JP6284184B2 - π-conjugated compound, adhesive using π-conjugated compound, method of using adhesive, method of peeling joint, and method of producing π-conjugated compound - Google Patents

Description

  The present invention relates to a π-conjugated compound and a method for producing the same. The present invention also relates to an adhesive using a π-conjugated compound and a method for using the same. Moreover, this invention relates to the peeling method of the structure provided with the junction part joined using the adhesive agent, and the junction part joined using the adhesive agent.

  In recent years, decomposable adhesives have been used in various wide fields including nanoimprint, photoresist, processing of optical components, processing of semiconductor mounting components, and the like. In addition, decomposable adhesives have attracted attention from the viewpoint of adherend recycling.

  On the other hand, materials that can be reversibly fluidized and non-fluidized by light irradiation are known. A liquid crystalline compound combining a sugar alcohol skeleton and a plurality of azobenzene groups has been proposed as a disassembling adhesive utilizing this property (Patent Document 1).

JP 2011-256291 A

  However, in the adhesive described in Patent Document 1, the fluidity is changed by light irradiation at room temperature, and desorption occurs. Therefore, when used in an environment irradiated with ultraviolet rays as in a lithographic process in a semiconductor manufacturing process. There is a risk that unintended adherend peeling or the like may occur.

  In the present invention, the adhesive strength is maintained even under light irradiation in a relatively low temperature region such as room temperature, while the adherend is peeled off by fluidizing by light irradiation under a predetermined high temperature region. It is an object of the present invention to provide a disintegrable adhesive that can be used and a compound that can realize such a dismantleable adhesive.

  In addition, the present invention provides a method for producing the above compound, a method for using the above adhesive, a structure including a joint joined by using the adhesive, and peeling of the joint joined by using the adhesive. One of the purposes is to provide a method.

  In order to achieve the above object, the present inventors have developed a special π having both the features of a π-conjugated skeleton having a high flatness and a flexible π-conjugated skeleton capable of converting molecular properties as the molecular skeleton moves. If we can design a conjugated compound and move the flexible π-conjugated skeleton in an agglomerated state like a liquid crystal, we will devote ourselves to the idea that the physical properties can be reversibly controlled in response to external stimuli. It was. As a result, it was found that a specific π-conjugated compound having a rigid acene skeleton and a flexible cyclooctatetraene skeleton can control fluidity by light irradiation in a temperature range showing a liquid crystal state.

［式中、Ｒ^１は炭素原子数３〜２０のアルキル基を少なくとも一つ有する基を示し、ｎは１〜３の整数を示す。複数のＲ^１は互いに同一であっても異なっていてもよく、複数のｎは互いに同一であっても異なっていても良い。］ One embodiment of the present invention relates to a π-conjugated compound represented by the following formula (1).

[Wherein, R ¹ represents a group having at least one alkyl group having 3 to 20 carbon atoms, and n represents an integer of 1 to 3. A plurality of R ¹ may be the same or different from each other, and a plurality of n may be the same or different from each other. ]

  The π-conjugated compound has a temperature range indicating a solid state, a temperature range indicating a liquid crystal state, and a temperature range indicating a liquid state, and after heating to a temperature range indicating a liquid state and interposing between members The members can be bonded by cooling to a solid state. The π-conjugated compound hardly changes in physical properties even when irradiated with light in a solid state, but changes in a part of molecular structure and shifts to a fluid liquid state when irradiated with light in a liquid crystal state. For this reason, according to the above-mentioned π-conjugated compound, light irradiation is performed under a predetermined high temperature region even though the adhesive force is maintained even under light irradiation under a relatively low temperature region such as room temperature. It is possible to easily realize a dismantling adhesive that can be fluidized and the adherend can be peeled off.

  In addition, after light irradiation in the liquid crystal state, the molecular structure of the π-conjugated compound can be returned to the initial state by heating to a temperature exceeding 150 ° C. and then cooling. That is, according to the above π-conjugated compound, the disassembling adhesive that can be reused through heat treatment after light irradiation and fluidization under a predetermined temperature range to peel off the adherend. Can be realized.

［式中、Ｒ^２は炭素原子数３〜２０のアルキル基又は炭素原子数３〜２０のアルコキシ基を示し、ｐは１〜５の整数を示す。ｐが２以上のとき、複数のＲ^２は互いに同一であっても異なっていてもよい。］ In the above aspect, R ¹ may be a group represented by the following formula (2).

Wherein, ^{R 2} represents an alkoxy group of the alkyl group or 3 to 20 carbon atoms having 3 to 20 carbon atoms, p is an integer of 1-5. When p is 2 or more, the plurality of R ² may be the same as or different from each other. ]

The π-conjugated compound in which R ¹ is a group represented by the above formula (2) is easy to produce, and the temperature range showing the liquid crystal state can be appropriately adjusted by changing R ² and p.

  In the above aspect, the π-conjugated compound may exhibit a liquid crystal state in at least a part of the temperature range of 35 to 150 ° C. Such a π-conjugated compound is practically useful because it can be peeled off at a temperature range that does not adversely affect the semiconductor manufacturing process at 35 to 150 ° C.

  Another embodiment of the present invention relates to an adhesive containing the above π-conjugated compound. Since such an adhesive contains the above-mentioned π-conjugated compound, the adhesive strength is maintained even when irradiated with light under a relatively low temperature range such as room temperature, while light irradiation is performed under a predetermined high temperature range. The adherend can be peeled off by fluidizing, and can be suitably used as a decomposable adhesive.

  The other aspect of this invention is related with a structure provided with the junction part joined using the said adhesive agent. In such a structure, since the bonded portion is bonded using the above-described adhesive, peeling of the bonded portion hardly occurs even when irradiated with light at a low temperature. The joint can be easily peeled and disassembled.

  Another aspect of the present invention relates to a method of using the above adhesive. The method of use includes the step of interposing the adhesive heated to a temperature at which the π-conjugated compound is in a liquid state between two members, and the adhesive interposed between the two members, Cooling to a temperature at which a solid state is formed, and joining the two members.

  In the above aspect, the method of use includes irradiating the adhesive that joins the two members with ultraviolet rays having a wavelength of 300 nm to 400 nm in a temperature range in which the π-conjugated compound exhibits a liquid crystal state. It may further include a step of peeling. According to such a process, two members can be easily peeled off.

In the above aspect, the ultraviolet rays can be irradiated so as to have an integrated light amount of, for example, 0.5 to 200 J / cm ² .

  Another aspect of the present invention relates to a peeling method for peeling a bonded portion bonded using the adhesive. The peeling method includes a step of irradiating the junction with ultraviolet rays having a wavelength of 300 nm to 400 nm in a temperature range where the π-conjugated compound exhibits a liquid crystal state.

［式中、ｎは１〜３の整数を示す。］ Another embodiment of the present invention relates to a method for producing the π-conjugated compound. The manufacturing method includes a step of reacting a tetraformyl compound represented by the following formula (3) with 2-butenedioic acid diester.

[In formula, n shows the integer of 1-3. ]

  According to the reaction of such a tetraformyl compound and 2-butenedioic acid diester, the acene skeleton can be extended and two ester groups can be provided on the benzene rings at both ends. In the said aspect, the said (pi) conjugated compound can be obtained as a product by the said reaction by selecting 2-butenedioic acid diester suitably. The π-conjugated compound can also be obtained through a transesterification reaction of a tetraester compound produced by a reaction between a tetraformyl compound and 2-butenedioic acid diester.

［式中、Ｒ^１は炭素原子数３〜２０のアルキル基を少なくとも一つ有する基を示す。］ In the above aspect, the 2-butenedioic acid diester may be a compound represented by the following formula (4-1) or (4-2). By using such a 2-butenedioic acid diester, the π-conjugated compound can be directly synthesized by a reaction between the tetraformyl compound and the 2-butenedioic acid diester.

[Wherein R ¹ represents a group having at least one alkyl group having 3 to 20 carbon atoms. ]

  According to the present invention, the adhesive strength is maintained even under light irradiation in a relatively low temperature region such as room temperature, while the adherend is fluidized by light irradiation under a predetermined high temperature region. Can be peeled off, and a compound capable of realizing such a dismountable adhesive can be provided.

  A preferred embodiment of the present invention will be described below.

(Π-conjugated compound)
The π-conjugated compound according to this embodiment is a compound represented by the following formula (1).

In the formula, R ¹ represents a group having at least one alkyl group having 3 to 20 carbon atoms, and n represents an integer of 1 to 3. A plurality of R ¹ may be the same or different from each other, and a plurality of n may be the same or different from each other.

  The π-conjugated compound has a temperature range indicating a solid state, a temperature range indicating a liquid crystal state, and a temperature range indicating a liquid state, and after heating to a temperature range indicating a liquid state and interposing between members The members can be bonded by cooling to a solid state. The π-conjugated compound hardly changes in physical properties even when irradiated with light in a solid state, but changes in a part of molecular structure and shifts to a fluid liquid state when irradiated with light in a liquid crystal state. For this reason, according to the above-mentioned π-conjugated compound, light irradiation is performed under a predetermined high temperature region even though the adhesive force is maintained even under light irradiation under a relatively low temperature region such as room temperature. It is possible to easily realize a dismantling adhesive that can be fluidized and the adherend can be peeled off.

  In addition, after light irradiation in a liquid crystal state, for example, the π-conjugated compound is heated to a temperature at which the π-conjugated compound exhibits a liquid state (for example, a temperature exceeding 150 ° C.) and then cooled, so that the molecular structure of the π-conjugated compound is brought into an initial state. Can be returned. That is, according to the above π-conjugated compound, the disassembling adhesive that can be reused through heat treatment after light irradiation and fluidization under a predetermined temperature range to peel off the adherend. Can be realized.

  More specifically, the π-conjugated compound is considered to have a V-shaped molecular skeleton bent by a cyclooctatetraene skeleton, and an integrated structure in which the V-shaped molecular skeleton is stacked in a specific temperature range. It is thought that the liquid crystal state is shown by taking.

In the following formula (1-a), R ^{1 in} the formula (1) is a group having an alkyl group having 12 carbon atoms, and n is 2 as an example of a π-conjugated compound. It is a formula explaining a molecular skeleton. Other π-conjugated compounds have the same V-shaped molecular skeleton.

  When the π-conjugated compound is irradiated with light in a liquid crystal state, it is considered that a dimer is formed by a photodimerization reaction of an acene skeleton or a cyclooctatetraene skeleton. And it is thought that a part of (pi) conjugated compound of a liquid crystal state dimerizes, the said integrated structure collapses, a liquid crystal state changes to a liquid state, and fluidity | liquidity will express. In addition, this dimerization reaction is caused by light irradiation in a liquid crystal state, and is not caused by light irradiation in a solid state. Therefore, fluidization does not occur even when light is irradiated in a temperature range indicating a solid state. .

  In addition, in the π-conjugated compound, for example, the reverse reaction of the dimerization reaction occurs when the π-conjugated compound is heated to a temperature at which the π-conjugated compound exhibits a liquid state, and a monomer is considered to be generated from the dimer. For this reason, even when the dimer is mixed and no longer shows a liquid crystal state due to light irradiation in the liquid crystal state, the π-conjugated compound is heated again to cause a reverse reaction of the dimerization reaction, thereby again in the liquid crystal state. Will come to show.

  The light irradiation may be performed so long as the π-conjugated compound in a liquid crystal state can form a dimer. For example, the light irradiation may be irradiation of ultraviolet rays having a wavelength of 300 to 400 nm. According to such ultraviolet rays, a π-conjugated compound in a liquid crystal state can be easily fluidized.

  Further, when n in the formula (1) is 1, the irradiated light preferably includes light having a wavelength of 254 nm. When n in the formula (1) is 2, the irradiated light has a wavelength of 365 nm. It is preferable that ultraviolet rays are included. Thereby, fluidization of the π-conjugated compound can be efficiently generated.

In formula (1), R ¹ represents a group having at least one alkyl group having 3 to 20 carbon atoms. When R ¹ is such a group, a π-conjugated compound that exhibits a liquid crystal state in a predetermined temperature range while having a rigid acene skeleton and a flexible cyclooctatetraene skeleton is realized. In such a π-conjugated compound, the temperature range in which the liquid crystal state is exhibited can be easily adjusted by changing the number of carbon atoms of the alkyl group of R ¹ .

The alkyl group possessed by R ¹ may be branched or linear, but is preferably linear. Moreover, the carbon atom number of an alkyl group becomes like this. Preferably it is 4-20, More preferably, it is 6-20. Several R < ¹ > may mutually be same or different, However, It is preferable that it is the same. A plurality of π-conjugated compounds having the same R ¹ are advantageous in that they are easy to produce.

  In formula (1), n shows the integer of 1-3. n may be the same or different from each other, but is preferably the same. A plurality of n-conjugated compounds having the same n are advantageous in that they are easy to produce.

R ¹ is preferably a group represented by the following formula (2). Such a π-conjugated compound having R ¹ can be easily produced by the production method described later. In addition, such a π-conjugated compound can easily adjust the temperature range showing the liquid crystal state by changing R2 and p.

In the formula, R ² represents an alkyl group having 3 to 20 carbon atoms or an alkoxy group having 3 to 20 carbon atoms, and p represents an integer of 1 to 5. When p is 2 or more, the plurality of R ² may be the same as or different from each other.

The alkyl group for R ² may be branched or linear, but is preferably linear. Moreover, it is preferable that it is 4-20, and, as for the carbon atom number of an alkyl group, it is more preferable that it is 6-20.

The alkoxy group for R ² may be branched or linear, but is preferably linear. The number of carbon atoms in the alkoxy group is preferably 4-20, and more preferably 6-20.

  p is preferably 1 to 3, more preferably 1 or 2.

Among the groups represented by the formula (2), R ¹ is particularly preferably a group represented by the following formula (2-1), (2-2), (2-3) or (2-4). is there.

R ¹ is not limited to the above group, and may be any group having at least one alkyl group having 3 to 20 carbon atoms. R ¹ may be a group that imparts liquid crystal properties to the π-conjugated compound, and R ¹ may be a group selected so that the π-conjugated compound exhibits a liquid crystal state in a predetermined temperature range. R ¹ can also be selected from all substituents introduced for imparting liquid crystallinity as described in Chemical Review, 2009, vol 109, 6275-6540, for example.

  The π-conjugated compound preferably exhibits a liquid crystal state in at least a part of the temperature range of 35 to 150 ° C. (more preferably 40 to 140 ° C., still more preferably 70 to 100 ° C.). Such a π-conjugated compound is practically useful because, when used as an adhesive, it can be peeled off at a temperature range that hardly adversely affects the semiconductor manufacturing process.

  The π-conjugated compound preferably has a temperature range showing a liquid crystal state of 35 ° C. or higher, more preferably 40 ° C. or higher, and further preferably 65 ° C. or higher. When the temperature range indicating the liquid crystal state is 35 ° C. or higher, fluidization due to unexpected light irradiation during the process is less likely to occur, and it can be more suitably used as a disassembling adhesive.

  The π-conjugated compound preferably has a temperature range showing a liquid crystal state of 150 ° C. or lower, more preferably 145 ° C. or lower. In such a π-conjugated compound, since the π-conjugated compound can be made into a liquid state relatively easily, connection between members can be easily performed when used as a disassembling adhesive.

(Method for producing π-conjugated compound)
One embodiment of the method for producing the π-conjugated compound will be described below. The manufacturing method according to the present embodiment includes a step of reacting a tetraformyl compound represented by the following formula (3) with 2-butenedioic acid diester. In the formula, n represents an integer of 1 to 3.

According to the reaction of such a tetraformyl compound and 2-butenedioic acid diester, the acene skeleton can be extended and two ester groups can be provided on the benzene rings at both ends. That is, according to the above reaction, a compound represented by the following formula (5) can be obtained. In the formula, R ³ represents a group derived from the ester portion of 2-butenedioic acid diester.

The compound represented by the formula (5) corresponds to the compound represented by the formula (1) when R ³ is a group having at least one alkyl group having 3 to 20 carbon atoms. That is, when 2-butenedioic acid diester having a group corresponding to R ¹ in formula (1) is used as the 2-butenedioic acid diester, the above π-conjugated compound can be obtained by the above reaction. In addition, as 2-butenedioic acid diester, a fumaric acid diester can also be used and a maleic acid diester can also be used.

Here, the 2-butenedioic acid diester having a group corresponding to R ¹ of the formula (1) in the ester moiety can be represented by the following formula (4-1) or (4-2). Wherein, ^{R 1} has the same meaning as ^{R 1} in formula (1).

In the compound represented by formula (5), R ³ may not be a group corresponding to R ¹ in formula (1). In this case, the π-conjugated compound can be obtained by performing transesterification of the compound represented by the formula (5) to convert R ³ into a group corresponding to R ¹ in the formula (1).

  The tetraformyl compound represented by the formula (3) can be produced by a known method. Am. Chem. Soc. , 2013, 135, 8842 (Yuan, C .; Saito, S .; Camacho, C .; Irle, S .; Hisaki, I .; Yamaguchi, S.) and the like.

  The reaction conditions for the reaction between the tetraformyl compound and 2-butenedioic acid diester are, for example, C.I. Lin et al, Chem. Commun. 2009, 45, 803, Y.I. Lin et al, Org. Biomol. Chem. It can be set as appropriate with reference to the description of the elongation reaction of acenes described in 2011, 9, 4507.

  For example, the above reaction can be carried out by reacting a tetraformyl compound and 2-butenedioic acid diester in the presence of tributylphosphine and diazabicycloundecene in a methylene chloride solvent under a nitrogen atmosphere. In addition, the compound obtained by the reaction can be purified by, for example, column chromatography (silica gel column chromatography and / or high performance liquid chromatography).

  As the reaction solvent used in the above reaction, in addition to the above methylene chloride, for example, a halogen solvent such as 1,2-dichloroethane, an aromatic solvent such as toluene, and the like can be used.

  In the above reaction, a trialkylphosphine such as trimethylphosphine, triethylphosphine, or tripropylphosphine can be used instead of the above-mentioned tributylphosphine. In the above reaction, the above-mentioned diazabicycloundecene base can also be used. Specifically, strong bases such as potassium tert-butoxide and sodium hydride can be preferably used.

  The reaction temperature of the above reaction may be, for example, 25 ° C. or higher, and may be raised to the boiling point of the solvent used.

(adhesive)
A decomposable adhesive using the π-conjugated compound will be described below. The adhesive according to this embodiment contains the π-conjugated compound. Since such an adhesive contains the above-mentioned π-conjugated compound, the adhesive strength is maintained even when irradiated with light under a relatively low temperature range such as room temperature, while light irradiation is performed under a predetermined high temperature range. The adherend can be peeled off by fluidizing, and can be suitably used as a decomposable adhesive.

  In the present embodiment, the members can be bonded together by interposing the adhesive heated in the temperature range in which the π-conjugated compound exhibits a liquid state between the members and then cooling.

  In the present embodiment, the bonding force between the members maintains the adhesive force even under light irradiation in a relatively low temperature region such as room temperature. In addition, after the π-conjugated compound is heated to a temperature range showing a liquid crystal state, the adhesive is flowed by irradiating the joint with light, and the joint can be peeled off.

The light irradiation to the joint is preferably irradiation with ultraviolet rays having a wavelength of 300 to 400 nm. Moreover, it is preferable that the light irradiated to a junction part is 0.5-200 J / cm < ² > of integrated light quantity. The integrated light quantity in light irradiation is more preferably 1.0 to 150 J / cm ² , and further preferably 3.0 to 180 J / cm ² .

  The adhesive may contain components other than the π-conjugated compound as long as the function as the above-described disassembling adhesive is maintained. Examples of such components include thermoplastic polymers such as poly (meth) acrylic acid ester, polysiloxane, polyimide, polyamideimide, polyester, polyamide, and styrene polymer; (meth) acrylic acid ester, epoxy compound, and the like. And a photoinitiator.

(Structure)
The structure according to the present embodiment includes a bonded portion bonded using the adhesive. In the structure according to the present embodiment, since the bonded portion is bonded using the above adhesive, the bonded portion hardly peels off even when irradiated with light at a low temperature, but is irradiated under a predetermined high temperature region. Thus, the joint can be easily peeled and disassembled.

  A structure should just be provided with the junction part joined using the said adhesive agent, and another component is not restrict | limited in particular.

  Examples of the structure include a structure including an optical component and a structure including a semiconductor mounting component. These structures may be temporarily manufactured in, for example, an optical component manufacturing process or a semiconductor manufacturing process, and may be disassembled by peeling off the joint after passing through a predetermined process.

(How to use adhesive)
One mode of using the adhesive will be described below. The method of using the adhesive according to the present embodiment includes a step of interposing the adhesive heated to a temperature at which the π-conjugated compound is in a liquid state between two members, and the adhesion interposed between the two members. And a step of cooling the agent to a temperature at which the π-conjugated compound is in a solid state and joining the two members (hereinafter, sometimes referred to as “joining step”).

  In the use method, the adhesive for joining the two members is irradiated with ultraviolet rays having a wavelength of 300 nm to 400 nm in a temperature range where the π-conjugated compound exhibits a liquid crystal state, and the two members are separated ( Hereinafter, it may further include a “peeling step” in some cases. According to such a process, two members can be easily peeled off.

The said ultraviolet-ray can be irradiated so that it may become the integrated light quantity of 0.5-200 J / cm < ² >, for example. Further, the integrated quantity of ultraviolet light is preferably 1.0~150J / cm ^2, more preferably 3.0~180J / cm ^2.

  Moreover, the usage method can be used for a peeling process, after passing through various processes like the lithography process in a semiconductor manufacturing process, for example after a joining process.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

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

(Production Example 1: Synthesis of fumaric acid diester)
Maleic acid (81.7 mg, 0.70 mmol) and cesium carbonate (688.2 mg, 2.10 mmol) were dissolved in anhydrous dimethylformamide (3 mL), and the mixture was stirred at room temperature under a nitrogen atmosphere for 50 minutes. 3,4-Bis (dodecyloxy) benzyl bromide (1.91 g, 3.50 mmol) was added dropwise to the reaction solution, and the mixture was stirred at 60 ° C. for 3 days. After returning to room temperature, the reaction solution was quenched with water and extracted with methylene chloride. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was distilled off. The residue was separated and purified by silica gel column chromatography using a mixed solvent of hexane-methylene chloride (mixing ratio 1: 2, R _f = 0.35) to give bis (3,4-bis (dodecyloxy) as a white solid. ) Benzyl) fumarate (305.3 mg, 0.29 mmol, 42% yield) was obtained.

The spectrum data of bis (3,4-bis (dodecyloxy) benzyl) fumarate was as follows.
¹ H NMR (400 MHz, CDCl ₃ ): δ 6.83-6.92 (m, 8H), 5.13 (s, 4H), 3.98 (t, J = 6.6 Hz, 8H), 1. 77-1.84 (m, 8H), 1.26-1.45 (m, 72H), 0.86-0.89 (m, 12H);
¹³ C NMR (100 MHz, CDCl ₃ ): δ 164.9, 149.7, 149.4, 133.9, 127.9, 121.7, 114.7, 113.9, 69.6, 69.5 67.4, 32.1, 29.9, 29.8, 29.8, 29.6, 29.6, 29.5, 29.5, 29.4, 26.2, 26.2, 22. 8, 14.2;
HRMS (APCI, positive): [M ⁺ ] calcd. for C ₆₆ H ₁₁₂ O ₈ , 1032.8352; found 1032.8379.

Example 1
A π-conjugated compound A1 was produced by a reaction represented by the following formula.

Specifically, tributylphosphine (325 μL, 1.30 mmol) was added to a methylene chloride solution (30 mL) of bis (3,4-bis (dodecyloxy) benzyl) fumarate (1.25 g, 1.20 mmol) in a nitrogen atmosphere. The reaction solution was stirred at room temperature for 40 minutes. Thereafter, the reaction solution was added dropwise to a methylene chloride solution (60 mL) of tetraformyl compound 1 (208.6 mg, 0.50 mmol) (compound 1 in the above formula) cooled to 0 ° C. in a nitrogen atmosphere, and further a base. Diazabicycloundecene (5 μL, 0.05 mmol) was added dropwise. After stirring at 50 ° C. for 2 days, the reaction solution was quenched with water and extracted three times with methylene chloride. The organic layer after extraction was dehydrated with anhydrous sodium sulfate, and then the solvent was distilled off. The residue was separated by silica gel column chromatography using a hexane-methylene chloride-triethylamine mixed solvent (mixing ratio 2: 48: 1) (R _f = 0.80) to obtain a crude product. Furthermore, the π-conjugated compound A1 (343.6 mg, 0.14 mmol, yield 28%) as a yellow solid was purified by high performance liquid chromatography using a mixed solvent of chloroform-triethylamine (mixing ratio 50: 1) as a solvent (above 28%) Compound A1) in the formula was obtained.

The π-conjugated compound A1 was confirmed to exhibit liquid crystallinity at 68 to 143 ° C. from the results of inspection scanning calorific value (DSC) described later and the results of observation with a polarizing microscope and X-ray diffraction measurement. Further, spectrum data of the π-conjugated compound A1 are as shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 8.32 (s, 8H), 7.81 (s, 4H), 7.16 (s, 4H), 6.82-6.95 (m, 12H) 5.17 (s, 8H), 3.95-4.00 (q, J = 6.6 Hz, 16H), 1.76-1.83 (m, 16H), 1.23-1.45 ( m, 144H), 0.87-0.92 (m, 24H);
¹³ C NMR (100 MHz, CDCl ₃ ): δ 167.9, 149.9, 149.7, 136.2, 133.6, 132.3, 131.8, 131.1, 128.7, 128.6 , 128.3, 128.0, 122.0, 115.0, 114.1, 69.8, 68.0, 32.4, 30.2, 30.1, 29.9, 29.9, 29 .8, 29.8, 26.6, 26.5, 23.2, 14.6;
MALDI-TOFMS (positive) [(M + Na) ⁺ ] calcd. for C ₁₆₀ H ₂₃₆ NaO ₁₆ , 2436.754; found 2437.034.

[Measurement by inspection scanning calorimeter]
The π-conjugated compound A1 was heated to 200 ° C. showing a liquid state at a rate of 2 ° C./min in a nitrogen atmosphere with a Seiko Instruments Inc. scanning scanning calorimeter (model: Exstar 6000 DSC 6200). After holding at 200 ° C. for 10 minutes and cooling at a rate of 2 ° C./minute, an exothermic peak of 18.3 mJ / mg accompanying a phase transition from liquid to liquid crystal was observed at the extrapolation start point of 142.7 ° C. It was. Furthermore, an exothermic peak of 14.8 mJ / mg accompanying a phase transition from liquid crystal to crystal was observed at an extrapolation starting point of 67.3 ° C.

(Example 2)
A π-conjugated compound A2 was produced by a reaction represented by the following formula.

Specifically, tributylphosphine (130 μL, 0.52 mmol) was added to a methylene chloride solution (4 mL) of bis (3,4-bis (dodecyloxy) benzyl) fumarate (495.5 mg, 0.48 mmol) in a nitrogen atmosphere. The reaction solution was stirred at room temperature for 40 minutes. Thereafter, the reaction solution was added dropwise to a methylene chloride solution (8 mL) of tetraformyl compound 3 (52.6 mg, 0.16 mmol) (compound 3 in the above formula) cooled to 0 ° C. under a nitrogen atmosphere, and further a base. Diazabicycloundecene (2 μL, 0.02 mmol) was added dropwise. After stirring at room temperature for 16 hours, the reaction solution was quenched with water and extracted three times with methylene chloride. The organic layer after extraction was dehydrated with anhydrous sodium sulfate, and then the solvent was distilled off. The residue was separated by silica gel column chromatography using methylene chloride (R _f = 0.75) to obtain a crude product. Furthermore, π-conjugated compound A2 (131.1 mg, 0.056 mmol, 35%) (compound A2 in the above formula) was obtained as a white solid by purification by size exclusion chromatography using chloroform as a solvent.

From the results of differential scanning calorimetry (DSC), polarization microscope observation, and X-ray diffraction measurement, the π-conjugated compound A2 was confirmed to exhibit liquid crystallinity at 35 to 103 ° C. Further, spectrum data of the π-conjugated compound A2 were as shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 8.07 (s, 4H), 7.62 (s, 4H), 7.04 (s, 4H), 6.80-6.90 (m, 12H) , 5.13 (s, 8H), 3.94-3.98 (m, 16H), 1.75-1.80 (m, 16H), 1.25-1.44 (m, 144H), 0 .86-0.89 (m, 24H);
¹³ C NMR (100 MHz, CDCl ₃ ): δ 167.5, 149.5, 149.4, 137.4, 133.4, 132.3, 130.1, 128.9, 128.3, 121.5, 114.7, 113.9, 69.5, 67.7, 32.1, 29.8, 29.6, 29.6, 29.5, 29.5, 29.2, 26.2, 26. 2, 22.8, 14.2;
MALDI-TOFMS (positive) [(M + Na) ⁺ ] calcd. for C ₁₅₂ H ₂₃₂ NaO ₁₆ , 2338.453; found 2338.585.

(Comparative Example 1)
A π-conjugated compound B1 was produced by a reaction represented by the following formula.

Specifically, tributylphosphine (65 μL, 0.26 mmol) was added to a methylene chloride solution (10 mL) of bis (3,4-bis (dodecyloxy) benzyl) fumarate (252.7 mg, 0.24 mmol) in a nitrogen atmosphere. The reaction solution was stirred at room temperature for 40 minutes. Thereafter, the reaction solution was added dropwise to a methylene chloride solution (3 mL) of diformyl compound 4 (38.0 mg, 0.20 mmol) (compound 4 in the above formula) cooled to 0 ° C. in a nitrogen atmosphere, and diaza which was a base. Bicycloundecene (2 μL, 0.02 mmol) was added dropwise to the reaction solution. After stirring at room temperature for 2 days, the reaction solution was quenched with water and extracted three times with methylene chloride. The organic layer after extraction was dehydrated with anhydrous sodium sulfate, and then the solvent was distilled off. The residue was separated by silica gel column chromatography using methylene chloride (R _f = 0.50) to obtain a crude product. Further, π-conjugated compound B1 (148.2 mg, 0.125 mmol, yield 62%) (compound B1 in the above formula) was obtained as a yellow solid by purification by size exclusion chromatography using chloroform as a solvent.

From the results of differential scanning calorimetry (DSC), polarization microscope observation, and X-ray diffraction measurement, the π-conjugated compound B1 was confirmed to exhibit liquid crystallinity at 23 to 34 ° C. Further, spectrum data of the π-conjugated compound B1 were as shown below.
¹ H NMR (400 MHz, CDCl ₃ ): δ 8.48 (s, 2H), 8.42 (s, 2H), 8.01-8.04 (m, 2H), 7.54-7.56 ( m, 2H), 6.84-6.97 (m, 6H), 5.21 (s, 4H), 3.96-4.02 (m, 8H), 1.76-1.84 (m, 8H), 1.24-1.51 (m, 72H), 0.85-0.88 (m, 12H);
¹³ C NMR (100 MHz, CDCl ₃ ): δ 167.4, 149.2, 149.1, 132.9, 131.2, 130.3, 128.2, 128.1, 127.6, 126.6, 121.3, 114.4, 113.6, 69.2, 67.4, 31.7, 29.5, 29.5, 29.3, 29.3, 29.2, 29.2, 25. 9, 25.9, 22.5, 13.9;
HRMS (APCI, positive): [M ⁺ ] calcd. _{for C 44 H 36 O 8,} 692.2405; found 692.2399.

(Example 3: Use 1 of π-conjugated compound A1 as an adhesive)
A silicone tape punched into a 6 mmφ circle (Chukoko Chemical Industries, Chuko Flow AGF-100, thickness 0.13 mm, width 13 mm) was pasted on a glass plate, and the π-conjugated compound A1 obtained in Example 1 was applied to the circular portion. The powder was placed. The glass plate was placed on a hot plate and heated at 170 ° C. for 30 minutes to liquefy the π-conjugated compound A1. Thereafter, a glass plate was placed so as to overlap with the liquefied π-conjugated compound A1, a 500 g weight was placed thereon, a load was applied, and the resultant was cooled to 25 ° C. to produce a glass laminate. One side of the produced glass plate laminate was fixed with a clamp, and the tip of a push-pull gauge (Shiro Sangyo Co., Ltd., WPARX-10) was hooked into the hole on the other glass plate side. The tensile shear bond strength until the glass laminate was peeled off was measured with a push-pull gauge. This measurement was repeated 5 times, and the result of arithmetically averaging the bond strength was 1.84 MPa.

(Example 4: Use of π-conjugated compound A1 as an adhesive 2)
After producing a glass plate laminate in the same manner as in Example 1, one side of the glass plate laminate was fixed with a clamp, and heated with a drier until the adhesion portion reached 100 ° C. The tensile shear bond strength was measured using a push-pull gauge in the same manner as in Example 1 while the bonded portion was held at 100 ° C. As a result, it was 1.55 MPa.

(Example 5: Use 3 of π-conjugated compound A1 as an adhesive)
After producing a glass plate laminate in the same manner as in Example 1, one side of the glass plate laminate was fixed with a clamp, heated with a drier until the bonded portion reached 100 ° C., and a wavelength of 365 nm maintained at 100 ° C. UV light (illuminance 2.6 W / cm ² ) was irradiated to the bonded portion for 10 seconds. Immediately after the ultraviolet irradiation, the tensile shear bond strength was measured using a push-pull gauge in the same manner as in Example 1. As a result, the bonded part peeled off due to the weight of the glass and showed no strength.

(Example 6: Use 1 of π-conjugated compound A2 as an adhesive)
The tensile shear bond strength was measured in the same manner as in Example 3 except that the π-conjugated compound A1 was changed to the π-conjugated compound A2 and the heating temperature was changed from 170 ° C. to 120 ° C. As a result of the measurement, the tensile shear bond strength was 1.45 MPa.

(Example 7: Use 2 of π-conjugated compound A2 as an adhesive)
The tensile shear bond strength was measured in the same manner as in Example 4 except that the π-conjugated compound A1 was changed to the π-conjugated compound A2 and the holding temperature was changed from 100 ° C. to 70 ° C. As a result of the measurement, the tensile shear bond strength was 1.33 MPa.

(Example 8: Use 3 of π-conjugated compound A2 as an adhesive)
The tensile shear bond strength was measured using a push-pull gauge in the same manner as in Example 5 except that the π-conjugated compound A1 was changed to the π-conjugated compound A2 and the holding temperature was changed from 100 ° C. to 70 ° C. The adhesive part peeled off due to the weight of the glass and showed no strength.

(Comparative Example 2: Use 1 of π-conjugated compound B1 as an adhesive)
The tensile shear bond strength was measured in the same manner as in Example 3 except that the π-conjugated compound A1 was changed to the π-conjugated compound B1 and the heating temperature was changed from 170 ° C. to 95 ° C. As a result of the measurement, the tensile shear bond strength was 0.65 MPa.

(Comparative Example 3: Use 2 of π-conjugated compound B1 as an adhesive)
The tensile shear bond strength was measured using a push-pull gauge in the same manner as in Example 5 except that the π-conjugated compound A1 was changed to the π-conjugated compound B1 and the holding temperature was changed from 100 ° C. to 28 ° C. The tensile shear bond strength before UV irradiation was 0.71 MPa, the tensile shear bond strength after UV irradiation was 0.65 MPa, and no difference in strength was observed before and after UV irradiation.

  Since the π-conjugated compound of the present invention can be reversibly fluidized and non-fluidized by light irradiation and temperature control, a fine structure is formed on various substrates such as plastics such as nanoimprint. Application to materials etc. can be expected. In addition, it can be expected to be applied in various fields including adhesives. In particular, the adhesive of the present invention is suitable as a temporary fixing adhesive in a semiconductor manufacturing process because it can be detached for the first time by irradiating light with a temperature applied. By setting the ambient temperature to a temperature lower than the liquid crystal region of the π-conjugated compound, the member bonded with the adhesive can be exposed to a process such as a lithography process without being detached even when irradiated with ultraviolet rays. Is possible. On the other hand, when detaching the member, it can be performed by setting the ambient temperature to the temperature of the liquid crystal region and irradiating with ultraviolet rays. In addition to the temporary fixing adhesive in the semiconductor manufacturing process, it is also useful as a disassembling adhesive applicable to various uses.

Claims (10)

A π-conjugated compound represented by the following formula (1).

[Wherein, R ¹ represents a group represented by the following formula (2), and n represents an integer of 1 to 3. A plurality of R ¹ may be the same or different from each other, and a plurality of n may be the same or different from each other. ]

Wherein, ^{R 2} represents an alkoxy group of the alkyl group or 3 to 20 carbon atoms having 3 to 20 carbon atoms, p is an integer of 1-5. When p is 2 or more, the plurality of R ² may be the same as or different from each other. ] The π-conjugated compound according to claim 1 , which exhibits a liquid crystal state in at least a part of a temperature range of 35 to 150 ° C. , Adhesives comprising π-conjugated compound according to claim 1 or 2. A structure provided with the junction part joined using the adhesive agent of Claim 3 . A method of using the adhesive according to claim 3 ,
Interposing the adhesive heated to a temperature at which the π-conjugated compound is in a liquid state between two members;
Cooling the adhesive interposed between the two members to a temperature at which the π-conjugated compound is in a solid state, and joining the two members;
Including usage. The method further includes irradiating the adhesive that joins the two members with ultraviolet rays having a wavelength of 300 nm to 400 nm and peeling the two members in a temperature range in which the π-conjugated compound exhibits a liquid crystal state. 5. Use according to 5 . The usage method according to claim 6 , wherein the ultraviolet rays are irradiated with an integrated light amount of 0.5 to ²⁰⁰ J / cm ² . It is a method of peeling the joined part joined using the adhesive according to claim 3 ,
A peeling method including a step of irradiating the junction with ultraviolet rays having a wavelength of 300 nm to 400 nm under a temperature range in which the π-conjugated compound exhibits a liquid crystal state. A method for producing a π-conjugated compound according to claim 1 or 2 ,
The manufacturing method including the process of making the tetraformyl compound and 2-butenedioic acid diester represented by following formula (3) react.

[In formula, n shows the integer of 1-3. ] The production method according to claim 9 , wherein the 2-butenedioic acid diester is a compound represented by the following formula (4).

[ Wherein R ¹ represents a group represented by the formula (2) . ]