JP2012017442A - Reverse photochromic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reverse photochromic material of a new type, which is colored as an initial state, has sensitivity in a visible light region, and presents a reversible structural change (color change) by light irradiation.SOLUTION: The reverse photochromic material comprises a biimidazole compound expressed by the formula for example.

Description

  The present invention relates to a reverse photochromic material, and more particularly to a reverse photochromic material comprising a novel biimidazole compound.

  Photochromic materials have a function (dimming function) that reversibly changes color (transmittance of visible light) by irradiating light, and glasses, optical switches, or display / non-glare to prevent glare It is used as a display material such as ink having display switching ability. In addition, applications as recording materials such as optical disks and holograms are being studied.

  The color change due to the photochromic material is manifested by a reversible chemical change of the material due to light irradiation. As typical photochromic materials, spiropyran compounds, spirooxazine compounds, naphthopyran compounds, fulgide compounds, diarylethene compounds, and the like are known.

  Photochromic materials can be broadly divided into those that exhibit a phenomenon called positive photochromism that changes from colorless to colored as the structure changes due to light irradiation, and conversely, a phenomenon called negative photochromism that changes from colored to colorless by irradiation. (Reverse photochromic material).

  Among these, as for the reverse photochromic material, several examples of materials such as spirobenzopyran derivatives (Patent Document 1), dimethyldihydropyrene derivatives (Patent Document 2), and diarylethene derivatives (Patent Document 3) have been reported.

JP 04-128834 A JP 07-009766 A JP 2009-062344 A

  By the way, the light control function is required to have characteristics such as color, color density and color speed suitable for the application. Therefore, it is necessary to develop various types of derivatives and compounds having a new molecular skeleton.

  However, the current situation is that there are few types of reverse photochromic materials compared to positive photochromic materials.

  Therefore, there has been a demand for an inverse photochromic material having a new structure.

  An object of the present invention is to provide a new type of inverse photochromic material which is colored as an initial state, is sensitive to the visible light region, and exhibits a reversible structural change (color change) by light irradiation.

（式中Ｒ_４及びＲ_５はそれぞれ独立してハロゲン原子又はアルキル基を示し、Ｒ_１〜Ｒ_３及びＲ_６〜Ｒ_８はそれぞれ独立して水素原子、ハロゲン原子、アルキル基、フルオロアルキル基、ヒドロキシル基、アルコキシル基、アミノ基、アルキルアミノ基、カルボニル基、アルキルカルボニル基、ニトロ基、シアノ基又はアリール基を示す。Ａｒ_１〜Ａｒ_４はそれぞれ独立して置換又は無置換のアリール基を示す。Ｒ_４は、Ｒ_３と共に、縮合した置換又は無置換のアリール環を形成してもよく、Ｒ_５は、Ｒ_６と共に、縮合した置換又は無置換のアリール環を形成してもよい。） As a result of intensive research to solve the above-mentioned problems, the present inventors have found that the process of improving cyclophane, which is a linking site of cyclophane-linked hexaarylbiimidazole, which is a high-speed photochromic material, into biphenyl type. We found reverse photochromic molecules. Specifically, the present inventors have found a new compound exhibiting negative photochromism by introducing a bulky substituent into R ₄ and R ₅ of the general formula (1) using biimidazole as a basic skeleton. This molecule was a colored body in a stable state and exhibited reverse photochromic properties that isomerized to a decolored body when irradiated with visible light.

(Wherein R ₄ and R ₅ each independently represent a halogen atom or an alkyl group, and R _{1 to} R ₃ and R _{6 to} R ₈ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a fluoroalkyl group, A hydroxyl group, an alkoxyl group, an amino group, an alkylamino group, a carbonyl group, an alkylcarbonyl group, a nitro group, a cyano group, or an aryl group, and Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aryl group. R ₄ together with R ₃ may form a fused substituted or unsubstituted aryl ring, and R ₅ together with R ₆ may form a fused substituted or unsubstituted aryl ring.

  That is, this invention is a reverse photochromic material characterized by consisting of the biimidazole compound represented by the said General formula (1).

  The reverse photochromic material provided by the present invention easily changes its color tone from a colored body to a decolored body by irradiation with visible light. This property can be applied to any application where photochromic molecules are used. Specific applications include optical switches, printing materials, recording materials, and hologram materials. In addition, since the reverse photochromic material of the present invention has a completely different structure from conventional molecules exhibiting reverse photochromism, it can provide a new option for device development using reverse photochromism.

It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state and excitation light irradiation of the reverse photochromic molecule [1] which concerns on Example 1. FIG. It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state and excitation light irradiation of the reverse photochromic molecule [2] which concerns on Example 2. FIG. It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state and excitation light irradiation of the reverse photochromic molecule [3] which concerns on Example 3. FIG. It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state of the inverse photochromic molecule [4] which concerns on Example 4, and excitation light irradiation. It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state and excitation light irradiation of the reverse photochromic molecule [5] which concerns on Example 5. FIG. It is a graph which shows the ultraviolet-visible absorption spectrum in the normal state of compound [6] which concerns on the comparative example 1, and excitation light irradiation.

The reverse photochromic material of the present invention has a structure having a spiro ring structure by introducing a sterically bulky substituent into both R ₄ and R ₅ sites of the biimidazole compound represented by the general formula (1). To get.

Examples of the bulky substituent at both sites of R ₄ and R ₅ include a halogen atom or an alkyl group. The substituent may be the smallest methyl group among the alkyl groups. That is, the reverse photochromic material is represented by the following general formula (2).

（式中Ｒ_１〜Ｒ_２及びＲ_７〜Ｒ_１４はそれぞれ独立して水素原子、ハロゲン原子、アルキル基、フルオロアルキル基、ヒドロキシル基、アルコキシル基、アミノ基、アルキルアミノ基、カルボニル基、アルキルカルボニル基、ニトロ基、シアノ基又はアリール基を示す。Ａｒ_１〜Ａｒ_４はそれぞれ独立して置換又は無置換のアリール基を示す。） Alternatively, R ₄ together with R ₃ forms a condensed substituted or unsubstituted aryl ring, and R ₅ together with R ₆ forms a condensed substituted or unsubstituted aryl ring. Good. Here, the aryl ring is preferably a benzene ring. The reverse photochromic material in this case is represented by the following general formula (3).

(Wherein R _{1 to} R ₂ and R _{7 to} R ₁₄ are each independently a hydrogen atom, a halogen atom, an alkyl group, a fluoroalkyl group, a hydroxyl group, an alkoxyl group, an amino group, an alkylamino group, a carbonyl group, or an alkylcarbonyl group. A group, a nitro group, a cyano group or an aryl group, and Ar _{1 to} Ar ₄ each independently represents a substituted or unsubstituted aryl group.)

  The reverse photochromic material of the present invention comprises, for example, a 2,2′-diformylbiphenyl derivative represented by the following general formula (4) and a diarylethanedione derivative represented by the following general formulas (5) and (6). It is obtained by reacting in the presence of a compound to obtain an intermediate containing an imidazole ring and then subjecting the intermediate to an oxidation reaction. Here, in place of the 2,2′-diformylbiphenyl derivative represented by the general formula (4), a 2,2′-diformyl-1,1′-binaphthalene derivative may be used. The 2,2'-diformylbiphenyl derivative does not include 2,2'-diformylbiphenyl. This is because if 2,2'-diformylbiphenyl is contained, the reverse photochromic material of the present invention cannot be obtained. The inverse photochromic material of the present invention can also be obtained by reacting two formyl groups with different diarylethanedione derivatives. The effect of the present invention may be any synthetic route as long as the structure molecule of the present invention can be obtained, and is not limited by the synthetic route.

（式中Ｒ_４及びＲ_５はそれぞれ独立してハロゲン原子又はアルキル基を示し、Ｒ_１〜Ｒ_３及びＲ_６〜Ｒ_８はそれぞれ独立して水素原子、ハロゲン原子、アルキル基、フルオロアルキル基、ヒドロキシル基、アルコキシル基、アミノ基、アルキルアミノ基、カルボニル基、アルキルカルボニル基、ニトロ基、シアノ基又はアリール基を示す。Ａｒ_１〜Ａｒ_４はそれぞれ独立して置換又は無置換のアリール基を示す。Ｒ_４は、Ｒ_３と共に、縮合した置換又は無置換のアリール環を形成してもよく、Ｒ_５は、Ｒ_６と共に、縮合した置換又は無置換のアリール環を形成してもよい。）

（式中Ａｒ_１、Ａｒ_２はそれぞれ独立して置換又は無置換のアリール基を示す。）

（式中Ａｒ_３Ａｒ_４はそれぞれ独立して置換又は無置換のアリール基を示す。）

(Wherein R ₄ and R ₅ each independently represent a halogen atom or an alkyl group, and R _{1 to} R ₃ and R _{6 to} R ₈ each independently represent a hydrogen atom, a halogen atom, an alkyl group, a fluoroalkyl group, A hydroxyl group, an alkoxyl group, an amino group, an alkylamino group, a carbonyl group, an alkylcarbonyl group, a nitro group, a cyano group, or an aryl group, and Ar _{1 to} Ar ₄ each independently represent a substituted or unsubstituted aryl group. R ₄ together with R ₃ may form a fused substituted or unsubstituted aryl ring, and R ₅ together with R ₆ may form a fused substituted or unsubstituted aryl ring.

(In the formula, Ar ₁ and Ar ₂ each independently represent a substituted or unsubstituted aryl group.)

(In the formula, Ar ₃ Ar ₄ each independently represents a substituted or unsubstituted aryl group.)

The 2,2′-diformylbiphenyl derivative used as a raw material for synthesizing the reverse photochromic molecule of the present invention represented by the general formula (2) preferably has a sterically large substituent at the 6,6 ′ position. . Examples of such 2,2′-diformylbiphenyl derivatives include 6,6′dimethyl-2,2′-diformylbiphenyl, 6,6′diethyl-2,2′-diformylbiphenyl, and 6,6 ′. Dimethyl-2,2′-di-npropylbiphenyl, 6,6′dimethyl-2,2′-diisopropylbiphenyl, 6,6′dimethyl-2,2′-di-nbutylbiphenyl, 6,6′dimethyl- 2,2′-diisobutylbiphenyl, 6,6′dimethyl-2,2′-di-tertbutylbiphenyl, 6,6′ditrifluoromethyl-2,2′-diformylbiphenyl, 4,4′dihydroxy-6, 6'-dimethyl-2,2'-diformylbiphenyl, 4,4'dimethoxy-6,6'-dimethyl-2,2'-diformylbiphenyl, 4,4'diacetoxy-6,6'-dimethyl-2 , 2'-Diformi Biphenyl, 4,4′diamino-6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′bis (dimethylamino) -6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′difluoro-6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′dichloro-6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′dibromo- 6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′diiodo-6,6′-dimethyl-2,2′-diformylbiphenyl, 4,4′dinitro-6,6′-dimethyl -2,2'-diformylbiphenyl, 4,4'dicyano-6,6'-dimethyl-2,2'-diformylbiphenyl, 4,4'dimethoxycarbonyl-6,6'-dimethyl-2,2 ' -Diformylbiphenyl, 3,3 ', 6,6'-tetramethyl- 2,2′-diformylbiphenyl, 4,4 ′, 6,6′-tetramethyl-2,2′-diformylbiphenyl, 5,5 ′, 6,6′-tetramethyl-2,2′-diformyl Biphenyl, 6,6′-dichloro-2,2′-diformylbiphenyl, 6,6′-dibromo-2,2′-diformylbiphenyl, 6,6′-diiodo-2,2′-diformylbiphenyl, 4,4 ′, 6,6′-tetrachloro-2,2′-diformylbiphenyl, 4,4 ′, 6,6′-tetrabromo-2,2′-diformylbiphenyl, 4,4′-difluoro- 6,6′-dichloro-2,2′-diformylbiphenyl, 4,4′-difluoro-6,6′-dibromo-2,2′-diformylbiphenyl, 4,4′-difluoro-6,6 ′ -Diiodo-2,2'-diformylbiphenyl, 3,3 ', 4,4', 5,5'-hex Fluoro-6,6 '
-Dibromo-2,2'-diformylbiphenyl, 5,5'dimethoxy-4,4 ', 6,6'-tetramethyl-2,2'-diformylbiphenyl, and the like, but are not limited thereto. It is not something.

  As the 2,2′-diformyl-1,1′-binaphthalene derivatives, 2,2′-diformyl-1,1′-binaphthalene, 3,3′-dibromo-2,2′-diformyl-1,1 '-Binaphthalene, 4,4'-dibromo-2,2'-diformyl-1,1'-binaphthalene, 6,6'-dibromo-2,2'-diformyl-1,1'-binaphthalene, 3,3' -Dichloro-2,2'-diformyl-1,1'-binaphthalene, 3,3'-diiodo-2,2'-diformyl-1,1'-binaphthalene, 3,3'-dimethoxymethyl-2,2 ' -Diformyl-1,1'-binaphthalene, 3,3'-diphenyl-2,2'-diformyl-1,1'-binaphthalene, 6,6'-dimethoxycarbonyl-2,2'-diformyl-1,1 ' -Binaphthalene, 4, '-Dicyano-2,2'-diformyl-1,1'-binaphthalene, 7,7'-dihydroxy-2,2'-diformyl-1,1'-binaphthalene, 7,7'-dimethoxy-2,2' -Diformyl-1,1'-binaphthalene, 7,7'-bis (metachlorobenzyloxy) -2,2'-diformyl-1,1'-binaphthalene, 6,6'-dibromo-3,3'-dimethoxy -2,2'-diformyl-1,1'-binaphthalene, 3,3'-dimethoxycarbonyl-4,4'-dihydroxy-2,2'-diformyl-1,1'-binaphthalene, 3,3 ', 6 , 6′-tetraphenyl-2,2′-diformyl-1,1′-binaphthalene, 6,6′-dimethyl-7,7′-dihydroxy-2,2′-diformyl-1,1′-binaphthalene, 6 , 6'-Dimethyl -7,7'-bis (metachlorobenzyloxy) -2,2'-diformyl-1,1'-binaphthalene, 3,3 ', 4,4'-tetrahydroxy-2,2'-diformyl-1, 1'-binaphthalene, 3,3'-dimethoxy-4,4'-diamino-2,2'-diformyl-1,1'-binaphthalene, 6,6'-dimethyl-7,7'-dihydroxy-2,2 '-Diformyl-1,1'-binaphthalene, 6-methoxycarbonylethyl-2,2'-diformyl-1,1'-binaphthalene and the like can be exemplified, but are not limited thereto.

Examples of the diarylethanedione derivative used as a raw material for the reverse photochromic material of the present invention include 2-fluorobenzyl, 3-fluorobenzyl, 4-fluorobenzyl, 2-chlorobenzyl, 3-chlorobenzyl, 4-chlorobenzyl, Bromobenzyl, 3-bromobenzyl, 4-bromobenzyl, 2-iodobenzyl, 3-iodobenzyl, 4-iodobenzyl, 2-hydroxybenzyl, 3-hydroxybenzyl, 4-hydroxybenzyl, 2-methoxybenzyl, 3- Methoxybenzyl, 4-methoxybenzyl, 2-ethoxybenzyl, 3-ethoxybenzyl, 4-ethoxybenzyl, 2-phenoxybenzyl, 3-phenoxybenzyl, 4-phenoxybenzyl, 2-acetoxybenzyl, 3-acetoxybenzyl, 4- Acetoki Benzyl, 2-methylbenzyl, 3-methylsibenzyl, 4-methylbenzyl, 2-carboxybenzyl, 3-carboxybenzyl, 4-carboxybenzyl, 2- (methylcarboxy) benzyl, 3- (methylcarboxy) benzyl, 4 -(Methylcarboxy) benzyl, 2- (phenylcarboxy) benzyl, 3- (phenylcarboxy) benzyl, 4- (phenylcarboxy) benzyl, 2-nitrobenzyl, 3-nitrobenzyl, 4-nitrobenzyl, 2-cyanobenzyl 3-cyanobenzyl, 4-cyanobenzyl, 2-methylthiobenzyl, 3-methylthiobenzyl, 4-methylthiobenzyl, 2-phenylthiobenzyl, 3-phenylthiobenzyl, 4-phenylthiobenzyl, 2-phenylacetylenyl Benzyl, 3-fu Nylacetylenylbenzyl, 4-phenylacetylenylbenzyl, 2-styrylbenzyl, 3-styrylbenzyl, 4-styrylbenzyl, 2-phenylmethylbenzyl, 3-phenylmethylbenzyl, 4-phenylmethylbenzyl, 2-amino Benzyl, 3-aminobenzyl, 4-aminobenzyl, 2-dimethylaminobenzyl, 3-dimethylaminobenzyl, 4-dimethylaminobenzyl, 2-bromomethylbenzyl, 3-bromomethylbenzyl, 4-bromomethylbenzyl, 2- Methoxymethylbenzyl, 3-methoxymethylbenzyl, 4-methoxymethylbenzyl, 2- (N-methylaminocarbonyl) benzyl, 3- (N-methylaminocarbonyl) benzyl, 4- (N-methylaminocarbonyl) benzyl, 2 -(N-phenyl Aminocarbonyl) benzyl, 3- (N-phenylaminocarbonyl) benzyl, 4- (N-phenylaminocarbonyl) benzyl, 2-trifluoromethylbenzyl, 3-trifluoromethylbenzyl, 4-trifluoromethylbenzyl, 3, 4-methylenedioxybenzyl, 3,4-ethylenedioxybenzyl, 3,4-ethylenedithiobenzyl, 2,4-dihydroxybenzyl, 2,4-dimethylbenzyl, 2,3-dimethylbenzyl, 3,4-dimethyl Benzyl, 3,4-dimethoxybenzyl, 2,4-dimethoxybenzyl, 2,4-dinitrobenzyl, 2-methyl-3-nitrobenzyl, 2-methoxy-3-nitrobenzyl, 2-chloro-4-methoxybenzyl, 3-chloro-4-aminobenzyl, 2,3-dichlorobenzyl, 3 4-dichlorobenzyl, 2-difluoromethyl-3-methylbenzyl, 3-fluoro-4-bromobenzyl, 3,5-dimethoxybenzyl, 3,5-difluorobenzyl, 3,4,5-trimethoxybenzyl, 4- (2-Oxo-phenylacetyl) naphthalene-1,8-dicarboxylic acid anhydride, 1- (9-oxofluoren-2-yl) -2-phenylethanedione, 1- (4-nitrophenyl) -3 -[4- (2-oxo-2-phenylacetyl) phenyl] urea, ethyl-4-methyl-2-{[4- (2-oxo-2-phenylacetyl) phenyl] carbonylamino} -1,3- Thiazole-5-carboxylate, N- (2-methoxy-5-methylphenyl) [4- (2-oxo-2-phenylacetyl) ) Phenyl] carboxamide, N- (2-methoxyethyl) [4- (2-oxo-2-phenylacetyl) phenyl] carboxamide, 4-chloro-2-methylphenyl-4- (2-oxo-2-) Phenylacetyl) benzoate, 1-phenyl-2- (2-naphthyl) ethanedione, 1-phenyl-2- (1-naphthyl) ethanedione, 1-phenyl-2- [4- (4-nitrophenoxy) phenyl] ethanedione, Carbamoylmethyl-4- (2-oxo-2-phenylacetyl) benzoate, 1-acenaphthen-5-yl-2-phenylethanedione, 2,3,4,5,6-pentachlorobenzyl, benzyl, 2,2 '-Difluorobenzyl, 3,3'-difluorobenzyl, 4,4'-difluorobenzyl, 2,2'-dichlorobenzene Gills, 3,3′-dichlorobenzyl, 4,4′-dichlorobenzyl, 2,2′-dibromobenzyl, 3,3′-dibromobenzyl, 4,4′-dibromobenzyl, 2,2′-diiodobenzyl 3,3′-diiodobenzyl, 4,4′-diiodobenzyl, 2,2′-dihydroxybenzyl, 3,3′-dihydroxybenzyl, 4,4′-dihydroxybenzyl, 2,2′-dimethoxybenzyl 3,3′-dimethoxybenzyl, 4,4′-dimethoxybenzyl, 2,2′-diethoxybenzyl, 3,3′-diethoxybenzyl, 4,4′-diethoxybenzyl, 2,2′-di Phenoxybenzyl, 3,3′-diphenoxybenzyl, 4,4′-diphenoxybenzyl, 2,2′-diacetoxybenzyl, 3,3′-diacetoxybenzyl, 4,4′-diacetoxybenzyl 2,2′-dimethylbenzyl, 3,3′-dimethylsibenzyl, 4,4′-dimethylbenzyl, 2,2′-dicarboxybenzyl, 3,3′-dicarboxybenzyl, 4,4′-dicarboxy Benzyl, 2,2′-bis (methylcarboxy) benzyl, 3,3′-bis (methylcarboxy) benzyl, 4,4′-bis (methylcarboxy) benzyl, 2,2′-bis (phenylcarboxy) benzyl, 3,3′-bis (phenylcarboxy) benzyl, 4,4′-bis (phenylcarboxy) benzyl, 2,2′-dinitrobenzyl, 3,3′-dinitrobenzyl, 4,4′-dinitrobenzyl, 2, 2'-dicyanobenzyl, 3,3'-dicyanobenzyl, 4,4'-dicyanobenzyl, 2,2'-dimethylthiobenzyl, 3,3'-dimethylthiobenzyl, 4,4 ' Dimethylthiobenzyl, 2,2′-diphenylthiobenzyl, 3,3′-diphenylthiobenzyl, 4,4′-diphenylthiobenzyl, 2,2′-diphenylacetylenylbenzyl, 3,3′-diphenylacetylene Nilbenzyl, 4,4′-diphenylacetylenylbenzyl, 2,2′-distyrylbenzyl, 3,3′-distyrylbenzyl, 4,4′-distyrylbenzyl, 2,2′-diphenylmethylbenzyl, 3,3′-diphenylmethylbenzyl, 4,4′-diphenylmethylbenzyl, 2,2′-diaminobenzyl, 3,3′-diaminobenzyl, 4,4′-diaminobenzyl, 2,2′-bis (dimethyl) Amino) benzyl, 3,3′-bis (dimethylamino) benzyl, 4,4′-bis (dimethylamino) benzyl, 2,2′-dibromomethylbenzyl 3,3′-dibromomethylbenzyl, 4,4′-dibromomethylbenzyl, 2,2′-dimethoxymethylbenzyl, 3,3′-dimethoxymethylbenzyl, 4,4′-dimethoxymethylbenzyl, 2,2′- Bis (N-methylaminocarbonyl) benzyl, 3,3′-bis (N-methylaminocarbonyl) benzyl, 4,4′-bis (N-methylaminocarbonyl) benzyl, 2,2′-bis (N-phenyl) Aminocarbonyl) benzyl, 3,3′-bis (N-phenylaminocarbonyl) benzyl, 4,4′-bis (N-phenylaminocarbonyl) benzyl, 2,2′-bis (trifluoromethyl) benzyl, 3, 3'-bis (trifluoromethyl) benzyl, 4,4'-bis (trifluoromethyl) benzyl, 3,4,3 ', 4'-dimethylenedioxyben 3,4,3 ′, 4′-diethylenedioxybenzyl, 3,4,3 ′, 4′-diethylenedithiobenzyl, 2,2 ′, 4,4′-tetramethylbenzyl, 3,3 ′, 4,4′-tetramethoxybenzyl, 2,2 ′, 4,4′-tetramethoxybenzyl, 2,2 ′, 4,4′-tetranitrobenzyl, 2,2′-dimethyl-3,3′-dinitro Benzyl, 2,2′-dimethoxy-3,3′-dinitrobenzyl, 2,2′-dichloro-4,4′-dimethoxybenzyl, 3,3′-dichloro-4,4′-diaminobenzyl, 2,2 ', 3,3'-tetrachlorobenzyl, 3,3', 4,4'-tetrachlorobenzyl, 2,2'-bis (difluoromethyl) -3,3'-dimethylbenzyl, 3,3'-difluoro -4,4'-dibromobenzyl, 3,3 ', 5,5'-tetramethoxybenzyl 3,3 ′, 5,5′-tetrafluorobenzyl, 3,3 ′, 4,4 ′, 5,5′-hexamethoxybenzyl, 4,4′-bis (3-methyl-3-hydroxy-1) -Butynyl) benzyl, 4,4′-diphenylbenzyl, 4,4′-bis (N-morpholinyl) benzyl, 1,2-bis (2,3,6,7-tetrahydro-1H, 5H-pyrido [3 2,1-ij] quinolin-9-yl) ethanedione, 3,3′-dinitro-4,4′-dichlorobenzyl, 3,3′-dinitro-4,4′-dimethoxybenzyl, 3,3′-dinitro -4,4'-dibromobenzyl, 4-methyl-4'-chlorobenzyl, 2-chloro-3 ', 4'-dimethoxybenzyl, 2,4'-dibromobenzyl, 2,3,4,5,6- Pentachloro-2 ', 3', 4 ', 5', 6 '
Examples include, but are not limited to, pentafluorobenzyl.

The temperature for reacting the 2,2′-diformylbiphenyl derivative represented by the general formula (4) and the diarylethanedione derivative represented by the general formulas (5) and (6) depends on the presence or absence of a catalyst and the use thereof. For example, when acetic acid is used as a solvent without using a catalyst, the reaction temperature is usually 80 to 120 ° C, preferably 100 to 120 ° C. When, for example, ZrCl ₄ or iodine is used as the catalyst, the reaction temperature can be 20 ° C. to 75 ° C. in the presence of the catalyst.

Although the reaction time varies depending on the presence or absence of the catalyst and the catalyst used, it cannot be generally stated. For example, when acetic acid is used as the solvent without using the catalyst, the reaction temperature is 4 to 32 hours, preferably 12 to 24 hours. It's time. When, for example, ZrCl ₄ or iodine is used as the catalyst, the reaction time can be 1 to 10 hours in the presence of the catalyst.

  Examples of the nitrogen compound include ammonium acetate and ammonia. Among them, ammonium acetate is preferable because it is difficult to volatilize when heated.

  Any solvent can be used as the solvent for the reaction as long as it can dissolve the raw materials. As such a solvent, for example, a polar solvent such as acetic acid and acetonitrile is preferable.

  The intermediate oxidation reaction can be performed, for example, by dissolving the intermediate in a solvent to prepare a solution and adding an oxidizing agent to the solution.

  Any solvent can be used without particular limitation as long as it can dissolve the intermediate. As such a solvent, for example, benzene, methylene chloride and the like can be used.

  The oxidizing agent can be used without particular limitation as long as it can oxidize the intermediate to obtain a reverse photochromic material. Examples of such an oxidizing agent include potassium ferricyanide and lead oxide. Among them, potassium ferricyanide is preferable. This is because potassium ferricyanide is more reactive.

  In addition to the oxidizing agent, an alkali is further added to the above solution. As such an alkali, for example, potassium hydroxide can be used.

  The oxidation reaction is preferably performed under an inert gas atmosphere under light shielding conditions. The inert gas atmosphere is used to suppress the reaction with oxygen. For example, nitrogen can be used as the inert gas. The oxidation reaction is preferably performed under light-shielding conditions in order to prevent the obtained reverse photochromic material from being changed from a colored body to a colorless body by light.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example.

  As raw materials, 6,6′dimethyl-2,2′-diformylbiphenyl, 2,2′-diformyl-1,1′-binaphthalene, and 2,2′-diformylbiphenyl were synthesized and used as benzyl, , 4′-dimethoxybenzyl, 4,4′-bis (dimethylamino) benzyl, 4,4′-dibromobenzyl, ammonium acetate, acetic acid, potassium ferricyanide, potassium hydroxide are commercially available reagents (manufactured by Tokyo Chemical Industry Co., Ltd.) Was used.

As an evaluation method, photochromic molecules are irradiated with UV-visible light from a UV spot light source L8333 (manufactured by Hamamatsu Photonics) as an excitation light to a benzene solution adjusted to 2.0 × 10 ⁻⁴ M, and the transmittance changes most in the visible light region. The transmittance of the color former and the decolored body was measured by ultraviolet-visible absorption spectrum analysis observing a change in transmittance at a large wavelength.

<Synthesis Example 1>
6,6′dimethyl-2,2′-diformylbiphenyl 100 mg, 4,4′-dimethoxybenzyl 270 mg, ammonium acetate 960 mg, and acetic acid 4.0 ml were mixed and heated and stirred in an oil bath at 110 ° C. for 16 hours. Then, 8.0 ml of 28% aqueous ammonia was added to neutralize the precipitate, and the solid was washed with water, filtered, and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 273 mg of intermediate (I). The formation of intermediate (I) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.92 (2H s), 8.38 (2H d), 7.53 (2H t), 7.46 (4H d), 7,40 (2H d), 6.94 (4H d), 6.80 (4H d), 6.75 (4H d) 3.78 (12H s), 1.99 (6H s)

A solution prepared by dissolving 120 mg of the above compound in 25 ml of benzene, and dissolving 4.1 g of potassium ferricyanide and 1.8 g of potassium hydroxide in 30 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. Thereafter, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated and recrystallized to obtain 102 mg of a mixture containing the reverse photochromic molecule [1] and 24 mg as the reverse photochromic molecule [1]. Formation of reverse photochromic molecule [1] was confirmed by NMR analysis. The NMR analysis was performed on the mixture, and although the reverse photochromic molecule [1] single NMR analysis result has not been obtained, the characteristic peaks of methoxy group and methyl group and the reverse photochromic characteristics are shown. From the above, it is considered that the reverse photochromic molecule [1] represented by the following structural formula is contained in the mixture.

<Synthesis Example 2>
2,2'-diformyl-1,1'-binaphthalene (100 mg), 4,4'-dimethoxybenzyl (183 mg), ammonium acetate (750 mg) and acetic acid (4.0 ml) were mixed and heated and stirred in an oil bath at 110 ° C. for 14 hours for reaction. Thereafter, 8.0 ml of 28% aqueous ammonia was added to neutralize the precipitate, and the solid was washed with water, filtered and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 158 mg of intermediate (II). The formation of intermediate (II) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ 8.78 (2H d), 8.45 (2H s), 8.19 (2H d), 8.02 (2H d) 7.55-7.51 (2H m), 7.42 (4H d), 7.32-7.30 ( 4H m), 6.78 (4H d) 6.69-6.64 (8H m), 3.77 (12H s)

84 mg of the above compound was dissolved in 25 ml of benzene, a solution of 2.5 g of potassium ferricyanide and 1.1 g of potassium hydroxide dissolved in 20 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. After that, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated and recrystallized to obtain 79 mg of reverse photochromic molecule [2]. Formation of inverse photochromic molecule [2] was confirmed by NMR analysis and X-ray crystal structure analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.24 (1H d), 7.92 (1H d), 7.90 (1H d), 7.77 (1H d), 7.50 (2H d), 7.47-7.42 (5H m), 7.30-7.20 (4H m), 7.09-7.05 (1H m), 6.93 (1H d), 6.89 (1H d), 6.85 (2H d), 6.80 (2H d) 6.73 (2H d), 6.54 (2H d), 6.44 ( 2H d), 3.82 (3H s), 3.81 (3H s), 3.73 (3H s), 3.73 (3H s)

<Synthesis Example 3>
2,2′-diformyl-1,1′-binaphthalene 100 mg, benzyl 149 mg, ammonium acetate 750 mg, and acetic acid 4.0 ml were mixed, heated and stirred in an oil bath at 110 ° C. for 14 hours, and then reacted with 28% aqueous ammonia. 8.0 ml was added for neutralization while precipitating the solid, and the solid was washed with water, filtered and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 162 mg of Intermediate (III). The formation of intermediate (III) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ 8.76 (2H d), 8.69 (2H s), 8.20 (2H d), 8.04 (2H d) 7.56-7.51 (2H m), 7.51-7.49 (4H m), 7.33 7.31 (4H m), 7.24-7.14 (12H m) 6.75-6.73 (4H m)

A solution prepared by dissolving 87 mg of the above compound in 25 ml of benzene, 2.9 g of potassium ferricyanide and 1.3 g of potassium hydroxide in 20 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. After that, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated and recrystallized to obtain 75 mg of reverse photochromic molecule [3]. The generation of reverse photochromic molecule [3] was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.26 (1H d), 7.93 (2H d), 7.80 (1H d), 7.57 (2H d), 7.47 (2H d), 7.47 (2H d), 7.44 (3H d) , 7.40 (1H d), 7.35-7.31 (4H m), 7.30-7.21 (3H m), 7.19-7.15 (3H m), 7.13-7.07 (2H m), 7.01 (2H t), 6.98 (1H d) , 6.94 (1H d), 6.55 (2H d)

<Synthesis Example 4>
2,2′-diformyl-1,1′-binaphthalene (100 mg), 4,4′-bis (dimethylamino) benzyl (210 mg), ammonium acetate (750 mg), and acetic acid (4.0 ml) were mixed and heated and stirred in an oil bath at 110 ° C. for 18 hours. After the reaction, 8.0 ml of 28% aqueous ammonia was added to neutralize the precipitate, and the solid was washed with water, filtered, and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 114 mg of intermediate (IV). The formation of intermediate (IV) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ 8.84 (2H br.s), 8.28 (2H br.s), 8.18 (2H d), 8.00 (2H d) 7.51-7.48 (2H m), 7.43 (4H br.s) ), 7.30-7.28 (4H m), 6.63 (8H br.s) 6.49 (4H br.s), 2.91 (24H s)

A solution prepared by dissolving 80 mg of the above compound in 25 ml of benzene and dissolving 2.3 g of potassium ferricyanide and 1.0 g of potassium hydroxide in 20 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. After that, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated to precipitate a solid. The precipitated solid was dissolved in ethanol and recrystallized to obtain 59 mg of reverse photochromic molecule [4]. The generation of inverse photochromic molecule [4] was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.23 (1H d), 7.91 (1H d), 7.86 (1H d), 7.74 (1H d), 7.52-7.50 (3H m), 7.47 (4H d), 7.23 (1H t), 7.19-7.17 (3H m), 7.02-6.98 (1H m), 6.89 (1H d), 6.76 (1H d), 6.62 (2H d), 6.59-6.56 (4H m) 6.40 (2H d), 6.33 (2H d), 3.00 (6H s), 2.99 (6H s), 2.87 (6H s), 2.86 (6H s)

<Synthesis Example 5>
2,2′-diformyl-1,1′-binaphthalene (100 mg), 4,4′-dibromobenzyl (261 mg), ammonium acetate (750 mg) and acetic acid (4.0 ml) were mixed, and the mixture was reacted by heating and stirring in an oil bath at 110 ° C. for 18 hours. Thereafter, 8.0 ml of 28% aqueous ammonia was added to neutralize the precipitate, and the solid was washed with water, filtered and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 249 mg of intermediate (V). The formation of intermediate (V) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.82 (2H s), 8.62 (2H d), 8.19 (2H d), 8.04 (2H d) 7.84-7.82 (4H m), 7.69-7.67 (4H m), 7.56 ( 2H t), 7.35-7.29 (8H m), 6.61 (4H d)

A solution prepared by dissolving 80 mg of the above compound in 10 ml of benzene and dissolving 2.0 g of potassium ferricyanide and 0.90 g of potassium hydroxide in 15 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. After that, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated to precipitate a solid. The precipitated solid was dissolved in ethanol and recrystallized to obtain 22 mg of reverse photochromic molecule [5]. The generation of reverse photochromic molecule [5] was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ8.21 (1H d), 7.95 (2H d), 7.83 (1H d), 7.49 (2H d), 7.43 (2H d), 7.40-7.29 (12H m), 7.23 (2H d), 7.16 (2H d), 7.08 (1H d), 6.96 (1H d) 6.36 (2H d)

<Synthesis Example 6>
After mixing 50 mg of 2,2'-diformylbiphenyl, 142 mg of 4,4'-dimethoxybenzyl, 550 mg of ammonium acetate and 3.0 ml of acetic acid and heating and stirring in an oil bath at 110 ° C for 24 hours, 28% ammonia 6.0 ml of water was added for neutralization while precipitating the solid, and the solid was washed with water, filtered and dried in a vacuum dryer. The dried solid was separated and purified on a silica gel column, and then the solvent was concentrated to obtain 136 mg of intermediate (VI). The formation of intermediate (VI) was confirmed by NMR analysis. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ 9.37 (2H s), 8.31 (2H d), 7.56 (2H t), 7.48-7.38 (8H m), 7,29 (2H d), 7.00 (2H br.s) , 6.77 (8H d) 3.78 (12H s)

A solution prepared by dissolving 89 mg of the above compound in 35 ml of benzene, 3.2 g of potassium ferricyanide and 1.4 g of potassium hydroxide in 25 ml of water was added under a light-shielding condition under nitrogen, and the mixture was stirred at room temperature for 2 hours to be reacted. After that, the aqueous layer was separated and extracted with benzene, and the solvent was concentrated to precipitate a solid. The precipitated solid was dissolved in ethanol and recrystallized, but 86 mg of compound [6] showing no photochromism was obtained. Formation of compound [6] was confirmed by NMR analysis and mass spectrum. The NMR analysis results are as follows. 1H-NMR (500 MHz CDCl3) δ 8.06 (2H d), 7.45 (2H t), 7.42 (8H d), 7,19 (2H t), 6.99 (2H d), 6.79 (8H d) 3.80 (12H s )
FD-MS m / z = 708 (M ⁺ )

<Example 1>
A 1.0 × 10 ⁻³ M benzene solution was prepared using the mixture containing the reverse photochromic molecule [1] synthesized in Synthesis Example 1. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 1, a solid line indicates a normal state (a state where no excitation light is irradiated), and a broken line indicates a state where the excitation light is irradiated. As shown in Table 1 and FIG. 1, the transmittance of the colored body at the maximum absorption wavelength of 496 nm decreased from 60% to 93%.

<Example 2>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the reverse photochromic molecule [2] synthesized in Synthesis Example 2. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 2, a solid line indicates a normal state where no light is irradiated, and a broken line indicates a state where excitation light is irradiated. As shown in Table 1 and FIG. 2, the transmittance of the color former at a maximum absorption wavelength of 493 nm was lowered from 17% to 88%.

<Example 3>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [3] synthesized in Synthesis Example 3. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 3, a solid line indicates a normal state (state in which excitation light is not irradiated), and a broken line indicates a state in which excitation light is irradiated. As shown in Table 1 and FIG. 3, the transmittance at the maximum absorption wavelength of 475 nm of the color former was reduced from 16% to 73%.

<Example 4>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [4] synthesized in Synthesis Example 4. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 4, a solid line indicates a normal state (a state where excitation light is not irradiated), and a broken line indicates a state where excitation light is irradiated. As shown in Table 1 and FIG. 4, the transmittance at the maximum absorption wavelength of 544 nm of the color former decreased from 23% to 74%.

<Example 5>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [5] synthesized in Synthesis Example 5. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 5, a solid line indicates a normal state (a state where no excitation light is irradiated), and a broken line indicates a state where the excitation light is irradiated. As shown in Table 1 and FIG. 5, the transmittance at the maximum absorption wavelength of 486 nm of the color former decreased from 39% to 74%.

<Comparative Example 1>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the compound [6] synthesized in Synthesis Example 6. This solution is put into a four-sided quartz cell and irradiated with excitation light, and the transmittance in the state where the excitation light is not irradiated and the transmittance in the state where the excitation light is irradiated are measured by ultraviolet-visible absorption spectrum analysis in which the transmittance of 500 nm is observed. did. The results are shown in Table 1 and FIG. In FIG. 6, a solid line indicates a normal state (a state in which excitation light is not irradiated), and a broken line indicates a state in which excitation light is irradiated. As shown in Table 1 and FIG. 6, the transmittance did not change from 93%.

From the results shown in Table 1, a molecule that exhibits reverse photochromism was obtained by introducing a sterically bulky substituent into R ₄ and R ₅ of the biimidazole compound represented by the general formula (1).

The reverse photochromic material of the present invention exhibits a red to purple color and exhibits reverse photochromic properties that are sensitive to visible light and absorb the light to increase the transmittance. Utilizing this characteristic, it can be used in fields such as optical switches, printing materials, and recording materials that have been proposed for application. For example, when used as a mask layer material for an optical memory element, it is possible to obtain a good reproduction signal from bits recorded at high density without degrading the reproduction signal. Moreover, the molecule of the present invention is completely different in structure from conventional molecules exhibiting reverse photochromism, and therefore provides a new option for device development using reverse photochromism.

<Example 1>
A 1.0 × 10 ⁻³ M benzene solution was prepared using the mixture containing the reverse photochromic molecule [1] synthesized in Synthesis Example 1. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 1, a solid line indicates a state in which excitation light is irradiated, and a broken line indicates a normal state (a state in which excitation light is not irradiated) . As shown in Table 1 and FIG. 1, the transmittance at the maximum absorption wavelength of 496 nm of the color former increased from 60% to 93%.

<Example 2>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the reverse photochromic molecule [2] synthesized in Synthesis Example 2. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 2, the solid line indicates a state in which excitation light is irradiated , and the broken line indicates a normal state in which light is not irradiated . As shown in Table 1 and FIG. 2, the transmittance at the maximum absorption wavelength of 493 nm of the color former increased from 17% to 88%.

<Example 3>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [3] synthesized in Synthesis Example 3. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 3, the solid line indicates a state of the excitation light, the broken line shows a normal state (a state that is not irradiated with excitation light). As shown in Table 1 and FIG. 3, the transmittance at the maximum absorption wavelength of 475 nm of the color former increased from 16% to 73%.

<Example 4>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [4] synthesized in Synthesis Example 4. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 4, a solid line indicates a state where excitation light is irradiated, and a broken line indicates a normal state (a state where excitation light is not irradiated) . As shown in Table 1 and FIG. 4, the transmittance at the maximum absorption wavelength of 544 nm of the color former increased from 23% to 74%.

<Example 5>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the inverse photochromic molecule [5] synthesized in Synthesis Example 5. This solution was placed in a four-sided quartz cell and irradiated with excitation light, and the color former and decolored material were measured by ultraviolet-visible absorption spectrum analysis in which the transmittance at the wavelength having the largest transmittance change in the visible light region was observed. The results are shown in Table 1 and FIG. In FIG. 5, the solid line indicates a state in which excitation light is irradiated , and the broken line indicates a normal state (a state in which excitation light is not irradiated) . As shown in Table 1 and FIG. 5, the transmittance at the maximum absorption wavelength of 486 nm of the color former increased from 39% to 74%.

<Comparative Example 1>
A 2.0 × 10 ⁻⁴ M benzene solution was prepared using the compound [6] synthesized in Synthesis Example 6. This solution is put into a four-sided quartz cell and irradiated with excitation light, and the transmittance in the state where the excitation light is not irradiated and the transmittance in the state where the excitation light is irradiated are measured by ultraviolet-visible absorption spectrum analysis in which the transmittance of 500 nm is observed. did. The results are shown in Table 1 and FIG. In FIG. 6, a solid line indicates a state where excitation light is irradiated, and a broken line indicates a normal state (a state where excitation light is not irradiated) . As shown in Table 1 and FIG. 6, the transmittance did not change from 93%.

Claims (3)

An inverse photochromic material comprising a biimidazole compound represented by the following general formula (1).

(In the formula, R ₄ and R ₅ each independently represent a halogen atom or an alkyl group, and R _{1 to} R ₃ and R _{6 to} R ₈ each independently represent a hydrogen atom, a halogen atom, an alkyl group, or a fluoroalkyl group. , A hydroxyl group, an alkoxyl group, an amino group, an alkylamino group, a carbonyl group, an alkylcarbonyl group, a nitro group, a cyano group or an aryl group, Ar _{1 to} Ar ₄ each independently represents a substituted or unsubstituted aryl group. the .R ₄ showing, together with R _3, may form a fused substituted or unsubstituted aryl ring, R ₅ together with R _6, may form a fused substituted or unsubstituted aryl ring. ) The reverse photochromic material according to claim 1, wherein R ₄ and R _{5 in the} general formula (1) are methyl groups, and the reverse photochromic material is represented by the following general formula (2).

Wherein R _{1 to} R ₃ and R _{6 to} R ₈ are each independently a hydrogen atom, halogen atom, alkyl group, fluoroalkyl group, hydroxyl group, alkoxyl group, amino group, alkylamino group, carbonyl group, alkylcarbonyl A group, a nitro group, a cyano group or an aryl group, and Ar _{1 to} Ar ₄ each independently represents a substituted or unsubstituted aryl group.) In the general formula (1), R ₄ together with R ₃ forms a condensed substituted or unsubstituted benzene ring, and R ₅ together with R ₆ forms a condensed substituted or unsubstituted benzene ring. Item 2. The inverse photochromic material according to Item 1, which is represented by the following general formula (3).

(Wherein R _{1 to} R ₂ and R _{7 to} R ₁₄ are each independently a hydrogen atom, a halogen atom, an alkyl group, a fluoroalkyl group, a hydroxyl group, an alkoxyl group, an amino group, an alkylamino group, a carbonyl group, or an alkylcarbonyl group. A group, a nitro group, a cyano group or an aryl group, and Ar _{1 to} Ar ₄ each independently represents a substituted or unsubstituted aryl group.)

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