70 nm. 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the thickness is preferably 40 to 65 nm, 50 to 60 nm, and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the thickness is preferably 40 to 60 nm and 45 to 55 nm in the following stepwise manner.

[0207] The luminescent composition (or coating film) has an excitation spectrum (or absorption spectrum) at a temperature of 25°C, with a maximum wavelength λ in the range of, for example, about 300 to 400 nm, preferably 320 to 380 nm, and more preferably 340 to 370 nm. ex,max and Z 1a and Z 1b is a fused polycyclic C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 350 to 360 nm. ex,max and Z 1a and Z 1b is a ring set C 16-18 In the case of an arene ring, the maximum wavelength λ is preferably in the range of 345 to 360 nm. ex,maxIt contains at least one emission (absorption) peak having the following structure:

[0208] Such a luminescent composition can be used in various forms or applications, for example, as a coating agent such as a paint or an ink composition. The luminescent composition may also be used as an invisible ink such as the security ink (or security marker) described in JP-A-2020-164518.

[0209] (Light-emitting element or photoelectric conversion element) The light-emitting element (or photoelectric conversion element) may contain at least the fluorene compound represented by the formula (1) as a light-emitting material and / or a sensitizer, and may contain the fluorene compound in the form of the light-emitting composition, for example, a coating film, etc. When the fluorene compound represented by the formula (1) is contained as a sensitizer, it is preferable that another light-emitting material is contained.

[0210] Representative examples of 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 (OLEDs)), with organic EL elements being preferred. Current-injection light-emitting elements such as organic EL elements are formed from an anode (transparent electrode) and a cathode (metal electrode), with an organic layer (organic thin film) or an organic-inorganic hybrid layer interposed between the electrodes. A typical configuration preferably has the layers formed in the following order: transparent substrate / anode / hole transport layer / light-emitting layer / electron transport layer / cathode. Note that if the light-emitting layer functions as a hole transport layer or electron transport layer, the hole transport layer or electron transport layer is not necessarily required.

[0211] Examples of transparent substrates include substrates made of inorganic materials such as glass; and substrates made of organic materials such as (meth)acrylic resins, styrene resins, polycarbonate resins, and polyester resins. Examples of polyester resins include polyalkylene arylate resins such as polyethylene terephthalate. The substrate may be in the form of a plate, sheet, or film.

[0212] The anode may be a transparent electrode, and is preferably made of a conductive metal oxide such as ITO (indium tin oxide), FTO (fluorine-doped tin oxide), or ZnO (zinc oxide).

[0213] Examples of hole transport materials for forming the hole transport layer include aromatic amines, phthalocyanines such as copper phthalocyanine, and conductive polymers such as polythiophenes. Specifically, the hole transport materials described in JP 2020-164518 A (Patent Document 1) may be used. These hole transport materials may be used alone or in combination. Among these, conductive polymers such as PEDOT:PSS are preferred.

[0214] The light-emitting layer may contain a fluorene compound represented by formula (1) as a light-emitting material, or may contain other conventional light-emitting materials. These light-emitting materials may be used alone or in combination of two or more. The light-emitting layer may be composed of only the light-emitting material, or may contain the light-emitting material as a guest material (or dopant) and a host material. Examples of host materials include host materials described in JP-A-2020-164518 (Patent Document 1), such as biphenyls; and binder components exemplified in the section on the light-emitting composition, such as (meth)acrylic resins, polycarbonate resins, and silicon resins. These host materials may be used alone or in combination of two or more.

[0215] Examples of electron transport materials that form the electron transport layer include light metal organic complexes such as aluminum complexes and beryllium complexes, bisstyrylarene derivatives, oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, and silole derivatives, and may also be the electron transport materials described in JP-A-2020-164518 (Patent Document 1). These electron transport materials can be used alone or in combination of two or more.

[0216] The cathode (metal electrode) is often formed of a single metal such as aluminum (Al), magnesium (Mg), or silver (Ag), or an alloy of these metals.

[0217] 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 (electron injection layer) such as an inorganic thin film such as a lithium fluoride (LiF) thin film or a lithium oxide (LiO) thin film, or an organic thin film doped with a metal such as lithium (Li) may be formed between the cathode and the electron transport layer.

[0218] 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. [Example]

[0219] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Evaluation methods are also shown below.

[0220] [Evaluation method] (NMR) Measurement was carried out using BRUKER's "ULTRASHIELD300".

[0221] (HPLC) Measurement was carried out using Shimadzu Corporation's "LC-20A."

[0222] (luminous characteristics) Using a spectrofluorometer (Hitachi High-Technologies Corporation "F-4500", light source: xenon lamp, detector: photomultiplier tube, spectroscope: diffraction grating), the excitation spectrum and emission (fluorescence or phosphorescence) spectrum of the sample were measured at room temperature (25°C), and the maximum wavelength λ of the excitation spectrum was measured. ex,max , the maximum wavelength λ of the emission spectrum em,max , and this λ em,maxThe half-width of the peak (or emission band) containing

[0223] (Quantum Efficiency) A fluorescence spectrophotometer (JASCO FP-6500, light source: xenon lamp, detector: photomultiplier tube, spectrometer: diffraction grating) equipped with a fluorescence integrating sphere unit (JASCO ILF-533, 100 mm diameter) was used. Spectral correction was performed using the instrument function obtained with the attached calibration standard light source, and the spectral area and photon count were proportional to each other. The luminescence quantum efficiency was then calculated using the absolute method. The excitation light was measured without a sample to determine the spectral area of ​​the irradiated excitation light. Next, the excitation light was measured with a sample to determine the spectral area of ​​the irradiated excitation light not absorbed by the sample. The number of photons absorbed by the sample was calculated by subtracting these values. The emission spectrum of the sample was simultaneously observed, and the number of emitted photons was calculated from the spectral area. Finally, the luminescence quantum efficiency was calculated from the number of emitted photons relative to the number of absorbed photons.

[0224] [Preparation of fluorene compounds] Example 1 Preparation of BEPF-TPh

[0225] [ka]

[0226] In a 100 mL three-necked flask, 9,9-bis(2-phenylethyl)-2,7-dibromofluorene [also referred to as BEPF-Br] (0.266 g, 0.50 mmol) represented by the above formula (2-1), prepared in accordance with Synthesis Example 1 of JP 2020-164518 A (Patent Document 1), 2-([1,1':4',1"-terphenyl]-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.392 g, 1.1 mmol) represented by the above formula (3-1), 2 M aqueous potassium carbonate solution (5 mL), and tetrahydrofuran (THF, 20 mL) were placed. Pd(PPh3)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.

[0227] After returning to room temperature, dichloromethane (10 mL) and distilled water (20 mL) were added for extraction. The organic layer was washed with distilled water (20 mL x 2). The washed organic layer was dehydrated with magnesium sulfate, and the solvent was removed to obtain a yellow solid.

[0228] After purifying by silica gel chromatography (solvent: hexane / dichloromethane = 10 / 1 (volume ratio)), recrystallization (solvent: toluene) was performed to obtain 9,9-bis(2-phenylethyl)-2,7-di(p-terphenyl-4-yl)fluorene (also called BEPF-TPh) represented by the above formula (1-2) as pale yellow crystals (0.172 g, yield 41%). 1 The results of the 1 H NMR spectrum are shown below.

[0229] 1 H NMR (600MHz, CDCl3): 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).

[0230] (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. However, the reaction did not proceed, and BEPF-TPh was not obtained (yield by NMR: 0%).

[0231] Example 2: Preparation of BEPF-Py

[0232] [ka]

[0233] A 100 mL three-necked flask was charged with BEPF-Br (0.106 g, 0.20 mmol) represented by the above formula (2-1), 1-pyreneboronic acid (0.108 g, 0.44 mmol) represented by the above formula (3-2), 2 M aqueous potassium carbonate solution (2 mL), and toluene (5 mL). Pd(PPh3)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.

[0234] After returning to room temperature, dichloromethane (10 mL) and distilled water (20 mL) were added for extraction. The organic layer was washed with distilled water (20 mL x 2). The washed organic layer was dehydrated with magnesium sulfate, and the solvent was removed to obtain a yellow solid.

[0235] After purifying by silica gel chromatography (solvent: hexane / dichloromethane = 10 / 1 (volume ratio)), recrystallization (solvent: toluene) was performed to obtain 9,9-bis(2-phenylethyl)-2,7-di(1-pyrenyl)fluorene (also called BEPF-Py) represented by the above formula (1-2) as white crystals (0.102 g, yield 66%). 1 The results of the 1 H NMR spectrum are shown below.

[0236] 1H NMR (600MHz, CDCl3): 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).

[0237] (Comparative Example 1) Preparation of BEPF According to Reference Example 1 of JP 2020-164518 A (Patent Document 1), 9,9-bis(2-phenylethyl)fluorene (also referred to as BEPF) represented by the following formula was prepared.

[0238] [ka]

[0239] (Comparative Example 2) Preparation of BEPF-Ph According to Example 1 of JP 2020-164518 A (Patent Document 1), 9,9-bis(2-phenylethyl)-2,7-diphenylfluorene (also referred to as BEPF-Ph) represented by the following formula was prepared.

[0240] [ka]

[0241] (Comparative Example 3) Preparation of BEPF-BPh According to Example 4 of JP 2020-164518 A (Patent Document 1), 9,9-bis(2-phenylethyl)-2,7-di(4-biphenylyl)fluorene (also referred to as BEPF-BPh) represented by the following formula was prepared.

[0242] [ka]

[0243] (Comparative Example 4) Preparation of BEPF-Np According to Example 3 of JP 2020-164518 A (Patent Document 1), 9,9-bis(2-phenylethyl)-2,7-di(2-naphthyl)fluorene (also referred to as BEPF-Np) represented by the following formula was prepared.

[0244] [ka]

[0245] [Emission properties of fluorene compounds] (Light-emitting properties in the solid state) The solid-state excitation and emission spectra, as well as the luminescence quantum efficiency, of the fluorene compounds prepared in the Examples and Comparative Examples were measured. Table 1 shows the correspondence between the samples and the obtained spectra, as well as the conditions for measuring the spectra, and Table 2 and Figures 1 and 2 show the measurement results. In Table 1, "emission wavelength" refers to the wavelength at which the emission intensity was monitored in the excitation spectrum, and "excitation wavelength" refers to the wavelength of the excitation light in the emission spectrum (the same applies hereinafter).

[0246] [Table 1]

[0247] [Table 2]

[0248] (Emission characteristics in solution) The fluorene compounds prepared in the 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, as well as the spectrum measurement conditions, and Table 4 and Figures 3 and 4 show the measurement results.

[0249] In addition, in the measurement of the solution state, all of the examples and comparative examples were sufficiently diluted, and no significant effects such as concentration quenching were observed.

[0250] [Table 3]

[0251] [Table 4]

[0252] As is clear from Tables 2 and 4 and Figures 1 to 4, in the examples, unlike the comparative examples, the maximum wavelength λ in the wavelength region of 410 to 460 nm in the emission spectrum was em,max It had blue light emission.

[0253] As mentioned above, it is generally expected that increasing the number of aromatic rings in a chemical structure through condensation or single bonds will increase the conjugation length and the emission wavelength, but it is not possible to predict how much the wavelength will increase. For example, pentacene, which has five benzene rings, has maximum wavelengths λ of 537 nm and 582 nm in solution. em,max In contrast to the examples, in which terphenyl rings or pyrene rings are bonded to the 2- and 7-positions of the fluorene ring, respectively, and although the structure has more benzene ring skeletons connected than pentacene, the light emitted is blue without shifting to a longer wavelength region into the green wavelength region. Furthermore, in the examples, not only does the light emit blue light in the specific wavelength region, but the quantum efficiency is high and the light is emitted with a relatively narrow half-width, but these light emission characteristics are also difficult to predict from the chemical structure.

[0254] The luminescence characteristics based on the compound (or chemical structure) are reflected in the results (Table 4) particularly in the solution state, and the fluorene compounds of the examples were found to be particularly suitable as blue luminescent materials because they can emit light in the wavelength range of 410 to 460 nm (brighter and purer blue). In particular, the quantum efficiency of BEPF-Py of Example 2 was not only remarkably high, but also unexpectedly showed a single emission peak, and the monochromaticity of visible light (blue emission) was high. In particular, the Z of BEPF-Py 1a , Z 1bPyrene, a compound equivalent to β-pyrene, is known to exhibit a single emission peak on the longer wavelength side in the excimer (excited dimer) state, but to exhibit multiple emission peaks on the shorter wavelength side in the monomer state (solution state) (the peak is split into smaller peaks). Therefore, it was unexpected that BEPF-Py exhibited a single emission peak in the wavelength region of 410 to 460 nm.

[0255] (Light-emitting properties in the coated film state) As shown in Table 6, 0.001 g of each fluorene compound prepared in the Examples or Comparative Examples and 0.01 g of each binder component described below were mixed in chloroform to a predetermined solid content concentration (Examples: 1 mass %, Comparative Examples: 5 mass %) to prepare a mixed solution (coating agent).

[0256] Each of the obtained coating agents was applied to 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 dried on a hot plate at 90°C for 30 minutes to form a coating film. The excitation spectrum, emission spectrum, and emission quantum efficiency of each formed coating film were measured. Table 5 shows the correspondence between the sample and the obtained spectrum, as well as the spectral measurement conditions, and Table 6 and Figures 5 to 12 show the measurement results. The resins used as binder components are listed below.

[0257] PS: Polystyrene, manufactured by PS Japan Co., Ltd. PC: Polycarbonate, manufactured by Mitsubishi Engineering Plastics Corporation PMMA: Polymethyl methacrylate, manufactured by Mitsubishi Rayon Co., Ltd. PPSQ: Polyphenylsilsesquioxane, prepared by the method described below.

[0258] 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 were mixed, and the mixture was heated and stirred at 90°C for 3 hours to carry out hydrolysis and condensation reactions, followed by drying. After cooling, the remaining acid was washed away with pure water, and 1.5 mL of tetrahydrofuran was added to reconstitute the solution. This was heated and stirred at 110°C for 2 hours, followed by drying, to synthesize PPSQ represented by the following formula.

[0259] [ka]

[0260] [Table 5]

[0261] [Table 6]

[0262] As is clear from Table 6 and Figures 5 to 12, even in the state of a coating film containing a binder component, the Examples differ from the Comparative Examples in that the maximum wavelength λ in the emission spectrum is in the wavelength region of 410 to 460 nm. em,max and emitted light with a relatively narrow half-width. Furthermore, high quantum efficiency was observed in all binder components. As in Patent Document 1, in ultraviolet-emitting organic electroluminescence (EL) applications, the luminescent material is actually used in a solid state without a binder component due to the tendency for energy transfer from the luminescent material to the binder component, and therefore the luminescent properties in the solid state are important. In contrast, in visible light (blue)-emitting EL applications, where the energy transfer is less likely to occur, the luminescent properties in the coated film state are important. Therefore, the fluorene compounds of the examples, which exhibit excellent quantum efficiency in the wavelength region, can be suitably used in blue-emitting EL applications.

[0263] Furthermore, as mentioned above, although an increase in conjugation length is expected to result in a longer emission wavelength, the inclusion of many aromatic rings in the chemical structure generally reduces dispersibility, and in particular in the coated film state, molecules (light-emitting materials) tend to aggregate, which is expected to result in a decrease in emission quantum efficiency due to concentration quenching. However, despite having a considerable number of benzene ring skeletons, the fluorene compounds of the examples exhibit unexpectedly high quantum efficiency in the coated film state, making them particularly useful as blue-emitting materials for organic light-emitting diodes (OLEDs). The quantum efficiency of BEPF-TPh in Example 1 was surprisingly significantly improved in the coated film state compared to the solution state.

[0264] Furthermore, when the luminescence characteristics of BEPF-Py in Example 2 were evaluated by preparing a coating film with a solids concentration of 5% by mass (i.e., a thick coating film), the film absorbed too much light, resulting in saturated measurements (all light was absorbed by the film, making it impossible to detect changes in the absorption coefficient with wavelength, resulting in a trapezoidal excitation spectrum rather than a peak). In the comparative example (solids concentration of 5% by mass), no saturation was observed for any of the fluorene compounds, 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 absorption coefficient (ability to absorb light) and luminescence quantum efficiency (conversion efficiency from absorbed excitation light), BEPF-Py with high absorption coefficients is thought to be able to emit light more brightly. [Industrial Applicability]

[0265] The fluorene compound of the present invention can be effectively used as a light-emitting material and / or a sensitizer, particularly as a blue light-emitting material. In particular, unlike inorganic light-emitting bodies formed from inorganic materials, the fluorene compound is soluble in organic solvents, easily disperses uniformly in matrix materials such as various resins, and can easily and efficiently form a coating layer or a paint film on substrates with complex shapes. Therefore, the fluorene compound can be effectively used as a light-emitting material and / or a sensitizer in applications such as coating agents for invisible inks and light-emitting devices (or photoelectric conversion devices).

[0266] Examples of the light-emitting element (or photoelectric conversion element) include current injection type light-emitting elements such as organic EL elements, etc. Representative examples include light sources for displays and lighting, etc., which can be effectively used in various applications.

Claims

1. A compound represented by the following formula (1): 【Chemistry 1】 (In the formula, Z １ａ and Z １ｂ each independently represents a terphenylene ring or a pyrene ring, R １ａ and R １ｂ are each independently an alkyl group, a cycloalkyl group, a halogen atom, a hydroxyl group, a group [—OR Ａ ] (wherein, R Ａ represents an alkyl group or a cycloalkyl group), a hydroxy(poly)alkoxy group, a thiol group, a group [—SR Ａ ] (wherein, R Ａ represents an alkyl group or a cycloalkyl group), a carboxyl group, an alkoxycarbonyl group, an amino group, a cyano group, a trialkylsilyl group, or a dialkylhydrosilyl group; k1 and k2 each independently represent an integer of 0 to 2; m1 and m2 represent 1; R ２ａ and R ２ｂ each independently represents a hydrocarbon group (excluding an aryl group), n1 and n2 each independently represent an integer of 0 to 2, A １ａ and A １ｂ are each independently a linear or branched chain C １－４ represents an alkylene group, Z ２ａ and Z ２ｂ are each independently C ６－１２ represents an arene ring, and R ３ａ and R ３ｂ are each independently C １－４ represents an alkyl group, a hydroxyl group, or a carboxyl group, and p1 and p2 each independently represent an integer of 0 to 2.

2. In the formula (1), Z １ａ and Z １ｂ is a pyrene ring, Z ２ａ and Z ２ｂ The compound according to claim 1, wherein is a benzene ring, a naphthalene ring or a biphenyl ring.

3. In the emission spectrum in dichloromethane solution, the maximum wavelength λ ｅｍ，ｍａｘ 3. The compound according to claim 1, which is a blue light-emitting material having at least one emission peak with a wavelength of 410 to 460 nm and a half-width of 70 nm or less, and having a luminescence quantum efficiency of 40% or more.

4. A method for producing the compound according to any one of claims 1 to 3, comprising either the following step (i) or (ii): (i) a step of subjecting a compound represented by the following formula (2) to a coupling reaction with a compound represented by the following formula (3): 【Chemistry 2】 (In the formula, X １ａ and X １ｂ each independently represents a group capable of forming a carbon-carbon bond by a coupling reaction, X ２ is the X １ａ and / or X １ｂ represents a group capable of forming a carbon-carbon bond by a coupling reaction together with Z １ is Z in the formula (1). １ａ and / or Z １ｂ is the same as R １ is R in the formula (1). １ａ and / or R １ｂ and k is the same as k1 and / or k2 in formula (1), Z ２ａ , Z ２ｂ , R ２ａ , R ２ｂ , R ３ａ , R ３ｂ , A １ａ , A １ｂ , m1, m2, n1, n2, p1 and p2 are the same as in formula (1). (ii) In the step (i), Z of the compound represented by the formula (3) １ is a terphenylene ring, reacting in the presence of an ether

5. A method for exciting the compound according to any one of claims 1 to 3 to cause it to emit light.

6. A luminescent composition comprising the compound according to any one of claims 1 to 3.

7. The luminescent composition according to claim 6, further comprising a binder component.

8. 8. The luminescent composition according to claim 7, wherein the binder component contains at least one resin selected from the group consisting of (meth)acrylic resins, styrene resins, polycarbonate resins, and silicon resins.

9. 9. The luminescent composition according to claim 7, wherein the ratio of the compound represented by formula (1) to the binder component is the former / latter (mass ratio) = 1 / 0.5 to 1 / 1000.

10. In the emission spectrum, the maximum wavelength λ ｅｍ，ｍａｘ 10. The luminescent composition according to claim 6, which has at least one luminescence peak having a wavelength of 410 to 460 nm and a half-value width of 70 nm or less, and has a luminescence quantum efficiency of 70% or more.

11. A light-emitting device comprising the compound according to any one of claims 1 to 3.

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