JP2008214344A - Aryl ethynyl compound, two-photon absorbing material and optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-photon absorbing material that exhibits easily two-photon absorption with its large cross-sectional area for two-photon absorption and is excellent in stability, solubility and efficiency. <P>SOLUTION: The two-photon absorbing compound containing as at least part of its components a new aryl ethynyl compound represented by formula (I) is provided (wherein, the center ring D indicates a 4-6C aromatic ring; Arx<SP>1</SP>to Arx<SP>4</SP>indicate each independently an aromatic ring or a substituent formed by combination of a plurality of aromatic-ring groups and linking groups). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a novel arylethynyl compound and a two-photon absorption material having a large two-photon absorption cross-section that can be applied to high-density optical recording media, three-dimensional optical modeling, and photodynamic therapy.
The present invention also relates to an optical recording medium containing the two-photon absorption material in a recording layer, and a recording / reproducing method for the optical recording medium.

  Two-photon absorption is a phenomenon in which a compound absorbs two photons and transitions from a ground state to an excited state, and two photons are converted into one by using light having a wavelength about twice the one-photon excitation wavelength. It can be excited by hitting a molecule. The probability of two photons hitting a molecule simultaneously is proportional to the square of the photon density, and when the laser beam is focused on the sample, the photon density is proportional to the square of the distance as it moves away from the focal plane. Then decrease. Therefore, the probability that two-photon absorption will occur decreases in proportion to the fourth power of the distance as the distance from the focal plane increases. Utilizing this phenomenon, application of two-photon absorption is expected in fields such as high-density optical recording media, three-dimensional stereolithography, and photodynamic therapy. In addition, two-photon emission, which is emitted in the radiation deactivation process from the excited state absorbed by two-photons, can extract light with a wavelength shorter than the wavelength of the incident light (= light with high energy), so that it is a light conversion material and a photosensitizer. As well as research.

  What is important when two-photon absorption is applied in various fields is a two-photon absorption cross section indicating the likelihood of two-photon absorption. In recent years, a compound having a high two-photon absorption cross-section has been disclosed in Patent Document 1. -3 and Non-Patent Documents 1-5.

  Among these, the fluorescence method is used for the two-photon absorption cross section measurement described in Patent Document 1 and Patent Document 2, but a large error is included because a compound having low fluorescence emission efficiency is evaluated. In addition, since the linear absorption of the compound is close to the excitation wavelength and the influence of the linear absorption overlaps, there are drawbacks in that the two-photon absorption cross section is largely estimated. In addition, examples of the compound are limited to cyanine-based compounds, and this compound is an ionic dye, which contributes to an increase in the two-photon absorption cross-sectional area. It has the disadvantage of being hardly soluble in organic solvents with low polarity.

  The compound described in Patent Document 3 also has an ionic property, which contributes to an increase in the two-photon absorption cross section, but is therefore hardly soluble in a low-polarity organic solvent such as toluene. Has the disadvantages.

  The compounds described in Non-Patent Documents 1 to 3 are porphyrin compounds, but are excited by linear absorption because linear absorption extends to near the excitation wavelength or has linear absorption at the excitation wavelength. It is strongly influenced by excited state absorption from the state. Therefore, a direct comparison with the usual two-photon absorption cross-section measurement value is not possible. Also, since it is easily affected by linear absorption in application, there is a drawback that it is difficult to use a characteristic effect in a two-photon absorption phenomenon such as causing absorption only in the vicinity of the focal point.

  The two-photon absorption cross-section measuring method described in Non-Patent Documents 4 and 5 uses a fluorescence method. This method measures the two-photon fluorescence intensity of the compound (= reference substance) and the target substance described in Non-Patent Document 6 with the same optical system, and calculates the relative cross-sectional area from the two-photon absorption cross-section of the reference substance. Although it is a calculation method, it tends to show a large cross-sectional area as compared with the transmission method that directly measures the two-photon absorption cross-sectional area. In addition, since the two-photon absorption cross section is affected by the pulse width, repetition frequency, and focusing conditions of the laser used, the measured values of both methods cannot be directly compared. Further, the paracyclophane compound shown in Non-Patent Document 5 has a drawback that it is difficult to synthesize.

  Regarding tetraethynylbenzene compounds, Non-Patent Documents 7 and 8 report that the third-order nonlinear optical constant is large, and reports on the correlation between the molecular structure and the absorption spectrum and fluorescence spectrum. There is no description regarding the area, and the spread of the conjugated system of the compound described is not sufficient, and it is not considered that a large two-photon absorption cross section can be obtained.

Similarly, regarding the hexaethynylbenzene compound having a similar structure, it has been reported in Non-Patent Document 9 that the second-order nonlinear optical constant is large, but there is no description and description regarding the two-photon absorption cross section. The spread of the conjugated system of the compound is not sufficient, and it is not considered that a large two-photon absorption cross section can be obtained.
JP-A-2005-164817 JP 2005-25152 A JP 2005-132663 A J. Phys. Chem. B, (2005) Vol. 109,7223-7236 J. Phys. Chem. A, (2005) Vol. 109, 2996-2999 J. Am. Chem. Soc. (2003) Vol. 125, 13356-13357 Org. Lett. (2003) Vol. 5, No. 5, 645-548 J. Am. Chem. Soc. (2004) Vol. 126, 11529-11542 J.Opt.Soc.Am.B, (1996) Vol.13,481-491 J. Chem. Soc. Chem. Commun. (1995), 55-56 J.Am.Chem.Soc. (2005) Vol.127,2464-2476 Chem. Eur. J., (2004) Vol. 10, 1227-1238

As mentioned above, for the application of two-photon absorption, it is premised that the two-photon absorption cross-section is large, but it is also less susceptible to linear absorption, material stability, material solubility, synthesis It is also necessary to be easy.
However, no compound or material has been reported so far that has a balance between a large two-photon absorption cross-section and these properties.

Accordingly, an object of the present invention is to provide a novel compound and a two-photon absorption material having a large two-photon absorption cross-sectional area, and having excellent stability and solubility in a solvent.
Another object of the present invention is to provide an optical recording medium containing the two-photon absorption material in a recording layer, and a recording / reproducing method for the optical recording medium.

As a result of intensive studies, the present inventors have found that the above problems can be solved if the material contains a specific compound represented by the following general formula (I) as at least a part of the constituent components. completed.
That is, the gist of the present invention is as follows.

［式（Ｉ）中、中心環Ｄは炭素数４〜６の芳香環を表し、Ａｒｘ^１〜Ａｒｘ^４−エチニレン基以外に置換基（該置換基としては、芳香環基、または芳香環基と連結基が複数結合した置換基がエチニレン基を介して結合する構造を除く。）を有していても良い。Ａｒｘ^１〜Ａｒｘ^４は、それぞれ独立に、芳香環基、または、芳香環基と連結基が複数結合した置換基を表す。Ａｒｘ^１〜Ａｒｘ^４の芳香環基は置換基を有していても、有していなくてもよいが、Ａｒｘ^１〜Ａｒｘ^４のうち少なくとも１つ以上が下記一般式（II）で表される芳香環基と連結基が結合した置換基である。

（式（II）中、Ａｒ^１〜Ａｒ^ｎは置換基を有していても有していなくてもよい、２価の芳香環基を表しており、Ｃｘ^１〜Ｃｘ^ｎは連結基を表しており、ｎは１以上５以下の整数である。Ｂは、置換基を有していても有していなくてもよい、電子供与性芳香環基、または、少なくとも１つ以上の電子供与性基が置換した芳香環基を表す。）
なお、ここで「連結基」は、これにより連結される基同士を共役可能とし得る基である。］ [1] An arylethynyl compound represented by the following general formula (I).

[In the formula (I), the central ring D represents an aromatic ring having 4 to 6 carbon atoms, and a substituent other than the Arx ^{1 to} Arx ⁴ -ethynylene group (the substituent includes an aromatic ring group or an aromatic ring group; And a structure in which a substituent having a plurality of linking groups bonded thereto is bonded through an ethynylene group. Arx ^{1 to} Arx ⁴ each independently represent an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded. Aromatic ring group Arx ¹ ~Arx ⁴ also have a substituent group, but may not have at ^least one or more represented by the following general formula (II) of Arx 1 ~Arx ⁴ A substituent in which an aromatic ring group and a linking group are bonded.

(In Formula (II), Ar ^{1 to} Ar ⁿ represent a divalent aromatic ring group that may or may not have a substituent, and Cx ^{1 to} Cx ⁿ represent a linking group. N is an integer of 1 to 5. B is an electron-donating aromatic ring group that may or may not have a substituent, or at least one or more electron-donating properties. Represents an aromatic ring group substituted with a group.)
Here, the “linking group” is a group capable of conjugating groups linked by this. ]

[2] The central ring D in the general formula (I) is an aromatic ring containing a heteroatom having 4 to 5 carbon atoms, the aromatic ring is a π-electron rich heterocycle, and the central ring D is Arx ¹ to Arx. Substituents that may be present in addition to ⁴ -ethynylene groups (excluding a structure in which an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded via an ethynylene group. The arylethynyl compound according to [1], wherein the arylethynyl compound is a substituent other than a substituent that is represented by a heavy atom such as a nitro group, iodine, or bromine, and that facilitates non-radiative transition .

[3] The central ring D in the general formula (I) is an aromatic ring containing a heteroatom having 4 to 5 carbon atoms, the aromatic ring is a π-electron deficient heterocycle, and the central ring D is Arx ¹ to Arx. Substituents that may be present in addition to ⁴ -ethynylene groups (excluding a structure in which an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded via an ethynylene group. The arylethynyl compound according to [1], wherein the arylethynyl compound is a substituent other than a substituent that is represented by a heavy atom such as a nitro group, iodine, or bromine, and that facilitates non-radiative transition .

[4] The central ring D in the general formula (I) is a benzene ring, and the central ring D may have a substituent other than the Arx ¹ to Arx ⁴ -ethynylene group (the substituent is an aromatic ring) Group, or a substituent in which multiple aromatic ring groups and linking groups are bonded via an ethynylene group.) Is further represented by a nitro group or a heavy atom such as iodine or bromine. The arylethynyl compound according to [1], wherein the arylethynyl compound is a substituent excluding a substituent that makes it more likely to occur.

[5] A two-photon absorption material comprising the arylethynyl compound according to any one of [1] to [4] as at least a part of a constituent component.

[6] In the general formula (I), at least two or more of Arx ^{1 to} Arx ⁴ are substituents in which an aromatic ring group represented by the general formula (II) and a linking group are bonded to each other. Two-photon absorbing material.

[7] The two-photon absorption material according to [5] or [6], wherein B in the general formula (II) is an aromatic ring group having a substituted amino group as an electron donating group.

[8] The two-photon absorption material according to any one of [5] to [7], wherein B in the general formula (II) has a photolabile protecting group containing a nitro group as a substituent.

[9] The two-photon absorption material according to any one of [5] to [8], wherein the two-photon absorption cross-section by the transmission method when the two-photon absorption cross-section of AF50 is 45 GM is 200 GM or more.

[10] An optical recording medium comprising the two-photon absorption material according to any one of [5] to [9] in a recording layer.

[11] Information is recorded on the optical recording medium according to [10] by dissociation of a photolabile protecting group by light irradiation, while fluorescence emission emitted from a fluorescent light-emitting host having a fluorescent group by light irradiation is emitted. A recording / reproducing method for an optical recording medium, wherein the recorded information is reproduced by reading.

According to the present invention, there is provided a two-photon absorption material having a large two-photon absorption cross-section, easily causing two-photon absorption, and having excellent material stability and material solubility in a solvent.
In particular, according to the two-photon absorption material of the present invention, it is excellent in stability and solubility, and the two-photon absorption sectional area by the transmission method when the two-photon absorption sectional area of AF50 is 45 GM is high efficiency. A two-photon absorbing material is provided. Among the two-photon absorption materials of the present invention, a preferable two-photon absorption cross-sectional area is 300 GM or more, and a particularly preferable one is 400 GM or more.

  According to the present invention, an optical recording medium having high characteristics is provided using such a two-photon absorption material.

  Embodiments of the present invention will be described in detail below. However, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

  The novel arylethynyl compound of the present invention is an arylethynyl compound represented by the following general formula (I) (hereinafter sometimes referred to as “the compound of the present invention”), and the two-photon absorption material of the present invention comprises: Such a compound of the present invention is included as at least a part of the constituent components.

（式（II）中、Ａｒ^１〜Ａｒ^ｎは置換基を有していても有していなくてもよい、２価の芳香環基を表しており、Ｃｘ^１〜Ｃｘ^ｎは連結基を表しており、ｎは１以上５以下の整数である。Ｂは、置換基を有していても有していなくてもよい、電子供与性芳香環基、または、少なくとも１つ以上の電子供与性基が置換した芳香環基を表す。）
なお、ここで「連結基」は、これにより連結される基同士を共役可能とし得る基である。］ [In the formula (I), the central ring D represents an aromatic ring having 4 to 6 carbon atoms, and a substituent other than the Arx ^{1 to} Arx ⁴ -ethynylene group (the substituent includes an aromatic ring group or an aromatic ring group; And a structure in which a substituent having a plurality of linking groups bonded thereto is bonded through an ethynylene group. Arx ^{1 to} Arx ⁴ each independently represent an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded. Aromatic ring group Arx ¹ ~Arx ⁴ also have a substituent group, but may not have at ^least one or more represented by the following general formula (II) of Arx 1 ~Arx ⁴ A substituent in which an aromatic ring group and a linking group are bonded.

(In Formula (II), Ar ^{1 to} Ar ⁿ represent a divalent aromatic ring group that may or may not have a substituent, and Cx ^{1 to} Cx ⁿ represent a linking group. N is an integer of 1 to 5. B is an electron-donating aromatic ring group that may or may not have a substituent, or at least one or more electron-donating properties. Represents an aromatic ring group substituted with a group.)
Here, the “linking group” is a group capable of conjugating groups linked by this. ]

  In the present invention, “aromatic ring” means “ring having aromaticity”, “aromatic hydrocarbon ring” means “hydrocarbon ring having aromaticity”, and “aromatic heterocycle”. “Ring” refers to “heterocyclic ring having aromaticity”. In addition, when the term “heterocycle” or “hydrocarbon ring” is used, it includes both a ring having aromaticity and a ring having no aromaticity. In the present invention, the “linking group” is a linking group capable of conjugating groups linked by the linking group. For example, a double bond such as a vinyl group, an ethynylene group, an azomethine group, or an azo group. Or a group having a triple bond.

In the present invention, “may have a substituent” means that it may have one or more substituents.
Hereinafter, the Arx ^{1 to} Arx ⁴ -ethynylene group of the central ring D is referred to as “arylethynyl group”, and the central ring D may have a substituent other than the Arx ¹ to Arx ⁴ -ethynylene group ( As the substituent, an aromatic ring group or a structure in which a substituent in which a plurality of aromatic ring groups and a linking group are bonded to each other is bonded through an ethynylene group) may be referred to as “another central ring substituent”. is there.

[Compound of the present invention]
Below, each component in the said general formula (I) is demonstrated.

<About center ring D>
In the general formula (I), the central ring D represents an aromatic ring having 4 to 6 carbon atoms. Specifically, an aromatic hydrocarbon ring having 4 to 6 carbon atoms such as cyclotetradiene, cyclopentadiene, and benzene, or 4 to 6 carbon atoms such as furan, pyrrole, thiophene, selenophene, telenophene, pyridine, pyridazine, pyrimidine, and pyrazine. Represents an aromatic heterocycle of 6;

  Although there is no restriction | limiting in particular as a hetero atom which comprises an aromatic heterocyclic ring, Usually, each atom, such as O, S, Se, Te, N, P, Si, is mentioned. In view of the stability of the heterocyclic ring, particularly preferred heteroatoms are O, S, and N.

  According to Albert-Pfleiderer, these aromatic heterocycles are classified into π-sufficient heteroaromatic rings and π-deficient heteroaromatic rings based on the difference in their electronic states. Yes (reference: published by Kodansha Scientific “Chemistry of heterocyclic compounds”). This classification is based on the benzene ring, and is determined based on the electron density on each carbon atom constituting the heterocycle.

The π electron density on one carbon atom constituting the aromatic ring is, for example, 6/6 = 1.0 in the case of benzene.
On the other hand, for example, pyrrole, thiophene, furan, etc. (including benzene condensed rings such as benzofuran and benzothiophene) have all the atoms constituting the heterocycle because the heteroatoms forming the ring have lone pairs. The average electron density of benzene is the same as that of benzene, but since the electronegativity of heteroatoms is larger than that of carbon atoms, the electron density on each carbon atom in the ring It is larger than 1.0 and 1.2 or less. Heteroaromatic rings having the above electron density are classified as π-electron rich heteroaromatic rings.
On the other hand, pyridine, pyridazine, pyrimidine, pyrazine, etc. are 6π electron systems, but the nitrogen atom in the ring has an electron withdrawing effect similar to the oxygen atom of the carbonyl group, so the π electron density on each carbon atom of the ring Is less than 1.0. Heteroaromatic rings having the above electron density are classified as π-electron deficient heteroaromatic rings.

The present inventors considered the center ring D and its substituents as follows, and reached the present invention.
Since the central ring D is the key to the conjugated system, an excess of π electrons is preferable for securing the conjugated system rather than a deficiency of π electrons, and therefore, heteroatoms are preferable to N for O and S. There may be cases.
In addition, as other central ring substituents of the central ring D, it was considered that an electron donating substituent such as an alkoxy group may be preferable to an electron withdrawing cyano group.

  The central ring D is preferably benzene or thiophene from the viewpoint of ease of synthesis and availability of raw materials, and further, benzene from the viewpoint of high performance such as a two-photon absorption cross section and a fluorescence quantum yield. May be preferred.

In particular, when the central ring D is a benzene ring, the structures of exemplary formulas D-1, D-2, and D-3 described later are preferable. That is, four of the six carbons of the benzene ring that is the central ring are substituted with an arylethynyl group (hereinafter also referred to as a 4-substituent), and the remaining carbon is unsubstituted or substituted with any other central ring By substituting with a group (corresponding to R ¹ and R ² in the exemplary formula), the following effects can be obtained.

(1) The central ring D is the basis of the spread of the π-conjugated system related to the two-photon absorption cross section and the wavelength of the absorption maximum. In the arylethynyl compound having the above structure of the present invention, since R ¹ and R ² are bonded to the central ring D, it directly acts on the central ring D, and the electron density can be controlled. In addition, the polarizability of the whole molecule can be changed. Therefore, according to the arylethynyl compound having the above structure of the present invention, the two-photon absorption cross section and the wavelength of the absorption maximum can be controlled by R ¹ and R ² . R ¹ and R ² that are preferably used for the purpose of such control include, in addition to hydrogen, among the substituents exemplified in the following section, among electron-donating methoxy groups, hydroxyl groups, amino groups, electron-withdrawing cyano groups, An aryl group, a carbonyl group, etc. are mentioned. Further, a substituent in which an alkyl group or a silyl group having a relatively small steric hindrance is bonded to an ethynyl group is also preferable. As R ¹ and R ² , nitro groups and halogen groups such as iodine and bromine, which are more likely to cause non-radiative transition, may greatly reduce the fluorescence quantum yield and emission intensity. Is not preferable.
These effects are effects that cannot be obtained with a 6-substituted product in which all six carbons of the benzene ring are substituted with Arx ¹ to Arx ⁴ -ethynylene groups.

(2) According to the arylethynyl compound having the above structure of the present invention, the solubility and storage stability can be controlled by R ¹ and R ² . For example, compounds having an electron-donating methoxy group, hydroxyl group, amino group, electron-withdrawing cyano group, aryl group, or carbonyl group listed in (1) as other central ring substituents are insoluble in water. . By making it insoluble in water, a preferable result that storage stability in a high temperature and high humidity environment is improved can be obtained. Conversely, for example, R ¹ and R ² can be solubilized in water by changing from methoxy group OCH ₃ to oligoether group (OCH ₂ CH ₂ ) _m OCH ₃ (m = 3 to 5). It is.

(3) According to the studies of the present inventors, all six carbons of the benzene ring of the central ring D is substituted with an aryl ethynyl group, furthermore, a conjugated system, Arx to linking group Cx ¹ ~Cx ^{n When a} photolabile linking group is bonded as B of ^{1 to} Arx ⁴ , it has been found that it is not preferable for the following reason. That is, there was a case where the compound had a high reaction activity and decomposed during the synthesis process. Therefore, it may not be easy to ensure the target final product stably and sufficiently. On the other hand, it was found that the 4-substitution product according to the present invention can easily adjust the reactivity to an appropriate range. That is, by making the central ring D into a 4-substituent, a compound (two-photon absorbing material having four photolabile groups) in which photodissociative groups are stably linked while securing a two-photon absorption cross-section is secured. It becomes possible to do.

As described above, the aryl ethynyl compound of the present invention represented by the general formula (I), Arx ¹ ~Arx 4 ^- both the ethynylene group, and any other central ring substituents differ from the aryl ethynyl group As a result, the above effects can be obtained, which is particularly preferable.

Arbitrary other central ring substituents will be described in the following section {Substituents that the central ring D may have other than Arx ¹ to Arx ⁴ -ethynylene groups}.

{- For ethynylene substituent which may have in addition based on the central ring D is ^Arx 1 ^{~Arx 4}}
The central ring D may have a substituent other than the Arx ¹ to Arx ⁴ -ethynylene group described later.
The substituent which may have, that is, the other central ring substituent is an arbitrary substituent except an aromatic ring group or a structure in which a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded through an ethynylene group. It is a group.
Examples of other central ring substituents, the aromatic ring group has a substituent group Q and will be described later as a substituent group optionally these substituents Arx ¹ ~Arx ⁴ contained from Arx ¹ to Arx ⁴ And a structure substituted through a group described later as a linking group.

When the central ring D is a cyclopentadiene ring, it is preferable to connect a conjugated system of an aromatic ring group and a cyclopentadiene ring contained in Arx ^{1 to} Arx ⁴ to create a delocalized state of π electrons. The position of the ring substituent is preferably at the 1-position (Exemplary Formula D-6 below).
Similarly, when the central ring D is a pyrrole ring, the position of the other central ring substituent is desirably at the 1-position (Exemplary Formula D-10 below).
In addition, when there are two other central ring substituents in the central ring D and they are adjacent to each other, the other adjacent central ring substituents may be bonded to each other to form a cyclic structure (explained below) Formula D-4, D-5).
Specific examples of the central ring D and other central ring substituents are given below, but the present invention is not limited thereto. In the following specific examples, R ¹ and R ² represent any other central ring substituent containing a hydrogen atom as described above.
More preferably, the hydrogen atom, electron-donating methoxy group, hydroxyl group, amino group, electron-withdrawing cyano group, aryl group, carbonyl group, ethynyl group mentioned in the items (1) and (2) with respect to the central ring D are used. And a substituent having an alkyl group or a silyl group having a relatively small steric hindrance.

<About the ^four Arx ¹ to Arx ⁴ -ethynylene groups of the central ring D>
In general, when π conjugation is considered, a group containing a double bond such as an ethenylene group is generally used for linking substituents. However, the 4-substitution product of the present invention links the central ring D and Arx ¹ to Arx ⁴ via an ethynylene group that is a group containing a triple bond instead of a double bond. This is due to the following three reasons.

(1) For example, when the central ring D is a benzene ring, if the number of Arx groups (Arx is synonymous with Arx ¹ to Arx ⁴ ) is 2-3, 1,4-diethenyl-benzene (disubstituted ) And 1,3,5-triethenyl-benzene (tri-substituted product) can also be combined to form a conjugated system via an ethenylene group. However, when the number of Arx groups is 4 or more, for example, 1,2,4,5-tetraethenyl-benzene (tetrasubstituted), a problem of steric hindrance occurs between adjacent ethenylene groups, and the ethenylene group and the benzene ring The twist of the bond is twisted (the dihedral angle between the ethenylene group and the benzene ring is no longer zero), and the planarity of the whole molecule is lost, and as a result, the expansion of π conjugation may be hindered.
On the other hand, when the group connecting the benzene ring and Arx is an ethynylene group consisting of a triple bond and a single bond, almost no twist is generated even in a tetra- or hexa-substitution, and the planarity of the whole molecule is almost maintained. It is considered possible.
Therefore, the conjugated system directly connected to the central ring D is preferably an ethynyl group, and the double bond is preferably bonded to the ethynyl group as a linking group connected to the aromatic ring-double bond.

 (2) Further, it is considered that the synthesis yield is higher when the ethynylene group is used as the linking group than when the ethenylene group is used. For example, as a reaction for introducing a double bond (ethenylene group) into a benzene ring to synthesize a tetrasubstituted product, there is a Suzuki-Miyaura cross-coupling reaction or a Heck reaction. In addition, when a triple bond (ethynylene group) is introduced into a benzene ring, a Sonogashira cross-coupling reaction or the like is used. However, when 1,2,4,5-tetraethenyl-benzene (tetrasubstituted product) is synthesized by the above method, it is considered that the problem of steric hindrance arises and the reaction yield is considerably lowered. On the other hand, if an ethynylene group is introduced, planarity around the benzene ring can be ensured, there is almost no steric hindrance, and the effect of improving the synthesis yield can be expected.

 (3) According to another study by the present inventors, when the conjugated system is extended by a triple bond and when the conjugated system is extended by a double bond, the former has a relatively shorter absorption band than the latter. Further, the emission intensity may increase. Therefore, for example, if an ethynylene group is bonded to the central ring D, the rate at which the absorption band shifts to the longer wavelength side can be adjusted smaller than when an ethenylene group is bonded. Therefore, if an ethenylene group is bonded to the central ring D, for example, a benzene ring, the effect that the absorption wavelength is not so large and shifted to the long wavelength side can be expected even if a double bond is further connected to extend the conjugated system.

<About Arx ^{1 to} Arx ⁴ >
Arx ¹ to Arx ⁴ in the general formula (I) are each independently an aromatic ring group, that is, an aromatic heterocyclic group or an aromatic hydrocarbon ring group, preferably a 5- or 6-membered monocyclic or 2- An aromatic hydrocarbon ring group or an aromatic heterocyclic group consisting of 6 condensed rings, or a group in which a plurality of these are linked via a linking group. These aromatic ring groups may or may not have a substituent independently, but at least one of Arx ^{1 to} Arx ⁴ is an aromatic ring represented by the following general formula (II) A substituent in which a group and a linking group are bonded.

（式（II）中、Ａｒ^１〜Ａｒ^ｎは置換基を有していても有していなくてもよい、２価の芳香環基を表しており、Ｃｘ^１〜Ｃｘ^ｎは連結基を表しており、ｎは１以上５以下の整数である。Ｂは、置換基を有していても有していなくてもよい、電子供与性芳香環基、または、少なくとも１つ以上の電子供与性基が置換した芳香環基を表す。）

(In Formula (II), Ar ^{1 to} Ar ⁿ represent a divalent aromatic ring group that may or may not have a substituent, and Cx ^{1 to} Cx ⁿ represent a linking group. N is an integer of 1 to 5. B is an electron-donating aromatic ring group that may or may not have a substituent, or at least one or more electron-donating properties. Represents an aromatic ring group substituted with a group.)

These Arx ^{1 to} Arx ⁴ may be the same as or different from each other.

{About the aromatic ring group contained in Arx ^{1 to} Arx ⁴ }
The aromatic hydrocarbon ring group contained in Arx ^{1 to} Arx ⁴ is preferably a group derived from a 6-membered monocyclic ring or a 2-10 condensed ring. Specifically, in the case of a monovalent group, a phenyl group, a naphthyl group, an anthranyl group, a phenanthryl group, a pyrenyl group, and the like can be mentioned. In particular, a phenyl group, a naphthyl group, a phenylene group, or a naphthylene group is preferable because of easy synthesis and easy availability of raw materials.

  On the other hand, examples of the aromatic heterocyclic group include a group derived from a monocyclic ring or a 2-10 condensed ring, preferably a 5- or 6-membered ring, particularly preferably a 5-membered ring. Although there is no restriction | limiting in particular as a hetero atom which comprises a heterocyclic ring, Usually, each atoms, such as O, S, Se, N, P, Si, are mentioned. When two or more of these heteroatoms are contained, the heteroatoms may be the same atom or different atoms. In view of the stability of the heterocyclic ring, particularly preferred heteroatoms are O, S, and N. Specific examples of the aromatic heterocyclic group include furan, thiophene, pyrrole, benzofuran, isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole, isoindole, indolizine, carbazole, xanthene, pyridine, quinoline, isoquinoline, Monovalent or divalent aromatic heterocycles derived from rings such as phenanthridine, acridine, oxazole, isoxazole, thiazole, isothiazole, furazane, imidazole, pyrazole, benzimidazole, 1,8-naphthyridine, pyrazine, pyrimidine, pyridazine A cyclic group is mentioned.

{About the linking group of Arx ^{1 to} Arx ⁴ }
Arx ¹ ~Arx ⁴ is an aromatic hydrocarbon ring group and / or an aromatic heterocyclic group, where is obtained by multiple linked via a linking group, the linking ^group includes the Arx 1 ~Arx ⁴ Although it is not particularly limited as long as it is a group that connects a conjugated system of an aromatic ring group and a substituted ethynyl aromatic ring that is a central skeleton of the compound of the present invention and creates a delocalized state of π electrons, specifically, , A group having a double bond or a triple bond, and preferably a group having 2 to 4 atoms, particularly preferably 2 atoms in terms of ease of synthesis and stability. The element constituting the linking group is preferably carbon or nitrogen. Examples of the linking group having a length of 2 atoms include a vinyl group (the vinyl group may be substituted with an arbitrary substituent), an ethynylene group, and an azomethine group (having a substituent). ) And azo groups.

{Regarding the substituents that the aromatic ring group contained in Arx ^{1 to} Arx ⁴ may have}
Examples of the substituent that the aromatic ring group included in Arx ^{1 to} Arx ⁴ may have include an alkyl group, a hydrocarbon ring group, a heterocyclic group, an alkoxy group, an aryloxy group, a heteroaryloxy group, and an aralkyloxy group. A heteroaralkyloxy group, an optionally substituted amino group, alkylsilyl group, acyl group, nitro group, cyano group, ester group, halogen atom, hydroxyl group, carboxyl group and the like. More specifically, an alkyl group having 1 to 9 carbon atoms, a hydrocarbon ring group having 3 to 20 carbon atoms, a 5- or 6-membered monocyclic ring or a heterocyclic group derived from 2 to 6 condensed rings, 9 alkoxy groups, aryloxy groups having 6 to 18 carbon atoms, heteroaryloxy groups having 2 to 18 carbon atoms, aralkyloxy groups having 7 to 18 carbon atoms, heteroaralkyloxy groups having 3 to 18 carbon atoms, 1 carbon atom -20, preferably an amino group substituted with an alkyl group having 1 to 10 carbon atoms, an amino group substituted with an aryl group having 6 to 30 carbon atoms, preferably 6 to 12 carbon atoms, preferably 2 to 30 carbon atoms, preferably Is an amino group substituted with a heteroaryl group having 2 to 10 carbon atoms, an alkylsilyl group substituted with an alkyl group having 1 to 4 carbon atoms, an acyl group having 1 to 20 carbon atoms, a nitro group, a cyano group, or a carbon number 2-6 ester groups, halogen Atom, a hydroxyl group, is a carboxyl group.
Specific examples of these substituents are exemplified as the substituent group Q below.

(Substituent group Q)
Examples of the alkyl group having 1 to 9 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, iso-butyl group, sec-butyl group, tert-butyl group, hexyl group and octyl group. .
Examples of the hydrocarbon ring group having 3 to 20 carbon atoms include a cyclopropyl group, a cyclohexyl group, a tetradecahydroanthranyl group, a phenyl group, an anthranyl group, and a phenanthryl group.
Examples of the heterocyclic group derived from a 5- or 6-membered monocyclic ring or a 2-6 condensed ring include 1-pyrenyl group, 1-naphthyl group, 2-naphthyl group, 1-phenanthrenyl group, 1-perylenyl group, 2-piperidinyl Group, 2-piperazinyl group, decahydroquinolinyl group, julolidin-9-yl group and the like.
Examples of the alkoxy group having 1 to 9 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, hexyloxy group, octyloxy group, etc. Is mentioned.
Examples of the aryloxy group having 6 to 18 carbon atoms and the heteroaryloxy group having 2 to 18 carbon atoms include aryloxy groups such as phenoxy group and naphthyloxy group, 2-thienyloxy group, 2-furyloxy group, 2- And heteroaryloxy groups such as a quinolyloxy group.
Examples of the aralkyloxy group having 7 to 18 carbon atoms and the heteroaralkyloxy group having 3 to 18 carbon atoms include aralkyloxy groups such as benzyloxy group, phenethyloxy group and naphthylmethoxy group, 2-thienylmethoxy group, and 2-furyl. And heteroaralkyloxy groups such as methoxy group and 2-quinolylmethoxy group.
Examples of the amino group substituted with an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, include a dimethylamino group, a methylethylamino group, a dibutylamino group, and a dioctylamino group.
An amino group substituted with an aryl group having 6 to 30 carbon atoms, preferably 6 to 12 carbon atoms, and an amino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms, may be diphenyl. Aryl groups such as amino group, dinaphthylamino group, naphthylphenylamino group, ditolylamino group, di (2-thienyl) amino group, di (2-furyl) amino group, phenyl (2-thienyl) amino group, etc. And heteroarylamino group.
Examples of the alkylsilyl group substituted with an alkyl group having 1 to 4 carbon atoms include a trimethylsilyl group, a triethylsilyl group, a triisopropylsilyl group, and a tert-butyldimethylsilyl group.
Examples of the acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, propionyl group, isobutyryl group, valeryl group, and cyclohexylcarbonyl group.
Examples of the ester group having 2 to 6 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, and an isopropoxycarbonyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Further, in Arx ^{1 to} Arx ⁴ , among the substituents as described above which each ring has, adjacent groups may be bonded to form a cyclic structure. As what forms a cyclic structure by bonding adjacent substituents, for example, substituents of the benzene ring are bonded to a benzene ring group as an aromatic ring group included in Arx ^{1 to} Arx ^4. Examples include phenoxatin, phenothiazine, and phenoxazine ring formed as shown in the following structural formula.

{Preferable substituents of Arx ^{1 to} Arx ⁴ }
Since the compound of the present invention represented by the general formula (I) has a large two-photon absorption cross section, at least one of the substituents Arx ^{1 to} Arx ⁴ is represented by the general formula (II). The aromatic ring group and the linking group must be bonded to each other, and preferably two or more of the substituents Arx ^{1 to} Arx ⁴ are linked to the aromatic ring group represented by the general formula (II). More preferably, among the substituents Arx ^{1 to} Arx ⁴ , three or more are substituents in which the aromatic ring group represented by the general formula (II) and a linking group are bonded. Most preferably, all of the substituents Arx ^{1 to} Arx ⁴ are substituents in which the aromatic ring group represented by the general formula (II) and a linking group are bonded.

When the central ring is benzene and all of Arx ¹ to Arx ⁴ are substituents in which an aromatic ring group represented by the general formula (II) and a linking group are bonded, the substitution position in the general formula (I) is As mentioned above, in order to make the effects of R ¹ and R ² for two-photon absorption more effective, and from the ease of synthesis and the availability of raw materials, 1, 2, 4, 5 Is preferred.
Below, each component in the said general formula (II) is demonstrated.

<About Ar ^{1 to} Ar ⁿ >
Ar ^{1 to} Ar ⁿ in the general formula (II) are each independently an aromatic ring group, that is, an aromatic heterocyclic group or an aromatic hydrocarbon ring group, preferably a 5- or 6-membered monocyclic ring or 2-6 It refers to a divalent aromatic hydrocarbon ring group or aromatic heterocyclic group composed of a condensed ring. These aromatic ring groups may independently have a substituent.

  Here, the aromatic hydrocarbon ring group is preferably a 6-membered monocyclic group or a group derived from 2 to 10 condensed rings. Specific examples include a phenylene group, a naphthylene group, an anthranylene group, a phenanthrylene group, a pyrenylene group, and the like. Particularly, a phenylene group and a naphthylene group are preferable from the viewpoint of ease of synthesis and availability of raw materials.

On the other hand, examples of the aromatic heterocyclic group include a group derived from a monocyclic ring or a 2-10 condensed ring, preferably a 5- or 6-membered ring, particularly preferably a 5-membered ring. Although there is no restriction | limiting in particular as a hetero atom which comprises a heterocyclic ring, Usually, each atoms, such as O, S, Se, N, P, Si, are mentioned. When two or more of these heteroatoms are contained, the heteroatoms may be the same atom or different atoms. In view of the stability of the heterocyclic ring, particularly preferred heteroatoms are O, S, and N. Specific examples of the aromatic heterocyclic group include furan, thiophene, pyrrole, benzofuran, isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole, isoindole, indolizine, carbazole, xanthene, pyridine, quinoline, isoquinoline, Divalent aromatic heterocyclic groups derived from rings such as phenanthridine, acridine, oxazole, isoxazole, thiazole, isothiazole, furazane, imidazole, pyrazole, benzimidazole, 1,8-naphthyridine, pyrazine, pyrimidine, pyridazine Can be mentioned.

These Ar ^{1 to} Ar ⁿ may be the same or different from each other, but no reason for positively changing them has been found.

Examples of the substituent that the aromatic ring group of Ar ^{1 to} Ar ⁿ may have include an alkyl group, a hydrocarbon ring group, a heterocyclic group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an aralkyloxy group, A heteroaralkyloxy group, an amino group which may have a substituent, an acyl group, a nitro group, a cyano group, an ester group, a halogen atom, a hydroxyl group, a carboxyl group and the like can be mentioned. More specifically, an alkyl group having 1 to 9 carbon atoms, a hydrocarbon ring group having 3 to 20 carbon atoms, a monocyclic ring having 5 or 6 members, or 2 to 6 as exemplified in the substituent group Q. A heterocyclic group derived from a condensed ring, an alkoxy group having 1 to 9 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, a heteroaryloxy group having 2 to 18 carbon atoms, an aralkyloxy group having 7 to 18 carbon atoms, and a carbon number Substituted with a 3-18 heteroaralkyloxy group, an amino group substituted with an alkyl group having 1-20 carbon atoms, preferably 1-10 carbon atoms, an aryl group having 6-30 carbon atoms, preferably 6-12 carbon atoms An amino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms, an acyl group having 1 to 20 carbon atoms, a nitro group, a cyano group, or 2 to 6 carbon atoms Ester group, halogen atom, hydroxyl group, Bokishiru groups, and the like.

Moreover, in Ar ^{< 1 >} -Arn, among the above substituents which each ring has, adjacent groups may couple | bond together and it may form the cyclic structure. As forming a cyclic structure adjacent substituents are bonded to, for example, Ar ¹ to the benzene ring as to Ar ^n, as shown in the following structural formulas each other substituents which the benzene ring has combine to Phenoxatin, phenothiazine, and phenoxazine ring formed.

<For ^Cx 1 ^{~Cx n>}
In the general formula (II), Cx ^{1 to} Cx ⁿ represent a linking group, and a conjugated system of an Ar ^{1 to} Ar ⁿ and B group and a 4-substituted ethynyl aromatic ring represented by the general formula (I). The group is not particularly limited as long as it is a group that creates a delocalized state of π electrons. Specifically, a specific example of a linking group that Arx ^{1 to} Arx ⁴ has corresponds to this. However, in order to improve the two-photon absorption cross-sectional area, it is preferable to include a group having a double bond, particularly an ethenyl group, because of its high conjugation property.

These linking groups connect Ar ^{1 to} Ar ⁿ and linking group B to the conjugated system of the 4-substituted ethynyl aromatic ring represented by the general formula (I), thereby creating a state in which π electrons are delocalized. It is possible to increase the two-photon absorption cross section of the compound of the present invention.

These Cx ^{1 to} Cx ⁿ may be the same or different from each other, but no reason for positively changing them has been found.

<About n>
In the general formula (II), n defines the degree of repetition of the aromatic ring group and the linking group, and n is an integer of 1 to 5. From the viewpoint of ease of synthesis, n is preferably as small as possible, but from the aspect of increasing the two-photon absorption cross-section, n is as large as possible. In addition, since the conjugated system spreads as n increases, the wavelength position at which linear absorption and two-photon absorption of the compound easily occur shifts to longer wavelengths. Furthermore, the solubility of the compound in the solvent and the stability of the compound generally tend to deteriorate as n increases. Considering these influences, a preferable range of n is 1 or more and 5 or less. However, in order to have a short wavelength absorption band suitable for high recording density, n is preferably 1 or more and 3 or less.

<About B>
B in the general formula (II) is an aromatic ring group, that is, an aromatic heterocyclic group or an aromatic hydrocarbon ring group, preferably a monovalent or 2-6 condensed ring having 5 or 6 members. Of the aromatic hydrocarbon ring group or aromatic heterocyclic group, or an aromatic ring group substituted with at least one electron donating substituent. However, the aromatic ring group of B may have a substituent other than the electron-donating substituent.

  Here, the aromatic hydrocarbon ring group is preferably a 6-membered monocyclic group or a group derived from 2 to 10 condensed rings. Specific examples include a phenyl group, a naphthyl group, an anthranyl group, a phenanthryl group, a pyrenyl group, and the like. Particularly, a phenyl group and a naphthyl group are preferable from the viewpoint of ease of synthesis and availability of raw materials.

  On the other hand, examples of the aromatic heterocyclic group include a group derived from a monocyclic ring or a 2-10 condensed ring, preferably a 5- or 6-membered ring, particularly preferably a 5-membered ring. Although there is no restriction | limiting in particular as a hetero atom which comprises a heterocyclic ring, Usually, each atoms, such as O, S, Se, N, P, Si, are mentioned. When two or more of these heteroatoms are contained, the heteroatoms may be the same atom or different atoms. In view of the stability of the heterocyclic ring, particularly preferred heteroatoms are O, S, and N. Specific examples of the aromatic heterocyclic group include furan, thiophene, pyrrole, benzofuran, isobenzofuran, 1-benzothiophene, 2-benzothiophene, indole, isoindole, indolizine, carbazole, xanthene, pyridine, quinoline, isoquinoline, Monovalent aromatic heterocyclic groups derived from rings such as phenanthridine, acridine, oxazole, isoxazole, thiazole, isothiazole, furazane, imidazole, pyrazole, benzimidazole, 1,8-naphthyridine, pyrazine, pyrimidine, pyridazine Can be mentioned.

  Among these, the electron-donating aromatic ring group is preferably a monovalent aromatic heterocyclic group derived from a ring such as furan, thiophene, pyrrole, carbazole, xanthene, pyridine, pyrazine, pyrimidine, pyridazine, furan, thiophene, A monovalent aromatic heterocyclic group derived from a pyrrole, pyridine, pyrazine, pyrimidine, or pyridazine ring is more preferable.

  The substituent that B may have includes an alkyl group, a hydrocarbon ring group, a heterocyclic group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an aralkyloxy group, a heteroaralkyloxy group, and a substituent. And an amino group, an acyl group, a nitro group, a cyano group, an ester group, a halogen atom, a hydroxyl group, a carboxyl group, and the like, which may be used. More specifically, an alkyl group having 1 to 9 carbon atoms, a hydrocarbon ring group having 3 to 20 carbon atoms, a monocyclic ring having 5 or 6 members, or 2 to 6 as exemplified in the substituent group Q. A heterocyclic group derived from a condensed ring, an alkoxy group having 1 to 9 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, a heteroaryloxy group having 2 to 18 carbon atoms, an aralkyloxy group having 7 to 18 carbon atoms, and a carbon number Substituted with a 3-18 heteroaralkyloxy group, an amino group substituted with an alkyl group having 1-20 carbon atoms, preferably 1-10 carbon atoms, an aryl group having 6-30 carbon atoms, preferably 6-12 carbon atoms An amino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms, an acyl group having 1 to 20 carbon atoms, a nitro group, a cyano group, or 2 to 6 carbon atoms Ester group, halogen atom, hydroxyl group, Bokishiru groups, and the like.

  Among these, the substituent having an electron donating effect is an amino group substituted with an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, 6 to 30 carbon atoms, preferably 6 to 12 carbon atoms. An amino group substituted with an aryl group, an amino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms, and the aromatic ring group of B has no electron donating property It is necessary to have at least one of these electron donating substituents.

  Among these electron donating substituents, a diamino group, that is, a dialkylamino group substituted with an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, preferably 6 to 30 carbon atoms, preferably Is a diarylamino group substituted with an aryl group having 6 to 12 carbon atoms, or a diheteroarylamino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms.

  Specifically, examples of the dialkylamino group substituted with an alkyl group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, include a dimethylamino group, a methylethylamino group, a dibutylamino group, and a dioctylamino group. It is done.

  A diarylamino group substituted with an aryl group having 6 to 30 carbon atoms, preferably 6 to 12 carbon atoms, a diheteroarylamino group substituted with a heteroaryl group having 2 to 30 carbon atoms, preferably 2 to 10 carbon atoms As an arylamino group such as diphenylamino group, dinaphthylamino group, naphthylphenylamino group, ditolylamino group, di (2-thienyl) amino group, di (2-furyl) amino group, phenyl (2-thienyl) Examples include heteroarylamino groups such as amino groups.

It is possible to adjust the solubility in various solvents by changing the nature of the substituent R bonded to the terminal amino group —NR ₂ of B.
For example, by setting R = C ₈ H ₁₇ or R = C ₆ H ₁₃ , the compound of the present invention can be changed to a molecule soluble in a nonpolar solvent such as hexane. Further, as described above, by setting R = (CH ₂ CH ₂ O) _m CH ₃ (m = 3 to 5), it is possible to make the molecule soluble in a polar solvent such as water.

  The aromatic ring of the aromatic ring group of B may have an electron donating property and may have an electron donating substituent, and in this case, a particularly preferable electron donating effect is obtained.

  Further, among the substituents as described above which the aromatic ring group of B has, adjacent groups may be bonded to form a cyclic structure. Adjacent substituents bonded to each other to form a cyclic structure include, for example, phenoxatin and phenothiazine as shown in the following structural formula by bonding substituents of the benzene ring to the benzene ring group as B And phenoxazine ring formed.

  Furthermore, the substituent which the aromatic ring group of B has may be a photolabile protecting group described below.

  The compound of the present invention represented by the general formula (I) is a compound that efficiently converts the energy absorbed by ultraviolet irradiation into fluorescence emission, as can be seen from the examples described later. When it has a photolabile protecting group, the fluorescence emission property is remarkably reduced. When such a compound is irradiated with light, the photolabile protecting group is dissociated from the compound main body and changes to a compound that emits stronger fluorescence than before light irradiation, and functions as an optical recording material in which the fluorescence intensity changes before and after the light irradiation. It is clear.

<About photolabile protecting group>
Specific examples of the photolabile protecting group include, for example, the following general formulas (IV), (V), (VI), (VII through a divalent group represented by the following general formula (III) as a linking group. ) And a substituent group represented by
The position at which these substituents are bonded is not particularly limited, and any of ring D in general formula (I), aromatic ring group of Ar ^{1 to} Ar ⁿ in general formula (II), and aromatic ring group B may be used. However, it is preferably bonded to the aromatic ring group B in the general formula (II) from the viewpoint of ease of synthesis and availability of raw materials. More preferably, these photolabile protecting groups are used as the electron-donating substituent of the aromatic ring group B as in the specific examples P-49 to P-54 of the substituent represented by the general formula (II) described later. It has the function of.

［式(III)中、Ｒ^３は、水素原子、ハロゲン原子、アルキル基、アルコキシ基、またはフェニル基を表す。］

[In Formula (III), R ³ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a phenyl group. ]

［式（IV）中、Ｒ^４は水素原子、ハロゲン原子、ニトロ基、ヒドロキシ基、カルボキシ基、アルキル基、アルコキシ基、アルコキシカルボニル基、アルキルアミノカルボニル基、フェニル基、またはベンジルオキシ基を表し、ｘは１〜４の整数である。なお、Ｒ^４が２以上の場合、それらは互いに同一であっても異なっていてもよい。］

[In the formula (IV), R ⁴ represents a hydrogen atom, a halogen atom, a nitro group, a hydroxy group, a carboxy group, an alkyl group, an alkoxy group, an alkoxycarbonyl group, an alkylaminocarbonyl group, a phenyl group, or a benzyloxy group, x is an integer of 1-4. In the case of R ⁴ is 2 or more, they may be be the same or different from each other. ]

［式（Ｖ）中、Ｒ^５は水素原子、ハロゲン原子、アルキル基、またはアルコキシ基を表し、Ｒ^６はヒドロキシ基、アルコキシ基、アルコキシメトキシ基、アルコキシカルボニルオキシ基、カルボキシメトキシ基、アルコキシカルボニルメトキシ基、アミノ基、アシルアミノ基、ジアルキルアミノ基、アルコキシカルボニルアミノ基、カルボキシメチルアミノ基、またはアルコキシカルボニルメチルアミノ基を表し、ｙは１〜３の整数である。なお、Ｒ^５が２以上の場合、それらは互いに同一であっても異なっていてもよい。］

[In the formula (V), R ⁵ represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and R ⁶ represents a hydroxy group, an alkoxy group, an alkoxymethoxy group, an alkoxycarbonyloxy group, a carboxymethoxy group, an alkoxycarbonylmethoxy group. Represents a group, an amino group, an acylamino group, a dialkylamino group, an alkoxycarbonylamino group, a carboxymethylamino group, or an alkoxycarbonylmethylamino group, and y is an integer of 1 to 3. When R ⁵ is 2 or more, they may be the same or different from each other. ]

［式（VI）中、Ｒ^７は水素原子、ハロゲン原子、ニトロ基、ヒドロキシ基、アルキル基、またはアルコキシ基を表し、ｚは１〜３の整数である。なお、Ｒ^７が２以上の場合、それらは互いに同一であっても異なっていてもよい。］

[In formula (VI), R ⁷ represents a hydrogen atom, a halogen atom, a nitro group, a hydroxy group, an alkyl group, or an alkoxy group, and z is an integer of 1 to 3. When R ⁷ is 2 or more, they may be the same or different. ]

［式(VII)中、Ｒ^８、Ｒ^９、Ｒ^１０は各々独立に、水素原子、アルキル基、またはベンジル基を表し、Ｒ^８、Ｒ^９、Ｒ^１０の少なくとも１つはアルキル基、またはベンジル基である。］

[In the formula (VII), R ⁸ , R ⁹ and R ¹⁰ each independently represents a hydrogen atom, an alkyl group or a benzyl group, and at least one of R ⁸ , R ⁹ and R ¹⁰ is an alkyl group or benzyl. It is a group. ]

In addition, as to which of the general formulas (IV), (V), (VI) and (VII) is preferably selected with respect to R ³ in the general formula (III), it is as follows. It is.
That is, this substituent ensures a suitable energy level and a suitable physical position, which is a requirement that when absorbed with the two-photon absorbing material of the present invention, the absorbed light can be sufficiently deactivated. Those which are possible substituents are preferred. In particular, the substituent represented by the general formula (IV) is one of the substituents that may satisfy the above requirements as a photolabile protecting group of a fluorescent dye having an absorption band in the wavelength range of 300 nm to 500 nm. It is thought that.

Specific examples of R ^{3 to} R ¹⁰ include specific examples of each substituent described as the substituent group Q.

<Specific examples of the substituent represented by the general formula (II)>
Specific examples of the substituent represented by the general formula (II) are given below, but the present invention is not limited thereto. In the following, “n-Oct” represents a normal octyl group, “Me” represents a methyl group, “Et” represents an ethyl group, “n-Bu” represents a normal butyl group, and “n-Hex” represents a normal Each hexyl group is shown.

{Molecular weight}
The compound of the present invention represented by the general formula (I) described above further includes a central ring D and Arx ^{1 to} Arx ⁴ from the viewpoint of ease of synthesis, stability of the compound, and solubility in a solvent. In the case of having a substituent, the molecular weight is usually 10,000 or less, particularly preferably 6,000 or less.
The compound of the present invention represented by the general formula (I) is usually preferably insoluble in water as an optical recording medium. However, when this compound is used for biochemical applications such as a fluorescent probe, it is also preferable that it is water-soluble.

Specific examples of the compound of the present invention represented by the general formula (I) are shown below, but the present invention is not limited to these. In the following exemplified compounds, compounds in which Arx ^{1 to} Arx ⁴ are appropriately substituted with the above-described exemplified substituents P-1 to P-55 are also preferred as the compounds of the present invention.

  The two-photon absorption material of the present invention may contain only one kind of the compound of the present invention represented by the general formula (I), or two or more kinds in any combination and in any ratio. It may be included.

[Method for producing compound of the present invention]
The compound of the present invention represented by the general formula (I) can be synthesized, for example, by the method described below.

<Synthesis Method of Compounds in Which All Substituents of Central Ring D are the Same>
In the presence of an inert gas, a halogen-substituted compound (a mol) represented by the following general formula (A), an ethynyl compound represented by the following general formula (B) (6 × a to 60 × a mol (a represents the following general formula ( A) The number of moles of the halogen-substituted compound represented by A). The same applies hereinafter.)) A monovalent copper halide catalyst (0.1 × a to 10 × a mol%), a zero-valent palladium catalyst (0.05 × a ˜5 × a mol%) and base (7 × a to 70 × a times mol) are dissolved in a dry polar solvent at a concentration of 0.1 to 100 M and heated in the range of 40 to 200 ° C. for 1 to 100 hours. After cooling to room temperature, the solvent is distilled off under reduced pressure. Add a non-polar solvent, a solvent that does not dissolve copper halides typified by halogen solvents to the residue, filter insoluble inorganic substances, concentrate the filtrate, and chromatograph, recrystallize, suspension wash, reprecipitate the residue. Purity can be improved by a purification method such as the above, and the compound of the present invention in which all the substituents of the central ring D represented by the following general formula (C) are the same can be obtained as the target product.

<Synthesis of compounds in which the substituents of the central ring D are not identical>
In the presence of an inert gas, a halogen-substituted compound (d mol) represented by the following general formula (D), an ethynyl compound represented by the general formula (B) (0.9 × d to 1.1 × d times mol (d) Is the number of moles of the halogen-substituted compound represented by the following general formula (D). The same applies hereinafter.)) A monovalent copper halide catalyst (0.1 × d to 10 × d mol%), a zero-valent palladium catalyst ( 0.05 × d to 5 × d mol%) and a base (1 × d to 1.5 × d mol) in a dry polar solvent at a concentration of 0.1 to 100 M, and 1 to 100 hours, 40 It heats in the range of -200 degreeC, and after standing_to_cool to room temperature, a solvent is distilled off under reduced pressure. Add a non-polar solvent, a solvent that does not dissolve copper halides typified by halogen solvents to the residue, filter insoluble inorganic substances, concentrate the filtrate, and chromatograph, recrystallize, suspension wash, reprecipitate the residue. Purity is improved by a purification method such as the above, and a compound represented by the following general formula (E) is obtained as a target product.

Next, the following second-stage reaction is performed using the compound represented by the general formula (E).
In the presence of an inert gas, a halogen-substituted compound (e mol) represented by the following general formula (E), an ethynyl compound represented by the following general formula (F) (1.0 × e to 10 × e times mol (e is the following) The number of moles represented by the general formula (E). The same applies hereinafter.)) A monovalent copper halide catalyst (0.1 × e to 10 × e mol%), a zero-valent palladium catalyst (0.05 × e to 5 × e mol%) and a base (1 × e to 20 × e times mol) are dissolved in a dry polar solvent at a concentration of 0.1 to 100 M and heated in the range of 40 to 200 ° C. for 1 to 100 hours. After cooling to room temperature, the solvent is distilled off under reduced pressure. Add a non-polar solvent, a solvent that does not dissolve copper halides typified by halogen solvents to the residue, filter insoluble inorganic substances, concentrate the filtrate, and chromatograph, recrystallize, suspension wash, reprecipitate the residue. Purity can be improved by a purification method such as the compound of the present invention in which the substituents of the central ring D represented by the general formula (G) are not the same.

[Two-photon absorption material of the present invention]
The two-photon absorption material of the present invention comprises a compound represented by the general formula (I), for example, a powdery crystal of the compound of the present invention represented by the general formula (I) obtained by the various synthesis methods described above. As it is, as a block or powder, or as hexane, toluene, xylene, methylene chloride, chloroform, ether, tetrahydrofuran, ethyl acetate, acetone, 2-butanone, methanol, ethanol, trifluoromethylbenzene, acetic acid, It is used for various applications as a solvent such as triethylamine, or as a liquid material dissolved or dispersed in a polymer or gel, or as a thin film obtained by removing the solvent after applying such a liquid material to a substrate. be able to.

In addition, resin pellets containing a predetermined amount of the two-photon absorption material are prepared in advance, and a recording layer is prepared by a method such as press or injection molding using the resin pellets, and mechanical strength is increased only by the recording layer. The function as a board | substrate may be provided collectively by ensuring.
In this case, the two-photon absorption material is not limited to one type, and two or more types may be used in combination.

  The two-photon absorption material contains the compound of the present invention represented by the above general formula (I), for example, after subjecting the material to treatment such as decomposition, extraction, etc., for example, liquid chromatography-mass This can be confirmed by analysis using an analysis method (LC-MS), a nuclear magnetic resonance spectrum method (NMR), or the like.

  In addition to having a large two-photon absorption cross-section, the compound of the present invention represented by the general formula (I) is less susceptible to linear absorption, excellent in stability, solubility, and ease of synthesis. Therefore, it is suitably used as a two-photon absorption material. According to the two-photon absorption material of the present invention containing this compound as at least a part of the constituent components, two-photon absorption is likely to occur, and the two-photon absorption cutoff by the transmission method when the two-photon absorption cross section of AF50 is 45 GM. Provided is a two-photon absorption material having an excellent two-photon absorption efficiency having an area of usually 200 GM or more, preferably 300 GM or more, and particularly preferably 400 GM or more.

  Here, the two-photon absorption cross section by the transmission method is Kato, S .; Matsumoto, T .; Ishi-I, T .; Thiemann, T .; Shigeiwa, M .; Gorohmaru, H .; Maeda, S .; Yamashita, Y .; Mataka, S. Chem. Commun. 2004, 2342-2343. The value obtained under the following conditions is the same as the method described in Supporting Information.

<Evaluation conditions for two-photon absorption cross section>
A femtosecond titanium sapphire laser (wavelength: 800 nm, pulse width: 120 fs, repetition rate: 1 kHz, output: 2 mJ / pulse) is used as a measurement light source, and the two-photon absorption cross section is measured by appropriately attenuating the output from the laser. To do. For the measurement, the excitation light density is changed in the range of 1 to 40 GW / cm ² using the Z-scan method. As a measurement sample, a solution in which the compound of the present invention represented by the general formula (I) is dissolved in toluene at a predetermined concentration is used, and this solution is put into a 4-sided transparent 1 cm square quartz cell for measurement. Next, AF50 as a standard sample is measured, and the two-photon absorption cross section of the AF50 is normalized as 45 GM.

  The two-photon absorption material of the present invention containing the compound of the present invention represented by the general formula (I) exhibits a high two-photon absorption cross-section, because the compound of the present invention has a sufficiently wide pi-conjugated system, And the existence of an electron-donating group, and the stability is presumed to be derived from the substituted ethynyl aromatic ring skeleton.

  The two-photon absorption material of the present invention containing the compound of the present invention represented by the general formula (I) can impart excellent stability and solubility by appropriate selection of substituents. In particular, having an alkyl-substituted amino group is preferable in terms of an increase in the two-photon absorption cross section and a solubility.

[Optical recording medium of the present invention]
The optical recording medium of the present invention has a recording layer containing the two-photon absorption material of the present invention. As described above, this recording layer is a thin film on a substrate using the two-photon absorption material of the present invention. Formed as. Alternatively, by molding a resin pellet containing the above-described two-photon absorption material of the present invention, it can be formed as a molded plate that serves as both a substrate and a recording layer.

  As the transparent substrate on which the recording layer is formed, a substrate transparent to the laser beam to be used, such as glass and various plastics, is preferably used. Examples of plastics include acrylic resin, methacrylic resin, polycarbonate resin, vinyl chloride resin, vinyl acetate resin, nitrocellulose, polyester resin, polyethylene resin, polypropylene resin, polyimide resin, polystyrene resin, epoxy resin, etc. A polycarbonate resin is preferable from the viewpoint of cost, moisture absorption resistance, and the like, and its injection-molded plate is more preferable. The resin material is also preferable when a recording layer is formed by a method such as pressing or injection molding using resin pellets and the function as a substrate is also provided by ensuring mechanical strength only by the recording layer. Used.

  Examples of the method for forming the recording layer on the transparent substrate include a doctor blade method, a cast method, a spin coating method, and an immersion method. Among these, the spin coating method is used from the viewpoint of mass productivity, cost, and the like. preferable.

  The thickness of the recording layer formed on the transparent substrate is not particularly limited, but is usually 5 nm to 50 μm, preferably 10 nm to 10 μm, and more preferably 50 nm to 5 μm. In addition, when a recording layer is prepared by a method such as press or injection molding using resin pellets and the function as a substrate is provided by securing the mechanical strength only by the recording layer or the like, it is usually 100 μm to 20 mm. The thickness is preferably 200 μm to 10 mm.

  In the optical recording medium of the present invention, a subbing layer may be provided on the transparent substrate, and a recording layer may be formed thereon. On the formed recording layer, gold, silver, aluminum, or A metal reflective layer and a protective layer made of such an alloy may be provided as a medium having a high reflectivity. In this case, silver is preferable as the metal.

  In this case, the metal reflective layer is formed by vapor deposition, sputtering, ion plating, etc., and further improves the adhesion between the recording layer and the metal reflective layer or increases the reflectivity. Therefore, an intermediate layer may be provided between both layers. Further, for example, an ultraviolet curable resin or the like is used for forming the protective layer.

[Reproduction method of optical recording medium of the present invention]
The method for reproducing an optical recording medium of the present invention is a method for using the optical recording medium of the present invention, in particular, a compound having the above-described photolabile protecting group as the compound of the present invention as a two-photon absorbing material. Information is recorded by the dissociation of the photolabile protecting group by light irradiation, and on the other hand, the recorded information is reproduced by reading the fluorescent light emitted from the fluorescent light-emitting matrix having the fluorescent light-emitting group by light irradiation. It is.

  Specifically, most of the compounds represented by the general formula (I) of the present invention themselves have the property as a fluorescent light-emitting matrix (Examples 2 to 9 described later). On the other hand, in the case of the compound in which the above-mentioned photolabile protecting group is bound to these compounds (Example 1), before light irradiation, is it protected by the photolabile protecting group, so that there is no fluorescence emission? However, the photolabile protecting group is dissociated by light irradiation, but the properties as an original fluorescent light-emitting matrix are exhibited (Example 7).

  That is, two-photon absorption by irradiation with ultraviolet light having a wavelength of about 300 to 450 nm absorbed by the compound represented by the general formula (I) of the present invention, or femtosecond titanium sapphire laser having a wavelength about twice that wavelength. Is caused to dissociate the photolabile protecting group from the fluorescent light-emitting matrix, information is recorded, and the recorded information can be reproduced by reading the fluorescence, so that the general formula (I) The two-photon absorption material of the present invention comprising a compound represented by the formula is suitable for use in a recording layer of an optical recording medium.

  When recording / reproduction is performed using the two-photon absorption of the two-photon absorption material of the present invention, recording / reproduction can be performed only with the focal portion of the laser beam, so that it is extremely high in any place in the three-dimensional space. Since information can be recorded with a spatial resolution and the record can be read out with fluorescence, it is considered that the ultimate high-density recording is possible.

  The recording light used in the optical recording medium of the present invention is preferably as short as possible for high-density recording, and laser light of 350 to 530 nm is particularly preferable. Typical examples of such laser light include blue laser light with center wavelengths of 405 nm and 410 nm, blue-green high-power semiconductor laser light with center wavelength of 515 nm, and the like.

  Further, by using a two-photon absorption of a two-photon absorption material using a long wavelength laser beam having a wavelength of about 500 to 900 nm, a higher density recording can be performed. Typical examples of such laser light include a titanium sapphire laser with a center wavelength of 800 nm, a fiber laser with a center wavelength of 780 nm, and the like. In particular, since the compound of the present invention represented by the general formula (I) has a large two-photon absorption cross-sectional area and excellent recording sensitivity, it is suitable as an optical recording medium for performing three-dimensional recording / reproduction utilizing two-photon absorption. It is.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples, and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

[Synthesis Example 1 (specific example including a photolabile protecting group)]
Compound of the present invention B-6: Synthesis of 1,2,4,5-tetrakis {4-[(p-N-hexyl-N-o-nitrobenzylamino) styryl] phenylethynyl} benzene

  Cuprous iodide (5.4 mg, 28.5 μmol), bis (triphenylphosphine) paradium (II) dichloride (10.0 mg, 14.3 μmol), triphenylphosphine (7.5 mg, 28.5 μmol), 1 , 2,4,5-tetrabromobenzene (37.4 mg, 95.0 μmol), trans-4-ethynyl-4 ′-(N-hexyl-No-nitrobenzylamino) stilbene (300 mg, 0.68 mmol) The rotor was put into a 50 mL two-necked eggplant type flask, a septum, a condenser tube and a three-way cock were attached, and the atmosphere was replaced with argon, and 25 mL of dry triethylamine was added and refluxed for 30 hours. The reaction solution was concentrated, and the residue was purified by silica gel filtration column with methylene chloride and preparative HPLC to obtain the target compound in a yield of 57.6% and a yield of 99.9 mg.

(Compound B-6)
Melting point: 72.5-78.5 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ8.18 (d, J = 8.3 Hz, 4H), 7.74 (s, 2H), 7.53-7.57 (m, 12H), 7.36-7.47 (m, 24H ), 7.08 (d, J = 16.1Hz, 4H), 6.90 (d, J = 16.1Hz, 4H), 6.60 (d, J = 8.8Hz, 8H), 4.96 (s, 8H), 3.43 (t, J = 7.6Hz, 8H), 1.67-1.77 (m, 8H), 1.28-1.40 (m, 24H), 0.92 (t, J = 6.8Hz, 12H).
¹³ CNMR (100 MHz, CDCl ₃ ) δ 148.1, 147.7, 138.5, 135.0, 133.9, 132.0, 129.7, 128.6, 128.02, 127.97, 127.8, 126.0, 125.6, 125.5, 125.2, 123.7, 120.9, 111.9, 96.0, 88.4, 52.6, 51.6, 31.6, 27.2, 26.7, 22.6, 14.1.
UV-vis: λ _max (CHCl ₃ ) 395.1 nm (log ε 5.15), 415.3 nm (5.14)
λ _max (toluene) 394.0nm (logε5.14), 415.0nm (5.13)

[Synthesis Example 2]
Synthesis of Compound B-1 of the Present Invention: 1,2,4,5-Tetrakis [4- (pN, N, -Dioctylaminostyryl) phenylethynyl] benzene

  Synthesis Example, except that p- (p-dioctylaminostyryl) phenylacetylene was used instead of trans-4-ethynyl-4 ′-(N-hexyl-No-nitrobenzylamino) stilbene as a starting material Synthesis and purification were performed in the same manner as in 1 to obtain the target compound in a yield of 75.5%.

(Compound B-1)
Melting point: 55 ° C
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ 7.76 (s, 2H), 7.55 (d, J = 8.3 Hz, 8H), 7.48 (d, J = 8.3 Hz, 8H), 7.40 (d, J = 8.3Hz, 8H), 7.10 (d, J = 16.1Hz, 4H), 6.89 (d, J = 16.1Hz, 4H), 6.63 (d, J = 8.3Hz, 8H), 3.29 (t, J = 7.6Hz, 16H) 1.54-1.64 (m, 16H), 1.22-1.38 (m, 80H), 0.90 (t, J = 6.6Hz, 24H).
¹³ CNMR (100 MHz, CDCl ₃ ) δ 148.1, 138.9, 134.7, 132.0, 130.2, 128.0, 125.9, 125.2, 124.2, 122.8, 120.7, 111.6, 96.1, 88.4, 51.1, 31.8, 29.5, 29.3, 27.3, 27.2, 22.7, 14.1
UV-vis: λ _max (CHCl ₃ ) 404.3 nm (log ε 5.22), 427.7 nm (5.24)
λ _max (toluene) 400.0nm (logε5.15), 426.1nm (5.17)
Fluorescence: λ _max (em) (CHCl ₃ ) 542 nm
λ _max (em) (toluene) 496nm

[Synthesis Example 3]
Compound B-2 of the present invention: Synthesis of 1,2,4,5-tetrakis [4- (pN, N, -dioctylaminostyryl) phenylethynyl] -3,6-bis (methoxycarbonyl) benzene

  The same as Synthesis Example 2 except that 1,2,4,5-tetrabromo-3,6-bis (methoxycarbonyl) benzene was used as a starting material instead of 1,2,4,5-tetrabromobenzene. The target compound was obtained in a yield of 87.8%.

(Compound B-2)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ 7.50 (d, J = 8.3 Hz, 8H), 7.46 (d, J = 8.3 Hz, 8H), 7.40 (d, J = 8.3 Hz, 8H) , 7.10 (d, J = 16.1Hz, 4H), 6.88 (d, J = 16.1Hz, 4H), 6.63 (d, J = 8.3Hz, 8H), 4.08 (s, 6H), 3.29 (t, J = 7.6Hz, 16H), 1.57-1.65 (m, 16H), 1.30-1.34 (m, 80H), 0.90 (t, J = 6.8Hz, 24H).
¹³ CNMR (100 MHz, CDCl ₃ ) δ 166.8, 148.1, 139.4, 132.1, 130.4, 128.1, 125.9, 124.0, 123.0, 122.7, 120.1, 111.6, 100.3, 85.8, 52.8, 51.1, 31.8, 29.5, 29.3, 27.3, 27.2, 22.7, 14.1.
UV-vis: λ _max (CHCl ₃ ) 442.7 nm (log ε 5.21).
λ _max (toluene) 439.1nm (logε5.17)
Fluorescence: λ _max (em) (CHCl ₃ ) 549.5nm, 583.5nm
λ _max (em) (toluene) 517nm

[Synthesis Example 4]
Compound B-3 of the Present Invention: Synthesis of 1,4-dicyano-2,3,5,6-tetrakis [4- (pN, N, -dioctylaminostyryl) phenylethynyl] benzene

  The same method as in Synthesis Example 2 except that 1,4-dicyano-2,3,5,6-tetrabromobenzene was used as a starting material instead of 1,2,4,5-tetrabromobenzene. The target compound was obtained in 66.0% yield.

(Compound B-3)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ7.61 (d, J = 8.3 Hz, 8H), 7.48 (d, J = 8.8 Hz, 8H), 7.40 (d, J = 8.3 Hz, 8H) 7.12 (d, J = 16.1Hz, 4H), 6.87 (d, J = 16.1Hz, 4H), 6.62 (d, J = 8.8Hz, 8H), 3.29 (t, J = 7.3Hz, 16H), 1.53 -1.67 (m, 16H), 1.31-1.34 (m, 80H), 0.92 (t, J = 6.8Hz, 24H).
¹³ CNMR (100 MHz, CDCl ₃ ) δ 148.1, 140.1, 132.6, 130.8, 128.2, 128.0, 125.9, 123.9, 122.5, 119.8, 119.0, 115.2, 111.5, 104.0, 85.6, 51.0, 31.8, 29.5, 29.4, 27.3, 27.2, 22.7, 14.1.
UV-vis: λ _max (CHCl ₃ ) 370.5 nm (log ε4.96), 492.0 nm (4.90)
λ _max (toluene) 365.0nm (logε4.96), 478.8nm (4.92), 506.6nm (4.92)
Fluorescence: λ _max (em) (toluene) 578nm

[Synthesis Example 5]
Compound B-5 of the Invention: Synthesis of tetrakis [4- (pN, N, -dioctylaminostyryl) phenylethynyl] thiophene

  Synthesis and purification were performed in the same manner as in Synthesis Example 2 except that tetrabromothiophene was used instead of 1,2,4,5-tetrabromobenzene as a starting material, and the target compound was obtained in a yield of 72. Obtained at 5%.

(Compound B-5)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ 7.59 (d, J = 8.3 Hz, 4H), 7.56 (d, J = 8.3 Hz, 4H), 7.49 (d, J = 8.3 Hz, 4H) , 7.48 (d, J = 8.3Hz, 4H), 7.40 (d, J = 8.3Hz, 8H), 7.11 (d, J = 16.1Hz, 4H), 6.89 (d, J = 16.1Hz, 2H), 6.88 (D, J = 16.1Hz, 2H), 6.63 (d, J = 8.3Hz, 8H), 3.30 (t, J = 7.6Hz, 16H), 1.54-1.65 (m, 16H), 1.30-1.34 (m, 80H), 0.90 (t, J = 6.8Hz, 24H).
¹³ CNMR (100 MHz, CDCl ₃ ) δ 148.1, 148.0, 139.1, 138.8, 132.0, 131.8, 130.3, 130.1, 128.1, 128.03, 127.99, 125.9, 124.9, 124.2, 124.1, 122.8, 122.7, 120.7, 120.0, 111.6, 99.4, 96.7, 83.8, 82.6, 51.0, 31.8, 29.5, 29.3, 27.3, 27.2, 22.6, 14.1.
UV-vis: λ _max (CHCl ₃ ) 419.8 nm (log ε 5.22).
λ _max (toluene) 416.2nm (logε5.23)
Fluorescence: λ _max (em) (CHCl ₃ ) 544.5 nm
λ _max (em) (toluene) 512nm

[Synthesis Example 6]
Compound B-4 of the Invention: Synthesis of tetrakis [4- (p-N, N, -dioctylaminostyryl) phenylethynyl] pyrazine

  Synthesis and purification were carried out in the same manner as in Synthesis Example 2 except that tetrabromopyrazine was used instead of 1,2,4,5-tetrabromobenzene as a starting material, and the target compound was obtained in a yield of 14. Obtained at 0%.

(Compound B-4)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ7.63 (d, J = 8.3 Hz, 8H), 7.50 (d, J = 8.3 Hz, 8H), 7.41 (d, J = 8.8 Hz, 8H) 7.13 (d, J = 16.1Hz, 4H), 6.89 (d, J = 16.1Hz, 4H), 6.64 (d, J = 8.8Hz, 8H), 3.30 (t, J = 7.6Hz, 16H), 1.54 -1.65 (m, 16H), 1.25-1.38 (m, 80H), 0.90 (t, J = 6.8Hz, 24H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 148.2, 140.0, 138.9, 132.6, 130.9, 128.1, 125.9, 124.0, 122.5, 119.3111.6, 98.4, 87.2, 51.1, 31.8, 29.5, 29.3, 27.3, 27.2, 22.6, 14.1.
UV-vis: λ _max (CHCl ₃ ) 465.2 nm (logε5.00)
λ _max (toluene) 453.2nm (logε5.01)
Fluorescence: λ _max (em) (CHCl ₃ ) 601 nm
λ _max (em) (toluene) 530nm

[Synthesis Example 7]
Synthesis of Compound B-7 of the Present Invention: 1,2,4,5-Tetrakis {4- [pN, N-bis (p-octylphenyl) aminostyryl] phenylethynyl} benzene

  As a starting material, instead of 4- (pN, N-dioctylaminostyryl) phenylacetylene, 4- [pN, N-bis (p-octylphenyl) aminostyryl] phenylacetylene was used, Synthesis and purification were performed in the same manner as in Synthesis Example 2 to obtain the target compound in 78% yield.

(Compound B-7)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ 7.75 (s, 2H), 7.56 (d, J = 8.3 Hz, 8H), 7.49 (d, J = 8.8 Hz, 8H), 7.37 (d, J = 8.8Hz, 8H), 7.02-7.13 (m, 44H), 6.98 (d, J = 16.1Hz, 4H), 2.59 (t, J = 7.6Hz, 16H), 1.64 (quin, J = 7.2Hz, 16H), 1.26-1.42 (m, 80H), 0.92 (t, J = 6.6Hz, 24H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 148.1, 145.0, 138.1, 137.9, 132.0, 130.0, 129.5, 129.2, 127.4, 126.2, 125.5, 125.2, 124.7, 122.2, 121.4, 95.9, 88.6, 35.4, 31.9, 31.5, 29.5, 29.4, 29.3, 22.7, 14.1.
UV-vis: λ _max (CHCl ₃ ) 425 nm (log ε 5.24)
λ _max (toluene) 425 nm (log ε 5.24)
Fluorescence: λ _max (em) (CHCl ₃ ) 532 nm, 570 nm
λ _max (em) (toluene) 488nm

[Synthesis Example 8]
Compound B-8 of the present invention: Synthesis of 1,2,4,5-tetrakis [4- (pN, N-dioctylaminostyryl) phenylethynyl] -3,6-dimethoxybenzene

  In the same manner as in Synthesis Example 2, except that 1,2,4,5-tetrabromo-3,6-dimethoxybenzene was used as a starting material instead of 1,2,4,5-tetrabromobenzene. Synthesis and purification were performed to obtain the target compound in a yield of 47%.

(Compound B-8)
Melting point: <40 ℃
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ7.55 (d, J = 7.8 Hz, 8H), 7.46 (d, J = 7.8 Hz, 8H), 7.49 (d, J = 8.3 Hz, 8H) , 7.09 (d, J = 16.1Hz, 4H), 6.87 (d, J = 16.1Hz, 4H), 6.61 (d, J = 8.3Hz, 8H), 4.14 (s, 6H), 3.27 (t, J = 7.6Hz, 16H), 1.54-1.62 (m, 16H), 1.24-1.35 (m, 80H), 0.88 (t, J = 6.8Hz, 24H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 157.8, 148.0, 138.9, 132.0, 130.1, 128.0, 125.8, 124.1, 122.7, 120.8, 120.7, 111.5, 100.1, 84.9, 61.4, 51.0, 31.8, 29.5, 29.3, 27.3, 27.1, 22.7, 14.1.
UV-vis: λ _max (CHCl ₃ ) 395 nm (log ε 5.13), 444 nm (log ε 5.17)
λ _max (toluene) 392 nm (log ε 5.11), 441 nm (log ε 5.16)
Fluorescence: λ _max (em) (CHCl ₃ ) 547 nm, 575 nm
λ _max (em) (toluene) 504nm

[Synthesis Example 9]
Compound B-9 of the Invention: Synthesis of 1,2,4,5-tetrakis [4- (pN, N-dioctylaminostyryl) phenylethynyl] -3,6-bis (trimethylsilylethynyl) benzene

  The same as Synthesis Example 2 except that 1,2,4,5-tetrabromo-3,6-bis (trimethylsilylethynyl) benzene was used as a starting material instead of 1,2,4,5-tetrabromobenzene. The target compound was obtained in a yield of 67%.

(Compound B-9)
Melting point: 150 ° C
Nuclear magnetic resonance spectrum: ¹ HNMR (400 MHz, CDCl ₃ ) δ 7.60 (d, J = 8.3 Hz, 8H), 7.50 (d, J = 8.3 Hz, 8H), 7.42 (d, J = 8.8 Hz, 8H) 7.13 (d, J = 16.1Hz, 4H), 6.90 (d, J = 16.1Hz, 4H), 6.64 (d, J = 8.8Hz, 8H), 3.30 (t, J = 7.6Hz, 16H), 1.55 -1.66 (m, 16H), 1.27-1.39 (m, 80H), 0.91 (t, J = 6.6Hz, 24H), 0.39 (s, 18H).
¹³ C NMR (100 MHz, CDCl ₃ ) δ 148.0, 139.0, 132.1, 130.2, 128.0, 127.6, 127.0, 125.8, 124.1, 122.7, 120.8, 111.5, 104.9, 101.7, 99.9, 88.0, 51.1, 31.8, 29.5, 29.3, 27.3, 27.2, 22.7, 14.1, 0.1.
UV-vis: λ _max (CHCl ₃ ) 443 nm (log ε 5.21)
λ _max (toluene) 440 nm (log ε 5.18)
Fluorescence: λ _max (em) (CHCl ₃ ) 547 nm, 575 nm
λ _max (em) (toluene) 513nm

[Examples and Comparative Examples]
For each of the compounds B-1 to B-9 obtained in Synthesis Examples 1 to 9, the two-photon absorption cross section, the two-photon excitation fluorescence peak wavelength, the two-photon excitation fluorescence intensity (relative value), and the fluorescence quantum yield are shown below. It measured by the method and the result was shown in Table 1 (Example 1- Example 9).

  For comparison, the following compounds X-1 and X-2 (Oct = octyl group) were similarly evaluated, and the results are shown in Table 1 (Comparative Examples 1 and 2).

<Evaluation method of two-photon absorption cross section>
Two-photon absorption cross-section evaluation was performed by Kato, S .; Matsumoto, T .; Ishi-I, T .; Thiemann, T .; Shigeiwa, M .; Gorohmaru, H .; Maeda, S .; Yamashita, Y .; The same method as described in Supporting Information of Mataka, S. Chem. Commun. 2004, 2342-2343 was used. A femtosecond titanium sapphire laser (wavelength: 800 nm, pulse width: 120 fs, repetition rate: 1 kHz, output: 2 mJ / pulse) is used as a measurement light source, and the two-photon absorption cross section is measured by appropriately attenuating the output from the laser. did. For the measurement, the Z-scan method was used to change the excitation light density in the range of 1 to 40 GW / cm ² . As a measurement sample, a solution in which each compound was dissolved in toluene at the concentration shown in Table 1 below was used, and this solution was put into a 4-cm transparent 1 cm square quartz cell for measurement.

  Moreover, AF50 of the following structural formula used as a standard sample was measured at the time of measuring each compound. In the above system, the numerical value of AF50 is obtained from 45 GM to 55 GM. In order to normalize the two-photon absorption cross section, the values of all the two-photon absorption cross-sections were calculated by measuring AF50 after measuring the sample and setting the two-photon absorption cross-section of the AF50 as 45 GM.

<Evaluation method of two-photon excitation fluorescence peak wavelength>
Two-photon excitation fluorescence wavelength evaluation was performed by the method according to the evaluation method of two-photon absorption cross section. The same arrangement as that of the two-photon absorption cross section was performed up to the portion where the sample was irradiated with the laser from the light source. The same sample and sample cell as those used for the two-photon absorption cross section measurement were used. The sample was excited under conditions of an excitation light intensity of 10 mW and an excitation light density of 10 GW / cm ² , and the fluorescence generated from the sample was condensed by placing a lens in a direction orthogonal to the incident laser light, and then the spectroscopic measurement was performed to measure the fluorescence spectrum. . The obtained fluorescence spectrum was read for the peak wavelength after correcting the wavelength dependence of the apparatus. The peak wavelength includes an error of ± 1 nm. As the fluorescence intensity, the intensity at the peak position of the fluorescence spectrum was read.

<Method for evaluating fluorescence quantum yield>
As a measurement sample, a solution in which a predetermined amount of each compound was dissolved in toluene was used. After adjusting the sample cell width to 1 cm and the peak absorbance to be 0.5 ± 10%, the sample was further diluted 20 times with toluene and measured. It was used for. In the same manner, a cyclohexane solution of 9,10-bis (phenylethynyl) anthracene (manufactured by Wako Pure Chemical Industries, Ltd., product number: 323-22401) was prepared as a standard sample. Each sample solution was subjected to nitrogen deaeration for 15 minutes immediately before the measurement and then measured. For the measurement of the fluorescence quantum yield, a fluorescence quantum yield measurement device (“Absolute PL quantum yield measurement device C9920-02 type” manufactured by Hamamatsu Photonics Co., Ltd., measurement wavelength range: <950 nm) was used. The sample was placed in a transparent 1 cm square quartz cell and subjected to measurement using an excitation wavelength of 415 nm. The fluorescence quantum yield of the standard sample was set to 1.00, and the value was calculated by correcting with the refractive index of the solvent.

[Example 10]
<Method for producing and evaluating optical recording medium>
0.5 mg of the specific example compound B-6 synthesized in Synthesis Example 1 was weighed, and a 5 wt% solution (solvent: toluene + methyl ethyl ketone (weight ratio 1: 1: Mitsubishi Rayon “Acrypet VH-5”)). 1) A coating solution was prepared by dissolving in 1 g. This coating solution was dropped on a slide glass, allowed to stand for one day and air-dried, and then dried at a temperature of 100 ° C. for 30 minutes to produce an optical recording medium having a recording layer with a thickness of 20 μm.

The fluorescence emission of the obtained optical recording medium was measured with a fluorescence spectrophotometer (“F-4500” manufactured by Hitachi, Ltd., excitation wavelength: 325 nm), and the fluorescence emission spectrum is shown in FIG. 1 (curve a).
Subsequently, a spot type ultraviolet irradiation device (“Spot Cure UIS-50101AA” manufactured by Ushio Electric Co., Ltd.), an ultra-high pressure mercury lamp (“USH-500BY1 manufactured by USHIO Electric Co., Ltd., main wavelength: 365 nm, irradiation intensity: 300 mW / cm ²⁾ )), And the fluorescence emission spectrum was measured with the fluorescence spectrophotometer in the same manner as shown in FIG. 1 (curve b). In the curve a, almost no fluorescence was observed, but in the curve b, the fluorescence emission intensity having a peak near the wavelength of 520 nm of the recording medium increased significantly. Table 2 shows the fluorescence intensity and intensity change rate (contrast) at a wavelength of 520 nm before and after ultraviolet irradiation.

Furthermore, using the same laser and optical system as those used for the evaluation of the two-photon absorption cross section, a laser beam having an average output of 44 mW / cm ² (because it is a 120 fs pulse, the energy density is about 10 GW / cm ² ) is about 1 mm in diameter And the recording layer of the optical recording medium was irradiated for 2 seconds. Thereafter, the optical recording medium is placed in a dark box and irradiated with ultraviolet rays using a handy UV lamp (“ASUV“ SLUV-6 ”manufactured by ASONE, irradiation light principal wavelength: 365 nm, irradiation surface intensity: 0.05 mW / cm ² ). As a result, it was possible to confirm a clear fluorescent spot having the same size as the beam diameter from the portion irradiated with the laser beam.
Therefore, after recording information by irradiating the optical recording medium with ultraviolet light or light with a wavelength twice that of the optical recording medium to cause two-photon absorption, information is recorded and reproduced by detecting fluorescence. Obviously it can be done.

From Table 1, it can be seen that the arylethynyl compound of the present invention has a two-photon absorption cross-sectional area of 5 times or more compared with AF50, and is excellent in two-photon absorption efficiency. In addition, it can be seen that some of the arylethynyl compounds of the present invention have large two-photon fluorescence intensity and fluorescence quantum yield, and are excellent in two-photon emission efficiency.
In particular, it can be seen that the quantum yield of fluorescence is very high and good for the compounds B-1, B-2, B-7, B-8 and B-9.
Moreover, the two-photon fluorescence intensity was extremely high in the compounds B-1, B-2, B-8, and B-9, and extremely good two-photon fluorescence characteristics were exhibited. Compounds B-5 and B-7 also showed good two-photon fluorescence properties. These tendencies can be recognized by looking at the relationship between the two-photon fluorescence peak wavelength and the two-photon absorption cross section in FIG.
On the other hand, the compound B-4 having a π-electron deficient heteroaromatic ring as a central ring D and the compound B-3 having a —CN group that tends to attract π electrons in the central ring D are a quantum yield of fluorescence. It can also be seen that the two-photon fluorescence characteristics at 800 nm excitation are slightly inferior. Compound B-3 has an absorption band on the longer wavelength side compared to the other compounds (B-2 to B-9, X-1 to X-2) in the first place (in the UV-vis of Synthesis Example 4). λ _max ). Therefore, care must be taken in the analysis of these properties of compound B-3.

  Further, from Table 2, the arylethynyl compound of the present invention containing a photolabile protecting group has a property of causing a large fluorescence intensity change before and after UV irradiation, and can be applied to an optical recording medium using the fluorescence intensity change. It turns out that it is.

[Examples 11 to 13]
For compounds B-1, B-3, and B-8, the two-photon absorption cross-section at an excitation wavelength of 750 nm was evaluated by the following method.
Table 3 shows the results (Examples 11 to 13). The two-photon absorption cross section of AF50 at an excitation wavelength of 750 nm was 140 GM.

<Method for measuring wavelength dependence of two-photon absorption cross section>
After wavelength conversion of 800 nm femtosecond laser light, evaluation was performed using the measurement method by the Z-scan method described in <Method for evaluating two-photon absorption cross section> described above. Regarding the Z-scan method after wavelength conversion of femtosecond laser light having a wavelength of 800 nm to 750 nm or the like, the present inventor Shigeiwa, M. et al., Chem. Eur. J. et al. 2006, 12, 2303-2317.

As shown in Table 3, when the excitation wavelength is shortened from 800 nm to 750 nm, the two-photon absorption cross sections of all of the compounds B-1, B-3, and B-8 are increased. The tendency that Compound B-8 was the largest and B-3 was the smallest was the same as in the case of 800 nm excitation.
In addition, in the sample solution of compound B-3, a very slight linear absorption edge was observed.

  Since the arylethynyl compound of the present invention has a large two-photon absorption cross section, it is expected to be applied as a two-photon absorption compound in the fields of high-density optical recording media, three-dimensional stereolithography, photodynamic therapy, and the like. In addition, since some of the arylethynyl compounds of the present invention are also excellent in two-photon emission efficiency, application as fluorescent reagents, light conversion materials, and photosensitizers is also expected.

1 shows fluorescence emission spectra before and after recording by irradiating the optical recording medium produced in Example 10 with ultraviolet rays (excitation light wavelength of 325 nm and its multiple wavelength of 650 nm are also mixed in the fluorescence emission spectrum of FIG. To do). It is a graph which shows the relationship between the two-photon fluorescence peak wavelength and the two-photon absorption cross section of the compounds B-1 to B-9 and the compounds X-1 to X-2 of the present invention.

Claims (11)

An arylethynyl compound represented by the following general formula (I):

[In the formula (I), the central ring D represents an aromatic ring having 4 to 6 carbon atoms, and a substituent other than the Arx ^{1 to} Arx ⁴ -ethynylene group (the substituent includes an aromatic ring group or an aromatic ring group; And a structure in which a substituent having a plurality of linking groups bonded thereto is bonded through an ethynylene group. Arx ^{1 to} Arx ⁴ each independently represent an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded. Aromatic ring group Arx ¹ ~Arx ⁴ also have a substituent group, but may not have at ^least one or more represented by the following general formula (II) of Arx 1 ~Arx ⁴ A substituent in which an aromatic ring group and a linking group are bonded.

(In Formula (II), Ar ^{1 to} Ar ⁿ represent a divalent aromatic ring group that may or may not have a substituent, and Cx ^{1 to} Cx ⁿ represent a linking group. N is an integer of 1 to 5. B is an electron-donating aromatic ring group that may or may not have a substituent, or at least one or more electron-donating properties. Represents an aromatic ring group substituted with a group.)
Here, the “linking group” is a group capable of conjugating groups linked by this. ] In the general formula (I), the central ring D is an aromatic ring containing a heteroatom having 4 to 5 carbon atoms, the aromatic ring is a π-electron rich heterocycle, and the central ring D is Arx ¹ to Arx ⁴ -ethynylene. In addition to the group, an optionally substituted substituent (excluding a structure in which an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded via an ethynylene group) is further included. 2. The arylethynyl compound according to claim 1, wherein the arylethynyl compound is a substituent other than a substituent represented by a heavy atom such as nitro group, iodine, bromine, or the like, which facilitates non-radiative transition. The central ring D in the general formula (I) is an aromatic ring containing a heteroatom having 4 to 5 carbon atoms, the aromatic ring is a π electron deficient heterocycle, and the central ring D is Arx ¹ to Arx ⁴ -ethynylene. In addition to the group, an optionally substituted substituent (excluding a structure in which an aromatic ring group or a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded via an ethynylene group) is further included. 2. The arylethynyl compound according to claim 1, wherein the arylethynyl compound is a substituent other than a substituent represented by a heavy atom such as nitro group, iodine, bromine, or the like, which facilitates non-radiative transition. The central ring D in the general formula (I) is a benzene ring, and the central ring D may have a substituent other than the Arx ¹ to Arx ⁴ -ethynylene group (the substituent includes an aromatic ring group, or (Excluding structures in which a substituent in which a plurality of aromatic ring groups and linking groups are bonded is bonded via an ethynylene group)) is further caused by a non-radiative transition represented by a heavy atom such as a nitro group, iodine, or bromine. The arylethynyl compound according to claim 1, wherein the arylethynyl compound is a substituent excluding a substituent to be facilitated.   A two-photon absorption material comprising the arylethynyl compound according to any one of claims 1 to 4 as at least a part of a constituent component. The two-photon according to claim 5, wherein, in the general formula (I), at least two of Arx ^{1 to} Arx ⁴ are substituents in which an aromatic ring group represented by the general formula (II) and a linking group are bonded. Absorbing material.   The two-photon absorption material according to claim 5 or 6, wherein B in the general formula (II) is an aromatic ring group having a substituted amino group as an electron donating group.   The two-photon absorption material according to any one of claims 5 to 7, wherein B in the general formula (II) has a photolabile protecting group containing a nitro group as a substituent.   The two-photon absorption material according to any one of claims 5 to 8, wherein a two-photon absorption sectional area by a transmission method when the two-photon absorption sectional area of AF50 is 45 GM is 200 GM or more.   An optical recording medium containing the two-photon absorption material according to claim 5 in a recording layer.   Information is recorded on the optical recording medium according to claim 10 by dissociation of a photolabile protecting group by light irradiation, and on the other hand, by reading fluorescence emitted from a fluorescent light-emitting host having a fluorescent group by light irradiation. A method for recording / reproducing an optical recording medium, wherein the recorded information is reproduced.

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