Biphenylene compound, organic semiconductor layer and organic thin film transistor

Abstract

To provide a novel biphenylene compound which is a coating type organic semiconductor material having high carrier mobility, high heat resistance and proper solubility, an organic semiconductor layer using the same, and an organic thin film transistor.SOLUTION: There is provided a biphenylene compound shown by general formula (1-I) or (1-II), where A1 to A4 independently represent oxygen, sulfur, and selenium respectively, R1 and R3 independently represent aryl groups having 4-20 carbon atoms respectively, R2 and R4 independently represent alkyl groups having 1-5 carbon atoms, and m and n represent integers of 0-4.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel biphenylene compound that can be applied to electronic materials such as organic semiconductor materials, an organic semiconductor layer using the same, and an organic thin film transistor. In particular, since it has excellent solubility and heat resistance, it relates to a novel biphenylene compound applicable to various device manufacturing processes, an organic semiconductor layer using the same, and an organic thin film transistor.

Background Art

[0002] Organic semiconductor devices typified by organic thin film transistors have attracted attention in recent years because they have characteristics that inorganic semiconductor devices do not have, such as energy saving, low cost, and flexibility. This organic semiconductor device is composed of several types of materials such as an organic semiconductor layer, a substrate, an insulating layer, and electrodes. Among them, the organic semiconductor layer that is responsible for charge carrier movement plays a central role in the device. And since the performance of the organic semiconductor device depends on the carrier mobility of the organic semiconductor material that constitutes this organic semiconductor layer, the emergence of an organic semiconductor material that gives high carrier mobility is desired.

[0003] As methods for manufacturing an organic semiconductor layer, a vacuum evaporation method in which an organic material is vaporized under high temperature and vacuum, a coating method in which an organic material is dissolved in an appropriate solvent and the solution is applied, etc. are generally known. Among these, in the coating method, since it can be carried out using printing technology without using high temperature and high vacuum conditions, it is expected to significantly reduce the manufacturing cost of device manufacturing, and it is an economically preferable process.

[0004] The organic semiconductor materials used in such coating methods preferably have a heat resistance of 130°C or higher and a solubility at room temperature of 0.1% by weight or more from the viewpoints of high carrier mobility and the process of device manufacturing. Furthermore, from the viewpoint of the device, it is preferably -5.4 eV or higher in the HOMO level in order to reduce the contact resistance with the electrode, and it is preferably close to the work function of the electrode.

[0005] Here, generally, it is known that low-molecular-weight semiconductors having a rod-shaped molecular major axis of a condensed ring system are likely to exhibit high carrier mobility because they have higher crystallinity than polymer semiconductors. However, when the number of condensed rings is 5 or less, there are problems of low melting point and low HOMO level, and when the number of condensed rings is 6 or more, there is a problem of low solubility. At present, there are few known low-molecular-weight organic semiconductor materials that combine high carrier mobility, high heat resistance, appropriate solubility, and a high HOMO level.

[0006] Currently, as low-molecular-weight materials, 2,7-dialkyl-substituted benzothieno[3,2-b]benzothiophene (condensed 4 rings) (see, for example, Patent Document 1 and Non-Patent Document 1), 6,6'-dialkyldinaphtho[2,3-b:2',3'-d]thiophene (condensed 6 rings) (see, for example, Patent Document 2), terphenylen compounds (see, for example, Patent Document 3), etc. have been proposed.

[0007] However, in the case of the dialkyl-substituted benzothieno[3,2-b]benzothiophene described in Patent Document 1 and Non-Patent Document 1, the HOMO level was -5.5 eV, and improvement of the HOMO level was required. In addition, there was a problem that transistor operation was lost when heated to 130 °C or higher.

[0008] The 6,6'-dialkyldinaphtho[2,3-b:2',3'-d]thiophene described in Patent Document 2 had a problem of low solubility of 0.08 g / L or less (0.01 wt% or less, toluene) at 60 °C.

[0009] Furthermore, the terphenylen compound described in Patent Document 3 had a problem of decreased solubility because it had a highly linear condensed ring skeleton composed of a benzene ring and a cyclobutene ring.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0011]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] The present invention has been made in view of the above problems, and an object thereof is to provide a novel coating-type organic semiconductor material having high carrier mobility, high heat resistance, appropriate solubility, and a high HOMO level.

Means for Solving the Problems

[0013] As a result of intensive studies to solve the above problems, the present inventors have found that a novel biphenylene compound gives high carrier mobility and becomes an organic semiconductor material having high heat resistance, appropriate solubility, and a HOMO level, and have completed the present invention.

[0014] That is, the present invention relates to a biphenylene compound represented by the following general formula (1-I) or (1-II), an organic semiconductor layer, and an organic thin film transistor using the same.

[0015]

Chemical Formula

[0016] (Here, A 1 ~A 4 each independently represents oxygen, sulfur, or selenium, and R 1 and R 3 each independently represents an aryl group having 4 to 20 carbon atoms, and R 2 and R 4Each independently represents an alkyl group having 1 to 5 carbon atoms, and m and n represent integers from 0 to 4.) The present invention will be described in detail below.

[0017] The biphenylene compound of the present invention is a compound represented by the above general formula (1-I) or (1-II).

[0018] A in the general formulas (1-I) and (1-II) 1 ~A 4 Each independently represents oxygen, sulfur, or selenium, and sulfur is preferred because of high mobility.

[0019] R in the general formulas (1-I) and (1-II) 1 and R 3 Each independently represents an aryl group having 4 to 20 carbon atoms.

[0020] The R 1 and R 3The aryl group having 4 to 20 carbon atoms in [reference] includes a heteroaryl group having 4 to 18 carbon atoms. Examples of the aryl group having 4 to 20 carbon atoms include a phenyl group; an alkyl-substituted phenyl group such as a p-tolyl group, a p-(n-ethyl)phenyl group, a p-(n-propyl)phenyl group, a p-(n-butyl)phenyl group, a p-(n-pentyl)phenyl group, a p-(n-hexyl)phenyl group, a p-(n-octyl)phenyl group, and a p-(2-ethylhexyl)phenyl group; a 2-condensed ring aryl group such as a 2,3-dihydro-1-benzofuran-5-yl group, a 2,3-dihydro-1-benzofuran-6-yl group, a 1,2-methylenedioxybenzene-4-yl group, a benzofuran-5-yl group, a 1-benzofuran-6-yl group, a 2-methyl-1-benzofuran-5-yl group, a 2-methyl-1-benzofuran-6-yl group, an indan-5-yl group, a 2-naphthyl group, a 1,2,3,4-tetrahydronaphthalen-6-yl group, a 1,4-benzodioxan-6-yl group, a 3,4-dihydro-2H-1-benzopyran-6-yl group, a 3,4-dihydro-2H-1-benzopyran-7-yl group, a 2,3-dihydro-1-benzothiophen-5-yl group, a 2,3-dihydro-1-benzothiophen-6-yl group, a 1-benzothiophen-5-yl group, and a 2-methyl-1-benzothiophen-5-yl group; a heteroaryl group such as a 2-furyl group, a 2-thienyl group; a 5-fluoro-2-furyl group, a 5-methyl-2-furyl group, a 5-ethyl-2-furyl group, a 5-(n-propyl)-2-furyl group, a 5-(n-butyl)-2-furyl group, a 5-(n-pentyl)-2-furyl group, a 5-(n-hexyl)-2-furyl group, a 5-(n-octyl)-2-furyl group, a 5-(2-ethylhexyl)-2-furyl group, a 4,5,6,7-tetrahydro-1-benzofuran-2-yl group, a 5-fluoro-2-thienyl group, a 5-methyl-2-thienyl group, a 5-ethyl-2-thienyl group, a 5-(n-propyl)-2-thienyl group, a 5-(n-butyl)-2-thienyl group, a 5-(n-pentyl)-2-thienyl group, a 5-(n-hexyl)-2-thienyl group, a 5-(n-octyl)-2-thienyl group, a 5-(2-ethylhexyl)-2-thienyl group, a 1-benzofuran-2-yl group, a 1-benzothiophen-2-yl group, and a 4,5,6,7-tetrahydro-1-benzothiophen-2-yl group can be mentioned.Among them, since it becomes a biphenylene compound showing particularly high mobility and high solubility, a phenyl group, p-tolyl group, p-(n-ethyl)phenyl group, p-(n-butyl)phenyl group, p-(n-hexyl)phenyl group, p-(n-octyl)phenyl group, 2,3-dihydro-1-benzofuran-5-yl group, 2,3-dihydro-1-benzofuran-6-yl group, 1,2-methylenedioxybenzene-4-yl group, indan-5-yl group, 2-naphthyl group, 1,2,3,4-tetrahydronaphthalene-6-yl group, 1,4-benzodioxane-6-yl group, 3,4-dihydro-2H-1-benzopyran-6-yl group, 3,4-dihydro-2H-1-benzopyran-7-yl group are preferable.

[0021] R in the general formulas (1-I) and (1-II) 2 and R 4 each independently represents an alkyl group having 1 to 5 carbon atoms.

[0022] The R 2 and R 4 Examples of the alkyl group having 1 to 5 carbon atoms in include linear, branched, or cyclic alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, 1,1-dimethylpropyl-1-yl group, cyclopropyl group, 2-methylcyclopropyl-1-yl group, cyclopropylmethyl group, cyclobutyl group, (2-methylcyclopropyl-1-yl)methyl group, 2-cyclopropyl-1-ethyl group, cyclobutylmethyl group, 3-methylcyclobutyl-1-yl group, cyclopentyl group, etc. Among them, since it becomes a biphenylene compound showing particularly high mobility and high melting point, a linear alkyl group having 2 to 4 carbon atoms and an alkyl group having a ring with 3 to 5 carbon atoms are preferable, and an ethyl group, n-propyl group, n-butyl group, cyclopropyl group, cyclopropylmethyl group, 2-cyclopropyl-1-ethyl group, cyclobutyl group, cyclobutylmethyl group are more preferable, and an ethyl group, n-propyl group, n-butyl group are particularly preferable.

[0023] In the general formulas (1-I) and (1-II), m and n represent integers from 0 to 4. For high mobility, m and n are preferably from 0 to 3, and more preferably 0 or 2.

[0024] Specific examples of the biphenylene compounds of the present invention include the following.

[0025]

Chemical formula

[0026]

Chemical formula

[0027]

Chemical formula

[0028]

Chemical formula

[0029]

Chemical formula

[0030]

Chemical formula

[0031]

Chemical formula

[0032] Preferably,

[0033]

Chemical formula

[0034]

Chemical formula

[0035] and particularly preferred examples thereof include the following.

[0036] [Chemical formula]

[0037] As a method for producing the biphenylene compound of the present invention, any production method can be used as long as it can produce the biphenylene compound.

[0038] As a method for producing the biphenylene compound of the present invention, for example, an unsubstituted compound in which two substituents of the biphenylene compound represented by the above general formula (1-I) or (1-II) are hydrogen is synthesized, and the two substituents are introduced step by step.

[0039] A in the general formula (1-I) 1 , A 2 is sulfur, and the biphenylene compound in which two substituents are hydrogen can be synthesized, for example, by the method described in JP 2018-174322.

[0040] A in the general formula (1-II) 1 , A 2 is sulfur, and the biphenylene compound (A) in which two substituents are hydrogen can be produced, for example, by a method passing through the following steps A0 to E0. (Step A0); A step of producing 2,2'-dibromo-4,5'-difluorobiphenyl from 1-bromo-4-fluorophenyl-2-zinc chloride derived from 1-bromo-4-fluoro-2-iodobenzene and 2-bromo-4-fluoro-1-iodobenzene in the presence of a palladium catalyst. (Step B0); A step of producing 2,6-difluorobiphenylene by converting 2,2'-dibromo-4,5'-difluorobiphenyl obtained in Step A0 into a dilithium salt with n-butyllithium and subjecting it to intramolecular cyclization with copper(II) chloride. (Step C0); A step of producing 2,6-difluoro-1,5-diiodobiphenylene by treating 2,6-difluorobiphenylene obtained in Step B0 with lithium 2,2,6,6-tetramethylpiperidide (hereinafter abbreviated as LTMP) and iodination. (Step D0); A step of producing 1,5-bis(trimethylsilylethynyl)-2,6-difluorobiphenylene by Sonogashira coupling of 2,6-difluoro-1,5-diiodobiphenylene obtained in Step C0 and trimethylsilylacetylene in the presence of a palladium and copper catalyst. (Step E0); A step of producing biphenylene compound (A) by reacting 1,5-bis(trimethylsilyl)-2,6-difluorobiphenylene obtained in Step D0 with sodium sulfide.

[0041] Details of each step are shown below.

[0042] The Step A0 is a step of producing 2,2'-dibromo-4,5'-difluorobiphenylene by cross-coupling of 1-bromo-4-fluorophenyl-2-zinc chloride derived from 1-bromo-4-fluoro-2-iodobenzene and 2-bromo-4-fluoro-1-iodobenzene in the presence of a palladium catalyst.

[0043] 1-Bromo-4-fluorophenyl-2-zinc chloride can be prepared, for example, by using an organometallic reagent such as ethylmagnesium chloride or isopropylmagnesium bromide to exchange the iodine of 1-bromo-4-fluoro-2-iodobenzene for a magnesium halide (preparation of 1-bromo-4-fluorophenyl-2-magnesium halide) and then performing a metal exchange with zinc chloride.

[0044] As conditions for preparing 1-bromo-4-fluorophenyl-2-magnesium halide, for example, it can be carried out within a temperature range of -80°C to 20°C in a solvent such as tetrahydrofuran (hereinafter referred to as THF) or diethyl ether. 1-Bromo-4-fluorophenyl-2-zinc chloride can be prepared by reacting zinc chloride with a solution of the magnesium halide (1-bromo-4-fluorophenyl-2-magnesium halide). Zinc chloride may be in its original state or may be a THF or diethyl ether solution. The reaction temperature between the magnesium salt and zinc chloride can be carried out within a range of -80°C to 30°C.

[0045] Examples of the palladium catalyst in the A0 step include tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, etc., and the reaction temperature can be in the range of 20°C to 80°C.

[0046] The B0 step is a step of producing 2,6-difluorobiphenylene by forming a dilithium salt with 2 equivalents or more of n-butyllithium or tert-butyllithium with respect to 1 equivalent of 2,2'-dibromo-4,5'-difluorobiphenyl obtained in the A0 step and performing intramolecular cyclization with copper(II) chloride.

[0047] As conditions for preparing the dilithium salt, for example, 2 to 3 equivalents of n-butyllithium or tert-butyllithium can be used with respect to 1 equivalent of the 2,2'-dibromo-4,5'-difluorobiphenyl, and it can be carried out within a temperature range of -80°C to 20°C in a solvent such as THF or diethyl ether.

[0048] Copper(II) chloride is used in an amount of 1 to 3 equivalents with respect to 1 equivalent of the dilithium salt, and the intramolecular cyclization reaction can be carried out within a temperature range of -80°C to 30°C.

[0049] The C0 process is a process for producing 2,6-difluoro-1,5-diiodobiphenylene by reacting 2,6-difluorobiphenylene obtained in the B0 process with LTMP to generate dilithium salts at the 1-position and 5-position and then iodinating them.

[0050] As the conditions for reacting with LTMP, for example, 2 to 4 equivalents of LTMP can be used with respect to 1 equivalent of 2,6-difluorobiphenylene, and the reaction can be carried out in a solvent such as THF or diethyl ether within a temperature range of -80°C to 20°C. The reaction of the dilithium salt with the iodinating agent can be carried out within a range of -80°C to 30°C.

[0051] The D0 process is a process for producing 1,5-bis(trimethylsilylethynyl)-2,6-difluorobiphenylene by the Sonogashira coupling of 2,6-difluoro-1,5-diiodobiphenylene obtained in the C0 process with trimethylsilylacetylene in the presence of a palladium catalyst and a copper catalyst.

[0052] Examples of the palladium catalyst at that time include tetrakis(triphenylphosphine)palladium, dichlorobis(triphenylphosphine)palladium, etc., and examples of the copper catalyst include copper(I) iodide, copper(I) bromide, copper(I) chloride, etc. Also, in the Sonogashira coupling, it can be carried out in a solvent such as triethylamine, diisopropylamine, diisopropylethylamine, piperidine, pyridine, etc. within a temperature range of 20°C to 80°C. In addition, solvents such as toluene and THF may be added.

[0053] The E0 process is a process for producing a biphenylene compound (A) by the reaction of 1,5-bis(trimethylsilylethynyl)-2,6-difluorobiphenylene obtained in the D0 process with sodium sulfide.

[0054] The reaction can be carried out, for example, in a solvent such as dimethyl sulfoxide, N,N-dimethylformamide (hereinafter abbreviated as DMF), N-methylpyrrolidone (hereinafter abbreviated as NMP), etc. within a temperature range of 30 to 200°C.

[0055] And a more preferable and specific production method is shown in the following reaction scheme.

[0056]

Chemical formula

[0057] The method for producing the biphenylene compound of the present invention can be synthesized, for example, by a method of stepwise introducing two substituents into the unsubstituted product obtained above.

[0058] The method of stepwise introducing two substituents is, for example, lithiating the 2-position of one thiophene ring with n-butyllithium, reacting with a brominating agent to form a monobromo product, and then introducing one substituent by Pd coupling with a zinc reagent having a substituent, and further introducing another substituent at the 7-position of the thiophene ring by the same method.

[0059] The production method of the general formula (1-I) of the present invention can be produced, for example, by a method passing through the following steps A1 to D1. (Step A1); A step of producing 2-bromodithieno[3,2-b:2',3'-d]biphenylene by monolithiating an unsubstituted product with n-butyllithium and reacting with 1,2-dibromo-1,1,2,2-tetrachloroethane. (Step B1); R 1 -(CH2) m ZnCl prepared from MgBr and ZnCl2 and 2-bromodithieno[3,2-b:2',3'-d]biphenylene obtained in step A1 are subjected to Pd coupling to produce 2-[R 1 -(CH2) m dithieno[3,2-b:2',3'-d]biphenylene. 1 -(CH2) m dithieno[3,2-b:2',3'-d]biphenylene. (Step C1); 2-[R 1 -(CH2) m dithieno[3,2-b:2',3'-d]biphenylene obtained in step B1 is monolithiated with n-butyllithium and reacted with 1,2-dibromo-1,1,2,2-tetrachloroethane to obtain 2-[R 1-(CH2) m A step of producing 7-bromodithieno[3,2-b:2',3'-d]biphenylene. (Step D1); R 2 ZnCl prepared from MgX (X is Cl or Br) and ZnCl2 and 2-[R 2 obtained in Step C1 are subjected to Pd coupling to produce biphenylene compound (1-I). 1 -(CH2) m A step of producing 7-bromodithieno[3,2-b:2',3'-d]biphenylene.

[0060] Details of each step are shown below.

[0061] This Step A1 is a step of producing 2-bromodithieno[3,2-b:2',3'-d]biphenylene by converting an unsubstituted compound into a monolithium salt with n-butyllithium or tert-butyllithium and reacting it with 1,2-dibromo-1,1,2,2-tetrachloroethane (bromination).

[0062] As conditions for preparing the monolithium salt, for example, 0.9 to 1.2 equivalents of n-butyllithium or tert-butyllithium with respect to 1 equivalent of 1,2-dibromo-1,1,2,2-tetrachloroethane can be used and the reaction can be carried out in a solvent such as THF or diethyl ether within a temperature range of -80°C to 20°C.

[0063] 1,2-Dibromo-1,1,2,2-tetrachloroethane is used in an amount of 0.9 to 1.2 equivalents with respect to 1 equivalent of the monolithium salt, and the intramolecular cyclization reaction can be carried out within a temperature range of -80°C to 30°C.

[0064] This Step B1 is a step of producing 2-[R 1 -(CH2) m dithieno[3,2-b:2',3'-d]biphenylene by subjecting ZnCl prepared from MgBr and ZnCl2 and 2-bromodithieno[3,2-b:2',3'-d]biphenylene obtained in Step A1 to Pd cross-coupling. 1 -(CH2) m ZnCl and 2-bromodithieno[3,2-b:2',3'-d]biphenylene obtained in Step A1 to Pd cross-coupling. 1 -(CH2) m dithieno[3,2-b:2',3'-d]biphenylene.

[0065] R 1 -(CH2) m MgBr is R 1 -(CH2) m prepared from Br and Mg metal in THF and can be converted to R 1 -(CH2) m -ZnCl by metal exchange with zinc chloride.

[0066] R 1 -(CH2) m As the conditions for preparing R-(CH2)-ZnCl, for example, it can be carried out within the temperature range of -10°C to 30°C in THF. The usage amount of the zinc compound is 1.5 to 2.8 equivalents relative to 1 equivalent of 2-bromodithienobiphenylene.

[0067] Examples of the Pd catalyst in the B1 step include [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) [hereinafter abbreviated as Pd(dppf)Cl2], tetrakis(triphenylphosphine)palladium(0), dichlorobis(triphenylphosphine)palladium(II), tris(dibenzylideneacetone)dipalladium(0), etc. The usage amount of the Pd catalyst is 0.01 to 0.07 equivalents relative to 1 equivalent of 2-bromodithienobiphenylene, and the reaction temperature can be in the range of 20°C to 80°C.

[0068] The C1 step can produce 2-[R-(CH2)]-7-bromodithienobiphenylene using the reagents and reaction conditions, etc. of the above A1 step, except using 2-[R-(CH2)]dithienobiphenylene. 1 -(CH2) m dithienobiphenylene. 1 (CH2) m -7-bromodithienobiphenylene.

[0069] The D1 step can produce the biphenylene compound (1-I) using the reagents and reaction conditions, etc. of the above B1 step, except using 2-[R-(CH2)]-7-bromodithienobiphenylene. 1 -(CH2) m -7-bromodithienobiphenylene.

[0070] The preferred and more specific manufacturing method is shown in the following reaction scheme.

[0071]

Chemical formula

[0072] (Here, R 1 represents an aryl group having 4 to 20 carbon atoms, R 2 represents an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 0 to 4.) In addition, by swapping the B1 step and the D1 step, the R 2 group can be introduced first and the R 1 -(CH2) m group can be introduced later.

[0073] The manufacturing method of the general formula (1-II) of the present invention can be manufactured, for example, by a method passing through the following steps A2 to D2. (Step A2); A step of producing 2-bromodithieno[3,2-b:2',3'-d]biphenylene by monolithiating the unsubstituted compound (A) with n-butyllithium and reacting it with 1,2-dibromo-1,1,2,2-tetrachloroethane. (Step B2); A step of producing 2-[R 4 dithieno[3,2-b:2',3'-d]biphenylene by Pd coupling of R 4 ZnCl prepared from MgX (X is Cl or Br) and ZnCl2 and 2-bromodithieno[3,2-b:2',3'-d]biphenylene obtained in Step A2. 4 dithieno[3,2-b:2',3'-d]biphenylene. (Step C2); A step of producing 2-[R 4 -7-bromodithieno[3,2-b:2',3'-d]biphenylene by monolithiating 2-[R 4 dithieno[3,2-b:2',3'-d]biphenylene obtained in Step B2 with n-butyllithium and reacting it with 1,2-dibromo-1,1,2,2-tetrachloroethane. (Step D2); R 3 -(CH2) n MgBr (prepared in THF from R 3 -(CH2) n Br and Mg metal) and R 3-(CH2) n 2-[R obtained by ZnCl and the C2 step 4 -7-bromodithienobiphenylene is subjected to Pd coupling to produce a biphenylene compound (1-II).

[0074] The details of each step can use the same reagents and reaction conditions as those described for the above A1 to D1 steps to produce the biphenylene compound (1-II).

[0075] And a more specific and preferred production method is shown in the following reaction scheme.

[0076] [Chemical formula]

[0077] (Here, R 3 represents an aryl group having 4 to 20 carbon atoms, R 4 represents an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 4.) Note that by swapping the B2 step and the D2 step, the R 3 -(CH2) n group can be introduced first and the R 4 group can be introduced later.

[0078] Furthermore, the produced biphenylene compound (1-I) or (1-II) can be purified using a separating agent by subjecting it to column chromatography or the like. Examples of the separating agent in this case include silica gel, activated alumina, and examples of the solvent include hexane, heptane, toluene, dichloromethane, chloroform, etc.

[0079] The produced biphenylene compound can be decolorized and purified in solution by subjecting it to activated carbon, zeolite, activated alumina, etc. Examples of the solvent in this case include hexane, heptane, toluene, dichloromethane, chloroform, etc.

[0080] In addition, the produced biphenylene compound (1-I) or (1-II) may be further purified by recrystallization, and the purity can be improved by increasing the number of recrystallization times. From the viewpoints of high purity and high yield, the number of recrystallization times is preferably 2 to 5 times. The purity can be improved by increasing the number of recrystallization times. Examples of the solvent used for recrystallization include hexane, heptane, octane, toluene, xylene, chloroform, chlorobenzene, dichlorobenzene, etc., and a mixture of these in any ratio may also be used.

[0081] In recrystallization, a solution of the biphenylene compound is prepared by heating (the concentration of the solution at that time is preferably in the range of 0.01 to 10.0% by weight, more preferably in the range of 0.05 to 5.0% by weight in order to efficiently remove impurities), and crystals of the biphenylene compound are precipitated and isolated by cooling the solution. The final cooling temperature at the time of isolation is preferably in the range of -20°C to 40°C in order to improve the purity and recovery rate. When measuring the purity, it is possible to analyze by liquid chromatography.

[0082] The biphenylene compound of the present invention can be made into a solution for forming an organic semiconductor layer containing the biphenylene compound by dissolving it in a solvent. Any solvent can be used as long as it can dissolve the biphenylene compound. When forming the organic semiconductor layer, since the drying rate of the solvent can be made suitable, an organic solvent having a boiling point of 100°C or higher at normal pressure is preferred.

[0083] The solvent that can be used in the present invention is not particularly limited. For example, aromatic hydrocarbons such as toluene, mesitylene, o-xylene, isopropylbenzene, pentylbenzene, cyclohexylbenzene, 1,2,4-trimethylbenzene, tetralin, indane; aromatic ethers such as anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, ethyl phenyl ether, butyl phenyl ether, 1,2-methylenedioxybenzene, 1,2-ethylenedioxybenzene; aromatic halogen compounds such as chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene; heteroaromatics such as thiophene, 3-chlorothiophene, 2-chlorothiophene, 3-methylthiophene, 2-methylthiophene, benzothiophene, 2-methylbenzothiophene, 2,3-dihydrobenzothiophene, furan, 3-methylfuran, 2-methylfuran, 2,5-dimethylfuran, benzofuran, 2-methylbenzofuran, 2,3-dihydrobenzofuran, thiazole, oxazole, benzothiazole, benzoxazole, pyridine; saturated hydrocarbons such as hexane, cyclohexane, heptane, octane, nonane, decane, p-menthane, undecane, dodecane, decalin; glycols such as 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, diethylene glycol monobutyl ether acetate;Esters such as dimethyl phthalate, diethyl phthalate, dimethyl terephthalate, phenyl acetate, cyclohexanol acetate, 3-methoxybutyl acetate, tetrahydrofurfuryl acetate, tetrahydrofurfuryl propionate, γ-butyrolactone; cyclic ethers such as THF and 2-methoxymethyltetrahydrofuran can be mentioned. Among them, since it has a suitable drying rate, preferably toluene, o-xylene, mesitylene, 1,2,4-trimethylbenzene, tetralin, indane, octane, nonane, decane, p-menthane, anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, ethyl phenyl ether, butyl phenyl ether, 1,2-methylenedioxybenzene, 1,2-ethylenedioxybenzene, 1,2-dichlorobenzene, 3-methylthiophene, benzothiazole, and more preferably toluene, o-xylene, mesitylene, tetralin, indane, octane, nonane, decane, anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene.;

[0084] In addition, the solvent used in the present invention can be used alone as one kind of solvent, or two or more kinds of solvents having different properties such as boiling point, polarity, solubility parameter, etc. can be mixed and used.

[0085] As the temperature for mixing and dissolving the aromatic compound represented by the general formula (1) in a solvent, for the purpose of promoting dissolution, it is preferably carried out in a temperature range of 0 to 80°C, and more preferably in a temperature range of 10 to 60°C.

[0086] Also, the time for dissolving and mixing the biphenylene compound represented by the general formula (1-I) or (1-II) in an organic solvent is preferably 1 minute to 1 hour for obtaining a uniform solution.

[0087] In the present invention, when the concentration of the biphenylene compound represented by the general formula (1-I) or (1-II) in the solution for forming the organic semiconductor layer of the present invention is in the range of 0.1 to 10.0% by weight, it becomes easy to handle and is excellent in efficiency when forming the organic semiconductor layer. Further, when the viscosity of the solution for forming the organic semiconductor layer is in the range of 0.3 to 10 mPa·s, more suitable coatability is exhibited.

[0088] Since the biphenylene compound itself has appropriate aggregability, the solution can be prepared at a relatively low temperature. Also, since it has oxidation resistance, it can be suitably applied to the production of organic thin films by a coating method. That is, since it is not necessary to remove air from the atmosphere, the coating process can be simplified. Further, the solution can contain, for example, polystyrene, poly(α-methylstyrene), poly(4-methylstyrene), poly(1-vinylnaphthalene), poly(2-vinylnaphthalene), poly(styrene-block-ethylene propylene-block-styrene), poly(styrene-block-butadiene-block-styrene), poly(styrene-block-isoprene-block-styrene), poly(vinyltoluene), poly(styrene-co-2,4-dimethylstyrene), poly(chlorostyrene), poly(styrene-co-α-methylstyrene), poly(styrene-co-butadiene), polycyclopentane, polyalkylnorbornene, polycyclohexane-ethylene copolymer, cycloolefin copolymers such as TOPAS (registered trademark) and Apel (registered trademark), polyphenylene ether, polycarbonate, polycarbazole, polytriarylamine, poly(9,9-dioctylfluorene-co-dimethyltriarylamine), poly(N-vinylcarbazole), polymethyl methacrylate, poly(styrene-co-methyl methacrylate), polyethyl methacrylate, poly(n-propyl methacrylate), poly(isopropyl methacrylate), poly(n-butyl methacrylate), polyphenyl methacrylate, poly(methyl acrylate), poly(ethyl acrylate), poly(n-propyl acrylate), etc. Preferably, polymers such as polystyrene, poly(α-methylstyrene), poly(ethylene-co-norbornene), and polymethyl methacrylate can be present as a polymer binder. The concentration of these polymer binders is preferably 0.001 to 10.0% by weight for an appropriate solution viscosity.

[0089] Since the glass transition temperature (Tg) of the polymer binder is suitable for the process temperature during the manufacture of electronic devices, it is preferably 105°C or higher, more preferably 120°C or higher, and particularly preferably 150°C or higher.

[0090] In addition, the molecular weight of the polymer in the polymer binder is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and particularly preferably 20,000 to 350,000 because it is suitable for obtaining an organic thin film transistor with a higher carrier mobility. In the present invention, the molecular weight of the polymer refers to the weight average molecular weight (Mw) in terms of polystyrene.

[0091] The polymer in the polymer binder has the effect as a general polymer binder and improves the film-forming property of the obtained organic semiconductor layer. An insulating polymer and a semiconducting polymer can also be used.

[0092] The weight ratio of the biphenylene compound represented by the general formula (1-I) or (1-II) to the polymer binder can be used in the range of 2:1 to 200:1. However, for a good semiconductor layer and high mobility, 3:1 to 100:1 is preferable, and 4:1 to 50:1 is more preferable.

[0093] Specific examples of the polymer that can be used as the polymer binder in the present invention include, in addition to the polymers mentioned above, for example, polar cyclic polyolefins, polysulfones, acrylonitrile-styrene copolymers, methyl methacrylate-styrene copolymers, and the like.

[0094] More specifically, the polar cyclic polyolefins are more preferably polymers represented by the following general formula (2).

[0095]

Chemical formula

[0096] (Here, R 5 ~R 7Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, an aryloxycarbonyl group having 7 to 20 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a hydroxyl group, an amino group, or an alkylamino group having 1 to 20 carbon atoms, and X represents a halogen atom, an alkyloxycarbonyl group having 2 to 20 carbon atoms, an aryloxycarbonyl group having 7 to 20 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a hydroxyl group, an amino group, or an alkylamino group having 1 to 20 carbon atoms. p represents an integer of 20 to 5,000, and q and r each independently represent an integer of 0 to 2. A bond consisting of a solid line and a dotted line represents a single bond or a double bond.) R in General Formula (2) 5 ~R 7 Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkyloxycarbonyl group having 2 to 20 carbon atoms, an aryloxycarbonyl group having 7 to 20 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a hydroxyl group, an amino group, or an alkylamino group having 1 to 20 carbon atoms. For high heat resistance, a hydrogen atom or an alkyl group having 1 to 20 carbon atoms is preferred.

[0097] R 5 ~R 7 Examples of the halogen atom in R~R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0098] R 5 ~R 7The alkyl group having 1 to 20 carbon atoms herein includes, for example, linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, sec-butyl group, n-pentyl group and the like. The aryl group having 6 to 20 carbon atoms includes, for example, phenyl group, p-tolyl group, p-(n-hexyl)phenyl group, p-(n-octyl)phenyl group, p-(2-ethylhexyl)phenyl group and the like. The alkyloxycarbonyl group having 2 to 20 carbon atoms includes, for example, methyloxycarbonyl group, ethyloxycarbonyl group, n-propyloxycarbonyl group and the like. The aryloxycarbonyl group having 7 to 20 carbon atoms includes, for example, phenoxycarbonyl group, 4-methylphenoxycarbonyl group and the like. The alkoxy group having 1 to 20 carbon atoms includes, for example, methoxy group, ethoxy group, n-propoxy group and the like. The aryloxy group having 6 to 20 carbon atoms includes, for example, phenoxy group, 4-methylphenoxy and the like. The alkylamino group having 1 to 20 carbon atoms includes, for example, methylamino group, ethylamino group, n-propylamino group and the like. And among them, due to high heat resistance, the substituent R 5 is preferably a methyl group, an ethyl group or an n-propyl group, and the substituents R 6 and R 7 are preferably hydrogen atoms.

[0099] X in the general formula (2) represents a halogen atom, an alkyloxycarbonyl group having 2 to 20 carbon atoms, an aryloxycarbonyl group having 7 to 20 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a hydroxyl group, an amino group, or an alkylamino group having 1 to 20 carbon atoms.

[0100] Examples of the halogen atom in the substituent X include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

[0101] The alkyloxycarbonyl group having 2 to 20 carbon atoms in the substituent X includes, for example, methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, n-butoxycarbonyl group, n-hexyloxycarbonyl group, cyclohexyloxycarbonyl group, etc. The aryloxycarbonyl group having 7 to 20 carbon atoms includes, for example, phenoxycarbonyl group, 4-methylphenoxycarbonyl group, 2,4-dimethylphenoxycarbonyl group, 4-ethylphenoxycarbonyl group, etc. The alkoxy group having 1 to 20 carbon atoms includes, for example, methoxy group, ethoxy group, etc. The aryloxy group having 6 to 20 carbon atoms includes, for example, phenoxy group, 4-methylphenoxy, etc. The alkylamino group having 1 to 20 carbon atoms includes, for example, methylamino group, ethylamino group, n-propylamino group, etc. Due to high solubility and high heat resistance, it is preferably an alkyloxycarbonyl group having 2 to 20 carbon atoms.

[0102] p represents an integer from 20 to 5,000, and is preferably from 40 to 2,000 because it is suitable for obtaining an organic thin film transistor with a larger carrier mobility. q represents an integer from 0 to 2, and is preferably 1. r represents an integer from 0 to 2, and is preferably 0 or 1. More preferably, it is 0.

[0103] The bond consisting of a solid line and a dotted line represents a single bond or a double bond, and is preferably a single bond for thermal stability.

[0104] The polysulfones used as the polymer binder in the present invention are not particularly limited as long as they have a polysulfone structure. More specifically, polysulfones represented by the following polysulfone 1 to 5 are included.

[0105]

Chemical formula

[0106] (Here, the substituent R 8 ~R 11Each independently represents an alkyl group having 1 to 20 carbon atoms, and s represents an integer of 10 to 20,000.) Substituent R 8 ~R 11 The alkyl group having 1 to 20 carbon atoms in ~R includes, for example, linear or branched alkyl groups such as methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, n-hexyl group, isohexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-octadecyl group, 2-ethylhexyl group, 3-ethylheptyl group, 3-ethyldecyl group, 2-hexyldecyl group, etc.

[0107] s represents an integer of 10 to 20,000, preferably an integer of 10 to 10,000.

[0108] The acrylonitrile-styrene copolymer used as the polymer binder in the present invention is a copolymer of acrylonitrile and styrene in any ratio, shows good electrical properties, and has improved reliability such as a smaller change in the threshold voltage when subjected to bias stress. Therefore, the weight ratio of acrylonitrile to styrene is preferably 10:90 to 50:50, and more preferably 20:80 to 40:60.

[0109] The methyl methacrylate-styrene copolymer used as the polymer binder in the present invention is a copolymer of methyl methacrylate and styrene in any ratio, shows good electrical properties, and has improved reliability such as a smaller change in the threshold voltage when subjected to bias stress. Therefore, the molar ratio of methyl methacrylate to styrene is preferably 1:99 to 90:10, and more preferably 1:99 to 70:30.

[0110] As the polymer used as the polymer binder in the present invention, a polymer whose surface energy has been adjusted with a surface treatment agent can be used. As the surface treatment agent, a silane coupling agent can be used, and specific examples thereof include, for example, 1,1,1,3,3,3 - hexamethyldisilazane, phenyltrimethoxysilane, octyltrichlorosilane, β - phenethyltrichlorosilane, β - phenethyltrimethoxysilane, and the like. Note that the polymer can be used alone as one type of polymer or as a mixture of two or more types of polymers. Furthermore, it is also possible to use a mixture of polymers with different molecular weights.

[0111] In the present invention, an organic semiconductor layer can be formed using a solution for forming an organic semiconductor layer.

[0112] As a coating method when forming an organic semiconductor layer using the solution for forming an organic semiconductor layer of the present invention, there is no particular limitation as long as it is a method capable of forming an organic semiconductor layer. For example, simple coating methods such as spin coating, drop casting, dip coating, cast coating, etc.; printing methods such as dispenser, inkjet, slit coating, blade coating, flexographic printing, screen printing, gravure printing, offset printing, etc. can be mentioned. Among them, since it is possible to easily and efficiently form an organic semiconductor layer, spin coating, drop casting, and inkjet are preferable.

[0113] After applying the solution for forming an organic semiconductor layer of the present invention, by drying and removing the solvent, it is possible to form an organic semiconductor layer using the solution for forming an organic semiconductor layer.

[0114] When drying and removing the solvent from the applied organic semiconductor layer, there are no particular limitations on the drying conditions. For example, it is possible to dry and remove the solvent under normal pressure or reduced pressure.

[0115] There is no particular limitation on the temperature for drying and removing the organic solvent from the applied organic semiconductor layer, but the organic solvent can be efficiently dried and removed from the applied organic semiconductor layer, and since it is possible to form the organic semiconductor layer, it is preferably carried out in the temperature range of 10 to 150°C.

[0116] When drying and removing the organic solvent from the applied organic semiconductor layer, it is possible to control the crystal growth of the aromatic compound represented by the general formula (1) by adjusting the vaporization rate of the organic solvent to be removed.

[0117] There is no limitation on the film thickness of the organic semiconductor layer formed by the solution for forming an organic semiconductor layer of the present invention, and since good carrier mobility can be obtained, it is preferably in the range of 1 nm to 1 μm, and more preferably in the range of 10 nm to 300 nm.

[0118] Further, the obtained organic semiconductor layer may be annealed at 40 to 180°C after forming the organic semiconductor layer.

[0119] The organic semiconductor layer formed from the solution for forming an organic semiconductor layer of the present invention can be used as an organic semiconductor device including the organic semiconductor layer, particularly an organic thin film transistor including the organic semiconductor layer.

[0120] An organic thin film transistor can be obtained by laminating an organic semiconductor layer provided with a source electrode and a drain electrode and a gate electrode on a substrate via an insulating layer, and by using the organic semiconductor layer formed by the solution for forming an organic semiconductor layer of the present invention for the organic semiconductor layer, it is possible to obtain an organic thin film transistor exhibiting excellent semiconductor and electrical characteristics.

[0121] Fig. 1 shows the structure according to the cross-sectional shape of a general organic thin-film transistor. Here, (A) is a bottom-gate - top-contact type, (B) is a bottom-gate - bottom-contact type, (C) is a top-gate - top-contact type, and (D) is a top-gate - bottom-contact type organic thin-film transistor. 1 represents an organic semiconductor layer, 2 represents a substrate, 3 represents a gate electrode, 4 represents a gate insulating layer, 5 represents a source electrode, and 6 represents a drain electrode. The organic semiconductor layer formed from the solution for forming an organic semiconductor layer of the present invention can be applied to any organic thin-film transistor.

[0122] The substrate according to the present invention is not particularly limited. For example, plastic substrates such as polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polymethyl acrylate, polyethylene, polypropylene, polystyrene, cyclic polyolefin, fluorinated cyclic polyolefin, polyimide, polycarbonate, polyvinyl phenol, polyvinyl alcohol, poly(diisopropyl fumarate), poly(diethyl fumarate), poly(diisopropyl maleate), polyether sulfone, polyphenylene sulfide, and cellulose triacetate; inorganic material substrates such as glass, quartz, aluminum oxide, silicon, highly doped silicon, silicon oxide, tantalum oxide, tantalum pentoxide, and indium tin oxide; and metal substrates such as gold, copper, chromium, titanium, and aluminum can be mentioned. When highly doped silicon is used as the substrate, the substrate can also serve as the gate electrode.

[0123] The gate electrode according to the present invention is not particularly limited. For example, inorganic materials such as aluminum, gold, silver, copper, highly doped silicon, tin oxide, indium oxide, indium tin oxide, chromium, titanium, tantalum, graphene, and carbon nanotube; and organic materials such as doped conductive polymers (e.g., PEDOT-PSS) can be mentioned.

[0124] In addition, the above inorganic material can also be used as a metal nanoparticle ink without any problem. In this case, for appropriate dispersibility, the solvent is a polar solvent such as water, methanol, ethanol, 2-propanol, 1-butanol, 2-butanol; an aliphatic hydrocarbon solvent having 6 to 14 carbon atoms such as hexane, heptane, octane, decane, dodecane, tetradecane; an aromatic hydrocarbon solvent having 7 to 14 carbon atoms such as toluene, xylene, mesitylene, ethylbenzene, pentylbenzene, hexylbenzene, octylbenzene, cyclohexylbenzene, tetralin, indane, anisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,2-dimethylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole. After applying the nanoparticle ink, it is preferably annealed in a temperature range of 80°C to 200°C to improve conductivity.

[0125] The gate insulating layer according to the present invention is not particularly limited. For example, inorganic materials such as silicon oxide, silicon nitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum dioxide, tantalum pentoxide, indium tin oxide, tin oxide, vanadium oxide, barium titanate, bismuth titanate; polystyrene, poly(α-methylstyrene), poly(4-methylstyrene), poly(1-vinylnaphthalene), poly(2-vinylnaphthalene), poly(styrene-block-ethylene propylene-block-styrene), poly(styrene-chalcone), crosslinked poly(styrene-chalcone), polymethyl methacrylate, polymethyl acrylate, polyimide, polyamic acid polycarbonate, polyvinylphenol, polyvinyl alcohol, poly(diisopropyl fumarate), poly(diethyl fumarate), polyethylene terephthalate, polyethylene naphthalate, ethyl polycinnamate, methyl polycinnamate, ethyl polycrotonate, polyethersulfone, polypropylene-co-1-butene, polyisobutylene, polypropylene, polycyclopentane, polycyclohexane, polycyclohexane-ethylene copolymer, polyalkyl norbornene, cycloolefin copolymers such as TOPAS (registered trademark) and Apel (registered trademark), polyfluorinated cyclopentane, polyfluorinated cyclohexane, polyfluorinated cyclohexane-ethylene copolymer, BCB resin (trade name: Cyclotene, manufactured by Dow Chemical Company), polymers of parylene (registered trademark) such as Cytop (registered trademark), Teflon (registered trademark), parylene C, etc. It is preferable that it is a polymer insulating material (polymer gate insulating layer) to which a coating method can be applied because the manufacturing method is simple.

[0126] The solvent used to dissolve the polymer insulating material is not particularly limited. For example, aliphatic hydrocarbon solvents having 6 to 14 carbon atoms such as hexane, heptane, octane, decane, p-menthane, dodecane, tetradecane; aromatic hydrocarbons such as toluene, mesitylene, o-xylene, isopropylbenzene, pentylbenzene, cyclohexylbenzene, 1,2,4-trimethylbenzene, tetralin, indane; aromatic ethers such as anisole, 2-methylanisole, 3-methylanisole, 2,3-dimethylanisole, 3,4-dimethylanisole, 2,6-dimethylanisole, 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, 1,4-dimethoxybenzene, ethyl phenyl ether, butyl phenyl ether, 1,2-methylenedioxybenzene, 1,2-ethylenedioxybenzene; ether solvents such as THF, 1,2-dimethoxyethane, dioxane; alcohol solvents such as ethanol, isopropyl alcohol, 1-butanol, 2-butanol, 2-ethylhexanol, tetrahydrofurfuryl alcohol; ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, diisopropyl ketone, acetophenone; ester solvents such as ethyl acetate, γ-butyrolactone, cyclohexanol acetate, 3-methoxybutyl acetate, tetrahydrofurfuryl acetate, tetrahydrofurfuryl propionate; amide solvents such as DMF, NMP; glycol solvents such as 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, 1,6-hexanediol diacetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate; fluorinated solvents such as perfluorohexane, perfluorooctane, 2-(pentafluoroethyl)hexane, 3-(pentafluoroethyl)heptane, etc.

[0127] The concentration of the polymer insulating material is, for example, 0.1 to 10.0% by weight at a temperature of 20 to 40°C. There is no limitation on the film thickness of the insulating layer obtained at this concentration, and from the viewpoint of insulation resistance, it is preferably 100 nm to 1 μm, more preferably 150 nm to 900 nm.

[0128] And the surfaces of these gate insulating layers can also be used after being modified with silanes such as octadecyltrichlorosilane, decyltrichlorosilane, decyltrimethoxysilane, octyltrichlorosilane, octadecyltrimethoxysilane, β-phenethyltrichlorosilane, β-phenethyltrimethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane; phosphonic acids such as octadecylphosphonic acid, decylphosphonic acid, octylphosphonic acid; silylamines such as hexamethyldisilazane. Generally, by performing surface treatment on the gate insulating layer, favorable results such as an increase in the crystal grain size and improvement in molecular orientation of the organic semiconductor material, an improvement in carrier mobility, an on / off current ratio, and a decrease in the threshold voltage can be obtained.

[0129] There is no particular limitation on the materials for the source electrode and drain electrode of the organic thin film transistor of the present invention, and the same materials as those for the gate electrode can be used, which may be the same as or different from the materials for the gate electrode, and different materials may be laminated. Further, in order to increase the injection efficiency of carriers, surface treatment can also be performed on these electrode materials. Examples of the surface treatment agent used for surface treatment include benzenethiol, pentafluorobenzenethiol, 4-fluorobenzenethiol, 4-methoxybenzenethiol, and the like.

[0130] Due to the fast operability, the carrier mobility of the organic thin film transistor of the present invention is preferably 0.20 cm 2 / V·sec or more. Also, due to the high switching characteristics, the on / off current ratio is preferably 1.0×10 6 or more.

[0131] The organic thin film transistor of the present invention can be used in applications of the organic semiconductor layer of transistors such as electronic paper, organic EL display, liquid crystal display, IC tag (RFID tag), pressure sensor, biosensor, etc.; organic EL display materials; organic semiconductor laser materials; organic thin film solar cell materials; photonic crystal materials and other electronic materials. Since the biphenylene compound represented by the general formula (1-I) or (1-II) forms a crystalline thin film, it is preferably used as the semiconductor layer of the organic thin film transistor.

Effects of the Invention

[0132] The novel biphenylene compound of the present invention has high carrier mobility, high heat resistance, appropriate solubility and HOMO level. Therefore, it is possible to provide an organic thin film transistor that exhibits excellent semiconductor characteristics by coating, and its effect is extremely high.

Brief Description of the Drawings

[0133]

Figure 1

Examples

[0134] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0135] For the identification of the product 1 1H NMR spectrum and liquid chromatography-mass spectrum (LCMS) analysis were used.

[0136] < 1 1H NMR Spectrum Analysis Apparatus; manufactured by JEOL, (trade name) Delta V5 (400 MHz) Measurement temperature; 23 °C (when no temperature is specified) <Liquid Chromatography-Mass Spectrum (LCMS) Analysis> Device; Bruker Daltonik, (product name) microTOF focus MS ionization; Atmospheric pressure chemical ionization (APCI) method LC conditions; Conditions described in the following items of liquid chromatography analysis The progress of the reaction was confirmed by thin-layer chromatography, gas chromatography (GC), and liquid chromatography (LC) analysis. Liquid chromatography analysis was also used for the purity measurement of the biphenylene compound.

[0137] <Thin-layer chromatography analysis> Merck's TLC silica gel 60F254 0.5mm for thin-layer chromatography was used, and hexane or / and toluene was used as the developing solvent.

[0138] <Gas chromatography analysis> Device; Shimadzu Corporation, (product name) GC2014 Column; RESTEK Corporation, (product name) Rxi-1HT, 30m <Liquid chromatography analysis> Device; Agilent Technologies, model: 1260 Infinity II Column; Tosoh Corporation, (product name) ODS-100V, 5μm, 4.6mm × 250mm Column temperature: 33°C Eluent; Dichloromethane: Acetonitrile = 2:8 (volume ratio) Flow rate: 1.0 ml / min Detector; UV (wavelength: 254 nm).

[0139] The melting point of the biphenylene compound was measured using DSC (differential scanning calorimeter).

[0140] <DSC measurement> Device; Hitachi High-Tech Science Corporation, model: DSC7000X Heating and cooling rate: 10°C / min Scanning range: -10°C to 220°C The HOMO level of the biphenylene compound was determined by measuring AC5 (Atmospheric Photoelectron Yield Spectrometer) of the thin film obtained by drop-casting on parylene C in a toluene solution.

[0141] <AC5 measurement> Device; Riken Keiki Co., Ltd. Measurement point; every 0.05 eV Synthesis Example 1 (Synthesis of 2-bromodithienobiphenylene) (A1 step) A of the general formula (1-I) 1 、A 2 A biphenylene compound (dithienobiphenylene) in which A is sulfur and the two substituents are hydrogen was synthesized by the method described in JP 2018-174322.

[0142] Under a nitrogen atmosphere, 2.04 g (7.73 mmol) of dithienobiphenylene and 170 ml of THF (dehydrated grade) were added to a 300 ml Schlenk reaction vessel. This solution was cooled to -78 °C, and 5.3 ml (8.5 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging this mixture at room temperature (19 °C) for 30 minutes, it was cooled again to -78 °C, and a solution consisting of 2.66 g (8.16 mmol) of 1,2-dibromo-1,1,2,2-tetrachloroethane (Tokyo Chemical Industry) and 30 ml of THF (dehydrated grade) was added dropwise. The resulting mixture was stirred while gradually warming to room temperature. After adding saturated brine, extraction with toluene was performed. The organic phase was washed with water and dried over anhydrous sodium sulfate. It was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent; hexane / toluene = 5 / 1 to 1 / 1). 1.91 g of an orange solid of 2-dibromodithienobiphenylene was obtained (crude yield 72%, GC purity 85.2%).

[0143] 1 H NMR (CDCl3): δ = 7.24~7.17 (m, 2H), 7.08~7.02 (m, 3H), 6.75~6.64 (m, 2H).

[0144] The structure of the obtained 2-bromodithienobiphenylene is shown below.

[0145]

Chem.

[0146] Synthesis Example 2 (Synthesis of 2-Phenyldithieno[3,2-b:2',3'-d]biphenylene) (Step B1) Under a nitrogen atmosphere, 310 mg (2.27 mmol) of zinc chloride (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 8 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white fine slurry solution, 0.58 ml (1.2 mmol) of a THF solution of phenylmagnesium chloride (Sigma-Aldrich, 2.0 M) was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the resulting slurry of phenylzinc chloride, 204 mg (0.594 mmol) of 2-bromodithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 1 and 20.4 mg (0.0279 mmol, 5.21 mol% based on 2-bromodithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 21 °C for 7 hours, the reaction vessel was cooled with water, and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, the organic phase was washed with water, and dried over anhydrous sodium sulfate. The residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (solvent: hexane / toluene = 3 / 1 to 1 / 1). 180 mg of a red powder of 2,2'-dibromo-4,5'-difluorobiphenyl was obtained (yield 89%).

[0147] 1 H NMR (CDCl3): δ = 7.68~7.64 (m, 2H), 7.45~7.39 (m, 2H), 7.37~7.34 (m, 1H), 7.28 (s, 1H), 7.22 (d, J = 7.6 Hz, 1H), 7.20 (d, J = 5.5 Hz, 1H), 7.15 (d, J = 7.5 Hz, 1H), 7.05 (d, J = 5.5 Hz, 1H), 6.76 (d, J = 6.6 Hz, 1H), 6.72 (d, J = 7.6 Hz, 1H).

[0148] The structure of the obtained 2-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0149]

Chem.

[0150] Synthesis Example 3 (Synthesis of 2-Bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene) (Step C1) Under a nitrogen atmosphere, 200 mg (0.587 mmol) of 2-phenyldithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 2 and 9 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. The mixture was cooled to -78°C, and 0.72 ml (1.2 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging the mixture at -78°C for 25 minutes, a solution consisting of 382 mg (1.17 mmol) of 1,2-dibromo-1,1,2,2-tetrachloroethane (Tokyo Chemical Industry) and 1.5 ml of THF (dehydrated grade) was added dropwise at -78°C. The resulting mixture was stirred while gradually warming to room temperature. After adding water to the reaction mixture, THF was removed under reduced pressure. The resulting red-orange slurry was filtered, washed with water and methanol, and the red-orange solid was dried under reduced pressure to obtain 233 mg of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (yield 94%).

[0151] 1 1H NMR (CDCl3): δ = 7.67~7.64 (m, 2H), 7.45~7.40 (m, 2H), 7.38~7.34 (m, 1H), 7.28 (s, 1H), 7.17 (d, J = 7.4 Hz, 1H), 7.06 (d, J = 7.4 Hz, 1H), 7.05 (s, 1H), 6.69 (d, J = 7.3 Hz, 1H), 6.68 (d, J = 7.5 Hz, 1H).

[0152] The structure of the obtained 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0153]

Chem.

[0154] Example 1 (Synthesis of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 1)) (Step D1) Under a nitrogen atmosphere, 119 mg (0.873 mmol) of zinc chloride (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 4.5 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white micro-slurry solution, 0.18 ml (0.36 mmol) of a THF solution of n-butylmagnesium chloride (Tokyo Chemical Industry Co., Ltd., 2.0 M) was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the resulting slurry of n-butylzinc chloride, 58.7 mg (0.140 mmol) of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 3 and 4.6 mg (0.0063 mmol, 4.5 mol% with respect to 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 21 °C for 5 hours, the reaction vessel was cooled with water, and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, the organic phase was washed with water, and dried over anhydrous sodium sulfate. The residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (solvent: hexane / toluene = 10 / 1 to 3 / 1), and 43.3 mg of a red powder of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene was obtained (yield 78%). Further, recrystallization was carried out 4 times from heptane / toluene = 1 / 1, and 23.1 mg of red needle crystals of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 1) were obtained. The purity was 99.5% by LC analysis.

[0155] Melting point: 171 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.68~7.64 (m, 2H), 7.44~7.39 (m, 2H), 7.37~7.32 (m, 1H), 7.27 (s, 1H), 7.13 (d, J = 7.3 Hz, 1H), 7.03 (d, J = 7.3 Hz, 1H), 6.72 (s, 1H), 6.69 (d, J = 7.4 Hz, 2H), 2.81 (t, J = 7.6 Hz, 2H), 1.71 (m, 2H), 1.42 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0156] The structure of the obtained 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0157] [Chemical formula]

[0158] Example 2 (Synthesis of 2-(n-propyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 2)) (D1 step) The same operations as in Example 1 were repeated, except that n-propylmagnesium bromide (FUJIFILM Wako Pure Chemical Industries, 2.0 M THF solution) was used instead of n-butylmagnesium chloride in Example 1, and 10.1 mg of red needle crystals of 2-(n-propyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 2) were obtained. The purity was 99.0% by LC analysis.

[0159] Melting point: 223 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.68~7.64 (m, 2H), 7.44~7.39 (m, 2H), 7.37~7.32 (m, 1H), 7.27 (s, 1H), 7.13 (d, J = 7.4 Hz, 1H), 7.03 (d, J = 7.3 Hz, 1H), 6.71 (s, 1H), 6.68 (d, J = 7.4 Hz, 2H), 2.78 (t, J = 7.0 Hz, 2H), 1.75 (m, 2H), 1.02 (t, J = 7.3 Hz, 3H).

[0160] The structure of the obtained 2-(n-propyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0161] [Chemical formula]

[0162] Example 3 (Synthesis of 2-(n-pentyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 3)) (D1 step) The same procedure as in Example 1 was repeated, except that n-pentylmagnesium chloride (Sigma-Aldrich, 2.0 M THF solution) was used instead of n-butylmagnesium chloride in Example 1, to obtain 22.8 mg of a red-orange solid of 2-(n-pentyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 3). The purity was 99.3% by LC analysis.

[0163] Melting point: 136 °C HOMO level; -5.4 eV 1 1H NMR (CDCl3): δ = 7.68~7.64 (m, 2H), 7.44~7.39 (m, 2H), 7.37~7.32 (m, 1H), 7.27 (s, 1H), 7.13 (d, J = 7.4 Hz, 1H), 7.03 (d, J = 7.3 Hz, 1H), 6.72 (s, 1H), 6.69 (d, J = 7.4 Hz, 2H), 2.80 (t, J = 7.2 Hz, 2H), 1.72 (m, 2H), 1.41~1.36 (m, 4H), 0.92 (t, J = 7.3 Hz, 3H).

[0164] The structure of the obtained 2-(n-pentyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0165] [Chemical formula]

[0166] Synthesis Example 4 (Synthesis of 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene) Under a nitrogen atmosphere, 331 mg (2.43 mmol) of zinc chloride (Fuji Film Wako Pure Chemical Industries) and 10 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white micro-slurry solution, 0.63 ml (1.3 mmol) of a THF solution of n-butylmagnesium chloride (Tokyo Chemical Industry, 2.0 M) was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the resulting slurry of n-butylzinc chloride, 230 mg (0.670 mmol) of 2-bromodithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 1 and 16.1 mg (0.0220 mmol, 3.28 mol% with respect to 2-bromodithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 23 °C for 5 hours, the reaction vessel was cooled with water and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, the organic phase was washed with water, and dried over anhydrous sodium sulfate. It was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent: hexane / toluene = 10 / 1). 198 mg of a red-orange solid of 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene was obtained (yield 92%).

[0167] The structure of the obtained 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0168]

Chemical formula

[0169] Synthesis Example 5 (Synthesis of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene) The same procedure as in Synthesis Example 3 was repeated except that 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 4 was used instead of 2-phenyldithieno[3,2-b:2',3'-d]biphenylene in Synthesis Example 3, and a pale yellow solid of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene was obtained. The yield was 98%.

[0170] 11H NMR (CDCl3): δ = 7.06~7.01 (m, 2H), 7.03 (s, 1H), 6.72 (s, 1H), 6.64 (d, J = 7.4 Hz, 1H), 6.63 (d, J = 7.4 Hz, 1H), 2.80 (t, J = 7.2 Hz, 2H), 1.70 (m, 2H), 1.42 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0171] The structure of the obtained 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0172]

Chemical Structure

[0173] Example 4 (Synthesis of 2-(n-butyl)-7-(4-ethylphenyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 4)) Under a nitrogen atmosphere, 139 mg (1.02 mmol) of zinc chloride (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 8 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white micro-slurry solution, 1.1 ml (0.44 mmol) of a THF solution of 4-ethylphenylmagnesium bromide (0.41 M) prepared from 1-bromo-4-ethylbenzene (Tokyo Chemical Industry Co., Ltd.) and Mg (FUJIFILM Wako Pure Chemical Industries, Ltd., in shavings) in THF was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the resulting slurry of 4-ethylphenylzinc chloride, 106 mg (0.265 mmol) of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 5 and 7.7 mg (0.011 mmol, 4.1 mol% based on 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 21 °C for 5 hours, the reaction vessel was cooled with water, and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, washed with water, and dried over anhydrous sodium sulfate. The residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (solvent: hexane / toluene = 10 / 1) to obtain 47.5 mg of an orange powder of 2-(n-butyl)-7-(4-ethylphenyl)dithieno[3,2-b:2',3'-d]biphenylene (yield 42%). Further, recrystallization was carried out twice from heptane / toluene = 1 / 1 to obtain 27.5 mg of red lumpy crystals of 2-(n-butyl)-7-(4-ethylphenyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 4). The purity was 98.7% by LC analysis.

[0174] Melting point: 183 °C HOMO level; -5.4 eV 11H NMR (CDCl3): δ = 7.57 (d, J = 8.2 Hz, 2H), 7.23 (s, 1H), 7.22 (d, J = 8.2 Hz, 2H), 7.11 (d, J = 7.4 Hz, 1H), 7.02 (d, J = 7.4 Hz, 1H), 6.71 (s, 1H), 6.68 (d, J = 7.2 Hz, 2H), 2.80 (t, J = 7.6 Hz, 2H), 2.69 (q, J = 7.5 Hz, 2H), 1.70 (m, 2H), 1.43 (m, 2H), 1.28 (t, J = 7.4 Hz, 3H), 0.96 (t, J = 7.3 Hz, 3H).

[0175] The structure of the obtained 2-(n-butyl)-7-(4-ethylphenyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0176] [Chemical formula]

[0177] Example 5 (Synthesis of 2-(n-butyl)-7-{4-(n-butyl)phenyl}dithieno[3,2-b:2',3'-d]biphenylene (Compound 5)) The same procedure as in Example 4 was repeated except that 1-bromo-4-(n-butyl)benzene (Tokyo Chemical Industry) was used instead of 1-bromo-4-ethylbenzene in Example 4, and 47.8 mg of orange crystals of 2-(n-butyl)-7-{4-(n-butyl)phenyl}dithieno[3,2-b:2',3'-d]biphenylene (Compound 5) was obtained. The purity was 99.4% by LC analysis.

[0178] Melting point: 157 °C HOMO level; -5.4 eV 11H NMR (CDCl3): δ = 7.57 (d, J = 8.2 Hz, 2H), 7.23 (d, J = 8.2 Hz, 2H), 7.22 (s, 1H), 7.11 (d, J = 7.4 Hz, 1H), 7.02 (d, J = 7.4 Hz, 1H), 6.71 (s, 1H), 6.68 (d, J = 7.4 Hz, 2H), 2.80 (t, J = 7.4 Hz, 2H), 2.65 (t, J = 7.8 Hz, 2H), 1.75~1.60 (m, 4H), 1.46~1.35 (m, 4H), 0.96 (t, J = 7.4 Hz, 3H), 0.95 (t, J = 7.4 Hz, 3H).

[0179] The structure of the obtained 2-(n-butyl)-7-{4-(n-butyl)phenyl}dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0180]

Chemical Structure

[0181] Synthesis Example 6 (Synthesis of 2-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene) (Step B1) A THF solution of 2-phenylethylmagnesium bromide (0.40 M) prepared from 2-bromoethylbenzene (Tokyo Chemical Industry) and Mg (Fuji Film Wako Pure Chemical Industries, shaved) in THF was used instead of phenylmagnesium chloride in Synthesis Example 2, and the same operations as in Synthesis Example 2 were repeated to obtain red-orange crystals of 2-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene. The yield was 83%.

[0182] 1 1H NMR (CDCl3): δ = 7.36~7.16 (m, 7H), 7.03 (d, J = 5.4 Hz, 1H), 7.00 (d, J = 7.3 Hz, 1H), 6.70 (d, J = 8.0 Hz, 1H), 6.69 (s, 1H), 6.66 (d, J = 7.4 Hz, 1H), 3.11 (t, J = 7.6 Hz, 2H), 3.03 (t, J = 8.0 Hz, 2H).

[0183] The structure of the obtained 2-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0184] [Chemical formula]

[0185] Synthesis Example 7 (Synthesis of 2-Bromo-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene) (Step C1) The same procedure as in Synthesis Example 3 was repeated except that 2-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 6 was used instead of 2-phenyldithieno[3,2-b:2',3'-d]biphenylene in Synthesis Example 3, and a red-orange solid of 2-bromo-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene was obtained. The yield was 84%.

[0186] 1 H NMR (CDCl3): δ = 7.33 - 7.27 (m, 2H), 7.24 - 7.20 (m, 3H), 7.04 - 7.00 (m, 2H), 7.03 (s, 1H), 6.69 (s, 1H), 6.63 (d, J = 7.6 Hz, 2H), 3.11 (t, J = 7.6 Hz, 2H), 3.03 (t, J = 8.0 Hz, 2H).

[0187] The structure of the obtained 2-bromo-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0188] [Chemical formula]

[0189] Example 6 (Synthesis of 2-Ethyl-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 6)) (Step D1) The same procedure as in Example 1 was repeated except that ethylmagnesium chloride (Sigma-Aldrich, 2.0 M THF solution) was used instead of n-butylmagnesium chloride in Example 1, and 2-bromo-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 7 was used instead of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene, and an orange solid of 2-ethyl-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 6) was obtained. The purity was 99.0% by LC analysis.

[0190] Melting point: 132 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.34~7.27 (m, 2H), 7.24~7.19 (m, 3H), 7.00 (d, J = 7.6 Hz, 1H), 6.99 (d, J = 7.3 Hz, 1H), 6.71 (s, 1H), 6.68 (s, 1H), 6.64 (d, J = 7.5 Hz, 1H), 6.63 (d, J = 7.4 Hz, 1H), 3.10 (t, J = 8.5 Hz, 2H), 3.02 (t, J = 8.5 Hz, 2H), 2.83 (q, J = 7.4 Hz, 2H), 1.34 (t, J = 7.4 Hz, 3H).

[0191] The structure of the obtained 2-ethyl-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0192] [Chemical formula]

[0193] Synthesis Example 8 (Synthesis of 2-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]biphenylene) (Step B1) The same operations as in Synthesis Example 2 were repeated, except that a THF solution of 2-(2,3-dihydrobenzofuran-5-yl)ethylmagnesium bromide (0.40 M) prepared from 5-(2-bromoethyl)-2,3-dihydrobenzofuran (Tokyo Chemical Industry) and Mg (Fuji Film Wako Pure Chemical Industries, shaved) in THF was used instead of phenylmagnesium chloride in Synthesis Example 2, and a red-orange solid of 2-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]biphenylene was obtained. The yield was 93%.

[0194] 11H NMR (CDCl3): δ = 7.21~7.16 (m, 2H), 7.05~6.98 (m, 3H), 6.95 (d, J = 8.0 Hz, 1H), 6.73~6.64 (m, 4H), 4.56 (t, J = 8.6 Hz, 2H), 3.19 (t, J = 8.7 Hz, 2H), 3.06 (t, J = 8.5 Hz, 2H), 2.85 (t, J = 8.2 Hz, 2H).

[0195] The structure of the obtained 2-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole was shown below.

[0196] [Chemical formula]

[0197] Synthesis Example 9 (Synthesis of 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole) (Step C1) The same operations as in Synthesis Example 3 were repeated except that 2-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole synthesized in Synthesis Example 8 was used instead of 2-phenyldithieno[3,2-b:2',3'-d]pyrrole in Synthesis Example 3, and a yellow solid of 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole was obtained. The yield was 82%.

[0198] 1 1H NMR (CDCl3): δ = 7.05~7.01 (m, 4H), 6.94 (d, J = 8.0 Hz, 1H), 6.71 (d, J = 8.0 Hz, 1H), 6.69 (s, 1H), 6.64 (d, J = 7.4 Hz, 2H), 4.55 (t, J = 8.7 Hz, 2H), 3.18 (t, J = 8.6 Hz, 2H), 3.07 (t, J = 8.5 Hz, 2H), 2.94 (t, J = 8.3 Hz, 2H).

[0199] The structure of the obtained 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole was shown below.

[0200] [Chemical formula]

[0201] Example 7 (Synthesis of 2-(n-propyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole (Compound 7)) (Step D1) The same procedures as in Example 1 were repeated, except that n-propylmagnesium bromide (Fuji Film Wako Pure Chemical Industries, 2.0 M THF solution) was used instead of n-butylmagnesium chloride in Example 1, and 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole synthesized in Synthesis Example 9 was used instead of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]pyrrole, to obtain orange needle crystals of 2-(n-propyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole (Compound 7). The purity was 99.2% by LC analysis.

[0202] Melting point: 155 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.04 (s, 1H), 7.00 (t, J = 7.0 Hz, 2H), 6.95 (d, J = 8.1 Hz, 1H), 6.73 - 6.66 (m, 3H), 6.64 (d, J = 7.3 Hz, 1H), 6.63 (d, J = 7.3 Hz, 1H), 4.55 (t, J = 8.6 Hz, 2H), 3.19 (t, J = 8.6 Hz, 2H), 3.06 (t, J = 8.0 Hz, 2H), 2.94 (t, J = 8.2 Hz, 2H), 2.77 (t, J = 7.5 Hz, 2H), 1.75 (m, 2H), 1.01 (t, J = 7.3 Hz, 3H).

[0203] The structure of the obtained 2-(n-propyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole is shown below.

[0204]

Chemical formula

[0205] Example 8 (Synthesis of 2-Ethyl-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole (Compound 8)) (Step D1) The same procedure as in Example 1 was repeated, except that ethylmagnesium chloride (Sigma-Aldrich, 2.0 M THF solution) was used instead of n-butylmagnesium chloride and 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole synthesized in Synthesis Example 9 was used instead of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]pyrrole, to obtain orange needle crystals of 2-ethyl-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole (Compound 8). The purity was 99.2% by LC analysis.

[0206] Melting point: 160 °C HOMO level; -5.4 eV 1 1H NMR (CDCl3): δ = 7.04 (s, 1H), 6.99 (t, J = 7.0 Hz, 2H), 6.95 (d, J = 8.1 Hz, 1H), 6.73 - 6.66 (m, 3H), 6.63 (d, J = 7.3 Hz, 2H), 4.55 (t, J = 8.6 Hz, 2H), 3.19 (t, J = 8.6 Hz, 2H), 3.06 (t, J = 8.0 Hz, 2H), 2.94 (t, J = 8.2 Hz, 2H), 2.82 (q, J = 7.4 Hz, 2H), 1.33 (t, J = 7.4 Hz, 3H).

[0207] The structure of the obtained 2-ethyl-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole is shown below.

[0208]

Chemical formula

[0209] Example 9 (Synthesis of 2-(n-Butyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]pyrrole (Compound 9)) (Step D1) In Example 1, the same procedures as in Example 1 were repeated except that 2-bromo-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 9 was used instead of 2-bromo-7-phenyldithieno[3,2-b:2',3'-d]biphenylene, and yellow needle crystals of 2-(n-butyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]biphenylene (Compound 9) were obtained. The purity was 99.5% by LC analysis.

[0210] Melting point: 137 °C HOMO level; -5.4 eV 1 1H NMR (CDCl3): δ = 7.05 (s, 1H), 7.00 (d, J = 7.3 Hz, 1H), 6.99 (d, J = 7.3 Hz, 1H), 6.95 (d, J = 7.9 Hz, 1H), 6.73 - 6.66 (m, 3H), 6.64 (d, J = 7.4 Hz, 1H), 6.63 (d, J = 7.4 Hz, 1H), 4.55 (t, J = 8.7 Hz, 2H), 3.19 (t, J = 8.7 Hz, 2H), 3.06 (t, J = 8.5 Hz, 2H), 2.94 (t, J = 8.3 Hz, 2H), 2.79 (t, J = 7.4 Hz, 2H), 1.71 (m, 2H), 1.43 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0211] The structure of the obtained 2-(n-butyl)-7-{(2,3-dihydrobenzofuran-5-yl)ethyl}dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0212]

Chemical formula

[0213] Synthesis Example 10 (Synthesis of 2,2'-dibromo-4,5'-difluoro-1,1'-biphenyl) (Step A0) Under a nitrogen atmosphere, 6.67 g (22.2 mmol) of 1-bromo-4-fluoro-2-iodobenzene (Tokyo Chemical Industry) and 25 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. The solution was cooled to 0 °C, and 11.4 ml (22.8 mmol) of a THF solution of ethylmagnesium chloride (Sigma-Aldrich, 2.0 M) was added dropwise. The mixture was aged at 0 °C for 20 minutes to prepare 1-bromo-4-fluorophenyl-2-magnesium chloride.

[0214] On the other hand, under a nitrogen atmosphere, 4.26 g (31.3 mmol) of zinc chloride (Wako Pure Chemical Industries) and 25 ml of THF (dehydrated grade) were added to another 300 ml Schlenk reaction vessel and cooled to 0 °C. The previously prepared 1-bromo-4-fluorophenyl-2-magnesium chloride solution was added dropwise to the resulting white micro-slurry solution using a Teflon (registered trademark) cannula, and 2 ml of THF (dehydrated grade) was used to wash and add the 100 ml Schlenk reaction vessel and the Teflon (registered trademark) cannula. The resulting mixture was stirred while gradually warming to room temperature. To the slurry of the generated 1-bromo-4-fluorophenyl-2-zinc chloride, 5.44 g (18.1 mmol) of 2-bromo-4-fluoro-1-iodobenzene (Tokyo Chemical Industry) and 155 mg (0.134 mmol, 0.74 mol% based on 2-bromo-4-fluoro-2-iodobenzene) of tetrakis(triphenylphosphine)palladium (Tokyo Chemical Industry) as a catalyst were added. After carrying out the reaction at 50 °C for 6 hours, the vessel was cooled with water and the reaction was stopped by adding 1 M hydrochloric acid. It was extracted with hexane, the organic phase was washed with water and dried over anhydrous sodium sulfate. It was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent: hexane). 5.94 g of a colorless oil of 2,2'-dibromo-4,5'-difluoro-1,1'-biphenyl was obtained (yield 91%).

[0215] 11H NMR (CDCl3): δ = 7.62 (dd, J = 8.7 Hz, J = 5.2 Hz, 1H), 7.42 (dd, J = 8.3 Hz, J = 2.6 Hz, 1H), 7.21 (dd, J = 8.6 Hz, J = 5.9 Hz, 1H), 7.11 (dt, J = 8.6 Hz, J = 2.7 Hz, 1H), 6.95 - 7.04 (m, 2H).

[0216] The structure of the obtained 2,2'-dibromo-4,5'-difluoro-1,1'-biphenyl is shown below.

[0217]

Chemical Structure

[0218] Synthesis Example 11 (Synthesis of 2,6-difluorobiphenylene) (Step B0) Under a nitrogen atmosphere, 5.84 g (16.8 mmol) of 2,2'-dibromo-4,5'-difluoro-1,1'-biphenyl synthesized in Synthesis Example 10 and 250 ml of THF (dehydrated grade) were added to a 500 ml Schlenk reaction vessel. The mixture was cooled to -78°C, and 22.5 ml (36.0 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging the mixture at -78°C for 80 minutes, 6.36 g (47.3 mmol) of copper(II) chloride (Fuji Film Wako Pure Chemical Industries) was added at -78°C. The resulting mixture was stirred while gradually warming to room temperature. After adding 6 M hydrochloric acid to the reaction mixture, it was extracted with hexane, the organic phase was washed with saturated brine, and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent; hexane). 2.55 g of a pale yellow solid of 2,6-difluorobiphenylene was obtained (yield 81%).

[0219] 1 1H NMR (CDCl3): δ = 6.56 (dd, J = 7.7 Hz, J = 4.2 Hz, 2H), 6.40 (d, J = 7.2 Hz, 2H), 6.38 (m, 2H).

[0220] The structure of the obtained 2,6-difluorobiphenylene is shown below.

[0221] [Chemical formula]

[0222] Synthesis Example 12 (Synthesis of 2,6-difluoro-1,5-diiodobiphenylene) (Step C0) Under a nitrogen atmosphere, 2.72 g (19.2 mmol) of 2,2,6,6-tetramethylpiperidine (Tokyo Chemical Industry) and 50 ml of THF (dehydrated grade) were added to a 300 ml Schlenk reaction vessel. The mixture was cooled to -55°C, and 11.8 ml (18.9 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging the mixture at -55°C for 30 minutes, a solution consisting of 1.42 g (7.55 mmol) of 2,6-difluorobiphenylene synthesized in Synthesis Example 11 and 25 ml of THF (dehydrated grade) was added dropwise at -78°C. Further, 5 ml of THF (dehydrated grade) was added for washing. After aging at -78°C for 2 hours, a solution consisting of 4.71 g (18.6 mmol) of iodine (Fuji Film Wako Pure Chemical Industries) and 30 ml of THF (dehydrated grade) was added dropwise at -78°C. The resulting mixture was stirred while gradually warming to room temperature. After adding saturated brine to the reaction mixture, extraction with toluene was performed, and the organic phase was washed with dilute aqueous sodium sulfite and water, and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent; hexane). 1.87 g of a pale yellow solid of 2,6-difluoro-1,5-diiodobiphenylene was obtained (yield 56%).

[0223] 1 H NMR (CDCl3): δ = 6.68 (dd, J = 7.2 Hz, J = 4.0 Hz, 2H), 6.43 (dd, J = 9.6 Hz, J = 7.3 Hz, 2H). The structure of the obtained 2,6-difluoro-1,5-diiodobiphenylene is shown below.

[0224] [Chemical formula]

[0225] Synthesis Example 13 (Synthesis of 2,6-difluoro-1,5-di(trimethylsilylethynyl)biphenylene) (D0 step) Under a nitrogen atmosphere, 561 mg (1.28 mmol) of 2,6-difluoro-1,5-diiodobiphenylene synthesized in Synthesis Example 12, 0.43 g (4.3 mmol) of ethynyltrimethylsilane (Tokyo Chemical Industry), 5 ml of toluene, and 3 ml of triethylamine were added to a 100 ml Schlenk reaction vessel. To this mixture, 7.3 mg (0.010 mmol) of dichlorobis(triphenylphosphine)palladium (Fuji Film Wako Pure Chemical Industries) and 6.9 mg (0.036 mmol) of copper(I) iodide (Fuji Film Wako Pure Chemical Industries) were added. This mixture was reacted at 21 °C for 3 hours. Water was added to the resulting reaction mixture, and extraction with toluene was performed. After phase separation, the organic phase was washed with water and dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure, and the resulting residue was purified by silica gel column chromatography (solvent; hexane / toluene = 20 / 1 to 10 / 1). 476 mg of a pale yellow solid of 2,6-difluoro-1,5-di(trimethylsilylethynyl)biphenylene was obtained (yield 98%).

[0226] 1 H NMR (CDCl3): δ = 6.58 (dd, J = 7.4 Hz, 3.7 Hz, 2H), 6.43 (dd, J = 11 Hz, 7.4 Hz, 2H), 0.26 (s, 18H).

[0227] The structure of the obtained 2,6-difluoro-1,5-di(trimethylsilylethynyl)biphenylene is shown below.

[0228] [Chemical formula]

[0229] Synthesis Example 14 (Synthesis of dithienobiphenylene) (E0 step) Under a nitrogen atmosphere, 476 mg (1.25 mmol) of 2,6-difluoro-1,5-di(trimethylsilylethenyl)biphenylene synthesized in Synthesis Example 13, 1.06 g (4.40 mmol) of sodium sulfide nonahydrate (Sigma-Aldrich), and 25 ml of NMP (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. After stirring the mixture at 21°C for 1 hour, it was heated to 70°C and stirred for 9 hours. After cooling the resulting reaction mixture to 0°C, water was added. The resulting suspension was filtered, and the solid was dried in vacuo to obtain 169 mg of a yellow solid of dithienobiphenylene (yield 51).

[0230] 1 H NMR (CDCl3): δ = 7.31 (d, J = 5.6 Hz, 2H), 7.18 (d, J = 7.2 Hz, 2H), 6.94 (t, J = 5.5 Hz, 2H), 6.66 (d, J = 7.6 Hz, 2H).

[0231] The structure of the obtained dithienobiphenylene is shown below.

[0232]

Chemical Structure

[0233] Synthesis Example 15 (Synthesis of 2-bromodithienobiphenylene) (Step A2) Under a nitrogen atmosphere, 316 mg (1.19 mmol) of the dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 14 and 25 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. This solution was cooled to -78°C, and 0.82 ml (1.3 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging this mixture at -78°C for 25 minutes, a solution consisting of 429 mg (1.32 mmol) of 1,2-dibromo-1,1,2,2-tetrachloroethane (Tokyo Chemical Industry) and 3 ml of THF (dehydrated grade) was added dropwise. The resulting mixture was stirred while gradually warming to room temperature. After adding water, THF was distilled off under reduced pressure, and the precipitated solid was washed with water, methanol, and acetone. The obtained solid was dried under reduced pressure to obtain 350 mg of an orange-yellow solid of 2-dibromodithieno[3,2-b:2',3'-d]biphenylene (crude yield 86%, GC purity 80.3%).

[0234] 1 1H NMR (CDCl3): δ = 7.32 (d, J = 5.8 Hz, 1H), 7.20 (d, J = 7.4 Hz, 1H), 6.99 (d, J = 8.1 Hz, 1H), 6.97 (s, 1H), 6.93 (d, J = 5.5 Hz, 1H), 6.63 (d, J = 7.7 Hz, 1H), 6.59 (d, J = 7.5 Hz, 1H).

[0235] The structure of the obtained 2-bromodithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0236]

Chemical Structure

[0237] Synthesis Example 16 (Synthesis of 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene) (Step B2) Under a nitrogen atmosphere, 201 mg (1.47 mmol) of zinc chloride (Fuji Film Wako Pure Chemical Industries) and 7 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white micro-slurry solution, 0.40 ml (0.80 mmol) of a THF solution of n-butylmagnesium chloride (Tokyo Chemical Industry, 2.0 M) was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the resulting slurry of n-butylzinc chloride, 114 mg (0.332 mmol) of 2-bromodithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 15 and 8.4 mg (0.011 mmol, 4.3 mol% with respect to 2-bromodithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 21 °C for 7 hours, the reaction vessel was cooled with water and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, the organic phase was washed with water, and dried over anhydrous sodium sulfate. The residue obtained by concentration under reduced pressure was purified by silica gel column chromatography (solvent: hexane / toluene = 1 / 0 to 10 / 1). 80.1 mg of a yellow powder of 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene was obtained (yield 75%).

[0238] 1 1H NMR (CDCl3): δ = 7.29 (d, J = 5.5 Hz, 1H), 7.17 (d, J = 7.3 Hz, 1H), 7.05 (d, J = 7.0 Hz, 1H), 6.93 (d, J = 5.5 Hz, 1H), 6.63 (d, J = 7.6 Hz, 1H), 6.61 (s, 1H), 6.57 (d, J = 7.4 Hz, 1H), 2.79 (t, J = 8.0 Hz, 2H), 1.71 (m, 2H), 1.38 (m, 2H), 0.93 (t, J = 6.9 Hz, 3H).

[0239] The structure of the obtained 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0240]

Chemical Structure

[0241] Synthesis Example 17 (Synthesis of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene) (Step C2) Under a nitrogen atmosphere, 80.1 mg (0.250 mmol) of 2-(n-butyl)dithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 16 and 5 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel. The mixture was cooled to -78 °C, and 0.40 ml (0.64 mmol) of a hexane solution of n-butyllithium (Fuji Film Wako Pure Chemical Industries, 1.6 M) was added dropwise. After aging the mixture at -78 °C for 25 minutes, a solution consisting of 212 mg (0.650 mmol) of 1,2-dibromo-1,1,2,2-tetrachloroethane (Tokyo Chemical Industry) and 1.5 ml of THF (dehydrated grade) was added dropwise at -78 °C. The resulting mixture was stirred while gradually warming to room temperature. After adding water to the reaction mixture, THF was removed under reduced pressure. The obtained yellow slurry was filtered, washed with water and methanol, and the yellow solid was dried under reduced pressure to obtain 84.8 mg of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene (yield 85%).

[0242] 1 H NMR (CDCl3): δ = 7.06 (d, J = 7.4 Hz, 1H), 6.98 (d, J = 7.8 Hz, 1H), 6.96 (s, 1H), 6.61 (s, 1H), 6.57 (d, J = 7.6 Hz, 1H), 6.55 (d, J = 7.5 Hz, 1H), 2.80 (t, J = 8.0 Hz, 2H), 1.71 (m, 2H), 1.43 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0243] The structure of the obtained 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0244]

Chemical Structure

[0245] Example 10 (Synthesis of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 10)) (Step D2) Under a nitrogen atmosphere, 121 mg (0.888 mmol) of zinc chloride (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 5 ml of THF (dehydrated grade) were added to a 100 ml Schlenk reaction vessel and cooled to 0 °C. To the resulting white micro-slurry solution, 0.20 ml (0.40 mmol) of a THF solution of phenylmagnesium chloride (Sigma-Aldrich, 2.0 M) was added dropwise, and the mixture was stirred at 0 °C for 20 minutes and at room temperature for 20 minutes. To the slurry of the generated phenylzinc chloride, 49.0 mg (0.122 mmol) of 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene synthesized in Synthesis Example 17 and 3.1 mg (0.0042 mmol, 4.0 mol% based on 2-(n-butyl)-7-bromodithieno[3,2-b:2',3'-d]biphenylene) of Pd(dppf)Cl2 (Sigma-Aldrich) as a catalyst were added. After carrying out the reaction at 21 °C for 5 hours, the reaction vessel was cooled with water, and the reaction was stopped by adding 1 M hydrochloric acid. Toluene and water were added, the organic phase was separated, the organic phase was washed with water, and dried over anhydrous sodium sulfate. It was concentrated under reduced pressure, and the obtained residue was purified by silica gel column chromatography (solvent: hexane / toluene = 15 / 1 to 10 / 1) to obtain 43.3 mg of a red powder of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (yield 68%). Further, recrystallization was carried out once from heptane / toluene = 7 / 1 to obtain 32.7 mg of red needle crystals of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 10). The purity was 99.5% by LC analysis.

[0246] Melting point: 146 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.69~7.65 (m, 2H), 7.45~7.39 (m, 2H), 7.38~7.35 (m, 1H), 7.16 (s, 1H), 7.11 (d, J = 7.4 Hz, 1H), 7.07 (d, J = 7.0 Hz, 1H), 6.62 (s, 1H), 6.61 (d, J = 7.4 Hz, 1H), 6.60 (d, J = 7.6 Hz, 1H), 2.80 (t, J = 7.2 Hz, 2H), 1.70 (m, 2H), 1.42 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0247] The structure of the obtained 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0248] [Chemical formula]

[0249] Example 11 (Synthesis of 2-(n-butyl)-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 11)) (Step D2) The same operations as in Example 10 were repeated except that a THF solution of 2-phenylethylmagnesium bromide (0.40 M) prepared from 2-bromoethylbenzene (Tokyo Chemical Industry) and Mg (Fuji Film Wako Pure Chemical Industries, shaved) in THF was used instead of phenylmagnesium chloride in Example 10, and yellow crystals of 2-(n-butyl)-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene (Compound 11) were obtained. The purity was 99.5% by LC analysis.

[0250] Melting point: 166 °C HOMO level; -5.3 eV 1 1H NMR (CDCl3): δ = 7.33 - 7.28 (m, 2H), 7.24 - 7.18 (m, 3H), 7.03 (brs, 2H), 6.61 (brs, 2H), 6.54 (d, J = 7.6 Hz, 1H), 6.52 (d, J = 7.6 Hz, 1H), 3.10 (t, J = 8.6 Hz, 2H), 3.02 (t, J = 8.5 Hz, 2H), 2.79 (t, J = 7.1 Hz, 2H), 1.69 (m, 2H), 1.43 (m, 2H), 0.96 (t, J = 7.3 Hz, 3H).

[0251] The structure of the obtained 2-(n-butyl)-7-(2-phenylethyl)dithieno[3,2-b:2',3'-d]biphenylene is shown below.

[0252] [Chemical formula]

[0253] Example 12 (Preparation of a solution for forming an organic semiconductor layer) Under air, 1.19 mg of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 1) synthesized in Example 1 and 515 mg of anisole (Tokyo Chemical Industry) were added to a 10 ml sample tube. After heating and dissolving at 40 °C, the mixture was allowed to cool to room temperature (23 °C) to prepare a solution for forming an organic semiconductor layer. The solution remained in a liquid state even after 10 hours at 23 °C (the concentration of Compound 1 was 0.23 wt%), and it was confirmed that the compound was suitable for film formation by drop casting and inkjet.

[0254] Example 13 (Preparation of Solution for Forming Organic Semiconductor Layer) Under air, 1.25 mg of 2-(n-butyl)-7-phenyldithieno[3,2-b:2',3'-d]biphenylene (Compound 1) synthesized in Example 1, 542 mg of anisole (Tokyo Chemical Industry), and 0.31 mg of polystyrene (PS) (Sigma-Aldrich, Mw = 280,000) were added to a 10 ml sample tube (Compound 1:PS = 4:1, weight ratio). After heating and dissolving at 40 °C, the mixture was allowed to cool to room temperature (23 °C) to prepare a solution for forming an organic semiconductor layer. The solution remained in a liquid state even after 10 hours at 23 °C (the concentration of Compound 1 was 0.23 wt%), and it was confirmed that the compound was suitable for film formation by drop casting and inkjet.

[0255] Examples 14 to 20 (Preparation of Solution for Forming Organic Semiconductor Layer) In Example 12 or Example 13, a solution for forming an organic semiconductor layer was prepared using the compounds, solvents, and PS (added polymer) shown in Table 1 instead of Compound 1 obtained in Example 1 (Table 1). In each case, the solution remained in a liquid state even after 10 hours at 23 °C (the concentration was 0.23 wt%), and it was confirmed that the compound was suitable for film formation by drop casting and inkjet.

[0256]

Table 1

[0257] Example 21 (Fabrication of Organic Semiconductor Layer and Organic Thin-Film Transistor) The solution for forming the organic semiconductor layer of Compound 1 obtained in Example 12 was drop-cast onto the bottom-gate / bottom-contact substrate shown in Table 2 under the atmosphere, and most of the solvent was dried by natural drying at room temperature (23 °C). Further, the residual solvent was removed on a hot plate at 80 °C for 30 minutes to fabricate a bottom-gate / bottom-contact type organic thin-film transistor. The materials and film-forming methods of each constituent member are shown in Table 2. The film thickness of the organic semiconductor layer thin film of Compound 1 was 48 nm.

[0258]

Table 2

[0259] The electrical properties of the fabricated organic thin-film transistor were evaluated by using a semiconductor parameter analyzer (Keithley 4200SCS) at a drain voltage (Vd = -20 V) while scanning the gate voltage (Vg) from +10 to -20 V in 0.5 V steps. As a result, p-type transistor operation was obtained, and the hole carrier mobility was 1.52 cm 2 / V·sec, and the current on / off ratio was 1.5×10 6 .

[0260] Furthermore, the electrical properties of this organic thin-film transistor were measured after annealing at 130 °C for 15 minutes. The hole carrier mobility was 1.55 cm 2 / V·sec, and the current on / off ratio was 1.6×10 6 . There was almost no performance degradation due to the heat treatment.

[0261] Examples 22 to 29 (Fabrication of Organic Semiconductor Layer and Organic Thin-Film Transistor) The same operations as in Example 21 were repeated except that the solutions for forming the organic semiconductor layer prepared in Examples 13 to 20 were used instead of the solution for forming the organic semiconductor layer prepared in Example 12. The results are shown in Table 3. All showed p-type transistor operation, and the carrier mobility and current on / off ratio after annealing at 130 °C for 15 minutes are shown in Table 3. There was almost no performance degradation due to the heat treatment.

[0262]

Table 3

[0263] Comparative Example 1 (Preparation of Solution for Forming Organic Semiconductor Layer) In Example 12, instead of 2-(n-「)-7-phenyldithienobiphenylene (Compound 1), 2,7-di(n-octyl)benzothieno[3,2-b]benzothiophene (Sigma-Aldrich) was used, and a solution for forming an organic semiconductor layer was prepared in the same manner as in Example 12. It was confirmed that the solution remained in a liquid state even after 10 hours at 23 °C (0.23 wt%), and it was a compound suitable for film formation by drop casting and inkjet printing.

[0264] Comparative Example 2 (Preparation of Organic Semiconductor Layer and Organic Thin Film Transistor) Using the solution for forming the organic semiconductor layer prepared in Comparative Example 1, a thin film of 2,7-dioctylbenzothieno[3,2-b]benzothiophene with a film thickness of 60 nm was prepared in the same manner as in Example 21, and a bottom-gate-bottom-contact type organic thin film transistor was fabricated.

[0265] As a result of evaluating the transfer characteristics of the transistor element, p-type transistor operation was obtained, and the hole carrier mobility was 0.01 cm 2 / V·sec, and the current on / off ratio was 3.0×10 5 .

[0266] Furthermore, the electrical properties of this organic thin film transistor were measured after annealing at 130 °C for 15 minutes. As a result, transistor operation was not obtained, and a significant performance degradation due to heat treatment was observed. It was confirmed from microscopic observation that the organic semiconductor layer was destroyed by heating.

Industrial Applicability

[0267] The biphenylene compound of the present invention can provide high carrier mobility and is excellent in heat resistance and solubility, so it can be expected to be applied as a semiconductor device material typified by organic thin-film transistors.

Explanation of symbols

[0268] (A): Bottom-gate - top-contact type organic thin-film transistor (B): Bottom-gate - bottom-contact type organic thin-film transistor (C): Top-gate - top-contact type organic thin-film transistor (D): Top-gate - bottom-contact type organic thin-film transistor 1: Organic semiconductor layer 2: Substrate 3: Gate electrode 4: Gate insulating layer 5: Source electrode 6: Drain electrode

Claims

1. A biphenylene compound represented by the following general formula (1-I) or (1-II). 【Chemical Formula 1】 (Here, A １ ~A ４ each independently represents oxygen, sulfur, or selenium, R １ and R ３ each independently represents an aryl group having 4 to 20 carbon atoms, R ２ and R ４ each independently represents an alkyl group having 1 to 5 carbon atoms, and m and n represent integers from 0 to 4.)

2. The biphenylene compound according to claim 1, wherein A １ ~A ４ is sulfur.

3. A solution for forming an organic semiconductor layer, comprising the biphenylene compound according to claim 1 or 2.

4. An organic semiconductor layer formed by using the solution for forming an organic semiconductor layer according to claim 3.

5. An organic thin film transistor comprising the organic semiconductor layer according to claim 4.

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