JP2020083782A - Organic compound, production method of the same, organic liquid crystal, organic semiconductor and the like - Google Patents

Abstract

To provide an organic semiconductor showing high mobility and high thermal stability and having excellent solubility, an organic compound for the organic semiconductor, and a production method of the compound.SOLUTION: The present invention discloses an organic compound represented by the formula (1) and a production method of the compound, and applications of an organic semiconductor and the like using the organic compound. In the formula, Ar is an aromatic group selected from a phenyl or a thienyl which may have a substituent; one of Rand Ris a linear aliphatic group and the other is a hydrogen atom; and an acetylene bond in the parenthesis may be present or absent.SELECTED DRAWING: None

Description

The present invention relates to an organic compound, a method for producing the same, an organic liquid crystal, an organic semiconductor, and the like. In particular, an organic compound exhibits liquid crystallinity and excellent solubility, and an organic liquid crystal, an organic semiconductor, and a transistor using the organic compound have high mobility. And an application of such an organic compound exhibiting heat resistance, a method for producing the same, an organic liquid crystal, an organic semiconductor and the like.

Organic substances capable of transporting electronic charges by holes and electrons can be used as organic semiconductors, and organic substances such as photoconductors for photocopiers, photosensors, organic EL elements, organic transistors, organic solar cells, and organic memory elements. It can be used as a material for electronic devices.

In general, an organic semiconductor has a lower carrier mobility than a silicon semiconductor, and as a result, the response speed of a transistor is slow, which has been a practical problem, but in recent years, an organic semiconductor having a mobility equivalent to that of amorphous silicon has been developed. Has been developed.

Regarding organic transistors, since an organic transistor using a pentacene crystal material (Non-Patent Document 1) was reported, oligothiophene (Non-Patent Document 2, Patent Document 1), TIPS-pentacene (Non-Patent Document 3, Patent Document 3). 2) and benzothienobenzothiophene [5,10] derivative (Patent Document 3) and the like are synthesized to produce a transistor. However, organic semiconductors are required to have higher mobility and performance stability in TFTs.

In liquid crystal substances, alignment defects peculiar to liquid crystals are unlikely to form electrically active levels, and it is easy to control molecular orientation in the liquid crystal phase, which is difficult with non-liquid crystal substances. It can be used as a liquid crystal organic semiconductor. In this case, as described in Non-Patent Document 4, as compared with a nematic (N) phase, a smectic A (SmA) phase, an SmC phase, or the like, which has a low orientational order in which ionic conduction is easily induced by mixing impurities, mB, SmBcrystal , SmI, SmF, SmG, SmE, SmJ, SmK, and SmH phases are particularly useful as organic semiconductors because they can suppress ionic conduction and exhibit high mobility. Furthermore, when a liquid crystal substance is used as a crystal film, the crystallinity and flatness are excellent and the crystal thin film with controlled orientation can be produced by utilizing the ease of orientation control. Also available as When the liquid crystal substance exhibits a higher order smectic phase, that is, an SmE phase, an SmG layer, an SmH layer, an SmJ phase, an SmK phase or an SmH phase capable of forming a solid-like thin film, at the same time, heat resistance can be secured. Is effective in. Further, the liquid crystal substance has a feature that it can be formed into a film by a solution process at a low temperature.

Further, the present inventors have taught that an organic thin film having a bimolecular layer structure of an organic compound having a structure in which four aromatic rings are condensed provides high mobility and performance stability (Patent Document 4). ).

JP, 10-190001, A JP, 2001-94107, A International Publication No. 2006/077888 Japanese Patent No. 3237595 JP 2005-330185 A International Publication No. 2017/159657

Y.-Y. Nelsona, Y.-Y. Lin, D.J. Gundlach, and T. N. Jackson, Appl. Phys. Lett., 72, 1854, (1998). F. Garnier, R. Hajlaoui, A. El Kassmi, G. Horowitz, L. Laigre, W. Porzio, M. Armanini, and F. Provasoli, Chem. Mater. 1998, 10, 3334-3339. E. Anthony, J.S. Brooks, D.L. Eaton, and S.R. Parkin, J. Am. Chem. Soc. 123, 9482-9483 (2001) F. Garnier, R. Hajlaoui, A. El Kassmi, G. Horowitz, L. Laigre, W. Porzio, M. Armanini, and F. Provasoli, Chem. Mater. 1998, 10, 3334-3339. J. E. Anthony, J.S. Brooks, D.L. Eaton, and S.R. Parkin, J. Am. Chem. Soc. one two Three, J. Hanna, A. Ohno, and H. Iino, Thin Solid Films 554 (2014) 58-63. H.IIno, T. Usui, and J. Hanna, Nature Commun., (2015) 6, Article Number 6828 (2015) 58-63. J. Hanna, OPTO-ELECTRONICS REVIEW 13(4), 259-267 (2005). H. Iino, T. Kobori, and J. Hanna, Jpn. J. Appl. Phys., 51, 11PD02 (2012) H. Maeda, M. Funahashi, and J. Hanna, Mol. Crysr. Liq. Cyst., 366, 369-376 (2001).

Conventionally, a high-mobility organic semiconductor has been realized by a compound having a skeleton of four or five or more condensed rings as described above. A crystalline substance having a structure in which three aromatic rings are condensed has been reported as an organic transistor material, but its mobility is as small as about 10 ^-2 cm ² /Vs and was not of interest. The inventors of the present invention described in Patent Document 4 have high mobility (0.1 to 0.5 cm ² /Vs) and high thermal stability comparable to those of amorphous silicon which is practically used in a bilayer structure of an organic semiconductor having four condensed rings. However, the solubility was not sufficient and there was a problem.

Therefore, there is a demand for organic semiconductors that exhibit high mobility as amorphous silicon and a small condensed ring structure of three rings that is easy to synthesize, yet exhibit high thermal stability, as well as excellent solubility, and organic compounds that realize the same. There is.

In addition, in Patent Document 5, a compound in which two phenyl derivatives are substituted in a benzodithiophene skeleton shows a smectic liquid crystal phase, and an electronic device such as an EL device, an optical sensor, an electrophotographic photosensitive member, and an image recording device can be produced. Have been described. However, it does not teach that a compound having a benzodithiophene skeleton substituted with one aromatic ring such as a phenyl group has a bilayer structure in the crystal phase when it exhibits a liquid crystal.

Further, Patent Document 6 teaches that a semiconductor material having a benzodithiophene skeleton realizes high mobility, and its nominal compound is related to the organic compound of the present invention. However, the organic compound that Patent Document 6 actually teaches in Examples has no description of the melting point, the substance cannot be specified from the ¹ H NMR data which is the basis thereof, and is not the same as the organic compound of the present invention. Absent. Further, it does not teach that the organic compound exhibits liquid crystallinity or has a bilayer structure.

In view of the above-mentioned conventional state of the art, the present inventors have synthesized a compound in which three specific aromatic rings are condensed, and an organic semiconductor composed of this organic compound is useful as a liquid crystalline organic semiconductor in the course of intensive studies. In addition to the above, it was found that a crystalline film having a bilayer structure has high mobility and high thermal stability comparable to those of amorphous silicon, and has excellent solubility, and it is a by-product that becomes an impurity of the organic compound. The present invention has been completed by establishing an advantageous manufacturing method capable of avoiding the formation of a compound, further forming a transistor by using the organic compound, and examining the mobility, clarifying the effectiveness of the crystal as a transistor material or the like, and completing the present invention.

According to the present invention, the following is provided.
<Aspect 1> An organic compound represented by the following formula (1).
[Wherein, Ar is an aromatic group selected from phenyl and thienyl which may have a substituent, _one of R ₁ and R ₂ is a chain aliphatic group, and the other is a hydrogen atom. The acetylene bond in parentheses may or may not be present. ]

<Aspect 2>
Chain aliphatic groups, -O in the main chain -, - S -, - NH -, - CO -, - OCO- or -SO ₂ - may comprise, or carbon atoms between the main chain double The organic compound according to aspect 1, which is a chain aliphatic group having 1 to 20 carbon atoms, which may be bonded by a bond.

<Aspect 3>
The organic compound according to aspect 1 or 2, wherein the substituent of Ar is a halogen group, a nitro group, a nitrile group, or an acyclic or cyclic aliphatic group.

<Aspect 3>
The organic compound according to aspect 1 or 2, which is represented by the following formula (2) or (3).
(In these formulas, both R ₁ and R ₂ are chain aliphatic groups.)

<Aspect 4>
The organic compound according to any one of aspects 1 to 3, which is a liquid crystal.

<Aspect 5>
The organic compound according to any one of aspects 1 to 4, which is capable of forming a crystal having a bilayer structure.

<Aspect 6>
A method for producing an organic compound, which comprises using a compound represented by the following formula (4) as an intermediate to produce a target compound represented by the following formula (5).
(In these formulas, _one of R ₁ and R ₂ is a chain aliphatic group and the other is a hydrogen atom, and the acetylene bond in the parentheses may or may not exist.)

<Aspect 7>
7. The method for producing an organic compound according to aspect 6, comprising a step of producing a compound represented by the following formula (6) using the compound represented by the formula (4) as an intermediate.
(In the formula, R ₂ is a chain aliphatic group or a hydrogen atom, and the acetylene bond in the parentheses may or may not exist.)

<Aspect 8>
Formula (1) below
[Wherein, Ar is an aromatic group selected from phenyl and thienyl which may have a substituent, _one of R ₁ and R ₂ is a chain aliphatic group, and the other is a hydrogen atom. The acetylene bond in parentheses may or may not be present. ]
An organic liquid crystal containing an organic compound represented by:
An organic liquid crystal wherein the organic compound exhibits a liquid crystal phase selected from SmB, SmBcrystal, SmI, SmF, SmG, SmE, SmJ, SmK or SmH phases.

<Aspect 9>
9. The organic liquid crystal according to aspect 8, wherein the organic compound is a compound represented by the following formula (2) or (3).
(In these formulas, both R ₁ and R ₂ are chain aliphatic groups.)

<Aspect 10>
The organic liquid crystal according to aspect 8 or 9, wherein the liquid crystal phase is an SmE phase.

<Aspect 11>
An organic semiconductor comprising a crystal of the compound represented by formula (1) according to any one of aspects 1 to 6.

<Aspect 12>
The organic semiconductor according to aspect 11, wherein the crystal has a bilayer structure.

<Aspect 13>
The bilayer structure is a structure in which the organic compounds are arranged in a layered structure, and a bilayer in which the axis of the organic compound is oriented in a direction perpendicular to the layer direction of the bilayer structure is a repeating unit. The organic semiconductor according to Aspect 11 or 12.

<Aspect 14>
14. The organic semiconductor according to any one of aspects 11 to 13, wherein the organic semiconductor is a crystal derived from a liquid crystal exhibiting a SmB, SmBcrystal, SmI, SmF, SmG, SmE, SmJ, SmK or SmH phase.

<Aspect 15>
15. The organic semiconductor according to aspect 14, wherein the organic semiconductor is a crystal derived from a liquid crystal exhibiting an SmE phase.

<Aspect 16>
A liquid crystal device comprising the organic liquid crystal according to any one of aspects 8 to 10.

<Aspect 17>
A semiconductor device comprising the organic liquid crystal according to any one of aspects 8 to 10 or the organic semiconductor according to any one of aspects 11 to 15.

<Aspect 18>
A transistor element containing the organic liquid crystal according to any one of aspects 8 to 10 or the organic semiconductor according to any one of aspects 11 to 15.

According to the present invention, an organic compound and a method for producing the same, and an organic liquid crystal, an organic semiconductor, an organic semiconductor element, which uses the organic compound, exhibits high mobility and high thermal stability, and is also excellent in solubility. An organic transistor device is provided.

FIG. 1 is a schematic diagram illustrating a bilayer structure and a monolayer structure. FIG. 2 is a cross-sectional view schematically showing the transistor. FIG. 3 is a differential scanning calorimetric analysis chart of Ph-BDT-C8 during cooling and during heating. FIG. 4 is a polarization micrograph at 180° C. when cooled from the liquid Ph-BDT-C8. FIG. 5 is a polarization microscope photograph at 30° C. when the Ph-BDT-C8 liquid was cooled. FIG. 6 is an X-ray diffraction chart of liquid crystals and crystals of Ph-BDT-C8 when heated to 180° C. and 30° C. FIG. 7 is an X-ray diffraction chart before and after thermal annealing of the Ph-BDT-C8 crystal. FIG. 8 is a graph showing the mobility of a transistor having crystals of Ph-BDT-C8 before and after thermal annealing. FIG. 9 is a differential scanning calorimetric analysis chart of Ph-BDT-C14 during cooling and during heating. FIG. 10 is a polarization micrograph at 130° C. when cooled from the liquid Ph-BDT-C14. FIG. 11 is a polarization micrograph at 30° C. when cooled from the liquid Ph-BDT-C14. FIG. 12 is an X-ray diffraction chart of liquid crystals and crystals of Ph-BDT-C14 when heated to 130° C. and 30° C. FIG. 13 is an X-ray diffraction chart before and after thermal annealing of the Ph-BDT-C14 crystal. FIG. 14 is a graph showing the mobility of a transistor having crystals of Ph-BDT-C14 before and after thermal annealing. FIG. 15 is an X-ray diffraction pattern of the crystal film of BDT-Ae-Ph-C8 heated at room temperature and at 60° C. and 130° C. FIG. 16 is a differential scanning calorimetric analysis chart of Ph-Ae-BDT-C8 during cooling and heating. FIG. 17 is a polarization micrograph of a BDT-Ae-Ph-C8 liquid crystal (160° C.) and a crystal (20° C.). FIG. 18 is an X-ray diffraction chart of the liquid crystal phase (160° C.) and the crystal phase (20° C.) of BDT-Ae-Ph-C8.

(New compound)
The novel compound of the present invention is an organic compound represented by the following formula (1).
[Wherein, Ar is an aromatic group selected from phenyl and thienyl which may have a substituent, _one of R ₁ and R ₂ is a chain aliphatic group, and the other is a hydrogen atom. The acetylene bond in parentheses may or may not be present. ]

The organic compound represented by the formula (1) of the present invention is an organic semiconductor having a structure in which three aromatic rings are condensed, and three aromatic rings containing a thiophene skeleton exhibiting a higher liquid crystal phase such as an SmE phase are It is a condensed liquid crystalline organic semiconductor and gives a crystal film exhibiting a bilayer structure in the crystal phase. It has been known that an organic semiconductor having a structure in which four aromatic rings are condensed gives a crystal film having a bilayer structure, but three aromatic rings which give a crystal film having a bilayer structure are condensed. No examples of substances are known. In addition, many substances having a skeleton in which three aromatic rings containing a thiophene skeleton are condensed are non-liquid crystalline, and a liquid crystal in which three aromatic rings containing a thiophene skeleton exhibiting a higher-order liquid crystal phase such as an SmE phase are condensed. Organic semiconductors are not known.

Benzodithiophene skeleton The organic compound represented by the formula (1) of the present invention has a main skeleton of benzo[1,2-b:4,5-b']dithiophene (benzodithiophene Benzodithiophene; benzothienothiophene) Hereinafter referred to as "benzodithiophene" or "BDT"). In an organic semiconductor composed of an organic compound represented by the formula (1), a benzodithiophene skeleton has a rod-like aromatic π-electron conjugated fused ring structure and functions as a charge transporting molecular unit. As a result of diligent research, the organic compound represented by the formula (1) having benzodithiophene as the main skeleton has excellent solubility even though the benzodithiophene-based compound has three condensed rings. In addition, it exhibits a smectic phase (SmE phase), which is a liquid crystal phase having a higher order of orientation, and can have a two-layer structure in the crystal phase, which is a liquid crystalline semiconductor material and a crystalline material. As an organic semiconductor, they have found that they exhibit high mobility and high thermal stability.

The organic compound represented by the formula (1) of the present invention is selected from phenyl and thienyl with or without a acetylene bond (-C≡C-; triple bond) at the 2-position of benzodithiophene by a single bond. Has a 2-aromatic group (-acetylene) benzodithiophene skeleton to which an aromatic group is bound, and has the 6-position of benzodithiophene and the 4-position of the aromatic group (may be 5 position when aromatic is thienyl) A) a chain aliphatic group is bonded to one of them by a single bond, and a hydrogen atom is bonded to the other. The organic compound represented by the formula (1) of the present invention is linear as a whole, and has a rigid aromatic group on one end side of its axis (longitudinal direction) and on the other end side. It is a compound having an asymmetric molecular structure having a flexible chain aliphatic group.

The organic compound represented by the formula (1) aromatic groups present invention is an aromatic group Ar via a single bond to the 2-position (or 6-position) of benzodithiophenes are attached, a benzodithiophene A single bond may be bonded to the aromatic group Ar via an acetylene bond (-C≡C-).

In the organic compound represented by the formula (1), the aromatic group Ar is effective for exhibiting liquid crystallinity, and an aromatic group consisting of a 5-membered ring, a 6-membered ring, or a combination of a 5-membered ring and a 6-membered ring is used. Available.

In the organic compound represented by the formula (1), the aromatic group is more preferably phenyl or thienyl which may have a substituent, from the viewpoint of solubility.

In the organic compound represented by the formula (1) of the present invention, the benzodithiophene skeleton forms a rod-like aromatic π-electron conjugated fused ring structure. By making a skeleton structure in which various structures (aromatic groups consisting of phenyl or thienyl) are linked by a single bond, the molecule can be flip-flop-moved in a rigid rod-like electron conjugated system structure, and therefore, a higher order It is considered that the development of the liquid crystal phase and the resulting high mobility are possible.

Moreover, in the organic compound represented by the formula (1) of the present invention, an acetylene bond (—C≡C—) may be present between the single bond between the benzodithiophene skeleton and the aromatic group. The acetylene bond (-C≡C-) is rigid in an electron conjugated system structure, but when the acetylene bond (-C≡C-) is bonded between the benzodithiophene skeleton and the aromatic group via a single bond, the whole structure is improved. As a result, it is considered that the flip-flop motion of the molecule is enabled in the rod-shaped rigid electronically conjugated system structure, and in particular, the manifestation of the liquid crystal phase of higher order and the higher mobility thereof are enabled.

In a preferred embodiment of the organic compound represented by formula (1), the aromatic group is not substituted at all, except that when R ₁ is a hydrogen atom, R ₂ which is a chain aliphatic group can be bonded. It may be a group in which a hydrogen atom is bonded to all carbon atoms constituting phenyl, phenyl or thienyl. It is preferable that the aromatic group is phenyl or thienyl having no substituent, from the viewpoint of improving the mobility.

Further, the aromatic group may have a substituent, and examples of the substituent include a halogen group, a nitro group, a nitrile group, and an acyclic or cyclic aliphatic group.

The acyclic or cyclic aliphatic groups may have 1 to 20, more preferably 3 to 20, and especially 6 to 14 carbon atoms.

The acyclic aliphatic group is preferably an alkyl group which may have a branch, and more preferably a linear alkyl group, but -O-, -S in the aliphatic main chain composed of carbon atoms. -, - NH -, - CO -, - OCO- or -SO 2 _- may comprise, or may be a carbon atom to each other in the main chain are bonded by a double bond or triple bond.

The cyclic aliphatic group may be a cycloaliphatic group such as cyclohexyl, cyclopentyl or cycloheptyl, or a combination of a cycloaliphatic group and an acyclic aliphatic group.

Preferred substituents for aromatic groups, -O in the main chain -, - S- or -NH ₂ - and comprise 1-20C also good carbon atoms linear aliphatic group, the number still 1 to 20 carbon atoms , More preferably 3 to 20, especially 6 to 14 alkyl groups.

The aromatic group may have one or more substituents.
In the organic compound represented by the formula (1) of the present invention, one of the benzodithiophene skeleton and Ar (aromatic group) is bonded to the chain aliphatic group, and the other is bonded to a hydrogen atom. When the chain aliphatic group is bonded to the benzodithiophene skeleton, the substituent of the aromatic group is preferably a hydrogen atom, but may be a halogen group, a nitro group and/or a nitrile group.

The chain aliphatic group bonded to phenyl or thienyl, which is an aromatic group, is at the 4-position of the phenyl ring, which is on the opposite side of the position where the aromatic group is bonded to the benzodithiophene skeleton, and the 2-position with benzodithiophene. Bonding at the 4-position or 5-position of the bonded thiophene ring, and at the 5-position of the thiophene ring also bonded at the 3-position, the molecular structure becomes linear, which is preferable from the viewpoint of liquid crystallinity and semiconductor properties.

The organic compound represented by chain aliphatic radical compounds of formula (1) is the 2-position of benzodithiophene, or aromatic bound to 6-position of the benzodithiophene group (4-position of the phenyl ring, Benzoji A chain aliphatic group is bonded by a single bond to the 4- or 5-position of the thiophene ring bonded to the 2-position with thiophene and the 5-position of the thiophene ring similarly bonded to the 3-position.

Chain aliphatic groups, -O in the main chain -, - S -, - NH -, - CO -, - OCO- or -SO ₂ - may comprise, or carbon atoms between the main chain double It may be a chain aliphatic group having 1 to 20 carbon atoms, which may be bonded by a bond or a triple bond. The chain aliphatic group may be an alkyl group having 1 to 20 carbon atoms. The chain aliphatic group may contain -O-, -S- or -NH- in the main chain having 1 to 20 carbon atoms. In the chain aliphatic group, the carbon atoms of the main chain do not have to be bound by a double bond or a triple bond. The chain aliphatic group is acyclic and does not include a cyclic aliphatic group. The chain-like aliphatic group may have a branch, but is preferably a straight chain from the viewpoint of improving film-forming property and mobility. When the flexible chain aliphatic group is linearly bonded to the rod-shaped and rigid benzodithiophene skeleton, anisotropy of the molecular structure and liquidity are imparted, which is preferable for manifesting a liquid crystal phase.

One preferred chain aliphatic _{group, - (CH 2) x -X-} (CH 2) y -CH 3 wherein, X represents a single bond, S, O, and NH, x is an integer of 2 or more , Y is an integer of 0 to 17, and x+y is an integer of 19 or less. ] May be sufficient.

One preferred chain aliphatic group may be a linear alkyl group having 1 to 20 carbon atoms, preferably 3 to 20 carbon atoms, more preferably 6 to 18 carbon atoms, and further 8 carbon atoms. It may be up to 14 straight chain alkyl groups.

Features of the novel compound of the present invention When a linear aliphatic group is linearly bonded to one end of a rigid rod-like skeleton structure containing a benzodithiophene skeleton and an aromatic group of the novel compound of the present invention, Adding a flexible unit to the skeleton not only improves the solubility but also imparts liquidity to the molecule, which is preferable for manifesting liquid crystallinity and facilitates alignment control, resulting in high mobility in semiconductor materials. Be done.

When the linear aliphatic group is linearly bonded to only one end of the rigid rod-like skeleton structure containing the benzodithiophene skeleton and the aromatic group of the organic compound represented by the formula (1) of the present invention, Since a flexible unit is added to the rigid skeleton to impart liquidity and liquid crystallinity to the molecule, a high-order liquid crystal phase can be expressed, and a crystal having a bilayer structure can be formed. It is preferable from the viewpoint of improving the characteristics, especially the mobility.

Preferred examples of the organic compound represented by the formula (1) of the present invention are as follows.

(Method for producing compound represented by formula (1))
The compound represented by formula (1) of the present invention may be produced, for example, by any of the production methods described below.

Examples of the compound represented by the formula (1) (an example in which a chain aliphatic group is bonded to phenyl or thienyl instead of BDT) may be produced, for example, by the following synthetic scheme (I). In this case, in the synthesis of the monohalogenated substitution product C of BDT, which is an intermediate, the method of halogenating the BDT ring described in Patent Document 6 to obtain the monohalogenated substitution product of BDT inevitably produces a dihalogen substitution product. When obtaining the final target product, a product derived from a dihalogen compound is produced and becomes an impurity. Since this impurity has a high similarity to the target product, it is extremely difficult to remove it as described later in Examples, and even if it is a trace amount, it becomes an electronically active impurity that traps carriers. Will be fatal. Therefore, for the synthesis of the monohalogen-substituted compound C, it is important to use a scheme that can suppress the production of the dihalogen-substituted compound of BDT, as shown in this synthetic scheme.

In the synthetic scheme (I), first, BDT (compound A) is subjected to silylation reaction with (CH ₃ ) ₃ SiCl in the presence of a BuLi catalyst (wherein Bu is butyl) to give hydrogen at the 2-position of compound A. atom to produce a silyl group substituted with _{((CH 3)} 3 Si group) 2- silyl BDT (compound B). Then, the compound B is reacted with a halogenating agent ICl to substitute the (CH ₃ ) ₃ Si group, which is a silyl group, with a halogen I to form a 2-halogen BDT (compound C), and then the compound C is treated with a Pd catalyst. In the presence of R-Ar-B(OH) ₂ (Ar is an aromatic group, R is a chained aliphatic group) and is substituted with halogen I to form an aromatic group bonded to the chained aliphatic group. R-Ar- is bonded to form compound D (a target compound in which an aliphatic group is bonded to an aromatic group bonded to BDT).

In the synthetic scheme (I), the aromatic group Ar is an optionally substituted phenol or thienyl. In the synthetic scheme (I), R-Ar-B(OH) ₂ is replaced with R-Ar-Ae-B(OH) ₂ (in the formula, Ae is an acetylene bond (-C≡C-)). be able to.

Further, an example of the compound represented by the formula (1) (an example in which a chain aliphatic group is bonded to BDT instead of phenyl or thienyl) may be produced, for example, by the following synthetic scheme (II). ..
In the synthetic scheme (II), it is the same as the synthetic scheme (I) until the synthesis of the compound C. The halogenated BDT (compound C) is reacted with PhB(OH) ₂ (wherein Ph is phenyl) in the presence of a Pd catalyst to replace the halogen I at the 2-position of the BDT with phenyl Ph to obtain Ph-BDT( After producing compound E), Ph-BDT (compound E) is further reacted with RBr (wherein R is a chained aliphatic group) in the presence of a BuLi catalyst (wherein Bu is butyl). Then, the compound F (target compound having an aliphatic group in the BDT bonded to the aromatic group Ph) is produced. In Synthesis Scheme _{(II), PhAeB (OH)} 2 ( wherein, Ae is a is acetylene bond (-C≡C-)) in place of PhB _{(OH) 2} using the Ae between BDT and Ph Can be intervened. Furthermore, by using thienyl in place of phenyl Ph of PhB(OH) ₂ , a target compound having an aliphatic group in BDT bound to thienyl can be obtained. These phenyl or thienyl may have a substituent.

Reactions and reaction conditions of the synthetic schemes (I) and (II) can be appropriately changed, and details thereof will be apparent to those skilled in the art, but detailed examples are also described in Examples.

Further, the method for producing the compound represented by the formula (1) of the present invention is a method for producing a monohalogenated product of BDT (compound C of synthetic schemes (I) and (II)) which is an intermediate, when It is desirable to use a scheme of synthesis via a TMS form (compound B of synthetic schemes (I) and (II)) and the like. When the BDT ring is directly halogenated, it is difficult to separate the by-produced dihalogenated compound. Therefore, particularly when it is used for semiconductors, the compound represented by the following formula (4) is used as an intermediate and The production method for producing the target compound represented by (5) is preferable.
(In these formulas, _one of R ₁ and R ₂ is a chain aliphatic group and the other is a hydrogen atom, and the acetylene bond in the parentheses may or may not exist.)

According to this preferred production method, the target compound represented by the formula (5) is treated as a pure (by-product without the reaction step in which an undesired by-product is inevitably produced during the synthesis. It is possible and preferred to produce it as a compound).

This preferable production method is characterized in that a thiophene compound having phenyl bonded thereto is used as an intermediate. In this intermediate, a chain aliphatic group can be bonded to phenyl, and an acetylene bond can be interposed between phenyl bonded to thiophene, but for the sake of simplicity, a chain aliphatic group is also included. Explaining with a thiophene compound (Ph-Tp) in which only phenyl is bonded without the presence of an acetylene bond, in this preferred production method, benzodithiophene (BDT) is synthesized starting from thiophene of the thiophene compound (Ph-Tp). However, phenyl is already bound to the synthesized benzodithiophene. As in the synthetic scheme (I) or (II), when benzodithiophene is first synthesized and then benzodithiophene is halogenated to bind phenyl, the symmetry of benzodithiophene causes halogen and phenyl to be A mixture with a by-product bound not only to the 2-position but also to the 6-position of dithiophene is obtained, and it is difficult to completely separate and remove the by-product even by using a purification technique such as recrystallization or chromatography. Is. However, according to the above-mentioned preferred production method, since phenyl is bonded to the 2-position of benzodithiophene to be synthesized in advance, there is a difference in reactivity between the bonding positions of R ₁ and R ₂ , so that a by-product is produced. It is possible to bond a chain aliphatic group only to the 6-position (bonding position of R ₁ ) of benzodithiophene without producing a compound, and to bond it in advance during the synthesis of benzodithiophene. It is also possible to bond the chain aliphatic group only to phenyl (the bonding position of R ₂ ) by bonding the chain aliphatic group to the existing phenyl.

The above preferred production method may preferably include a step of producing a compound represented by the following formula (6) using the compound represented by the formula (4) as an intermediate.
In formula (6), R ₂ is a chain aliphatic group or a hydrogen atom, and the acetylene bond in the parentheses may or may not be present. In the compound represented by the formula (6), when R ₂ is a chain aliphatic group, R ₂ is bonded to the 4-position of phenyl bonded to thiophene of benzodithiophene to be synthesized in advance. , Does not participate in the synthesis reaction of benzodithiophene. When R ₂ is a hydrogen atom, the reactivity at the 6-position of benzodithiophene is significantly different from the reactivity at the 4-position of phenyl, so that the chain aliphatic group R ₁ is bonded only to the 6-position of benzodithiophene. It is possible.

In the synthetic schemes (I) and (II), there is no difference in reactivity between the 2-position and the 6-position of benzodithiophene, and therefore it is not possible to halogenate only the 2-position, so that the 2-position and the 6-position are both present. A halogen-bonded intermediate product (by-product) is inevitably produced in a small amount, and it is extremely difficult to completely isolate the target compound. By using the synthetic schemes (I) and (II), it is possible to suppress the production of the dihalogen compound, and it is possible to reduce the impurity concentration to such an extent that it cannot be detected by thin-layer chromatography by column chromatography or recrystallization. .. When used as an organic semiconductor, particularly when used as a crystal film, even if the concentration is in the order of ppm, the semiconductor characteristics are affected. Therefore, it is even more difficult to reduce the concentration of the dihalogenated compound to ppm or less. According to the production method using the above intermediate, it is possible in principle to eliminate the concentration of impurities (by-products) in which chain-like aliphatic groups are bound to both ends of the rod-shaped compound, and the concentration can be reduced to ppm or less. It goes without saying that you can do it. When the organic compound represented by the formula (1) of the present invention is crystallized and used as an organic semiconductor, if the organic semiconductor contains impurities, the crystal quality is lowered and the mobility is lowered, which is not preferable.

An intermediate of formula _{(4) 2- (4-R} 2) phenyl (acetylene) thiophene, a compound represented by the formula (6) from the intermediate 2- _{(4-R 2} ) Synthesis of phenyl(acetylene)-benzodithiophene, 2-(4-R ₁ )phenyl(acetylene)-(6-- which is a compound represented by formula (5) from the compound represented by formula (6) The specific mode of R ₂ )benzodithiophene synthesis is not limited, but can be, for example, according to the following synthetic scheme (III). In this synthetic scheme, since a BDT ring is formed starting from a substituted thiophene, the by-product of the di-substituted form of BDT can be suppressed in principle as compared with the method via a halogen-substituted form of BDT.

In the above synthetic scheme (III), compound 1 (2-phenylthiophene)→compound 2 (2-bromo-5-phenylthiophene)→compound 3 (3-bromo-5-phenyl-α-(3-thienyl)- 2-Thiophenmethanol)→Compound 4 (3-Bromo-5-phenyl-2-(3-thienylmethyl)thiophene)→Compound 5 (5-Phenyl-2-(3-thienylmethyl)-3-thiophenecarboxaldehyde) → Compound 6 (2-phenyl-benzo[1,2-b:4,5-b']dithiophene) → Compounds 7a, 7b ((2-phenyl-benzo[1,2-b:4,5-b' ] Dithiophene)-6-alkan-1-one)→compounds 8a, 8b (6-alkyl-2-phenyl-benzo[1,2-b:4,5-b′]dithiophene) are synthesized in this order. The reactions and reaction conditions in each synthesis are described in the above schemes and details are given in the examples, but it will be apparent to those skilled in the art that the reactions and reaction conditions are not limiting.

In the synthetic scheme (III), first, the compound represented by the formula (4), compound 1 (2-phenylthiophene), is prepared. For example, it is synthesized by reacting 2-halogenthiophene and halogenated benzene with magnesium in the presence of a suitable catalyst.

Then, starting from the thiophene moiety of compound 1 (2-phenylthiophene), benzodithiophene is synthesized to produce compound 6 (2-phenyl-benzodithiophene), where the starting thiophene moiety of benzodithiophene is Remains bound to phenyl.

For example, halogenating the 5-position of thiophene of 2-phenylthiophene to form compound 2 (2-bromo-5-phenylthiophene), and then reacting with 3-thiophenecarboxaldehyde to give the 3-position at the 5-position of thiophene of 2-phenylthiophene A compound 3 (3-bromo-5-phenyl-α-(3-thienyl)-2-thiophenemethanol) bound with -thienylmethanol is synthesized.
The hydroxyl group of compound 3 (3-bromo-5-phenyl-α-(3-thienyl)-2-thiophenemethanol) was removed by reaction with a metal hydride to give compound 4 (3-bromo-5-phenyl-2 -(3-thienylmethyl)thiophene) is produced.
Then, the halogen of compound 4 (3-bromo-5-phenyl-2-(3-thienylmethyl)thiophene) was formylated with NN-dimethylformamide (DMF) to give compound 5 (5-phenyl-2-(3-thienyl) Methyl)-3-thiophenecarboxaldehyde) is produced.
Then, polyphosphoric acid (PPA) is used to complete the benzodithiophene structure by ring-fusing the aldehyde bound to thiophene to the other thiophene to obtain compound 6 (2-phenyl-benzodithiophene), That is, the compound represented by the formula (6) is synthesized.

The compound 1 (2-phenylthiophene) may be one having a chain aliphatic group R ₂ bonded to phenyl, in which case the compound 6 (2-(4-R ₂ )phenyl-benzodiene Thiophene) is the final target product (compound represented by formula (5)).

Compound 1 (2-phenylthiophene) can be phenylacetylene instead of phenyl. In this case, compound 6 (2-phenyl-benzodithiophene) is a compound (2-phenylacetylene-benzodithiophene) in which acetylene is interposed between phenyl and benzodithiophene. Further, when the chain aliphatic group R ₂ is bonded to phenyl, the compound 6 is 2-(4-R ₂ )phenylacetylene-benzodithiophene.

Compound 1 (2-phenylthiophene) does not need to have a chain aliphatic group R ₂ bonded to phenyl, and in this case, compound 6 (2-(4-R ₂ )phenyl-benzodithiophene) benzo A chain aliphatic group R ₁ is bonded to dithiophene to synthesize compounds 8a and 8b (compound 8) to obtain a final target product (compound represented by formula (5)). The reaction for attaching the chain aliphatic group R ₁ to benzodithiophene of Compound 6 is known. For example, as shown in the synthetic scheme (II), Ph-BDT (compound 6) is reacted with RBr (wherein R is a chained aliphatic group) in the presence of a BuLi catalyst (Bu is butyl). To produce compound 8. Further, as shown in the synthetic scheme (III), for example, compound 6 (2-(4-R ₂ )phenyl-benzodithiophene) is reacted with an acyl halide RCOCl ₃ to give an acyl group at the 6-position of benzodithiophene. Compounds 7a and 7b ((2-phenyl-benzodithiophene)-6-alkane-1-one) are bound to each other and then the carbonyl group is reduced with hydrazine hydrate to form a chain at the 6-position of benzodithiophene. Compounds 8a,8b (6-alkyl-2-phenyl-benzodithiophene) having an aliphatic group (alkyl) attached may be formed. In addition, in this reaction, alkyl can be replaced with another chain aliphatic group, or compound 6 (2-(4-R ₂ )phenyl-benzodithiophene) can be converted to a chain aliphatic group by a method other than this reaction. Group groups may be attached. Alternatively, the synthetic route shown in the examples may be used.

In the synthetic scheme (III), in the formula (1), the aromatic group is phenyl and the chain aliphatic group is alkyl, but the phenyl group of Compound 1 may have a substituent, or the phenyl group of Compound 1 The group may be replaced with a thienyl group which may have a substituent, and the acyl group-COC _n-1 H _2n-1 or its alkyl group moiety of the compounds 7a and 7b may be replaced with another chain aliphatic group. It is possible to replace the phenyl group of the compounds 8a and 8b with a thienyl group, or the phenyl group or the thienyl group has a substituent (an aromatic group of the formula (1)) or an alkyl group to another chain. It can be replaced with a aliphatic group. Further, in the compound 1 of the synthetic scheme (I), the phenyl group (chained aliphatic group of the formula (1)) may have an acetylene bond (-C≡C-) between it and the thienyl group. Although an acyl group is used in the synthetic scheme (III), it may have various chain aliphatic groups.

Synthetic scheme (III) is based on the reactive nature of compound 1 (2-phenylthiophene) and 2-phenyl-benzodithiophene (compound 6). This is a preferred method for producing the compound represented by the formula (5) because it is a synthetic scheme that can bind only to the position and does not form an inseparable by-product.

Furthermore, in the synthesis scheme (III), when 2-(4-thienyl)-thiophene is used as an intermediate in place of 2-phenylthiophene (Compound 1), in compound 6, 2-(4-thienyl)-benzo Dithiophene (a compound represented by the formula (1) of the present invention) can be produced. The bond between the chain aliphatic group and acetylene may be the same as in the case of 2-phenylthiophene (Compound 1).

Further, the compound represented by the formula (1) of the present invention may be produced by a method other than these synthetic schemes.

(Organic liquid crystal phase and organic liquid crystal)
According to the present invention, it was found that the organic compound represented by the formula (1) of the present invention exhibits a liquid crystal phase and can be used as a liquid crystalline organic liquid crystal material. The organic liquid crystal of the present invention means a material that exhibits a liquid crystal phase or is in a liquid crystal state when kept at a predetermined temperature.

The organic compound represented by the formula (1) of the present invention exhibits the above-mentioned smectic phase with high orientational order. In particular, it can exhibit a liquid crystal phase selected from SmB, SmBcrystal, SmI, SmF, SmG, SmE, SmJ, SmK or SmH phases. In particular, the SmE phase is a preferable liquid crystal phase as an organic semiconductor because it exhibits high mobility among various liquid crystal phases and does not exhibit fluidity.

The fact that the organic compound represented by the formula (1) of the present invention forms a liquid crystal (phase) means that in the differential scanning calorimetry, two endothermic peaks ( Since it becomes a crystal (solid) after undergoing phase transition), the analysis of the liquid crystal phase can be carried out by observation with a polarization microscope at the liquid crystal temperature, and further by X-ray diffraction analysis.

As described above, the organic compound represented by the formula (1) of the present invention is an organic liquid crystal characterized by exhibiting a liquid crystal phase alone. However, as is known in general liquid crystal materials, other organic compounds are used. It can be used as an organic liquid crystal mixed with a compound exhibiting a phase, or mixed with a resin or the like, and further dissolved in a solvent, and is contained in the organic liquid crystal of the present invention of the organic liquid crystal as such a mixture or solution. is there.

The organic liquid crystal containing the organic compound represented by the formula (1) of the present invention forms a liquid crystal (phase), and the liquid crystal phase is also analyzed by differential scanning calorimetry, polarization microscope observation, and X-ray diffraction analysis. It is possible to do.

The organic liquid crystal comprising the organic compound represented by the formula (1) of the present invention or containing the organic compound represented by the formula (1) exhibits excellent alignment and mobility by itself, and thus is a useful organic compound. Although it is a semiconductor, it is also very useful as a precursor for producing a (solid) crystalline organic semiconductor, which will be described later, because it exhibits excellent solubility and orientation. This is because a crystal film formed by cooling a liquid crystal material from a temperature at which it exhibits a liquid crystal phase has a liquid crystal phase, that is, a film derived from the liquid crystal phase, which is excellent in uniformity, flatness, and orientation. Unlike a liquid crystal phase prepared from a low-order liquid crystal phase, a crystal film formed from a liquid crystal material having an alignment order of is formed from a liquid crystal phase having an alignment order closer to that of a crystal. As described above, the formation of cracks and the like that impair the quality of the crystal film is suppressed.

Such properties of the organic liquid crystal phase and the organic liquid crystal of the present invention will be described later in connection with the organic semiconductor of the present invention, and the liquid crystallinity and liquid crystal properties thereof have been confirmed in Examples. The usefulness and the mode of using it as an organic liquid crystal material are described.

Liquid crystal materials have high solubility in organic solvents due to the structural characteristics of having alkyl side chains, and spin coating, dipping, film forming methods using doctor blades, etc. By using this, a film can be produced, and the obtained film is uniform and has excellent flatness.

In addition, by utilizing the fluidity of an isotropic phase or a low-order liquid crystal phase, it is injected into a cell composed of two base materials whose gaps are controlled by a spacer or the like to form a cell. The film can be easily manufactured.

Although the mobility of the liquid crystal film thus manufactured is smaller than that of the crystal film, as described in Non-Patent Document 8, unlike the crystal film, the domain interface does not serve as a trap, so a material having a large area is required. It is an advantageous material for device applications. In addition, since the material is softer than that of crystal, not only it is rich in flexibility, but also a thick film without cracks can be formed. The characteristics of this liquid crystal material give the degree of freedom in the device manufacturing process and device structure.

The configurations and manufacturing methods of display devices, optical devices, semiconductor devices and other liquid crystal devices using liquid crystal cells are widely known.

For example, in a liquid crystal display device, a liquid crystal material is injected between transparent electrode substrates on which an alignment film is arranged or alignment-treated as necessary to form a liquid crystal cell. The target liquid crystal display device is configured by combining various constituent members such as a reflective plate and a black matrix.

Other liquid crystal substances to be mixed with the organic liquid crystal compound exhibiting a higher liquid crystal phase of the present invention include, for example, nematic liquid crystal, resins such as polystyrene and acrylate, and solvents such as amide and sulfoxide. , Pyridine, toluene, hexane, ether, ketone and the like.

In order to align the liquid crystal material in the cell, in addition to the alignment film or the alignment treatment, a treatment of heating the liquid crystal material to a temperature exhibiting a higher order liquid crystal phase is also performed.

(Organic semiconductor)
The organic semiconductor of the present invention contains the organic compound represented by the formula (1) of the present invention. An organic semiconductor can be produced using the organic compound represented by the formula (1) of the present invention.

The method for forming an organic semiconductor using the organic compound represented by the formula (1) of the present invention is generally a solution process such as a spin coating method, a drop casting method, a dip coating method, a spray method, and a flexographic printing method. , Letterpress printing methods such as resin letterpress printing, offset printing methods, dry offset printing methods, flat plate printing methods such as pad printing methods, intaglio printing methods such as gravure printing methods, silk screen printing methods, transcription printing methods, lingograph printing methods, etc. Stencil printing method, inkjet printing method, microcontact printing method, etc.; vacuum process, resistance heating evaporation method, electron beam evaporation method, sputtering method, molecular lamination method, etc.; Etc. Among these, the solution process, particularly the spin coating method is preferable.

In the solution process, a composition or ink in which the organic compound represented by formula (1) is dissolved or dispersed in a solvent is prepared.

The solvent is not particularly limited as long as it dissolves or disperses the organic compound represented by the formula (1) of the present invention, and examples thereof include toluene, xylene, mesitylene, ethylbenzene, pentylbenzene, hexylbenzene and octyl. Aroma such as benzene, cyclohexylbenzene, indane, tetralin, anisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,2-dimethylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, nitrobenzene Group hydrocarbons, aliphatic hydrocarbons such as hexane, heptane, octane, decane, dodecane, tetradecane, decalin, etc., dichlorobenzene, chlorobenzene, trichlorobenzene, 1-chloronaphthalene, 1,2-dichloroethane, 1,1,2,2 -Halogenated hydrocarbons such as tetrachloroethane, chloroform, dichloromethane, ethers such as diisopropyl ether, dibutyl ether, CPME, THF, 2-methyltetrahydrofuran, 1,4-dioxane, acetone, methyl ethyl ketone, diethyl ketone, diisopropyl ketone, cyclohexanone, Ketones such as acetophenone, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, γ-butyrolactone, cyclohexanol acetate, esters such as 3-methoxybutyl acetate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate. Carbonic acid esters such as ethyl methyl carbonate and 4-fluoroethylene carbonate, nitriles such as acetonitrile, propionitrile, valeronitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, DMF, DMAc, NMP, etc. Amide, dipropylene glycol dimethyl ether, dipropylene glycol diacetate, dipropylene glycol methyl-n-propyl ether, dipropylene glycol methyl ether acetate, 1,4-butanediol diacetate, 1,3-butylene glycol diacetate, 1, 3-butylene glycol diacetate, 1,6-hexanediol diacetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, Examples thereof include glycol such as diethylene glycol monobutyl ether acetate. Of these, aromatic hydrocarbons are preferable, and toluene, mesitylene, cyclohexylbenzene, tetralin, or 3,4-dimethylanisole is more preferable because they have a high boiling point and are gently volatilized. The amount of the solvent used is not particularly limited, and the concentration of the organic compound represented by the formula (1) is preferably 0.001 to 95% by weight, more preferably 0.01 to 10% by weight. The solvent can be added so that

As a method of dissolution or dispersion, for example, a method well known to those skilled in the art such as stirring, shaking, and ball mill can be used. At this time, heating may be performed.

Although not essential, a binder for improving film-forming property may be added to the ink of the present invention. Examples of such a binder include polystyrene, poly-α-methylstyrene, polyvinylnaphthalene, poly(ethylene-cornorbornene), polymethylmethacrylate, polytriarylamine, poly(9,9-dioctylfluorene-co-dimethyl). Examples thereof include polymers such as triphenylamine). The concentration of the binder is not particularly limited, but is preferably 0.1 to 10.0% by weight from the viewpoint of good coatability.

The film-forming composition of the present invention preferably has a viscosity in the range of 0.5 to 50 mPa·s from the viewpoint of good coatability.

The film-forming composition of the present invention may contain additives such as a resin, a pigment, a surfactant, a leveling agent, a dispersant, and an antifoaming agent, if necessary.

The organic semiconductor of the present invention can be obtained by applying the above ink and then drying the solvent. Ink application and drying may be performed at room temperature or at an elevated temperature. As a result of the organic compound of the present invention based on the organic compound represented by the formula (1), crystals derived from higher-order liquid crystals (SmE phase etc.) can be obtained even at room temperature.

The organic semiconductor of the present invention may be in the form of a film, but the film thickness of the thin film may vary depending on its application, but may be usually 0.1 nm to 10 μm, preferably 0.5 nm to 3 μm, and more preferably 1 nm to It may be 1 μm.

In addition, if necessary, the ink is heated to an appropriate temperature, for example, the organic compound represented by the formula (1) is applied at a temperature exhibiting a liquid crystal phase (SmE phase and the following phases), and then cooled. Then, it may be crystallized from the liquid crystal phase (SmE phase or the like). The organic compound represented by the formula (1) of the present invention is a high-order smectic phase as a liquid crystal phase based on the above-mentioned unique molecular structure, specifically, SmB phase, SmBcrystal phase, SmI phase, SmF phase, A liquid crystal substance selected from the SmG phase, SmE phase, SmJ phase, SmK phase and SmH phase, especially SmE phase, SmG phase, SmH phase, SmK phase, and especially SmE phase, and therefore a liquid crystal substance showing these liquid crystal phases And the crystals obtained therefrom have a high mobility in the first place. In liquid crystal substances, alignment defects peculiar to liquid crystals are unlikely to form electrically active levels, and it is easy to control the molecular alignment in the liquid crystal phase, which is difficult for non-liquid crystal substances. Since it has a feature that a crystalline thin film having excellent properties can be produced, there is a possibility that an excellent organic semiconductor can be provided. When the liquid crystal substance develops a high-order smectic phase, that is, a high-order liquid crystal phase capable of forming a solid-like thin film, particularly a SmE phase, SmG phase, SmH phase, SmK phase, etc. Can be secured. In addition, liquid crystal materials have the advantage that they can be formed into films at low temperatures.

Furthermore, the organic compound represented by the formula (1) can be a crystal having a bilayer structure, and a crystal having a bilayer structure can provide a material having higher mobility. It was confirmed. Conventionally, it has been known that an organic semiconductor having a structure in which four aromatic rings are condensed has a bilayer structure, but an organic compound having a structure in which three aromatic rings are condensed has a bilayer structure. The organic semiconductor forming the crystal having is the first to be found by the present invention. A bilayer structure is a structure in which molecules constituting a crystal are arranged in a layer and a molecular layer which is a repeating unit constituting a crystal is composed of one molecule, and is referred to as a monolayer structure. On the other hand, it means a structure in which the molecules are arranged in layers and the molecular layer serving as a repeating unit that constitutes a crystal is composed of two molecules. The bilayer structure is a structure in which organic compounds are arranged in layers, the axis of the organic compound is oriented in a direction perpendicular to the layer direction of the bilayer structure, and the bilayer of the organic compound is a repeating unit. The aromatic groups at the ends or the benzodithiophene skeletons may be aligned close to each other without overlapping in the layer direction. In order to schematically explain the molecular layer structure of the organic compound represented by the formula (1), referring to FIG. 1(a), the organic compound 1 represented by the formula (1) has a linear molecular structure. And one end side thereof has a portion 2 composed of a rigid BDT and an aromatic group, and the other end side thereof has a portion composed of a flexible chain aliphatic group 3, and such a compound 1 is layered. Two molecules that are arranged, and a layer (two-molecule layer) 4 composed of two molecules in which two rigid molecules of the BDT and the aromatic group in the two molecules adjacent to each other in the stacking direction face each other in the stacking direction is a repeating unit. The layer structure is shown. On the other hand, referring to FIG. 1( b ), the organic compound 1 represented by the formula (1) has two parts 2 composed of BDT and an aromatic group and two parts 3 composed of a chain aliphatic group, All of them are arranged adjacent to each other in the plane direction of the molecular layer (direction perpendicular to the stacking direction), not in the stacking direction of the molecular layer, and in the stacking direction, the sublayer 2 of the part consisting of BDT and the aromatic group and the chain shape. There is shown a monomolecular layer structure in which a layer (1 molecular layer) 5 composed of a sublayer 3 of an aliphatic group is repeated. These structures can be judged by taking the X-ray diffraction spectrum of the crystal and comparing the molecular layer thickness estimated from the peak observed on the low angle side with the molecular length predicted from the molecular structure. It is possible to easily know whether it has a molecular layer structure or a bilayer structure.

When the organic compound represented by the formula (1) is cooled from a liquid, it becomes a liquid crystal at a temperature equal to or lower than the melting point (isotropic phase) and becomes a crystal (solid) at a lower temperature. The organic compound represented by the formula (1) is a liquid crystal such as an SmE phase, but under normal cooling conditions, the obtained crystal of the compound of the formula (1) has a monolayer structure.

However, by thermally annealing the crystal (monomolecular layer structure) of the organic compound represented by the formula (1) at a temperature lower than the phase transition temperature from the crystal to the liquid crystal, the organic compound represented by the formula (1) Crystals having a bilayer structure can be obtained. The condition of the thermal annealing may be a temperature lower than the phase transition temperature from the crystal to the liquid crystal, but a temperature close to the phase transition temperature is preferable, and the phase transition temperature from the crystal to the liquid crystal varies depending on the target compound. It is preferably 50° C. to 10° C. lower than the temperature at which the crystal phase of the organic compound represented by the formula (1) transitions to the liquid crystal phase, more preferably 30° C. to 10° C., further preferably 20° C. to 10° C. A crystal having a bilayer structure of an organic compound can be obtained by thermal annealing at a low temperature. To set the optimum conditions, it is effective to determine the annealing temperature and time while confirming the formation of the bilayer structure by X-ray diffraction. For example, for alkylphenyl benzodithiophene, the temperature may be around 100 to 140°C. The time of thermal annealing may be a time sufficient to form crystals of a bilayer structure, but may be, for example, 5 to 20 minutes.

However, when the organic compound represented by the formula (1) is cooled from a liquid, crystals having a monomolecular layer structure are usually obtained. As a result of investigating by changing various cooling conditions, by selecting the cooling conditions, It was also confirmed that it is possible to obtain a crystal having a bilayer structure when changing from a liquid to a crystal (solid) and to obtain a crystal having a bilayer structure without thermal annealing.

The fact that the crystal has a bilayer structure can be confirmed by analyzing the crystal structure by X-ray diffraction as described above. The organic semiconductor of the present invention comprising a crystal having a bilayer structure means that the X-ray diffraction chart has a characteristic peak of a crystal having a bilayer structure, and preferably a characteristic peak of a crystal having a bilayer structure. It is said that the size is larger than the size of the characteristic peak of the crystal having a monomolecular layer structure. More preferably, the former is 1.5 times or more, 2 times or more, further 3 times or more and 4 times or more of the latter. Good.

A compound having a structure in which three aromatic rings are condensed is generally low in melting point and inferior in heat resistance as compared with a substance having a four-membered condensed ring structure in melting point. , Benzodithiophene (BDT) is a substance in which three highly linear aromatic ring structures are condensed, has a high melting point, and the organic compound represented by the formula (1) having BDT as a skeleton is In addition to finding out that it exhibits a liquid crystal phase, it has been found that high mobility can be realized while maintaining high solubility, especially by being able to express a bilayer structure in a crystal film, and further, the organic compound represented by the formula (1) The mobility was investigated by manufacturing a transistor by using, and the effectiveness of a crystal film having a bilayer structure as a transistor material was clarified.

In order to form a bilayer structure, it is essential to have one asymmetric side chain, and in order to secure heat resistance, it is important to express a higher order smectic phase. There is a method of utilizing crystal film growth from a solution to form a bimolecular structure, but it is convenient to use the crystal phase-crystal phase transition by thermal annealing after forming a monomolecular structure film by a solution process. Compared with the case of forming by a crystal growth method, the formation speed of the thin film is faster, and it is effective for producing a uniform and flat crystal thin film.

Further, as described in Non-Patent Document 5, it is known that in a molecule in which four aromatic rings are condensed, a crystal film having a bilayer structure has a higher mobility than a crystal film having a monolayer structure. However, it is not known in the condensed ring system consisting of three aromatic rings. The crystal film having a bilayer structure obtained by using the organic compound represented by the formula (1) retains the surface smoothness and uniformity of the crystal film produced through a high-order liquid crystal phase such as SmE phase. Therefore, it is useful as an organic semiconductor. Further, the condensed ring system composed of three aromatic rings has higher solubility than a substance composed of four aromatic rings and is effective in producing a semiconductor thin film by a solution process.

In addition, the organic semiconductor crystal film material of the present invention has a mobility that is about two orders of magnitude higher than that of a conventional organic semiconductor crystal material having a BDT skeleton. Also, in the liquid crystal phase, since the SmE phase, which is a high order liquid crystal phase, is expressed, the mobility is about two orders of magnitude higher than that of the low order liquid crystal phase.

(Organic semiconductor element)
An organic semiconductor element, for example, a transistor element; a diode; a thyristor; a photoelectric conversion element such as a photodiode, a solar cell, or a light receiving element, using the organic compound represented by the formula (1) of the present invention and the organic semiconductor using the organic compound. EL element; memory; can be applied to various organic semiconductor elements such as various sensors such as temperature sensor, biosensor, pressure sensor, etc., but as a particularly preferred embodiment of the present invention, production of an organic transistor element will be exemplified.

(Organic transistor element)
An organic transistor element is an element that has a source electrode and a drain electrode in contact with a semiconductor thin film, and controls a current flowing between these electrodes with a voltage applied to a gate electrode.

Generally, a structure (MIS structure) in which a gate electrode is insulated by an insulating film is often used for an organic transistor element. Among MIS structures, a structure using a metal oxide film as an insulating film is called a MOS structure. As an organic transistor element having another structure, there is a structure in which a gate electrode is formed on a semiconductor thin film via a Schottky barrier (that is, a MES structure). However, in the case of an organic transistor element using an organic semiconductor, MIS is used. The structure is often used.

Hereinafter, an example of an organic transistor element including a semiconductor thin film containing an organic compound represented by the formula (1) of the present invention will be described in more detail with reference to FIG. 2, but the organic transistor element of the present invention has this structure. It is not limited to.

The organic transistor element includes a source electrode 1, an organic semiconductor layer 2, a drain electrode 3, an insulator layer 4, a gate electrode 5, and a substrate 6. The arrangement of each layer and electrode can be appropriately selected depending on the application of the organic transistor element. The organic transistor element is called a lateral transistor because a current flows in a direction parallel to the substrate 6. In the organic transistor element, the organic semiconductor layer 2 is provided on the gate electrode 5 via the insulator layer 4, and the source electrode 1 and the drain electrode 3 are further formed thereon, which is called a top contact-bottom gate structure. The organic transistor element of the present invention is not limited to a lateral transistor and a top contact-bottom gate structure.

The substrate 6 is, for example, an insulating substrate such as a resin plate, a resin film, paper, a glass plate, a quartz plate, or a ceramic plate; an insulating layer is formed by coating on a conductive substrate made of metal or alloy. A multi-layer substrate; a composite substrate made of various combinations such as a combination of a resin and an inorganic material; and the like can be used. Examples of the resin film that can be used for the substrate 6 include films such as polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, polyamide, polyimide, polycarbonate, cellulose triacetate, and polyetherimide. When a resin film or paper is used as the substrate 6, the organic transistor element can be made flexible, and the organic transistor element is flexible and lightweight, thus improving the practicality. The thickness of the substrate 6 may be usually 1 μm to 10 mm, preferably 5 μm to 5 mm.

A material having conductivity is used for the source electrode 1, the drain electrode 3, and the gate electrode 5. Examples of the conductive material include platinum, gold, silver, aluminum, chromium, tungsten, tantalum, nickel, cobalt, copper, iron, lead, tin, titanium, indium, palladium, molybdenum, magnesium, calcium, barium. , Metals such as lithium, potassium, sodium, and alloys containing them; conductive oxides such as InO ₂ , ZnO ₂ , SnO ₂ , ITO; polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene, vinylene, polydiacetylene, etc. Conductive polymer compounds; semiconductors such as silicon, germanium and gallium arsenide; carbon materials such as carbon black, fullerene, carbon nanotubes, graphite and graphene; and the like can be used. Further, the conductive polymer compound or the semiconductor may be doped. Examples of the dopant used for doping include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids having an acidic functional group such as sulfonic acid; Lewis acids such as PF ₅ , AsF ₅ , FeCl ₃ ; halogen atoms such as iodine; lithium; Metal atoms such as sodium and potassium; and the like. Boron, phosphorus, arsenic, etc. are often used as dopants for inorganic semiconductors such as silicon. Further, a conductive composite material in which conductive molecules such as carbon black and metal particles are dispersed in the above dopant is also used as the material having the above conductivity.

Further, the structure such as the distance between the source electrode 1 and the drain electrode 3 (channel length) and the width of the channel region between the source electrode 1 and the drain electrode 3 (channel width) determines the characteristics of the organic transistor element. It will be an important factor. The channel length may be generally 0.01 to 300 μm, preferably 0.1 to 100 μm. If the channel length is short, the amount of current that can be extracted increases, but conversely, a short channel effect such as the effect of contact resistance occurs and control becomes difficult, so an appropriate channel length is required. The width of the channel region between the source electrode 1 and the drain electrode 3 (channel width) may be usually 10 to 10000 μm, preferably 100 to 5000 μm.

The structure of the source electrode 1 and the structure of the drain electrode 3 may be the same or different. The source electrode 1 and the drain electrode 3 can be manufactured by vapor deposition using a shadow mask or the like. The electrode pattern may be directly printed using a method such as inkjet. The lengths of the source electrode 1 and the drain electrode 3 may be the same as the channel width described above. The widths of the source electrode 1 and the drain electrode 3 are not particularly limited, but are preferably short in order to reduce the area of the organic transistor element within a range in which electric characteristics can be stabilized. The width of the source electrode 1 and the drain electrode 3 is usually 0.1 to 1000 μm, and preferably 0.5 to 100 μm. The thickness of the source electrode 1 and the drain electrode 3 may be usually 0.1 to 1000 nm, preferably 1 to 500 nm, more preferably 5 to 200 nm. Wirings are connected to the source electrode 1, the drain electrode 3, and the gate electrode 5, but the wirings may be made of substantially the same material as the electrodes.

A material having an insulating property is used for the insulator layer 4. Examples of the insulating material include, for example, polyparaxylylene, polyacrylate, polymethylmethacrylate, polyolefin, polystyrene, polyvinylphenol, polyamide, polyimide, polycarbonate, polyester, polyvinyl alcohol, polyvinyl acetate, polyurethane, polysulfone, Polymers such as fluororesins, epoxy resins and phenol resins, and copolymers combining them; metal oxides such as silicon dioxide, aluminum oxide, titanium oxide and tantalum oxide; ferroelectric metal oxides such as SrTiO ₃ and BaTiO ₃ . A dielectric such as a nitride such as silicon nitride or aluminum nitride, a sulfide or a fluoride; or a polymer in which particles of these dielectrics are dispersed; Although the layer thickness of the insulator layer 4 varies depending on the material, it may be usually 0.1 nm to 100 μm, preferably 0.5 nm to 50 μm, and more preferably 1 nm to 10 μm.

As the material of the organic semiconductor layer 2, the organic compound represented by the formula (1) of the present invention is used. Using the organic compound represented by the formula (1) of the present invention, the organic semiconductor layer 2 is formed as an organic thin film by the above-described forming method. For the purpose of improving characteristics and imparting other characteristics to the organic transistor device, if necessary, other organic semiconductors and various additives are mixed with the organic compound represented by the formula (1) of the present invention. Is also possible.

In the organic transistor element, the organic compound represented by the formula (1) of the present invention is used as the organic semiconductor forming the organic semiconductor layer 2. For the purpose of improving the characteristics of the organic transistor element, the organic semiconductor forming the organic semiconductor layer 2 may contain an additive such as a dopant. The above additive is added in an amount of usually 0.01 to 10% by mass, preferably 0.05 to 5% by mass, and more preferably 0.1 to 3% by mass, based on the total amount of the material of the organic semiconductor layer 2. To be done.

Also, a plurality of layers may be formed for the organic semiconductor layer 2. The layer thickness of the organic semiconductor layer 2 is preferably as thin as possible within a range in which necessary functions are not lost. The layer thickness of the organic semiconductor layer 2 for exhibiting the necessary function may be usually 1 nm to 1 μm, preferably 5 nm to 500 nm, more preferably 10 nm to 300 nm.

In the organic transistor element, for example, another layer is provided, if necessary, between the substrate 6 and the insulator layer 4, between the insulator layer 4 and the organic semiconductor layer 2, or on the outer surface of the organic transistor element. be able to. For example, when the protective layer is formed directly on the organic semiconductor layer 2 or via another layer, the influence of outside air such as humidity can be reduced.

The material of the protective layer is not particularly limited, and examples thereof include various resins such as epoxy resin, acrylic resin such as polymethylmethacrylate, polyurethane, polyimide, polyvinyl alcohol, fluororesin, polyolefin; silicon oxide, aluminum oxide, silicon nitride. Inorganic oxides such as; dielectrics such as nitride films; and the like are preferably used, and in particular, resins (polymers) having a small oxygen or water permeability and a small water absorption are preferable. The layer thickness of the protective layer can be selected according to the purpose, but is usually 100 nm to 1 mm.

In these aspects, for example, as a method of providing each layer such as the substrate 6, the insulator layer 4, and the organic semiconductor layer 2, for example, a vacuum vapor deposition method, a sputtering method, a coating method, a printing method, a sol-gel method or the like can be appropriately adopted. ..

The organic transistor element of the present invention can be used as an element constituting a digital or analog circuit such as a memory circuit, a signal driver circuit, a signal processing circuit. Furthermore, by combining these circuits, a display, an IC card, an IC tag, or the like can be manufactured. Further, since the organic transistor element of the present invention can change its characteristics by external stimuli such as chemical substances, it can be used as an FET (field effect transistor) sensor.

Hereinafter, the present invention will be described based on Examples, but the present invention is not limited to these Examples.

In all Examples and Comparative Examples, all commercially available reagents and solvents were Aldrich Chemical, Tokyo Chemical Industry, Wako Pure Chemical Industries and Kanto unless otherwise specified. Obtained from Kanto Chemical Co., Inc.

Various measuring methods and evaluation methods are as follows.
( ¹ H-NMR spectrum)
¹ H-NMR spectrum was measured using a Bruker NMR spectrometer (DMX 400 MHz) using tetramethylsilane (TMS) as an internal standard. NMR data s, d, t, and m indicate singlet, doublet, triplet, and multiplet, respectively. For high resolution mass spectrometry (HRMS), a double focusing magnetic sector mass spectrometer JEOL JMS-700 was used.

(Differential scanning calorimetry)
For differential scanning calorimetry (DSC), Shimadzu DSC-60 was used. Polarization microscopy was performed with a Nikon OPTIPHOT2-POL microscope equipped with a Mettler Toledo FP82HT hot stage. 1D WXRD analysis was performed using Rigaku RAD-2X diffractometer (CuKα ray).

(X-ray diffraction)
A bulk film sample for XRD measurement was prepared by melting a sample powder from an isotropic phase to room temperature using a glass slide substrate and a polyimide cover film. Prior to the measurement, the polyimide film was removed, and spin coating was performed at SmE temperature at 3000 rpm for 30 seconds to prepare a thin film sample. This is similar to OFET thin film fabrication, except that a glass slide is used as the substrate.

(Method for manufacturing and evaluating transistor device)
To fabricate an FET, a SO ₂ (300 nm)/p ⁺ -Si substrate is spin-coated (3000 rpm 30s) with a p-diethylbenzene (DEB, Iwt%) solution prepared by dissolving a preheated liquid crystal substance at the temperature of the SmE phase. Thus, a thin film was formed and cooled to room temperature to obtain a crystalline thin film. Then, Au was vapor-deposited on the thin film at 2×10 ⁻⁶ Torr via an electrode pattern by a vacuum vapor deposition method to fabricate a top-contact/bottom-gate transistor. The channel length/channel width is 100/500 μm.

Transistor characteristics before and after thermal annealing (15 minutes at each set temperature) were evaluated using a source measurement unit (8252, ADCMT). The mobility is calculated by plotting the square root of the source-drain current (I _ds ) in the saturation region (V _ds =-60V) against the gate voltage, and using the slope of the equation, I _ds =C _i (W/L)μ(V _g- V _th ) ² , and the threshold voltage (V _th ) was determined from the intercept. Here, C _i represents the capacitance of the gate insulating film.

Examples 1 and 2
6-octyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene (Compound 8a: Ph-BDT-C8) as Example 1 and 6-tetradecyl-2- as Example 2. Phenyl-benzo[1,2-b:4,5-b']dithiophene (Compound 8b: Ph-BDT-C14) was synthesized and evaluated for its properties. However, hereinafter, the syntheses of Example 1 and Example 2 may be collectively referred to as octyl C8 and detradecyl C14 as alkyl Cn. The synthetic scheme followed the synthetic scheme (I) described earlier in this specification, and is described in detail below.

(Compound 1: Synthesis of 2-phenylthiophene)
2-Phenylthiophene (Compound 1) was synthesized by a method described in a known document.

(Compound 2: Synthesis of 2-bromo-5-phenylthiophene)
To 200 ml of a methylene chloride solution containing 8.0 g (50 mmol) of stirred 2-phenylthiophene, 9.8 g (55 mmol) of NBS was added little by little, and then the mixture was reacted overnight at room temperature. Na ₂ SO ₃ solution was added to the reaction solution, the mixture was extracted with CH ₂ Cl ₂ , the extract was washed with water, and then anhydrous Na ₂ SO ₄ was added and dried, and the solvent was distilled off. Left. The obtained crude product was isolated by silica gel column chromatography (hexane) and recrystallized from ethanol to give 8.2 g (74%) as white crystals. ¹ H-NMR (CDCl ₃ , 400 MHz): δ 7.51-7.53 (d, 2H), 7.36-7.39 (t, 2H), 7.28-7.31 (t, 1H), 7.02-7.06 (m, 2H).

(Compound 3: Synthesis of 3-bromo-5-phenyl-α-(3-thienyl)-2-thiophenemethanol)
Synthesis of lithium diisopropylamide (LDA): under argon atmosphere, stirred N, N-diisopropylamine 4.2 ml (30 mmol) in dry THF (15 ml) solution, 18.8 ml n-BuLi solution (1.6 M in hexane, 30 mmol). ) Was slowly added at -78°C, and after 30 minutes, the temperature was slowly returned to room temperature, and lithium diisopropylamide (LDA) was adjusted.

To a dry THF (60 ml) solution containing 7.2 g (30 mmol) of stirred 2-bromo-5-phenylthiophene, the freshly prepared LDA solution was slowly added at -78 °C, and 1 hour later, 3-thiophenecarboxaldehyde was added. After adding 10 ml of a dry THF solution containing 3.7 g (33 mmol), the temperature was returned to room temperature and the mixture was stirred at room temperature overnight. Saturated NH ₄ Cl solution was slowly added to the reaction solution, the mixture was extracted with CH ₂ Cl ₂ , washed with water, anhydrous Na ₂ SO ₄ was added to the extract, and the mixture was dried. Then, Na ₂ SO ₄ was filtered off and the solvent was distilled off. The resulting crude product was isolated and purified by silica gel column chromatography (ethyl acetate:hexane/1:10) to give 9.1 g (86.7%) of 3-bromo-5-phenyl-α-(3- A yellow viscous liquid of thienyl)-2-thiophenemethanol was obtained. ¹ H-NMR (CDCl ₃ , 400 MHz): δ 7.51-7.53 (d, 2H), 7.28-7.38 (m, 5H), 7.13-7.17 (m, 2H), 6.23 (s, 1H).

(Compound 4: Synthesis of 3-bromo-5-phenyl-2-(3-thienylmethyl)thiophene)
To a 300 ml _three- necked flask equipped with a reflux condenser, dry ether (40 ml) and LiAlH ₄ 4.0 g (105 mmol) were added, and 80 ml of a dry ether solution containing AlCl ₃ 25 g (192 mmol) was added at 0° C. for 5 minutes. After that, the refrigerant is removed and 9.1 g of 2-bromo-5-phenylthiophene in 40 ml of dry ether solution are slowly added. Reflux for 30 minutes, carefully add 80 ml of ethyl acetate and then pour into 2M HCl solution. The mixture was extracted with ethyl acetate, washed with NaHCO ₃ solution and then with water, the organic layer was separated and anhydrous Na ₂ SO ₄ was added and dried. After Na ₂ SO ₄ was filtered off and the solvent was distilled off, the desired product was isolated and purified by silica gel column chromatography (ethyl acetate:hexane/1:5). 3-Bromo-5-phenyl-2-(3-thienylmethyl)thiophene was obtained as white crystals in an amount of 7.3 g (83.8%). ¹ H-NMR (d-Acetone, 400MHz): δ 7.60-7.62 (m, 2H), 7.39-7.45 (m, 3H), 7.27-7.35 (m, 3H), 7.08-7.10 (m, 1H), 4.18 (s, 2H).

(Compound 5: Synthesis of 5-phenyl-2-(3-thienylmethyl)-3-thiophenecarboxaldehyde)
In a 200 ml two-necked flask equipped with a reflux condenser, under an argon atmosphere, dry ether (80 ml) was treated with 3-bromo-5-phenyl-2-(3-thienylmethyl)thiophene 6.7 g (20 mmol) in dry ether (80 ml). Add the dissolved solution, add 13 ml n-BuLi (20.8 mmol in 1.6 M hexane) at -78 °C with stirring and stir for 30 minutes, then add 4 ml of dried DMF and react for 1 hour. After that, the refrigerant is removed, the temperature is returned to room temperature, and the reaction is continued for 2 hours. Then saturated NH ₄ Cl solution is added slowly and the mixture is extracted with ethyl acetate and hexane (1:1) solution. The organic layer is separated, dried over anhydrous Na ₂ SO ₄ , Na ₂ SO ₄ is filtered off, and the solvent is distilled off. The crude product was isolated and purified by silica gel column chromatography (Ethyl acetate: hexane/1:5) to give 4.4 g (77.5%) of 5-phenyl-2-(3-thienylmethyl)-3. -Thiophenecarboxaldehyde was obtained as a yellow viscous liquid. ¹ H-NMR (d-acetone, 400 MHz): δ 10.15 (s, 1H), 7.69 (s, 1H), 7.64-7.66 (m, 2H), 7.40-7.46 (m, 3H), 7.33-7.36 (m , 2H), 7.11-7.12 (m, 1H), 4.66 (s, 2H).

(Compound 6: Synthesis of 2-phenyl-benzo[1,2-b:4,5-b']dithiophene)
Under an argon atmosphere, 2.7 g (9.5 mmol) of 5-phenyl-2-(3-thienylmethyl)-3-thiophenecarboxaldehyde is added with polyphosphoric acid (PPA 20 g) and reacted at 110°C for 30 min. Then, it was separated by filtration, and the obtained solid was recrystallized from toluene to give 2.4 g (95%) of 2-phenyl-benzo[1,2-b:4,5-b']dithiophene as ocher. Obtained as a solid. ¹ H-NMR (CDCl ₃ , 400MHz): 8.26 (s, 1H), 7.74-7.76 (d, 2H), 7.59 (s, 1H), 7.44-7.47 (m, 2H), 7.42 (s, 1H), 7.35-7.37 (m, 3H).

(Compound 7: (Synthesis of 2-phenyl-benzo[1,2-b:4,5-b']dithiophene)-6-alkane-1-one)
2-Phenyl-benzo[1,2-b:4,5-b']dithiophene (0.27 g (1 mmol) was dissolved in 20 ml of dry methylene chloride, 0.4 g (3 mmol) of AlCl ₃ was added little by little, and the mixture was added at 0°C. Until cooling, nonanoyl chloride or tridecanoyl chloride (1.1 mmol) is added, the mixture is allowed to react overnight at room temperature, then the reaction solution is poured into cold methanol and the precipitate is filtered off. By recrystallizing the solid from CHCl ₃ , the desired (2-phenyl-benzo[1,2-b:4,5-b′]dithiophene)-6-octane-1-one, or (2 -Phenyl-benzo[1,2-b:4,5-b']dithiophene)-6-tetradecane-1-one as yellow solids, 0.19 g (58.7%) and 0.23 g (58.7%) respectively were obtained. It was
(2-phenyl - benzo [1,2-b: 4,5-b '] dithiophene) -6-octan-1-one _{^{1 H-NMR (CDCl 3,}} 400 MHz): δ 8.37 (s, 1H) , 8.28 (s, 1H), 8.00 (s, 1H) 7.78-7.81 (m, 2H), 7.62(s, 1H), 7.48-7.52 (m, 2H), 7.42-7.44 (m, 1H), 3.03- 3.07 (t, 2H), 1.83-1.94 (m, 2H), 1.37-1.47 (m, 8H), 0.95-1.36 (t, 3H).
(2-Phenyl-benzo[1,2-b:4,5-b']dithiophene)-6-tetradecane-1-one had a low solubility and NMR measurement was impossible.

(Compound 8: Synthesis of 6-alkyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene)
(2-Phenyl-benzo[1,2-b:4,5-b']dithiophene)-6-octane-1-one (0.58 mmol) was dissolved in 15 ml diethylene glycol, 0.2 g KOH and 0.5 ml hydrazine hydrate (80% aqueous solution) was added, the mixture was heated at 110°C for 1 hour, and then reacted at 220°C for 5 hours. Then, the mixture was cooled to room temperature, water was added, the precipitate was collected by filtration, and washed with methanol. The target product was isolated and purified by silica gel chromatography (cyclohexane), and recrystallized several times from toluene to give 6-octyl-2-phenyl-benzo[1,2-b:4,5 as a yellow solid. -b']Dithiophene (Ph-BDT-C8) was obtained in a yield (71.7%).
¹ H-NMR (CDCl ₃ , 400 MHz): δ 8.16 (s, 1H), 8.11 (s, 1H), 7.75-7.77 (d, 2H), 7.58 (s, 1H), 7.46-7.48 (t, 2H ), 7.35-7.38 (m, 1H), 7.03 (s, 1H), 2.92-2.96 (t, 2H), 1.76-1.83 (m, 2H), 1.31-1.46 (m, 10H), 0.89-0.93 (t , 3H). HRMS (FAB): calc.m/z 378.1476 (C24H26S2), found m/z 378.1466 [M] ⁺ .
Similarly, 6-detradecanyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene (Ph-BDT-C14) was obtained in a yield (72.2%). ¹ H-NMR (CDCl ₃ , 400 MHz): δ.8.13 (s, 1H), 8.08 (s, 1H), 7.72-7.74 (d, 2H), 7.56 (s, 1H), 7.41-7.45 (t, 2H), 7.32-7.36 (m, 1H), 7.01 (s, 1H), 2.89-2.93 (t, 2H), 1.73-1.81 (m, 2H), 1.26-1.43 (m, 22H), 0.86-0.90 ( HRMS (FAB): calc.m/z 462.2415 (C30H38S2), found m/z 462.2421 [M] ⁺ .

(Evaluation of compound 8a)
When the compound 8a (Ph-BDT-C8) was heated to a predetermined temperature to be a liquid and then cooled at a rate of 10° C./min, and the crystallized compound 8a (Ph-BDT-C8) was liquid again from room temperature. A differential scanning calorimetric analysis chart when heated to a temperature is shown in FIG. The upper line in the figure is a calorimetric analysis chart when cooling from liquid to room temperature, and the lower line is a calorimetric analysis chart when heating from room temperature to liquid. Compound 8a shows a liquid crystal phase between the liquid and the crystal.

FIGS. 4 and 5 show polarization microscope photographs at 180° C. and 30° C. when compound 8a (Ph-BDT-C8) was heated to a liquid and then cooled at a rate of 10° C./min. A mosaic-like structure peculiar to a high-order smectic phase, which is often seen in a liquid crystal substance that does not develop a low-order smectic phase, is observed, and it is observed that at 30° C., cracks are generated in the crystal (solid).

FIG. 6 shows an X-ray diffraction pattern when the compound 8a (Ph-BDT-C8) was heated to 180° C. and 30° C. At 180° C., it was a liquid crystal (SnE phase), and at 30° C., it was a crystal. Analysis of the X-ray diffraction pattern is effective for identifying the liquid crystal phase. Three diffraction peaks that characterize the SmE phase in the high-angle region in the liquid crystal phase are seen, and more diffraction peaks appear in the crystal phase.

(Evaluation of compound 8b)
When the compound 8b (Ph-BDT-C14) is heated to a predetermined temperature to be a liquid and then cooled at a rate of 10° C./min, and the crystallized compound 8b (Ph-BDT-C14) is again a liquid from room temperature. The differential scanning calorimetric analysis chart when heated to the temperature is shown in FIG. The upper line in the figure is a calorimetric analysis chart when cooling from liquid to room temperature, and the lower line is a calorimetric analysis chart when heating from room temperature to liquid. The compound 8b exhibits a liquid crystal phase between the liquid and the crystal.

FIGS. 10 and 11 show polarization microscope photographs at 130° C. and 30° C. when compound 8b (Ph-BDT-C14) was heated and cooled from the liquid at a rate of 10° C./min. SnE phase) is observed, and cracks are observed in the crystal (solid) at 30°C.

FIG. 12 shows an X-ray diffraction pattern when the compound 8b (Ph-BDT-C14) was heated to 130° C. and 30° C., which was a liquid crystal (SnE phase) at 130° C. and a crystal at 30° C.

According to these results, the phase changes of compound 8a (Ph-BDT-C8) and compound 8b (Ph-BDT-C14) are as follows.

Examples 3 and 4
The thin film of the compound 8a (Ph-BDT-C8) was subjected to thermal annealing (TA) at 130° C. for 15 minutes, and the X-ray diffraction patterns of the thin film at room temperature before and after the thermal annealing are shown in FIG. 2θ=22.5Å is a diffraction pattern based on a crystal having a monolayer structure, and 2θ=44.1Å is a diffraction pattern based on a crystal having a bilayer structure. Before the thermal annealing, there are almost no peaks due to the bilayer crystal structure, but after the thermal annealing, the peaks due to the bilayer structure crystal are significantly large, and the diffraction pattern based on the monolayer structure crystal becomes It is slight (the former has a peak height ratio of 4 times or more). Therefore, before the thermal annealing, the monomolecular layer structure is almost present, and the bimolecular layer structure hardly exists. After the thermal annealing, the bimolecular layer structure is remarkable, but the monomolecular layer structure slightly exists. I just do it.

Using the compound 8a (Ph-BDT-C8), the above FET device was prepared, and further thermally annealed under the same conditions as above (130° C. for 15 minutes) to form two molecules of the organic semiconductor layer of the thin film OFET device. The mobility of the thin film OFET device before and after thermal annealing was measured after conversion into an organic semiconductor layer composed of a layered crystal. The results are shown in Table 2.

Table 2 also shows evaluation of Ion/off, heat resistance and solubility. Ion/off is the current value between the source and drain in the mobility evaluation, heat resistance is evaluated by whether the phase transition temperature from crystal to liquid crystal is 150°C or higher, and solubility is 0.1 It was evaluated depending on whether it is wt% or more.

A thin film of the compound 8b (Ph-BDT-C14) was thermally annealed at 130° C. for 15 minutes, and the X-ray diffraction patterns of the thin film at room temperature before and after the thermal annealing are shown in FIG. 2θ=about 28Å is a diffraction pattern based on a crystal having a monolayer structure, and 2θ=54.2Å is a diffraction pattern based on a crystal having a bilayer structure. Before the thermal annealing, there are almost no peaks due to the bilayer crystal structure, but after the thermal annealing, the peaks due to the bilayer structure crystal are significantly large, and the diffraction pattern based on the monolayer structure crystal becomes Few. Therefore, before the thermal annealing, the monomolecular layer structure is almost present, and the bimolecular layer structure hardly exists. After the thermal annealing, the bimolecular layer structure is remarkable, but the monomolecular layer structure hardly exists. (The peak height ratio is 30 times or more in the former).

Using the compound 8b (Ph-BDT-C14), an FET was prepared as described above, and then thermally annealed under the same conditions as above (130° C. for 15 minutes) to form an organic semiconductor layer of the FET with a bilayer structure. The mobility was measured before and after thermal annealing of the FET after conversion into the organic semiconductor layer made of the crystal. The results are shown in Table 2.

Table 2 also shows evaluation of Ion/off, heat resistance and solubility. Ion/off, heat resistance and solubility were evaluated in the same manner as in Example 3.

Comparative Examples 1 and 2
Known methods (for example, T. Kashiki, S. Shinamura, M. Kohara, E. Miyazaki, and K. Takimiya, M. Ikeda, H. Kuwabara, Organic Letters (2009), 11(11), 2473-2475. ), Ph-BDT-Ph and Cn-BDT-Cn were synthesized, FETs were prepared in the same manner as in Examples 3 and 4, and the mobility was measured. evaluated. The results are shown in Table 2. The compounds of Comparative Examples 1 and 2 did not form a bilayer structure even when thermally annealed.

Table 2 also shows evaluation of Ion/off, heat resistance and solubility. Ion/off, heat resistance and solubility were evaluated in the same manner as in Example 1.

Example 5
(Compound 13: Synthesis example of 4'-decyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene)
4'-decyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene (Compound 13 in the formula below: BDT-Ph-C10) was prepared from commercially available benzo[1,2 -B:4,5-b']dithiophene (Compound 10 in the following) was used as a starting material and synthesized by the following three-step route. Each step is shown.

Synthesis of Compound 11 A THF (150 ml) solution of Compound 10 (4.29 g) was cooled to -40°C, and a hexane solution of butyllithium (1.6M, 15.0 ml) was added dropwise over 15 minutes while maintaining the temperature. After stirring at -40 for 1 hour and at -10°C for 1 hour, the mixture was cooled to -40°C again. Chlorotrimethylsilane (4.0 ml) was added dropwise over 5 minutes while maintaining the temperature at -40°C, and the mixture was stirred at that temperature for 30 minutes and then returned to room temperature and stirred for 30 minutes. After adding water, the mixture was extracted with chloroform, and the chloroform phase was washed with 25% saline. After evaporation of the volatile matter, recrystallization from ethanol (80 ml) gave compound 11 (yield 4.43 g). ¹ H-NMR(500MHz,CDCl ₃ ): δ 8.30(s,1H), 8.28(s,1H), 7.48(s,1H), 7.46(d,J=5.7Hz,1H), 7.35(d,J =5.7Hz,1H), 0.40(s,9H).

Synthesis of compound 12 To a solution of compound 11 (3.61 g) in dichloromethane (150 ml), a solution of iodine monochloride in dichloromethane (1.0 M, 16.5 ml) was added dropwise at -60 to -50°C over 15 minutes, and at the same temperature. It was stirred for 6 hours. Then, the mixture was left standing at -15°C for 18 hours and then poured into an aqueous solution of sodium sulfite. The soluble matter was extracted with chloroform, and the chloroform phase was washed with 25% saline. After the volatile matter was distilled off, the residue was recrystallized twice with toluene (first 25 ml, second 15 ml) to obtain Compound 12 (yield 1.50 g). ¹ H-NMR(500MHz,CDCl ₃ ): δ 8.21(s,1H), 8.19(s,1H), 7.57(s,1H), 7.51(d,J=5.5Hz,1H),7.34(d,J =5.5Hz, 1H).

Synthesis of compound 13 A mixture of compound 12 (0.34 g), 4-decylphenylboronic acid (0.60 g), potassium carbonate (0.4 g), dioxane (20 ml) and water (2 ml) was freeze-deaerated. After adding Pd(PPh ₃ ) ₄ (0.06 g) and tri(t-butyl)phosphine (0.05 g), the mixture was heated under reflux with Ar gas flow for 5 hours. After cooling, water and chloroform were added for liquid separation, and the chloroform phase was washed with 25% saline. After the volatile matter was distilled off, the residue was purified by column chromatography (supporting phase: silica gel, developing solution: cyclohexane) to obtain a crude product of compound 15 (0.41 g). Further, recrystallization from toluene (8 ml) gave purified crystals of compound 13 (yield 0.32 g). ¹ H-NMR(500MHz,CDCl ₃ ): δ 8.24(s,2H), 7.65(d,J=8.2Hz,,2H), 7.54(s,1H), 7.45(d,J=5.4Hz,1H) , 7.35(d,J=5.4Hz,1H), 7.25d,J=8.2Hz,2H), 2.65(t,J=7.9Hz,2H), 1.64(m,2H), 1.39-1.24(m,14H ), 0.88 (t, J=6.9Hz, 3H). Compound 2 is a rod-shaped molecule, and has a temperature range in which a liquid crystal phase (SmE phase) is exhibited. The phase transition temperature was 144°C for the crystalline phase-SmE phase and 241°C for the SmE phase-isotropic phase.

Example 6
(Compound 14: Synthesis example of 6-decyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene)
6-decyl-2-phenyl-benzo[1,2-b:4,5-b']dithiophene (Compound 15 in the following formula: Ph-BDT-C10) was commercially available as benzo[1,2- b:4,5-b′]dithiophene (Compound 10 in the following formula) was used as a starting material and synthesized by the following four-step route. Each step is shown.

Synthesis of Compound 11-12 The processes from Compound 10 to Compound 12 are the same as in the synthesis of Compound 13 in Example 5.

Synthesis of compound 14
A mixture of 1c (1.50 g), phenylboronic acid (1.20 g), potassium carbonate (2.0 g), dioxane (100 ml) and water (10 ml) was freeze-deaerated. After Pd(PPh ₃ ) ₄ (0.30 g) and tri(t-butyl)phosphine (0.15 g) were added, the mixture was heated under reflux with Ar gas flow for 5 hours. After allowing to cool, water (100 ml) was added, and the insoluble matter was collected by filtration. The solid was washed with methanol (100 ml) and further purified by column chromatography (supporting phase: silica gel, developing solution: hexane/chloroform (1/1)) to obtain Compound 14 (yield 1.18 g). ¹ H-NMR(500MHz,CDCl ₃ ): δ 8.26(s,2H), 7.75(d,J=7.4Hz,,2H), 7.59(s,1H), 7.46(d,J=5.4Hz,1H) , 7.45(t,J=7.4Hz,2H), 7.36(d,J=5.3Hz,1H), 7.35(t,J=7.4Hz,1H).

Synthesis of Compound 15 A solution of Compound 14 (0.29 g) in THF (40 ml) was cooled to -40°C, and a hexane solution of butyllithium (1.6M, 1.0 ml) was added dropwise over 5 minutes while maintaining the temperature. After stirring at -40 for 1 hour and at -10°C for 1 hour, the mixture was cooled to -40°C again. 1-Bromodecane (1.0 ml) was added dropwise over 5 minutes while maintaining the temperature at -40°C, and the mixture was stirred at that temperature for 2 hours, and further stirred for 16 hours while returning to room temperature. After water was added and THF was distilled off, hexane was further added and the insoluble matter was collected by filtration. The solid product was purified by column chromatography (supporting phase: silica gel, developing solution: hexane/chloroform (100/0⇒80/20)) to obtain a crude product of 1 (0.18 g). Further, recrystallization from toluene (3 ml) gave a purified product of compound 15 (yield 0.12 g). ¹ H-NMR(500 MHz, CDCl ₃ ): δ 8.11(s,1H), 8.06(s,1H), 7.72(d,J=7.5Hz,,2H), 7.53(s,1H), 7.41(t, J=7.6Hz,2H),7.32(t,J=7.5Hz,1H),6.99(s,1H),2.91(t,J=7.7Hz,2H),1.69(m,2H),1.45-1.25( m, 14H), 0.88 (t, J=7.3Hz, 3H). Compound 1 is a rod-shaped molecule, and has a temperature region where a liquid crystal phase (SmE phase) is exhibited. The phase transition temperatures were 148°C for the crystalline phase-SmE phase and 229°C for the SmE phase-isotropic phase.

The structural formula of compound 15 is described in Patent Document 5 (International Publication WO2017/159657), but the nmr spectrum data described in Patent Document 5 lacks the number of protons and is also described. The chemical shift does not agree with the chemical shift of the compound 15 represented by the formula (1) of the present invention. From this, the structural formula of Patent Document 5 is presumed to be incorrect, and it can be said that Compound 15, which is the compound represented by Formula (1) of the invention, is not a compound known in Patent Document 5. Also, in many examples, the number of protons in the nmr spectrum, which is a proof of the substance confirmation of the compound, is insufficient.

Example 7
(Compound 22: Synthesis example of 2-(4-octylphenylacetylene)-benzodithiophene (BDT-Ae-Ph-C8))
Compound 22 was synthesized by the following synthetic route.

Synthesis of 2-iodo-BDT (Compound 21) To 0.5 g (2.6 mmol) of BDT dissolved in dry ether is slowly added 7 ml (2.7 mmol) of n-BuLi hexane solution under argon atmosphere at room temperature with stirring. After stirring at room temperature for 1 hour, the mixture was cooled to -78°C, 0.99 g (3.9 mmol) of iodine was dissolved in 5 mml of dry ether, and the solution was added little by little. After returning the temperature to room temperature, the mixture is left overnight with stirring. Water is slowly added to the reaction solution, extracted with hexane, washed with water, Na ₂ SO ₄ is added and dried. After filtering off the desiccant, the solution is concentrated, methanol is added and the precipitate is collected. By recrystallizing the obtained crude product from acetonitrile, 0.47 g (57.2%) of 2-iodo-BDT was obtained. The obtained 2-iodo-BDT contained a trace amount of 2,6-diiodo BDT, and its separation was difficult. ¹ H-NMR (CDCl ₃ , 400MHz): δ 8.19-8.20 (d, 2H), 7.57 (s, 1H), 7.50-7.51 (d, 1H), 7.33-7.34 (d, 1H).

Synthesis of 2-(4-octylphenylacetylene)-BDT (Compound 22)
In 10 ml of THF solution containing 0.3 g (0.9 mmol) of 2-iodo-BDT, 5 ml of N,N-diisopropylamine and 90 mg of PdCl ₂ (PPh ₃ ) ₂ 60 mg of CuI, 0.4 ml (1.4 mmol) of 4- Octylphenylacetylene is added with stirring under an argon atmosphere and left at room temperature overnight. Water is added to the reaction solution and the precipitate is collected. The resulting crude product was isolated and purified twice by silica gel column chromatography (cyclohexane) and recrystallized several times from toluene to give 2-(4-octylphenylacetylene)-BDT as a white solid 0.13 g (33.6 %). ¹ H-NMR (CDCl ₃ , 400MHz): δ 8.24 (s, 1H), 8.20 (s, 1H), 7.46-7.51 (m, 4H), 7.34-7.36 (d, 1H), 7.17-7.19 (d, 2H), 2.60-2.64 (t, 2H), 1.58-1.64 (m, 2H), 1.27-1.31 (m, 10H), 0.87-0.90 (t, 3H).

(Evaluation of Compound 22)

From the X-ray diffraction pattern of the crystal film of compound 22 (BDT-Ae-Ph-C8) in Fig. 15, it was judged from the diffraction peak in the low angle region and the molecular length by MOPAC (25.4Å) at each temperature, It can be seen that it has a bilayer structure (interlayer distance: 48.0Å).

Example 8
(Compound 26: Synthesis example of 2-phenylacetylene-6-octyl-benzodithiophene (Ph-Ae-BDT-C8))
Compound 26 was synthesized by the following synthetic route.

Synthesis of 2-iodo-BDT (Compound 21)
The synthesis of 2-iodo-BDT (Compound 21) is exactly the same as in Example 7.

Synthesis of 2-(1-octyne)-BDT (Compound 23)
0.6 g (1.9 mmol) 2-iodo-BDT was dissolved in THF (20 ml), 10 ml N,N-diisopropylamine, 180 mg PdCl ₂ (PPh ₃ ) ₂ , 120 mg CuI, 0.6 ml (3.8 mmol). 1-octyne was added under an argon atmosphere and left at room temperature overnight. To the reaction solution, 2M HCl was added, extracted with ethyl acetate and hexane (1:1), Na ₂ SO ₄ was added and dried, the desiccant was filtered off, and the crude product excluding the solvent was subjected to silica gel column chromatography ( Isolation and purification with hexane) gave 2-(1-octyne)-BDT (>90%) containing 0.6 g of a trace amount of 2,6-(1-octyne)-BDT. ¹ H-NMR (CDCl ₃ , 400MHz): δ 8.16-8.19 (d, 2H), 7.44-7.46 (d, 1H), 7.35 (s, 1H), 7.32 (d, 1H), 2.45-2.49 (m, 2H), 1.60-1.67 (m, 2H), 1.32-1.35 (m, 6H), 0.90-0.93 (m, 3H).

Synthesis of 2-octyl-BDT (Compound 24)
0.6 g (2.1 mmol) of 2-(1-octyne)-BDT was dissolved in THF (20 ml), CHCl ₃ 20 ml, Pd/C (containing 10 wt%) 200 mg, AcOH 5 ml, NaBH ₄ 0.6 g (16.4 mmol) ) Was added slowly. The reaction solution was stirred for 30 minutes at room temperature, 0.1M HCl was slowly added, the mixture was extracted with CHCl ₃ , Na ₂ SO ₄ was added, and the mixture was dried. After the desiccant was filtered off, the solvent was removed and the product was isolated and purified by silica gel column chromatography (hexane) to obtain 0.5 g (~78.8%) of 2-octyl-BDT. The obtained 2-octyl-BDT contained a trace amount of 2,6-(1-octyl)-BDT and its separation was difficult. ¹ H-NMR (CDCl ₃ , 400MHz): δ 8.17 (s, 1H), 8.12 (s, 1H), 7.39-7.40 (d, 1H), 7.30-7.32 (m, 1H), 7.00 (s, 1H) , 2.88-2.92 (t, 2H), 1.72-1.79 (m, 2H), 1.27-1.43 (m, 10H), 0.86-0.90 (t, 3H).

Synthesis of 2-iodo-6-octyl-BDT (Compound 25)
0.5 g (1.6 mmol, mixture) of 2-octyl-BDT was dissolved in 30 ml of dry ether, and 1.1 ml of n-BuLi solution (1.6 M in hexane, 1.7 mmol) was slowly added under argon atmosphere and ice cooling, After 2 hours, the reaction solution is cooled to -78°C and 5 ml dry ether in which 0.6 g (2.4 mmol) of iodine is dissolved is added in small portions. After that, the temperature is slowly returned to room temperature and left overnight. Water is slowly added to the reaction solution, extracted with ethyl acetate, and the extract is washed with water. The extract is concentrated, methanol is added, and the precipitate is collected. 0.36 g (~52.6%) of a crude product of 2-iodo-6-octyl-BDT was obtained. ¹ H-NMR (CDCl ₃ , 400MHz): δ 8.06 (s, 1H), 8.00 (s, 1H), 7.51 (s, 1H), 6.98 (s, 1H), 2.87-2.91 (t, 2H), 1.72 -1.79 (m, 2H), 1.27-1.40 (m, 10H), 0.86-0.89 (t, 3H).

Synthesis of 2-phenylacetylene-6-octyl-BDT (Compound 26)
0.36 g (0.84 mmol) of 2-iodo-6-octyl-BDT (crude product) was dissolved in 10 ml of THF, N,N-diisopropylamine 5 ml, PdCl ₂ (PPh ₃ ) ₂ 90 mg and CuI 60 mg, phenylacetylene Add 0.14 ml (1.26 mmol) under Argo atmosphere and leave at room temperature overnight. Water is added to the reaction solution and the precipitate is collected. The obtained crude product was purified twice by silica gel column chromatography (cyclohexane) and recrystallized several times from toluene to give 2-phenylacetylene-6-octyl-BDT 0.13 g (33.6%) as white crystals. It was ¹ H-NMR (CDCl ₃ ,400MHz): δ 8.12 (s, 1H), 8.03 (s, 1H), 7.55-7.57 (m, 2H), 7.50 (s, 1H), 7.36-7.37 (m, 3H) , 7.00 (s, 1H), 2.89-2.93 (t, 2H), 1.73-1.80 (m, 2H), 1.28-1.43 (m, 10H), 0.86-0.90 (t, 3H).

(Evaluation of Compound 26)
When the compound 26 (Ph-Ae-BDT-C8) was heated to a predetermined temperature to become a liquid and then cooled at a rate of 10°C/min, and the crystallized compound 8a (Ph-BDT-C8) was again cooled to room temperature. FIG. 16 shows a differential scanning calorimetric analysis chart when heated from the temperature to the liquid temperature. The upper line in the figure is a calorimetric analysis chart when cooling from liquid to room temperature, and the lower line is a calorimetric analysis chart when heating from room temperature to liquid. The compound 26 shows a liquid crystal phase between the liquid and the crystal centering around 160.

As shown in FIG. 17, the compound 26 (Ph-Ae-BDT-C8) was heated to a liquid and then cooled at a rate of 10° C./min. A mosaic-like structure peculiar to a high-order smectic phase, which is often seen in a liquid crystal substance that does not develop a low-order smectic phase, is observed, and it is observed that at 20° C., cracks are generated in the crystal (solid).

Analysis of the X-ray diffraction pattern is effective for identifying the liquid crystal phase. From the X-ray diffraction pattern of Compound 26 (Ph-Ae-BDT-C8) shown in FIG. 18 at 160° C. and 30° C., it was confirmed that it was a liquid crystal (SmE phase) at 160° C. and a crystal at 30° C. Recognize. Three diffraction peaks that characterize the SmE phase in the high-angle region in the liquid crystal phase are seen, and more diffraction peaks appear in the crystal phase.

Example 9
Transistor Fabrication Method A 0.4 wt% p-xylene solution of BDT-≡-Ph-C8 prepared in Example 7 was prepared and p-xylene was heated to 80° C. on a washed SiO ₂ (300 nm)/Si n+ substrate. The solution is applied with a spin coater at 3000 rpm. Au (50 nm) was vacuum-deposited on the obtained sample through a vapor deposition mask having source and drain electrode patterns to prepare a sample for measurement. The channel length/channel width L/W was 100/500 nm.

The manufactured transistor was connected to a source measurement unit for transistor characteristic evaluation, and the transistor characteristic was evaluated. Compound 22 (BDT-≡-Ph-C8) The mobility of each transistor immediately after fabrication and after heat treatment (TA) at 80° C. (5 minutes) and 110° C. (5 minutes) is shown in Table 3. It was on the street.

1 Source Electrode 2 Organic Semiconductor Layer 3 Drain Electrode 4 Insulator Layer 5 Gate Electrode 6 Substrate

Claims (19)

An organic compound represented by the following formula (1).
[Wherein, Ar is an aromatic group selected from phenyl and thienyl which may have a substituent, _one of R ₁ and R ₂ is a chain aliphatic group, and the other is a hydrogen atom. The acetylene bond in parentheses may or may not be present. ] Chain aliphatic groups, -O in the main chain -, - S -, - NH -, - CO -, - OCO- or -SO ₂ - may comprise, or carbon atoms between the main chain double The organic compound according to claim 1, which is a chain aliphatic group having 1 to 20 carbon atoms, which may be bonded by a bond. The organic compound according to claim 1 or 2, wherein the substituent of Ar is a halogen group, a nitro group, a nitrile group, or an acyclic or cyclic aliphatic group. The organic compound according to claim 1 or 2, which is represented by the following formula (2) or (3).
(In these formulas, both R ₁ and R ₂ are chain aliphatic groups.) The organic compound according to claim 1, which shows a liquid crystal. The organic compound according to claim 1, which is capable of forming a crystal having a bilayer structure. A method for producing an organic compound, which comprises using a compound represented by the following formula (4) as an intermediate to produce a target compound represented by the following formula (5).
(In these formulas, _one of R ₁ and R ₂ is a chain aliphatic group and the other is a hydrogen atom, and the acetylene bond in the parentheses may or may not exist.) The method for producing an organic compound according to claim 6, comprising a step of producing a compound represented by the following formula (6) using the compound represented by the formula (4) as an intermediate.
(In the formula, R ₂ is a chain aliphatic group or a hydrogen atom, and the acetylene bond in the parentheses may or may not exist.) Formula (1) below
[Wherein, Ar is an aromatic group selected from phenyl and thienyl which may have a substituent, _one of R ₁ and R ₂ is a chain aliphatic group, and the other is a hydrogen atom. The acetylene bond in parentheses may or may not be present. ]
An organic liquid crystal containing an organic compound represented by:
An organic liquid crystal wherein the organic compound exhibits a liquid crystal phase selected from SmB, SmBcrystal, SmI, SmF, SmG, SmE, SmJ, SmK or SmH phases. The organic liquid crystal according to claim 8, wherein the organic compound is a compound represented by the following formula (2) or (3).
(In these formulas, both R ₁ and R ₂ are chain aliphatic groups.) The organic liquid crystal according to claim 8 or 9, wherein the liquid crystal phase is an SmE phase. An organic semiconductor comprising a crystal of the compound represented by formula (1) according to any one of claims 1 to 6. The organic semiconductor according to claim 11, wherein the crystal has a bilayer structure. The bilayer structure is a structure in which the organic compound is arranged in a layered form and a bilayer having the axis of the organic compound oriented in a direction perpendicular to the layer direction of the bilayer structure is a repeating unit. The organic semiconductor according to claim 11 or 12. 14. The organic semiconductor according to claim 11, wherein the organic semiconductor is a crystal derived from a liquid crystal exhibiting a SmB, SmBcrystal, SmI, SmF, SmG, SmE, SmJ, SmK, or SmH phase. The organic semiconductor according to claim 14, wherein the organic semiconductor is a crystal derived from a liquid crystal exhibiting an SmE phase. A liquid crystal device comprising the organic liquid crystal according to claim 8. A semiconductor device comprising the organic liquid crystal according to any one of claims 8 to 10 or the organic semiconductor according to any one of claims 11 to 15. A transistor element comprising the organic liquid crystal according to any one of claims 8 to 10 or the organic semiconductor according to any one of claims 11 to 15.