JP2023128945A - Dibenzopentafulvalene oligomer and method for producing the same - Google Patents

Abstract

To provide a new compound having excellent electron-accepting properties.SOLUTION: The present invention provides an oligomer that includes n-mers of 1,1'-biindenylidene or a derivative thereof (n is a natural number of 2-5).SELECTED DRAWING: Figure 1

Description

Application for application of Article 30, Paragraph 2 of the Patent Act (1) Posting on the website (Proceedings of the 101st Spring Annual Meeting of the Chemical Society of Japan) ▲1▼Publication date: March 4, 2021 ▲2▼Address: https ://confit. atlas. jp/guide/event/csj101st/static/yokou (2) Presentation at the academic conference (101st Spring Annual Meeting of the Chemical Society of Japan) ▲1▼Date: March 19, 2021 ▲2▼Meeting name: Chemical Society of Japan No. 101 Spring Annual Meeting Location: Online (3) Presentation at the seminar (Kinki Chemical Society 1st Synthesis Forum of 2021) ▲1▼Date: May 31, 2021 ▲2▼Meeting name: Kinki Chemical Association 1st Synthesis Forum in 2021 Location: Online (4) Presentation at the presentation (Master's thesis presentation, Department of Materials and Energy Chemistry, Graduate School of Engineering, Kyoto University) ▲1▼Date: February 8, 2022 ▲2▼ Meeting name: Kyoto University Graduate School of Engineering, Department of Materials and Energy Chemistry Master's Thesis Presentation Venue: Kyoto University

The present disclosure relates to dibenzopentafulvalene oligomers and methods for producing the same. The present disclosure also relates to intermediate compounds that can be used in the production of the dibenzopentafulvalene oligomers described above. Further, the present disclosure relates to an electron-accepting material containing the dibenzopentafulvalene oligomer described above.

Conventionally, π-electron compounds have been widely studied as molecular materials exhibiting high electron-accepting properties. Among them, fullerene C ₆₀ is particularly well known as a robust electron-accepting material that can accept as many as 12 electrons per molecule. Research is also being conducted on polycyclic aromatic hydrocarbon (PAH) compounds having a partial structure of fullerene _C60 . For example, Coranulene C ₂₀ H ₁₀ and its derivatives are disclosed in Non-Patent Document 1.

Alexander V. Zabula et al. “Record Alkali Metal Intercalation by Highly ChargedCorannulene” Acc. Chem. Res. 2018, 51, 1541-1549

However, since fullerene C ₆₀ has a spherical molecular structure, there is a problem in that there are relatively few stacking and orbital interactions between molecules in the solid state. Further, examples of non-spherical polycyclic aromatic hydrocarbon compounds having a partial structure of fullerene C ₆₀ are limited, and their electron-accepting properties are not necessarily sufficiently high. Therefore, an object of the present invention is to provide a new compound having excellent electron-accepting properties.

Aspects of the present invention are, for example, as follows.
[1] An oligomer containing an n-mer (n is a natural number from 2 to 5) of 1,1'-biindenylidene or its derivative.
[2] The oligomer according to [1], which is represented by the following formula (I).
In formula (I),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of A is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5.
[3] Each of A is independently selected from the group consisting of an aryl group, an alkenyl group, an alkynyl group, an alkyl group, an alkoxy group, an amino group, a silyl group, a boryl group, a stannyl group, and a halogen atom, The oligomer according to [2].
[4] The oligomer according to [2] or [3], which is represented by the following formula (II).
In formula (II),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ² is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5.
[5] Each of R ² is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group. The oligomer according to [4], which is selected from the group consisting of a carbamate group, an amide group, an amino group, a phosphoryl group, and a boryl group.
[6] Each of R ¹ independently represents a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, an alkylthio group, an arylthio group, an acyl group, an acyloxy group, The R 1 group is selected from the group consisting of a carbamate group, an amide group, and a silyl group, or adjacent R ^1s are bonded to each other to form a ring structure, according to any one of [2] to [5]. oligomers.
[7] Each of R ¹ is the same as each other, or adjacent R ^1s are bonded to each other to form a symmetrical ring structure, according to any one of [2] to [6] oligomer.
[8] A compound represented by the following formula (III).
In formula (III),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ³ is independently selected from the group consisting of an aryl group, an alkyl group, an alkenyl group, an alkynyl group, a silyl group, a boryl group, and a stannyl group, and at least one of the two R ³ is a silyl group, It is a boryl group or a stannyl group, and two ^R3s are not trimethylsilyl groups at the same time.
[9] The compound according to [8], which is represented by the following formula (III-A).
In formula (III-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of silyl group, boryl group, and stannyl group,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, It is selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group.
[10] A compound represented by the following formula (IV).
In formula (IV),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of aryl group, alkyl group, alkenyl group, alkynyl group, silyl group, boryl group, and stannyl group,
X is a halogen atom.
[11] The compound according to [10], which is represented by the following formula (IV-A).
In formula (IV-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group,
X is a halogen atom.
[12] The compound according to any one of [8] to [11], which is used in the production of the oligomer according to any one of [1] to [7].
[13] A step of preparing at least one compound selected from the group consisting of the compound according to any one of [8] to [12] and a compound represented by the following formula (V),
performing a coupling reaction using the at least one compound;
The method for producing an oligomer according to any one of [1] to [7], comprising:
In formula (V),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
X is a halogen atom.
[14] The step of preparing the at least one compound includes synthesizing the compound according to any one of [8] to [12] using the compound represented by the formula (V). The manufacturing method according to [13].
[15] An electron-accepting material containing the oligomer according to any one of [1] to [7].

According to the present invention, it is possible to provide a new compound having excellent electron-accepting properties.

FIG. 1 is a conceptual diagram showing the design concept of an oligomer according to one embodiment of the present invention. FIG. 2 shows the results of crystal structure analysis of compound 2b. FIG. 3 shows the results of crystal structure analysis of compound 3b. FIG. 4 shows the results of crystal structure analysis of Compound 8. FIG. 5 shows the results of crystal structure analysis of compound 10b. FIG. 6 shows the results of crystal structure analysis of compound 10c. FIG. 7 shows the measurement results of ultraviolet-visible and near-infrared absorption spectra for compounds 3b and 3c. FIG. 8 shows the measurement results of ultraviolet-visible-near-infrared absorption spectrum for compound 8. FIG. 9A shows cyclic voltammetry (CV) measurement results for compounds 3b and 3c. FIG. 9B shows cyclic voltammetry (CV) measurement results for compounds 3b and 3c. FIG. 10 shows the results of cyclic voltammetry (CV) measurements for Compound 8. FIG. 11 shows changes in calculated values of carbon-carbon bond distances in the dianion structures of compounds 3b and 3c. FIG. 12 shows changes in the calculated value of the carbon-carbon bond distance in the dianion structure of Compound 8. FIG. 13 shows an example of calculating the frontier orbital level of a chain trimer according to one embodiment of the present invention. FIG. 14 shows calculation results of frontier orbital levels and their orbital distributions for compounds 3b and 3c. FIG. 15 shows an example of calculating the frontier orbital level of an oligomer according to one embodiment of the present invention.

Hereinafter, an oligomer and a method for producing the same according to one embodiment of the present invention will be described. In addition, intermediate compounds that can be used for producing the above oligomer will also be explained. Note that when referring to drawings or chemical formulas, components that perform the same or similar functions are given the same reference numerals or symbols, and redundant explanations will be omitted.

The present inventors conducted various studies in order to design a new compound having excellent electron-accepting properties.

FIG. 1 is a conceptual diagram showing the design concept of an oligomer according to one embodiment of the present invention. The left side of FIG. 1 shows the structure of fullerene C ₆₀ . The center of FIG. 1 is a hypothetical partial structure extracted from the equatorial portion of fullerene C ₆₀ , which has a cyclic trimer structure of dibenzopentafulvalene. The right side of FIG. 1 shows a dibenzopentafulvalene oligomer developed into a one-dimensional shape by unraveling the above-mentioned cyclic structure, and this is an example of an oligomer according to one embodiment of the present invention. Although such oligomers have a relatively simple structure, there have been no reports of oligomers having dimers or more. However, the present inventors discovered a method for synthesizing such oligomers (dimers to pentamers) and completed the present invention.

That is, the oligomer according to one embodiment of the present invention contains an n-mer (n is a natural number of 2 to 5) of 1,1'-biindenylidene or a derivative thereof. Such oligomers have excellent electron-accepting properties, as described below. Note that the term "derivative" herein refers to a compound in which any substituent is introduced at any position of the 1,1'-biindenylidene skeleton. A plurality of substituents may be bonded to each other to form a ring structure.

The oligomer according to one embodiment of the present invention is, for example, a compound represented by the following formula (I).

In formula (I),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of A is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5.

In the 1,1'-biindenylidene skeleton of formula (I), when a substituent or ring structure is present at the R ¹ position, from the viewpoint of steric hindrance etc., it is different from when a substituent or ring structure is present at other positions. In comparison, oligomers or their intermediates are relatively easy to synthesize. Moreover, in such a case, the flatness of the compound of formula (I) in the solid state is likely to be ensured for the same reason.

It is preferable that each R ¹ is the same or that adjacent R ^1s are bonded to each other to form a symmetrical ring structure. In such a case, isomers are not generated during oligomer synthesis, and isolation of the desired compound is relatively easy. Moreover, in such a case, the crystallinity of the compound of formula (I) also becomes relatively high. Note that the term "symmetrical ring structure" as used herein means a ring structure that is line-symmetrical with respect to the perpendicular bisector of the line segment connecting the two carbon molecules to which each of the adjacent ^R1s is bonded. There is.

When at least one of R ¹ is an arbitrary substituent, the substituent can be appropriately selected from the viewpoint of electron-withdrawing property, steric hindrance, optimization of crystal structure, etc. In this case, the substituent as R ¹ is preferably an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, an alkylthio group, an arylthio group, an acyl group, an acyloxy group, a carbamate group. , an amide group, and a silyl group. R ¹ is preferably a hydrogen atom, an alkyl group, or an alkoxy group, more preferably a hydrogen atom or an alkoxy group.

The alkyl group may be linear, branched, or cyclic. This alkyl group may be further substituted with other substituents. The alkyl group has, for example, 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms.

The perfluoroalkyl group may be linear, branched, or cyclic. This perfluoroalkyl group may be substituted with another substituent at a position that is not substituted with a fluorine atom. The perfluoroalkyl group has, for example, 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms.

The alkoxy group may be linear, branched, or cyclic. This alkoxy group may be further substituted with other substituents. The alkoxy group has, for example, 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, and more preferably 1 to 10 carbon atoms.

The polyalkylene glycol group may be linear or branched. This polyalkylene glycol group may be further substituted with other substituents. The polyalkylene glycol group is, for example, a polyethylene glycol group or a polypropylene glycol group, preferably a polyethylene glycol group. The number of repeating units of the polyalkylene glycol group is, for example, 2 to 12, preferably 2 to 8, and more preferably 2 to 5.

The aryl group constituting the aryloxy group is, for example, a phenyl group, a naphthyl group, or an anthracenyl group, preferably a phenyl group or a naphthyl group, and more preferably a phenyl group. These aryl groups may be further substituted with other substituents.

A siloxy group is a substituent represented by R ₃ SiO-. Each R is independently, for example, a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group, preferably an alkyl group, an aryl group, or an alkoxy group. Preferred examples of the alkyl group, aryl group, or alkoxy group include those described above. It is preferable that two or more of the three R's are the same. Preferred examples of the siloxy group include trimethylsiloxy group (TMSO-), triethylsiloxy group (TESO-), triisopropylsiloxy group (TIPSO-), t-butyldimethylsiloxy group (TBDMSO-), and t-butyldiphenylsiloxy group. Group (TBDPSO-) can be mentioned.

Examples of the alkyl group constituting the alkylthio group include those described above. Examples of the aryl group constituting the arylthio group include those described above.

An acyl group is a substituent represented by R(C=O)-. Each R is independently, for example, a hydrogen atom, an alkyl group, or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

An acyloxy group is a substituent represented by RCO ₂ -. Each R is independently, for example, a hydrogen atom, an alkyl group, or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

A carbamate group is a substituent represented by RNHCO ₂ -. Each R is independently, for example, a hydrogen atom, an alkyl group, or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

An amide group is a substituent represented by RCONH- or RCONR'-. R and R' are each independently, for example, a hydrogen atom, an alkyl group, or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

A silyl group is a substituent represented by R ₃ Si-. Each R is independently, for example, a hydrogen atom, an alkyl group, an aryl group, or an alkoxy group, preferably an alkyl group, an aryl group, or an alkoxy group. Preferred examples of the alkyl group, aryl group, or alkoxy group include those described above. It is preferable that two or more of the three R's are the same. Preferred examples of the silyl group include trimethylsilyl group (TMS-), triethylsilyl group (TES-), triisopropylsilyl group (TIPS-), t-butyldimethylsilyl group (TBDMS-), and t-butyldiphenylsilyl group. (TBDPS-).

When adjacent R ^1s are bonded to each other to form a ring structure, the ring structure may be an aromatic ring or a non-aromatic ring. Further, the ring structure may be a heterocycle. This ring structure may be further substituted with other substituents. Examples of the ring structure that R ¹ can form include a benzene ring, a naphthalene ring, an anthracene ring, a cyclohexane ring, a pyrrole ring, a thiophene ring, and a furan ring.

When at least one of A is an arbitrary substituent, the substituent can be appropriately selected from the viewpoint of electron-withdrawing property, steric hindrance, optimization of crystal structure, etc. In this case, the substituent as A is preferably selected from the group consisting of an aryl group, an alkenyl group, an alkynyl group, an alkyl group, an alkoxy group, an amino group, a silyl group, a boryl group, a stannyl group, and a halogen atom, More preferably, it is selected from an aryl group, a silyl group, a boryl group, a stannyl group, and a halogen atom, and even more preferably an aryl group or a silyl group. Preferably, the two A's are the same.

Preferred examples of the aryl group include those described above. A particularly preferred example where both A's are aryl groups will be described later with reference to formula (II).

The alkenyl group may be linear, branched, or cyclic. This alkenyl group may be further substituted with other substituents. The alkenyl group has, for example, 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms.

The alkynyl group may be linear or branched. This alkynyl group may be further substituted with other substituents. The alkynyl group has, for example, 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 6 carbon atoms.

Preferred examples of the alkyl group and alkoxy group include those described above.

An amino group is a substituent represented by H ₂ N-, RHN-, or RR'N-. R and R' are each independently, for example, an alkyl group or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

Preferred examples of the silyl group include those described above.

A boryl group is a substituent containing a boron atom, typically represented by Y ₂ B-. Each Y is independently, for example, an alkyl group, an aryl group, a hydroxy group, or an alkoxy group. Preferred examples of the alkyl group, aryl group, and alkoxy group include those described above. Y is preferably an alkoxy group. Two Y's may be bonded to each other to form a ring structure. A typical example of such a boryl group is a boronic acid pinacol ester group (pin) B-.

A stannyl group is a substituent containing a tin atom, typically represented by R ₃ Sn-. Each R is independently, for example, a hydrogen atom, an alkyl group, or an aryl group, preferably an alkyl group or an aryl group. Preferred examples of the alkyl group or aryl group include those described above. It is preferable that two or more of the three R's are the same. The stannyl group is preferably a trialkylstannyl group, more preferably a tributylstannyl group or a trimethylstannyl group.

The halogen atom is selected from, for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The halogen atom is preferably a chlorine atom or a bromine atom, more preferably a bromine atom.

As described above, n is a natural number from 2 to 5. The value of n can be appropriately selected in consideration of ease of synthesis, desired physical properties, and the like. As previously explained with reference to FIG. 1, the case where n=3 corresponds to one round of the equatorial portion of fullerene _C60 .

The oligomer according to one aspect of the present invention may be a compound represented by the following formula (II). The compound represented by formula (II) corresponds to the compound represented by formula (I) in which A is a phenyl group or a p-substituted phenyl group.

In formula (II),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ² is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5.

R ¹ and n are the same as those described above with reference to formula (I).

When at least one of R ² is an arbitrary substituent, the substituent can be appropriately selected from the viewpoints of electron-withdrawing property, steric hindrance, optimization of crystal structure, and the like. In this case, the substituent as ^R2 is preferably an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group. , an acyloxy group, a carbamate group, an amide group, an amino group, a phosphoryl group, and a boryl group. R ² is preferably a hydrogen atom, an alkyl group, an alkoxy group, or a silyl group, and more preferably a hydrogen atom, an alkoxy group, or a silyl group. Preferably, the two R ² 's are the same.

Preferred examples of alkyl groups, perfluoroalkyl groups, alkoxy groups, polyalkylene glycol groups, aryloxy groups, siloxy groups, silyl groups, alkylthio groups, arylthio groups, acyl groups, acyloxy groups, carbamate groups, and amide groups as R ² Examples include those similar to those described above in relation to ^R1 . As the amino group and boryl group as R ² , the same ones as explained above in relation to A can be mentioned.

A sulfonyl group is a substituent represented by RSO ₂ -. Each R is independently, for example, a hydrogen atom, an alkyl group, or an aryl group, preferably an alkyl group or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

A phosphoryl group is a substituent represented by (HO) ₂ OP- or (RO) ₂ OP-. Each R is independently, for example, an alkyl group or an aryl group. Preferred examples of the alkyl group or aryl group include those described above.

The oligomer according to one embodiment of the present invention can be synthesized using, for example, the following intermediate compounds.

A compound according to one embodiment of the present invention is represented by formula (III), for example.

In formula (III),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ³ is independently selected from the group consisting of an aryl group, an alkyl group, an alkenyl group, an alkynyl group, a silyl group, a boryl group, and a stannyl group, and at least one of the two R ³ is a silyl group, It is a boryl group or a stannyl group, and two ^R3s are not trimethylsilyl groups at the same time.

R ¹ is the same as described above with reference to formula (I).

Preferred examples of the aryl group as R ³ include those described above in relation to R ² . Preferred examples of the alkyl group, alkenyl group, alkynyl group, silyl group, boryl group, and stannyl group as R ³ include those described above in relation to A. Preferably, two R ³ 's are the same. At least one of the two ^R3s is preferably selected from the group consisting of a silyl group, a boryl group, and a stannyl group, and more preferably selected from the group consisting of a boryl group and a stannyl group.

Note that when both R ³ are trimethylsilyl groups, it is possible to use the compound represented by formula (III) in the synthesis of the oligomer according to one embodiment of the present invention, but such a compound can be used in the following manner. It has already been reported in Document R1 and is not a new compound.
Document R1: Mark Stradiotto et al. Organometallics 2000, 19, 590-601

The compound according to one embodiment of the present invention may be a compound represented by formula (III-A). The compound represented by formula (III-A) corresponds to the compound represented by formula (III) in which one of R ³ is a phenyl group or a p-substituted phenyl group.

In formula (III-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of silyl group, boryl group, and stannyl group,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, It is selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group.

R ¹ is the same as described above with reference to formula (I). R ³ is the same as described above with reference to formula (III), except that the aryl group, alkyl group, alkenyl group, and alkynyl group are excluded. Note that R ³ is preferably selected from the group consisting of a boryl group and a stannyl group. Preferred examples of R ⁴ are the same as those described above for R ² in formula (II).

A compound according to one embodiment of the present invention is represented by formula (IV), for example.

In formula (IV),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of aryl group, alkyl group, alkenyl group, alkynyl group, silyl group, boryl group, and stannyl group,
X is a halogen atom.

R ¹ is the same as described above with reference to formula (I). R ³ is the same as described above with reference to formula (III). Preferred examples of the halogen atom as X are the same as those described above in relation to A in formula (I).

The compound according to one embodiment of the present invention may be a compound represented by formula (IV-A). The compound represented by formula (IV-A) corresponds to the compound represented by formula (IV) in which R ³ is a phenyl group or a p-substituted phenyl group.

In formula (IV-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group,
X is a halogen atom.

R ¹ is the same as described above with reference to formula (I). R ⁴ is the same as described above with reference to formula (II). X is the same as described above with reference to formula (IV).

The oligomer according to one embodiment of the present invention can be produced, for example, by the following method. That is, first, an intermediate compound as described above is synthesized. Thereafter, these compounds are appropriately combined to perform a coupling reaction, preferably a cross-coupling reaction. In this way, oligomers are obtained.

Hereinafter, the synthesis of the intermediate compound and the synthesis of the oligomer will be explained in order. Note that, as described later, the oligomer can also be directly synthesized without going through the above-mentioned intermediate compound.

Moreover, although the synthesis method of the compound represented by Formula (III) or (IV) and the oligomer represented by Formula (I) is explained below, these are only examples. It is also possible to synthesize other oligomers of 1,1'-biindenylidene derivatives by a similar method.

[Synthesis of intermediate compound]
The intermediate compound can be synthesized using, for example, a compound represented by the following formula (V).

In formula (V),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
X is a halogen atom.

R ¹ is the same as described above with reference to formula (I). X is the same as described above with reference to formula (IV).

The compound represented by formula (V) can be synthesized according to the following scheme S1, for example, according to the known method described in the following documents R2 and/or R3.
Literature R2: H. Taniguchi et al. Chem. Lett. 1978, 73
Document R3: D. Rehder et al. Chem. Ber. 1988, 121, 1971

As can be seen from this scheme, if each R ¹ is the same or if adjacent R ^1s combine with each other to form a symmetrical ring structure, no isomers will occur and the formula The compound represented by (V) can be easily isolated.

Next, in the compound represented by formula (V), at least one of the two Xs is substituted with R ³ . That is, at least one of the two X's is substituted with an aryl group, an alkyl group, an alkenyl group, an alkynyl group, a silyl group, a boryl group, or a stannyl group. When only one of the two Xs is substituted, a compound represented by formula (IV) is obtained. Substitution of both of the two X's yields a compound represented by formula (III).

The substitution of X with R ³ can be carried out, for example, by a cross-coupling reaction as shown in Scheme S2 below. These cross-coupling reactions are carried out, for example, under palladium or nickel catalysts, typically under palladium catalysts.

In scheme S2, R ³ is the substituent described above for formula (III) or (IV), and M is a functional group containing an atom commonly used in various cross-coupling reactions. For example, when M contains Zn, the above reaction can be performed by Negishi coupling. When M contains Sn, the above reaction can be performed by Migita-Kosugi-Stille coupling. When M contains B, the above reaction can be carried out by Suzuki-Miyaura coupling (Miyaura-Ishiyama boration reaction). When M contains Si, the above reaction can be performed by Hiyama coupling. Note that when R ³ is a boryl group or a stannyl group, R ³ and M may be the same. Furthermore, when R ₃ is an alkenyl group, substitution of X with R ³ can also be performed using the Mizorogi-Heck reaction. When R ³ is an alkynyl group, substitution of X with R ³ can also be performed using Sonogashira coupling.

In addition, in the above scheme, either of the compounds represented by formula (III) or (IV) can be produced preferentially by controlling reaction conditions such as reaction time. When a mixture containing a compound represented by formula (III) and a compound represented by formula (IV) is obtained, these compounds can be isolated using column chromatography, gel permeation chromatography (GPC), etc. can do.

[Synthesis of dimer or trimer]
Oligomers according to one aspect of the present invention can be synthesized by various methods. Here, the case where n=2 or 3 will be explained.

First, a method for directly synthesizing an oligomer from a compound represented by formula (V) will be described. The present inventors unexpectedly found that a dimer and/or trimer according to one embodiment of the present invention can be produced simultaneously in a reaction similar to Scheme S2 above. Formation of such dimers and trimers is likely to be observed when M contains Zn, that is, when Negishi coupling is used.

In scheme S3, R ³ and M are as described above for scheme S2. In the product on the left, the case where n=1 corresponds to the compound represented by formula (III). In the product on the left, the case where n=2 or 3 and R ³ =A corresponds to a compound represented by formula (I). In the product on the right, the case where n=1 corresponds to the compound represented by formula (IV). In the product on the right, the case where n=2 and R ³ =A corresponds to the case where one of A is X (halogen atom) in the compound represented by formula (I). Note that the compound represented by formula (I) can also be synthesized by performing post-synthesis modification of converting R ³ to A to the oligomer obtained in Scheme S3.

The monomer, dimer, and trimer obtained by the above scheme can be isolated from each other using column chromatography, gel permeation chromatography (GPC), or the like. Note that the formation of oligomers can be confirmed by NMR measurement, mass spectrometry, ultraviolet/visible/near-infrared absorption spectroscopy, crystal structure analysis, and the like.

Next, a method for synthesizing an oligomer via the above-mentioned intermediate compound will be explained.

The first example is a method using homocoupling. In this method, for example, a compound represented by formula (IV) is subjected to homocoupling using a stoichiometric amount of nickel.

In the product of scheme S4, the case where R ³ =A corresponds to a compound represented by formula (I). As before, the oligomer obtained in Scheme S4 can also be subjected to post-synthetic modification to convert R ³ to A to synthesize a compound represented by formula (I).

A second example is a method using cross-coupling. This cross-coupling reaction is carried out, for example, under a palladium or nickel catalyst, typically under a palladium catalyst. A specific method includes, for example, a method according to scheme S5 or S6 below.

In Scheme S5, the reactant on the left is a compound represented by formula (III). The reactant on the right corresponds to the case where R ³ =A in the compound represented by formula (IV). If a mixture of dimers and trimers is obtained by the above scheme, these compounds can be isolated from each other using column chromatography, gel permeation chromatography (GPC), or the like.

In Scheme S6, the reactant on the left corresponds to the case where one of R ³ is A in the compound represented by formula (III). The reactant on the right is a compound represented by formula (V). The product on the left corresponds to the compound represented by formula (I) where n=2 and one of A is X (halogen atom). The product on the right corresponds to the case where n=3 in the compound represented by formula (I). If a mixture of dimers and trimers is obtained by the above scheme, these compounds can be isolated from each other using column chromatography, gel permeation chromatography (GPC), or the like.

Note that in schemes S5 and S6, when at least one of R ³ is a silyl group, the above reaction proceeds, for example, via Hiyama coupling. When at least one of R ³ is a boryl group, the above reaction proceeds, for example, via Suzuki-Miyaura coupling. When at least one of R ³ is a stannyl group, the above reaction proceeds, for example, via Migita-Kosugi-Stille coupling. Among the various cross-coupling reactions mentioned above, from the viewpoint of ease of synthesis, it is more preferable to use the Suzuki-Miyaura coupling or the Migita-Kosugi-Stille coupling, and it is particularly preferable to use the Suzuki-Miyaura coupling. .

[Synthesis of tetramer]
An example of a method for synthesizing an oligomer according to one embodiment of the present invention where n=4 will be described.

The first example is a method using homocoupling. This method uses, for example, a dimer capped with X (halogen atom) on one side, obtained by scheme S3 or S6. These dimers are subjected to homocoupling using a stoichiometric amount of nickel to obtain tetramers.

A second example is a method using cross-coupling. In this method, for example, in a dimer capped with X (halogen atom) on one side, which is obtained according to scheme S3 or S6, substitution from X to R ³ is carried out in the system. Thereafter, a cross-coupling reaction occurs between the dimer capped with X on one side and the dimer capped with R ³ on one side to obtain a tetramer. This cross-coupling reaction is carried out, for example, under a palladium or nickel catalyst, typically under a palladium catalyst.

In scheme S8, R ³ and M are as described above for scheme S2. As this cross-coupling reaction, from the viewpoint of ease of synthesis, it is more preferable to use Suzuki-Miyaura coupling or Migita-Kosugi-Stille coupling, and it is particularly preferable to use Suzuki-Miyaura coupling.

[Synthesis of pentamer]
Regarding the oligomer synthesis method according to one embodiment of the present invention, an example in which n=5 will be described. The pentamer can be synthesized, for example, by a method including the following two steps.

First, in a dimer capped with X (halogen atom) on one side, X is substituted with R ³ . At this time, care is taken to prevent the tetramer formation shown in Scheme S8 above from occurring as much as possible.

Then, secondly, the dimer obtained in the first step and the compound represented by formula (V) are linked by a cross-coupling reaction to obtain a pentamer.

In addition, in this exemplary method, from the viewpoint of ease of synthesis, etc., it is particularly preferable that the first step is carried out by Miyaura-Ishiyama boronation reaction, and the second step is carried out by Suzuki-Miyaura coupling. .

The oligomer according to one embodiment of the present invention has excellent electron-accepting properties, as demonstrated in the following examples. Therefore, such oligomers can be used as electron-accepting materials.

Oligomers according to one aspect of the invention typically have a LUMO as low as fullerene _C60 . Additionally, the oligomer according to one aspect of the present invention typically has a higher HOMO than fullerene _C60 . That is, the oligomer according to one aspect of the present invention typically has a smaller HOMO-LUMO gap than fullerene C ₆₀ .

As described above, the oligomer according to one embodiment of the present invention has an electron-accepting property comparable to that of fullerene C ₆₀ , so it can also be used as an n-type semiconductor material (electron transport material). Further, since the oligomer according to one embodiment of the present invention typically has an electronic structure similar to polyacetylene, it can also be used as a p-type semiconductor material.

The oligomer according to one embodiment of the present invention typically exhibits strong light absorption at longer wavelengths (particularly in the visible light region) than fullerene C ₆₀ due to the above-mentioned small HOMO-LUMO gap. Such oligomers can therefore also be used as dyes. Such oligomers can also be used as non-fullerene electron transport materials for organic solar cells.

Oligomers according to one aspect of the invention typically have robustness to multi-electron reduction. More specifically, the oligomer according to one embodiment of the present invention can reversibly accept 2n electrons per n-mer molecule. In this way, in the oligomer according to one embodiment of the present invention, multi-step reversible reduction depending on the chain length can be performed. Therefore, such oligomers can also be used as negative electrode materials for batteries. Further, since such oligomers typically have a stable anionic structure, it is also possible to form metal salts and the like. Therefore, such oligomers are expected to be applied as superconducting materials, Mott insulators, quantum spin liquids, and the like.

Hereinafter, synthesis and identification methods, as well as physical properties and simulation evaluation results will be specifically described for some examples of oligomers according to one embodiment of the present invention.

The list of abbreviations used in this example is as follows.
THF: tetrahydrofuran
PPh ₃ : triphenylphosphine
TMEDA: tetramethylethylenediamine
cod: 1,5-cyclooctadiene
DMF: N,N'-dimethylformamide
OAc: acetate
Bu: butyl
Et: ethyl
Me: methyl
PCy ₃ : tricyclohexylphosphine

[Synthesis]
In the following synthesis examples, compounds were identified using the following equipment. Melting point (mp) was measured using Yanaco MP-S3. ¹ H, ¹³ C { ¹ H}, ¹⁹ F, and ¹¹⁹ Sn NMR spectra were measured using a Bruker AVANCE III (500 MHz for ¹ H, 125 MHz for ¹³ C). CDCl ₃ or CD ₂ Cl ₂ was used as the measurement solvent. Mass spectra were measured by APCI or MALDI using a Bruker solarix (FT-ICR) system.

In the following synthesis examples, compounds were isolated as follows. Thin layer chromatography (TLC) was performed using plates coated with 0.25 mm thick silica gel 60F ₂₅₄ (Merck). Column chromatography was performed using silica gel: Wakosil (registered trademark) HC-N (Fujifilm Wako Pure Chemical Industries, Ltd.). Recycling preparative gel permeation chromatography (GPC) was performed using LaboACE LC-5060 (Nippon Analytical Industry). At that time, a polystyrene gel column (JAIGEL-2HR-40) was used as the column, and CHCl ₃ was used as the eluent.

In the following synthesis examples, anhydrous THF was purchased from Kanto Kagaku and further purified using a GlassContour organic solvent purification device. Other reagents were used as purchased. (E)-3,3'-dibromo-1,1'-biindenylidene (compound 1), 1-bromo-4-(tert-butyldimethylsilyl)benzene, and 4,4,5,5-tetramethyl-2-( triethylsilyl)-1,3,2-dioxaborolane was synthesized according to literature methods.

Oligomers were synthesized according to the scheme below. This synthesis corresponds to the case where Negishi coupling is used in the above scheme S3.

(If R=H)
To a solution of bromobenzene (335 mg, 2.13 mmol) in anhydrous THF (10 mL) was added nBuLi hexane solution (1.6 M, 1.45 mL, 2.32 mmol) dropwise over 2 minutes at -78°C. After stirring for 1 hour, ZnCl ₂ .TMEDA (593 mg, 2.35 mmol) was added to this solution, and the mixture was stirred at the same temperature for 15 minutes. The obtained phenylzinc chloride solution was added dropwise to a THF solution (3 mL) of Compound 1 (1.16 g, 3.00 mmol) and Pd(PPh ₃ ) ₄ (104 mg, 0.090 mmol), and then stirred at 70° C. for 21 hours. did. The resulting mixture was quenched with H ₂ O and then diluted with CH ₂ Cl ₂ , the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×50 mL). The combined organic layers were washed with saturated brine, dried over anhydrous Na ₂ SO ₄ and concentrated under reduced pressure. The resulting crude product was purified by silica gel column chromatography (hexane to CH ₂ Cl ₂ and then ethyl acetate as eluent), followed by recycle preparative GPC (CHCl ₃ as eluent) to obtain 40 mg of the compound. 2a as a red solid (0.10 mmol, 4% yield), 12 mg of compound 2b as a black solid (0.020 mmol, 1% yield), 7.3 mg of compound 2c as a black solid (8.8 μmol, 169 mg of compound 4a was obtained as a red solid (0.44 mmol, yield 15%), and 13 mg of compound 4b was obtained as a black solid (0.021 mmol, yield 1%), respectively. Ta.

Compound 2a
Mp: 210.9-211.0℃
¹ H NMR (500 MHz, CDCl ₃ ): δ8.11-8.09 (m, 2H), 7.76 (dd, J = 8.3 Hz, 1.3 Hz, 4H), 7.62-7.60 (m, 2H), 7.55 (s 2H) ), 7.52 (td, J = 7.5 Hz, 1.3 Hz, 4H), 7.44 (tt, J = 7.5 Hz, 1.5 Hz, 2H), 7.31 (ddd, J = 4.5 Hz, 2.0 Hz, 4H).
¹³ C{ ¹ H} NMR (100 MHz, CD ₂ Cl ₂ ): δ149.1, 142.4, 140.4, 138.7, 135.6, 129.2, 129.1, 128.2, 126.5, 125.8, 124.8, 121.7.
HRMS (APCI): m/z Calcd. for C ₃₀ H ₂₁ : 381.1368 ([M] ⁺ ). Obsd. 381.1367.

Compound 2b
Mp: 239.5-239.8℃
¹ H NMR (500 MHz, CDCl ₃ ): δ8.16 (d, J = 7.5 Hz, 2H), 8.11-8.09 (m, 2H), 7.95 (s, 2H), 7.81 (d, J = 7.5 Hz, 2H), 7.79 (d, J = 7.5 Hz, 4H), 7.64-7.62 (m, 2H), 7.75 (s, 2H), 7.53 (t, J = 7.5 Hz, 4H), 7.45 (q, J = 7.5 Hz, 4H), 7.39 (td, J = 7.5 Hz, 1.0 Hz, 2H), 7.34-7.33 (m, 4H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ149.5, 142.4, 142.3, 141.8, 141.3, 140.5, 138.5, 138.4, 135.5, 129.0, 128.9, 128.4, 128.3, 128.0 , 126.7, 126.5, 126.3 , 125.5, 124.7, 121.8, 121.7.
HRMS (MALDI): m/z calcd for C ₄₈ H ₃₀ : 606.2342 ([M] ⁺ ), found: 606.2343.

Compound 2c
Mp: >300℃
¹ H NMR (500 MHz, CDCl ₃ ): δ7.34-7.36 (m, 2H), 7.40-7.42 (m, 2H), 7.46 (dd, J = 13.9 Hz, 7.5 Hz, 3H), 7.54 (t, J = 7.5 Hz, 3H), 7.57 (s, 1H), 7.62-7.64 (m, 2H), 7.68-7.71 (m, 2H), 7.79 (d, J = 7.3 Hz, 1H), 7.83-7.85 (m , 1H), 7.98 (d, J = 2.1 Hz, 1H), 8.10-8.11 (m, 1H), 8.16 (t, J = 7.3 Hz, 1H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): Could not be measured due to poor solubility.
HRMS (MALDI): m/z Calcd. for C ₆₀ H ₄₀ : 832.3124 ([M] ⁺ ). Obsd. 832.3124.

Compound 4a
Mp: 171.1-171.8℃.
¹ H NMR (500 MHz, CDCl ₃ ): δ8.00 (d, J = 7.5 Hz, 2H), 7.74 (dd, J = 8.3 Hz, 1.3 Hz, 2H), 7.65 (s, 1H), 7.59-7.57 (m, 1H), 7.51 (td, J = 7.5 Hz, 1.2 Hz, 2H), 7.47-7.45 (m, 1H), 7.44 (s, 1H), 7.41-7.40 (m, 1H), 7.37 (td, J = 7.3 Hz, 1.0 Hz, 1H), 7.35-7.31 (m, 3H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ149.9, 142.3, 141.2, 140.2, 138.11, 138.09, 136.1, 135.3, 129.0, 128.9, 128.5, 128.5, 128.4, 127 .9, 127.4, 127.0, 126.5 , 125.4, 124.7, 124.4, 121.6, 121.0.
HRMS (APCI): m/z Calcd. for C ₂₄ H ₁₆ ⁷⁹ Br: 383.0430 ([M+H] ⁺ ). Obsd. 383.0427.

Compound 4b
Mp: >300℃.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ7.36 (dd, J = 5.6 Hz, 2.9 Hz, 2H), 7.38-7.44 (m, 5H), 7.46-7.49 (m, 3H), 7.55 ( t, J = 7.3 Hz, 2H), 7.59 (s, 1H), 7.64 (dd, J = 5.6 Hz, 2.6 Hz, 1H), 7.71 (s, 1H), 7.80-7.84 (m, 4H), 7.88 ( s, 1H), 7.99 (s, 1H), 8.05 (d, J = 7.0 Hz, 1H), 8.08 (d, J = 7.9 Hz, 1H), 8.12 (dd, J = 5.6 Hz, 2.9 Hz, 1H) , 8.19 (d, J = 7.0 Hz, 1H).
¹³ C{ ¹ H} NMR: Could not be measured due to poor solubility.
HRMS (MALDI): m/z calcd for C ₄₂ H ₂₅ ⁷⁹ Br: 608.1140 ([M] ⁺ ), found: 608.1136.

(When R= _SiMe2tBu )
A solution of 1-bromo-4-(tert-butyldimethylsilyl)benzenebromobenzene (571 mg, 2.11 mmol) in anhydrous THF (10 mL) was added with a solution of nBuLi in hexane (1.6 M, 1.45 mL, 2.32 mmol). was added dropwise over 2 minutes at -78°C. After stirring for 1 hour, ZnCl ₂ .TMEDA (584 mg, 2.31 mmol) was added to this solution, and the mixture was stirred at the same temperature for 15 minutes. The obtained phenylzinc chloride solution was added dropwise to a THF solution (4 mL) of Compound 1 (1.16 g, 3.00 mmol) and Pd(PPh ₃ ) ₄ (104 mg, 0.090 mmol), and then stirred at 70° C. for 21 hours. did. The resulting mixture was quenched with H ₂ O before CH ₂ Cl ₂ was added, the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×15 mL). The combined organic layers were washed with saturated brine, dried over anhydrous Na ₂ SO ₄ and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (hexane to CH ₂ Cl ₂ and then ethyl acetate as eluent) and then subjected to recycle preparative GPC (CH ₂ Cl ₂ as eluent) to obtain 137 mg. Compound 3a as a red solid (0.23 mmol, yield 7%), 39 mg of compound 3b as a black solid (0.047 mmol, yield 3%), 10 mg of compound 3c as a black solid (9.4 μmol, 244 mg of compound 5a as a red solid (0.49 mmol, yield 16%), and 10 mg of compound 5b as a black solid (0.014 mmol, yield 0.9%). I got each.

Compound 3a
¹ H NMR (500 MHz, CDCl ₃ ): δ8.10 (dt, J = 11.0 Hz, 3.7 Hz, 2H), 7.74 (d, J = 8.0 Hz, 4H), 7.66 (d, J = 7.9 Hz, 4H ), 7.65-7.62 (m, 2H), 7.56 (s, 2H), 7.34-7.27 (m, 4H), 0.94 (s, 18H), 0.33 (s, 12H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ148.8, 142.2, 140.3, 138.9, 138.6, 135.8, 135.0, 128.0, 126.8, 126.2, 125.5, 124.8, 121.5, 77.4, 77.2, 76.9, 26.7 , 17.2, -6.0.
HRMS (APCI): m/z Calcd. for C ₄₂ H ₄₉ Si ₂ : 609.3367 ([M] ⁺ ). Obsd. 609.3368.

Compound 3b
Mp: >300℃.
¹ H NMR (500 MHz, CDCl ₃ ): δ8.15 (d, J = 7.6 Hz, 2H), 8.11-8.08 (m, 2H), 7.95 (s, 2H), 7.81 (d, J = 7.5 Hz, 2H), 7.76 (d, J = 8.1 Hz, 4H), 7.67 (d, J = 8.2 Hz, 4H), 7.66-7.64 (m, 2H), 7.59 (s 2H), 7.43 (td, J = 11.1 Hz) , 0.9 Hz, 2H), 7.38 (td, J = 7.6 Hz, 1.1 Hz, 2H), 7.36-7.32 (m, 4H), 0.95 (s, 18H), 0.34 (s, 12H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ149.5, 142.4, 142.2, 141.8, 141.4, 140.5, 139.2, 138.6, 138.4, 135.7, 135.1, 128.4, 128.3, 126.8 , 126.6, 126.5, 126.3 , 125.5, 124.8, 121.8, 121.7, 26.7, 17.2, -6.0.
HRMS (MALDI): m/z Calcd. for C ₆₀ H ₅₉ Si ₂ : 835.4150 ([M+H] ⁺ ), Obsd. 835.4139.

Compound 3c
Mp: >300℃.
¹ H NMR (500 MHz, CDCl ₃ ): δ8.16 (d, J = 7.6 Hz, 3H), 8.11-8.09 (m, 2H), 7.97 (d, J = 2.6 Hz, 3H), 7.85-7.82 ( m, 3H), 7.76 (d, J = 7.9 Hz, 4H), 7.68 (d, J = 8.2 Hz, 5H), 7.66-7.65 (m, 2H), 7.56 (s, 2H), 7.48-7.33 (m , 14H), 0.95 (s, 18H), 0.35 (s, 12H).
¹³ C{ ¹ H} NMR: Could not be measured due to poor solubility.
HRMS (MALDI): m/z Calcd. for C ₇₈ H ₆₈ Si ₂ : 1060.48541 ([M] ⁺ ), Obsd. 1060.48413.

Compound 5a
Mp: 185.9-186.3℃.
¹ H NMR (500 MHz, CDCl ₃ ): δ7.99 (d, J = 7.4 Hz, 2H), 7.71 (d, J = 8.0 Hz, 2H), 7.65 (d, J = 8.0 Hz, 2H), 7.64 (s, 1H), 7.61 (dd, J = 6.5, 1.7 Hz, 1H), 7.45 (s, 1H), 7.41-7.29 (m, 5H), 0.94 (s, 9H), 0.34 (s 6H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ150.0, 142.3, 141.2, 140.3, 139.2, 138.2, 138.1, 136.1, 135.6, 135.0, 128.5, 128.5, 128.3, 127.4 , 127.1, 126.7, 126.5 , 125.4, 124.7, 124.5, 121.7, 121.0, 26.7, 17.2, -6.0.
HRMS (APCI): m/z Calcd. for C ₃₀ H ₃₀ Si ⁷⁹ Br: 497.1295 ([M] ⁺ ). Obsd. 497.1292.

Compound 5b
Mp: >300℃.
¹ H NMR (500 MHz, CDCl ₃ ): δ8.18 (d, J = 7.5 Hz, 1H), 8.13-8.10 (m, 1H), 8.07 (d, J = 7.6 Hz, 1H), 8.04 (d, J = 7.3 Hz, 1H), 7.98 (s, 1H), 7.88 (s, 1H), 7.82 (t, J = 8.5 Hz, 2H), 7.78 (d, J = 8.0 Hz, 2H), 7.70 (d, J = 8.3 Hz, 3H), 7.68-7.65 (m. 1H), 7.60 (s, 1H), 7.49-7.34 (m, 9H), 0.95 (s, 9H), 0.35 (s, 6H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ150.0, 143.1, 142.6, 142.4, 141.9, 141.4, 140.8, 140.5, 139.2, 138.7, 138.5, 138.1, 136.2, 135.8 , 135.4, 129.2, 129.2 , 129.0, 128.70, 128.66, 127.8, 127.6, 127.2, 127.02, 126.99, 126.8, 126.3, 125.8, 125.6, 125.0, 122.3, 122.1, 122.0, 121 .3, 26.7, 17.3, -6.0.
HRMS (APCI): m/z Calcd. for C ₄₈ H ₄₀ ⁷⁹ BrSi: 723.2077 ([M+H] ⁺ ), Found. 723.2077.

Oligomers were synthesized according to the scheme below. In this synthesis, first, a compound represented by formula (IV) is synthesized by using Negishi coupling in the above scheme S2. Thereafter, a dimer is obtained by performing a homocoupling reaction according to the above scheme S4.

In addition, the identification of the compound in this scheme was performed using the following apparatus. That is, ¹ H-NMR was measured using JEOL AL-400. Moreover, the mass spectrum was measured using Bruker microOTOF Focus (ionization method: APCI).

(Synthesis of intermediate compound 7)
Compound 7 (3-bromo-3'-(4-methoxyphenyl)-5,5',6,6'-tetra(n-butoxy)-1,1'-biindenylidene) was synthesized as follows.

First, (E)-3,3'-dibromo-5,5',6,6'-tetra(n-butoxy)1,1'-biindenylidene (compound 6) was prepared in the same manner as compound 1 according to the literature method. Synthesized. Next, 4-methoxyphenylmagnesium bromide was added dropwise to a THF solution (4 mL) of ZnCl ₂ TMEDA (90.1 mg, 0.357 mmol), and the mixture was stirred at room temperature for more than 1 hour to prepare the 4-methoxyphenyl zinc chloride solution. prepared. The above compound 6 and 4-methoxyphenylzinc chloride solution were added to a THF solution (4.0 mL) of Pd(PPh ₃ ) ₄ (6.9 mg, 5.95 μmol), washed with THF (2.0 mL), Heated at 75°C for 50 hours. The resulting reaction mixture was separated into an aqueous layer and an organic layer using water (100 mL) and ethyl acetate. The aqueous layer was extracted with ethyl acetate (50 mL x 3) and added to the organic layer, and the combined organic layers were washed with saturated brine and dried using anhydrous sodium sulfate. Anhydrous sodium sulfate was filtered off, and the solvent was distilled off under reduced pressure. The obtained crude product was purified by column chromatography (basic alumina; hexane/ethyl acetate 10/1 to 0/10 (v/v)) to obtain compound 7 as a brown solid (0.148 mmol , yield 50%).

Intermediate compound 7
¹ H NMR (400 MHz, C ₆ D ₆ ): δ7.83 (s, 1H), 7.73 (s, 1H), 7.72 (s, 1H) 7.64 (d, J = 7.6 Hz, 2H), 7.42 (s , 1H), 7.29 (s, 1H), 7.13 (s, 1H), 6.85 (d, J = 7.6 Hz, 2H), 3.91 (t, J = 6.4 Hz, 2H), 3.80 (t, J = 6.4 Hz , 4H), 3.74 (t, J = 6.4 Hz, 2H), 3.30 (s, 3H), 1.59-1.66 (m, 8H), 1.37-1.53 (m, 8H), 0.82-0.94 (m, 12H).

(Synthesis of compound 8)
Dimer compound 8 was synthesized using intermediate compound 7 obtained as described above.

_2,2' -bipyridyl (10.9 mg, 0.0698 mmol) and 1,5-cyclooctasidiene (7 .5 μL, 0.0610 mmol) and Compound 7 (40.1 mg, 0.0573 mmol) were added, and the mixture was heated and stirred at 65° C. for 47 hours. The resulting reaction mixture was separated into an aqueous layer and an organic layer using water (40 mL) and ethyl acetate. The aqueous layer was extracted with ethyl acetate (30 mL x 3) and added to the organic layer, and the combined organic layers were washed with saturated brine and dried using anhydrous sodium sulfate. Anhydrous sodium sulfate was filtered off, and the solvent was distilled off under reduced pressure. The obtained crude product was purified by column chromatography (basic alumina; hexane/ethyl acetate 10/1 to 0/10 (v/v)) to obtain Compound 2 as a black solid (9.41 μmol , yield 33%).

Compound 8
¹ H NMR (400 MHz, C ₆ D ₆ ): δ8.22 (s, 1H), 8.09 (s, 1H), 8.05 (s, 1H), 7.75 (s, 1H), 7.68 (d, J = 8.7 Hz, 2H), 7.63 (s, 1H), 7.35 (s, 1H), 6.86 (d, J = 8.7 Hz, 2H), 4.06 (t, J = 6.4 Hz, 2H), 3.99 (td, J = 6.3 , 2.4 Hz, 4H), 3.82 (t, J = 6.4 Hz, 2H), 3.31 (s, 3H), 1.36-1.80 (m, 16H), 0.85-0.96 (m, 12H)

Oligomers were synthesized according to the scheme below. In this synthesis, various intermediate compounds are first synthesized by performing boronation, siliconization, or stannification according to the above scheme S2. Thereafter, an oligomer is obtained by performing a cross-coupling reaction according to the above scheme S5.

(Synthesis of intermediate compound 9a)

Compound 9a ((E)-3,3'-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,1'-biindenylidene) was prepared as follows. It was synthesized by

Compound 1 (390 mg, 1.01 mmol), bis(pinacolato)diboron (619 mg, 2.44 mmol), KOAc (507 mg, 5.16 mmol), and Pd(PPh ₃ ) ₄ (25 mg, 0.022 mmol) in THF (20 mL) ) The solution was stirred at 75°C for 12 hours. After adding CH ₂ Cl ₂ to the resulting mixture, the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×30 mL). The combined organic layers were washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (eluent: hexane/CH ₂ Cl ₂ from 4/1 to 1/1, R _f =0.43 (hexane/CH ₂ Cl ₂ 1/1)). After purification, recycle preparative GPC (CH ₂ Cl ₂ as eluent) was performed to obtain 102 mg of compound 9a as a red solid (0.21 mmol, 21% yield).

Intermediate compound 9a
Mp: 273.5-274.3℃
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ1.38 (s, 24H), 7.21 (td, J = 7.6 Hz, 1.2 Hz, 2H), 7.27 (td, J = 7.4 Hz, 1.1 Hz, 2H ), 7.72 (dd, J = 7.3 Hz, 0.6 Hz, 2H), 7.90 (s, 2H), 8.00 (d, J = 7.3 Hz, 2H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ25.1, 83.8, 123.4, 125.7, 125.8, 128.8, 137.3, 139.2, 143.1, 146.2 (one signal of a carbon atom bonded to a boron atom is (not observed due to quadrupole relaxation)
HRMS (APCI): m/z Calcd. for C ₃₀ H ₃₅ B ₂ O ₄ : 481.2716 ([M+H] ⁺ ). Obsd. 481.2722

(Synthesis of intermediate compounds 10a and 11a)

Compound 10a ((E)-3,3'-bis(triethylsilyl)-1,1'-biindenylidene) was synthesized as follows.

Compound 1 (116 mg, 0.30 mmol), 4,4,5,5-tetramethyl-2-(triethylsilyl)-1,3,2-dioxaborolane (447 mg, 1.84 mmol), K ₂ CO ₃ (215 mg, 1. A solution of Pd(PPh ₃ ) ₄ (7 mg, 6.2 μmol) in THF (6 mL) and H ₂ O (1.2 mL) was stirred at 75° C. for 48 hours. CH ₂ Cl ₂ was added to the resulting mixture, the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×20 mL). The combined organic layers were washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (hexane as eluent, R _f =0.50) to obtain 720 mg of Compound 10a as a red solid (0.16 mmol, yield 52%).

Intermediate compound 10a
Mp: 122.2-123.2℃
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.90-0.95 (m, 12H), 1.01-1.05 (m, 18H), 7.21 (td, J = 7.5 Hz, 1.2 Hz, 2H), 7.26 ( td, J = 7.5 Hz, 1.2 Hz, 2H), 7.40 (dd, J = 7.2 Hz, 0.8 Hz, 2H), 7.61 (s, 2H), 7.95 (d, J = 7.3 Hz, 2H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ4.0, 7.8, 123.2, 125.5, 125.8, 128.8, 137.9, 138.1, 141.1, 147.9, 148.9
HRMS (APCI): m/z Calcd. for C ₃₀ H ₄₁ Si ₂ : 457.2741 ([M+H] ⁺ ). Obsd. 457.2737

Compound 11a ((E)-3-bromo-3'-triethylsilyl-1,1'-biindenylidene) was synthesized as follows.

Compound 1 (774 mg, 2.00 mmol), 4,4,5,5-tetramethyl-2-(triethylsilyl)-1,3,2-dioxaborolane (1.17 g, 4.81 mmol), K ₂ CO ₃ (1. A solution of Pd(PPh ₃ ) ₄ (48 mg, 0.042 mmol) in THF (40 mL) and H ₂ O (8 mL) was stirred at 75° C. for 12 hours. Toluene was added to the resulting mixture, the layers were separated, and the aqueous layer was extracted with toluene (3 x 30 mL). The combined organic layers were washed with saturated brine, dried over anhydrous Na ₂ SO ₄ and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (hexane as eluent, R _f =0.50), and then subjected to recycle preparative GPC (CHCl ₃ as eluent) to obtain 420 mg of compound 11a. Obtained as a red solid (1.00 mmol, yield 50%).

Intermediate compound 11a
Mp: 50.5-51.5℃
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.90-0.95 (m, 6H), 1.02-1.05 (m, 9H), 7.21 (td, J = 7.6 Hz, 1.1 Hz, 1H), 7.28 ( td, J = 7.5 Hz, 1.0 Hz, 1H), 7.33-7.37 (m, 1H), 7.38-7.41 (m, 3H), 7.57 (s, 1H), 7.63 (s, 1H), 7.91 (d, J = 7.3 Hz, 1H), 7.97 (d, J = 7.3 Hz, 1H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ3.9, 7.7, 121.2, 123.4, 125.1, 125.2, 126.0, 127.5, 127.8, 128.8, 128.9, 129.2, 136.6, 137.47, 1 37.54, 137.7, 141.5 , 141.9, 147.9, 149.9
HRMS (APCI): m/z Calcd. for C ₂₄ H ₂₆ ⁷⁹ BrSi: 421.0982 ([M+H] ⁺ ). Obsd. 421.0980

(Synthesis of intermediate compound 12a)

Compound 12a ((E)-3,3'-bis(tributylstannyl)-1,1'-biindenylidene) was synthesized as follows.

Compound 1 (79mg, 0.20mmol), _Sn2Bu6 ( _1.02mL , 2.04mmol), Pd(OAc) ₂ (1mg, 4.9μmol), and _PCy3 (2mg, 8.6μmol) in THF ( 4 mL) solution was stirred at 75° C. for 24 hours. The resulting mixture was cooled to room temperature and volatiles were removed by rotary evaporation. The obtained crude product was purified by silica gel column chromatography (hexane as eluent, R _f =0.45) to obtain 97 mg of compound 12a as a red solid (0.12 mmol, yield 59%). .

Intermediate compound 12a
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.91 (t, J = 14.7 Hz, 18H), 1.17-1.20 (m, J _C-Sn = 51.9 Hz, 12H), 1.37 (td, J = 14.7 Hz, 7.3 Hz, 12H), 1.58-1.65 (m, 12H), 7.19 (td, J = 7.1 Hz, 1.9 Hz, 2H), 7.22-7.28 (m, 4H), 7.58 (s, J _H- ¹¹⁷ _Sn = 29.0 Hz, J _H- ¹¹⁹ _Sn = 40.0 Hz, 2H), 7.95 (d, J = 7.6 Hz, J _H-Sn = 31.4 Hz, 4H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ10.0 (J _C- ¹¹⁷ _Sn = 333.3 Hz, J _C- ¹¹⁹ _Sn = 348.8 Hz), 13.8, 27.5 (J _C-Sn = 58.1 Hz) , 29.4 (J _C-Sn = 19.9 Hz), 123.2, 125.0, 125.4, 128.4, 137.5, 137.7, 139.8 (J _C-Sn = 50.9 Hz), 149.4 (J _C-Sn = 33.6 Hz), 153.7 (J _{C -} ¹¹⁷ _Sn = 328.8 Hz, J _C- ¹¹⁹ _Sn = 344.2 Hz)
¹¹⁹ Sn NMR (186.5 MHz, CDCl ₃ ): δ-55.7 (J ¹¹⁷ _{Sn -} ¹¹⁹ _Sn = 347.6 Hz)
HRMS (APCI): m/z Calcd. for C ₄₂ H ₆₅ ¹²⁰ Sn ₂ : 809.3130 ([M+H] ⁺ ). Obsd. 809.3142

(Synthesis of compounds 10b and 10c)

Dimeric compound 10b ((1E,1'''E)-3,3'''-bis(triethylsilyl)-1,1':3',1'':3'',1'''-quaterindene ) and trimer compound 10c ((1E, 1'''E, 1'''''E)-3,3'''''-bis(triethylsilyl)-1,1':3',1' ':3'',1''':3''',1'''':3'''',1'''''-sexiindene) was synthesized as follows.

(Synthesis of compounds 10b and 10c by Suzuki-Miyaura coupling)
Compound 9a (15 mg, 0.031 mmol), Compound 11a (30 mg, 0.071 mmol), K ₂ CO ₃ (24 mg, 0.18 mmol), and Pd(PPh ₃ ) ₄ (1 mg, 1 μmol) in THF (1 mL) and A H ₂ O (0.2 mL) solution was stirred at 75° C. for 24 hours. CH ₂ Cl ₂ was added to the resulting mixture, the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×10 mL). The combined organic layers were washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (hexane to hexane/CH ₂ Cl ₂ 9/1 as eluent) to obtain 1 mg of compound 10b as a black-red solid (2 μmol, yield 2%). , 8 mg of Compound 10c were obtained as a green solid (8.2 μmol, yield 26%), respectively.

(Synthesis of compound 10c by Migita-Kosugi-Stille coupling)
Compound 12a (35 mg, 0.043 mmol), Compound 11a (40 mg, 0.095 mmol), LiCl in THF (0.5 M, 0.19 mL, 0.095 mmol), and Pd(PPh ₃ ) ₄ (6 mg, 5 μmol) A THF (1 mL) solution of was stirred at 75°C for 32 hours. CH ₂ Cl ₂ was added to the resulting mixture, the layers were separated and the aqueous layer was extracted with CH ₂ Cl ₂ (3×15 mL). The combined organic layers were washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained crude product was purified by silica gel column chromatography (hexane to hexane/CH ₂ Cl ₂ 9/1 as eluent) to obtain 2 mg of compound 10c as a green solid (2.6 μmol, yield 6%).

Compound 10b
Mp: >300℃
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.93-0.98 (m, 6H), 1.03-1.08 (m, 9H), 7.24 (td, J = 7.5 Hz, 1.2 Hz, 1H), 7.28 ( td, J = 7.3 Hz, 1.2 Hz, 1H), 7.38-7.46 (m, 3H), 7.68 (s, 1H), 7.80 (dd, J = 7.3 Hz, 0.6 Hz, 1H), 7.92 (s, 1H) , 8.02 (d, J = 7.0 Hz, 1H), 8.11 (d, J = 7.3 Hz, 1H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ4.0, 7.8, 122.1, 123.4, 125.4, 125.9, 126.0, 126.7, 127.0, 128.7, 129.0, 137.7, 138.1, 138.4, 13 9.9, 142.4, 142.5 , 143.0, 147.9, 149.2
HRMS (APCI): m/z Calcd. for C ₄₈ H ₅₁ Si ₂ : 683.3524 ([M+H] ⁺ ). Obsd. 683.3520

Compound 10c
Mp: >300℃
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ0.96 (ddd, J = 15.9 Hz, 7.6 Hz, 1.6 Hz ,6H), 1.04-1.11 (m, 9H), 7.26 (dtd, J = 18.7 Hz , 7.4 Hz, 1.3 Hz, 2H), 7.39-7.48 (m, 5H), 7.69 (s, 1H), 7.82-7.85 (m, 2H), 7.95 (s, 1H), 7.97 (s, 1H), 8.02 (d, J = 7.0 Hz, 1H), 8.12 (d, J = 7.6 Hz, 1H), 8.15 (d, J = 7.0 Hz, 1H)
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ4.0, 7.8, 122.1, 122.3, 123.4, 125.4, 125.7, 125.9, 126.0, 126.6, 127.0, 127.2, 128.7, 128.9, 12 9.0, 137.7, 138.1 , 138.4, 138.5, 139.9, 141.8, 142.38, 142.44, 142.45, 142.48, 143.1, 147.9, 149.4
HRMS (APCI): m/z Calcd. for C ₆₆ H ₆₁ Si ₂ : 909.4306 ([M+H] ⁺ ). Obsd. 909.4298

Oligomers were synthesized according to the scheme below. This synthesis corresponds to the case using Suzuki-Miyaura coupling in Scheme S6 above.

Here, the case where R is a t-butyldimethylsilyl group or a hydrogen atom will be explained. In other cases, synthesis, isolation, and identification can be performed by similar methods.

(Synthesis of intermediate compound 15a by Miyaura-Ishiyama boration reaction)
Compound 5a (101 mg, 204 μmol), bispinacolate diboron (56.8 mg, 224 μmol), potassium acetate (101 mg, 1.03 mmol), Pd(PPh ₃ ) ₄ (7.1 mg, 6.1 μmol) were added to the reaction vessel. ), and THF (2 mL) were added, and the mixture was stirred at 80°C for 34 hours. Water (30 mL) and dichloromethane (30 mL) were added to the resulting reaction mixture, extracted with dichloromethane (10 mL x 3), and the solvent was distilled off under reduced pressure. Thereafter, the product was purified by silica gel column chromatography (hexane to dichloromethane to ethyl acetate) to obtain 68.0 mg of Compound 15a as a red solid (125 μmol, yield 61%).

Compound 15a
Mp: 206.5-206.6℃.
^1H NMR (500 MHz, CDCl ₃ ): δ8.16-8.15 (m, 1H), 8.02-7.98 (m, 2H), 7.82-7.80 (m, 1H), 7.73 (d, J = 7.8 Hz, 2H ), 7.66 (d, J = 8.0 Hz, 2H), 7.61-7.60 (m, 1H), 7.52 (d, J = 3.0 Hz, 1H), 7.33-7.27 (m, 3H), 7.23-7.20 (m, 1H), 1.41 (d, J = 1.4 Hz, 12H), 0.94 (d, J = 3.4 Hz, 9H), 0.34 (d, J = 3.2 Hz, 6H).
¹³ C{ ¹ H} NMR (125 MHz, CDCl ₃ ): δ150.2, 146.3, 142.3, 142.0, 141.4, 139.1, 138.4, 137.5, 135.4, 128.9, 128.5, 128.3, 127.9, 126.4 , 126.1, 125.6, 125.1 , 124.8, 123.7, 121.4, 83.8, 25.1.

(Synthesis of compounds 15b and 3c by Suzuki-Miyaura coupling)
To the reaction vessel, compound 15a (32.6 mg, 59.9 μmol), compound 1 (116 mg, 404 μmol), potassium carbonate (41.4 mg, 300 μmol), Pd(PPh ₃ ) ₄ (3.6 mg, 3.1 μmol) , THF (10 mL), and water (2 mL) were added, and the mixture was stirred at 75°C for 5 hours. Water (20 mL) and dichloromethane (50 mL) were added to the resulting reaction mixture, extracted with dichloromethane (10 mL x 3), and the solvent was distilled off under reduced pressure. Thereafter, by purifying with silica gel column chromatography (dichloromethane) and gel permeation chromatography (chloroform), 6.6 mg of compound 3c was obtained as a black solid (6.2 μmol, yield 21%), and 17.2 mg of compound 3c was obtained as a black solid. Compound 15b was obtained as a black solid (23.8 μmol, yield 40%).

Compound 15b
Mp: >300℃.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ8.18 (d, J = 7.5 Hz, 1H), 8.13-8.10 (m, 1H), 8.07 (d, J = 7.6 Hz, 1H), 8.04 ( d, J = 7.3 Hz, 1H), 7.98 (s, 1H), 7.88 (s, 1H), 7.82 (t, J = 8.5 Hz, 2H), 7.78 (d, J = 8.0 Hz, 2H), 7.70 ( d, J = 8.3 Hz, 3H), 7.68-7.65 (m, 1H), 7.60 (s, 1H), 7.49-7.34 (m, 9H), 0.95 (s, 9H), 0.35 (s, 6H).
¹³ C{ ¹ H} NMR (125 MHz, CD ₂ Cl ₂ ): δ150.0, 143.1, 142.6, 142.4, 141.9, 141.4, 140.8, 140.5, 139.2, 138.7, 138.5, 138.1, 136.2, 13 5.8, 135.4, 129.2 , 129.2, 129.0, 128.70, 128.66, 127.8, 127.6, 127.2, 127.02, 126.99, 126.8, 126.3, 125.8, 125.6, 125.0, 122.3, 122.1, 122 .0, 121.3, 26.7, 17.3, -6.0.
HRMS (MALDI): m/z Calcd for C ₄₈ H ₄₀ ⁷⁹ Br: 725.2077 ([M+H] ⁺ ). Obsd.: 723.2077.

(Synthesis of intermediate compound 14a by Miyaura-Ishiyama boration reaction)
Compound 14a was synthesized in the same manner as compound 15a, except that compound 4a was used instead of compound 5a (yield: 17%).

Compound 14a
^1H NMR (500 MHz, CDCl ₃ ): δ8.06-8.04 (m, 1H), 7.19 (s, 1H), 7.88 (d, J = 7.6 Hz, 1H), 7.71 (d, J = 7.3 Hz, 1H), 7.66-7.64 (m, 2H), 7.48-7.46 (m, 1H), 7.43-7.40 (m, 3H), 7.36-7.33 (m, 1H), 7.22-7.17 (m, 3H), 7.13- 7.09 (m, 1H), 1.31 (s, 12H).
^13C NMR (125 MHz, CDCl ₃ ): δ150.2, 146.3, 142.3, 142.0, 141.4, 139.1, 138.4, 137.5, 135.4, 128.9, 128.5, 128.3, 127.9, 126.4, 126 .1, 125.6, 125.1, 124.8, 123.7 , 121.4, 83.8, 25.1.

(Synthesis of compounds 14b and 2c by Suzuki-Miyaura coupling)
Compound 14b (yield 34%) and compound 2c (yield 18%) were synthesized in the same manner as compounds 15b and 3c, except that compound 14a was used instead of compound 15a.

Compound 14b
Mp: >300℃.
¹ H NMR (500 MHz, CD ₂ Cl ₂ ): δ8.19 (d, J = 7.1 Hz, 1H), 8.13-8.11 (m, 1H), 8.08 (d, J = 7.7 Hz, 1H), 8.05 ( d J = 7.2 Hz, 1H), 7.99 (s, 1H), 7.88 (s, 1H), 7.84-7.80 (m, 4H), 7.71 (s, 1H), 7.65-7.63 (m, 1H), 7.59 ( s, 1H), 7.55 (t, J = 7.4 Hz, 2H), 7.49-7.35 (m, 10H).
HRMS (MALDI): m/z Calcd for C ₄₂ H ₂₅ ⁷⁹ Br: 608.1140 ([M] ⁺ ), Obsd. 608.1136.

Oligomers were synthesized according to the scheme below. This synthesis corresponds to the case using Suzuki-Miyaura coupling in Scheme S8 above.

Here, the case where R is a t-butyldimethylsilyl group will be explained. That is, the case where compound 3d is synthesized from compound 15b will be explained. In other cases, synthesis and identification can be performed using similar methods.

Compound 15b (17.2 mg, 23.8 μmol), bispinacolate diboron (6.6 mg, 26 μmol), potassium carbonate (16.4 mg, 119 μmol), Pd(PPh ₃ ) ₄ (1.4 mg) were added to the reaction vessel. , 1.2 μmol), THF (10 mL), and water (2 mL) were added, and the mixture was stirred at 75° C. for 13 hours. Water (10 mL) and dichloromethane (30 mL) were added to the obtained reaction mixture, extracted with dichloromethane (15 mL x 3), the obtained organic layer was washed with water (30 mL), and the solvent was distilled off under reduced pressure. Thereafter, it was purified by silica gel column chromatography (dichloromethane to ethyl acetate) and filtered with dichloromethane using a membrane filter to obtain 2.1 mg of compound 3d as a black solid (1.6 μmol, in the case of 100% purity) yield of 14%).

compound 3d
In the mass spectrum, a clear peak was observed at the position corresponding to the tetramer compound 3d. This revealed that a tetrameric compound was indeed formed.
HRMS (MALDI): m/z Calcd for C ₉₆ H ₇₈ Si ₂ : 1286.5636 ([M] ⁺ ). Obsd.: 1286.5652.

[Crystal structure analysis]
Crystal structure analysis was performed on a part of the obtained oligomer.

Compound 2b
A black plate-like single crystal was grown by slowly diffusing n-hexane into a CH ₂ Cl ₂ solution of compound 2b. Intensity data of synchrotron radiation (λ=0.4137 Å) at BL02B1 beamline of SPring-8 (JASRI) was collected at 100K. We measured 16301 reflections with a maximum 2θ angle of 31.2°, of which 3339 were independent reflections (R _int =0.0877). The structure was analyzed by the direct method (SHELXT-2018/2) and refined by full matrix least squares on F ² (SHELXL-2018/3). All hydrogen atoms were placed using the AFIX command and all non-hydrogen atoms were refined anisotropically.

Crystal data: C ₄₈ H ₃₀ ; FW = 606.72, crystal size = 0.02x0.01x0.01 mm ³ , triclinic, P-1 (#2), a = 3.8411(3) Å, b = 11.5144(9) Å, c = 17.6125(13) Å, α= 107.216(7)°, β= 90.470(6)°, γ= 97.393(6)°, V = 737.00(10) Å ³ , Z = 1, D _c = 1.367 g cm ^-3 , μ= 0.036 mm ^-1 , R ₁ = 0.0632 (I > 2σ(I)), wR ₂ = 0.1397 (all data), GOF = 1.108.

FIG. 2 shows the results of crystal structure analysis of compound 2b. As shown in FIG. 2, it was found that in Compound 2b, the fulvalenes were directly bonded to each other, and a dimer was indeed formed. Furthermore, each molecule had a relatively flat structure, and the distance between the closest carbon atoms between molecules was 3.372 Å.

Compound 3b
Yellow plate-like single crystals were grown by slow diffusion of i-PrOH into a CH ₂ Cl ₂ solution of compound 3b. Intensity data of synchrotron radiation (λ = 0.4125 Å) at BL02B1 beamline of SPring-8 (JASRI) was collected at 100K. We measured 56114 reflections with a maximum 2θ angle of 31.1°, of which 5732 were independent reflections (R _int =0.1759). The structure was analyzed by the direct method (SHELXT-2018/2) and refined by full matrix least squares on F ² (SHELXL-2018/3). All hydrogen atoms were placed using the AFIX command and all non-hydrogen atoms were refined anisotropically. Note that this compound was crystallized in a state in which CH ₂ Cl ₂ was solvated.

Crystal data: C ₆₀ H ₅₉ Si ₂ ^. CH ₂ Cl ₂ ; FW = 920.17, crystal size = 0.01x0.01x0.01 mm ³ , orthorhombic, Ccc2 (#37), a = 23.5244(14) Å, b = 29.1379 (16) Å, c = 7.2938(4) Å, V = 4999.5(5) Å ³ , Z = 4, D _c = 1.222 g cm ^-3 , μ = 0.061 mm ^-1 , R ₁ = 0.0653 (I > 2σ (I)), wR ₂ = 0.1656 (all data), GOF = 1.004.

FIG. 3 shows the results of crystal structure analysis of compound 3b. As shown in FIG. 3, it was found that in Compound 3b, the fulvalenes were directly bonded to each other, and a dimer was definitely formed. Furthermore, each molecule had a slightly curved polar structure compared to Compound 2b, and the distance between the closest carbon atoms in the molecule was 3.654 Å.

Compound 8
Crystal structure analysis was performed using the BL02B1 beamline of SPring-8 (JASRI) in the same manner as for compounds 2b and 3b. The results are shown in FIG.

FIG. 4 shows the results of crystal structure analysis of Compound 8. As shown in FIG. 4, Compound 8 had a relatively large dihedral angle and did not have very high planarity. However, in Compound 8, it was confirmed that the fulvalenes were directly bonded to each other to form a dimer.

Compound 10b
A red plate-like single crystal was grown by slowly diffusing MeOH into a CH ₂ Cl ₂ solution of compound 10b. Intensity data were collected at 133 K using a Rigaku XtaLAB AFC10 diffractometer equipped with a FR-X generator, Varimax optics, and a PILATUS 200K photon counting detector with MoKα radiation (λ = 0.71073 Å). We measured 11398 reflections at a maximum 2θ angle of 55.0°, of which 4233 were independent reflections (R _int =0.0296). The structure was analyzed by the direct method (SHELXT-2018/2) and refined by full matrix least squares on F ² (SHELXL-2018/3). All hydrogen atoms were placed using the AFIX command and all non-hydrogen atoms were refined anisotropically.

Crystal data: C ₄₈ H ₅₀ Si ₂ ; FW = 683.06, crystal size = 0.20x0.05x0.01 mm ³ , tetragonal, I-4 (#82), a = 23.1624(9) Å, b = 23.1624(9) Å, c = 7.2304(4) Å, V = 3879.1(4) Å ³ , Z = 4, D _c = 1.170 g cm ^-3 , μ= 0.124 mm ^-1 , R ₁ = 0.0417 (I > 2σ(I) ), wR ₂ = 0.1100 (all data), GOF = 1.056.

FIG. 5 shows the results of crystal structure analysis of compound 10b. In FIG. 5, (a) is a thermal ellipsoid plot (probability 50%), (b) is a side view, and (c) and (d) show the packing structure. As shown in FIG. 5, it was found that in Compound 10b, the fulvalenes were directly bonded to each other, and a dimer was definitely formed.

Compound 10c
A green block-like single crystal was grown by slowly diffusing MeCN into a CH ₂ Cl ₂ solution of compound 10c. Intensity data were collected at 128K using a Rigaku XtaLAB AFC10 diffractometer equipped with a FR-X generator, Varimax optics, and a PILATUS 200K photon counting detector with MoKα radiation (λ = 0.71073 Å). We measured 63302 reflections with a maximum 2θ angle of 55.0°, of which 11386 were independent reflections (R _int =0.0669). The structure was analyzed by the direct method (SHELXT-2018/2) and refined by full matrix least squares on F ² (SHELXL-2018/3). All hydrogen atoms were placed using the AFIX command and all non-hydrogen atoms were refined anisotropically.

Crystal data: C ₆₆ H ₆₀ Si ₂ ; FW = 909.32, crystal size = 0.20x0.10x0.10 mm ³ , monoclinic, P2 ₁ /n (#14), a = 18.8784(12) Å, b = 13.8630(6 ) Å, c = 20.8684(15) Å, β= 114.320(8)°, V = 4976.8(6) Å ³ , Z = 4, D _c = 1.214 g cm ^-3 , μ = 0.114 mm ^-1 , R ₁ = 0.0771 (I > 2σ(I)), wR ₂ = 0.2331 (all data), GOF = 1.093.

FIG. 6 shows the results of crystal structure analysis of compound 10c. In FIG. 6, (a) is a thermal ellipsoid plot (probability 50%) of two crystallographically independent molecules, (b) is a side view, and (c) shows the packing structure. As shown in FIG. 6, it was found that in Compound 10c, the fulvalenes were directly bonded to each other, and a trimer was certainly formed.

As mentioned above, it was confirmed from the crystal structure analysis results that compounds 2b, 3b, 8, 10b, and 10c had certainly formed oligomer structures. Furthermore, since differences in steric structure and packing structure were observed in these compounds, it was found that the crystal structure of the oligomer can be controlled by changing the substituents in the 1,1'-biindenylidene skeleton or the cap portion.

[UV-visible near-infrared absorption spectrum]
A portion of the obtained oligomer was subjected to ultraviolet-visible near-infrared absorption spectroscopy. Further, for comparison purposes, similar measurements were performed on the monomer of n=1 and fullerene C ₆₀ . UV/Vis/NIR absorption spectra were measured on a Shimadzu UV-3600 spectrophotometer with a resolution of 0.2 nm using diluted sample solutions in spectral grade THF in 1 cm square quartz cuvettes.

FIG. 7 shows the measurement results of ultraviolet-visible and near-infrared absorption spectra for compounds 3b and 3c. FIG. 7 also shows the measurement results for Compound 3a and Fullerene C ₆₀ .

As shown in Figure 7, in the order of compound 3a (monomer), compound 3b (dimer), and compound 3c (trimer), the shoulder-like absorption on the longer wavelength side is red-shifted (longer wavelength). I found out that it was. Specifically, the respective absorption wavelengths increased to 476 nm, 616 nm, and 670 nm in this order. At the same time, the molar extinction coefficient ε also increased. This result suggested that the π conjugation between units expanded as oligomers formed and n increased.

Further, in FIG. 7, in fullerene C ₆₀ , the absorption band at the longest wavelength (623 nm) was prohibited and its intensity was weak. On the other hand, in Compound 3b and Compound 3c, the absorption band in the long wavelength region was permissible and the intensity thereof was high. More specifically, it was found that Compound 3b and Compound 3c have molar extinction coefficients that are more than two orders of magnitude higher than Fullerene C ₆₀ , and Compound 3c exhibits a higher absorption wavelength (670 nm) than Fullerene C ₆₀ . Ta.

FIG. 8 shows the measurement results of ultraviolet-visible-near-infrared absorption spectrum for compound 8. FIG. 8 also shows the measurement results for the monomer corresponding to Compound 8.

As shown in FIG. 8, a longer absorption wavelength and an increase in molar extinction coefficient were also observed in Compound 8 compared to the corresponding monomer. This result also suggested that the formation of oligomers expanded the π-conjugation between units.

[Electrochemical measurement]
Cyclic voltammetry (CV) measurements were performed on an ALS/chi-670A electrochemical analyzer (BAS). A CV cell was used consisting of a glassy carbon electrode, a Pt wire counter electrode, and an Ag/AgNO 3 reference electrode. Measurements were performed under a _N2 atmosphere using a sample solution in THF at a concentration of 1 mM containing 0.1 M tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The redox potential was calibrated with a ferrocene/ferrocenium ion pair.

9A and 9B show the results of cyclic voltammetry (CV) measurements for compounds 3b and 3c. FIGS. 9A and 9B also show measurement results for compound 3a and fullerene C ₆₀ .

As shown in FIG. 9A, the first reduction potential is shifted to the positive side in the order of compound 3a (monomer), compound 3b (dimer), and compound 3c (trimer), that is, higher It has been revealed that it has electron affinity. Specifically, the respective first reduction potentials increase in order to -1.48V, -1.19V, and -1.09V, and reach the first reduction potential (-0.89V) of fullerene C _60. They had comparable electron affinities. Moreover, these compounds, like fullerene C ₆₀ , showed reversible redox processes. A two-step reversible reduction process was observed for compound 3a (monomer), whereas a four-step reversible reduction process was observed for compound 3b (dimer), and a five-step reversible reduction process for compound 3c (trimer). process was observed.

Furthermore, as shown in Figure 9B, analysis using the Randles-Sevcik equation based on the results of cyclic voltammetry revealed that the first-stage reduction of compound 3c (trimer) is a two-electron reduction. It became clear that That is, it was found that compound 3a (monomer) can be reversibly reduced with 2 electrons, compound 3b (dimer) with 4 electrons, and compound 3c (trimer) with 6 electrons. This suggests that in the oligomer according to the present invention, reversible reduction of 2n electrons to the n-mer is possible.

Furthermore, as shown in FIG. 9B, the difference between the first reduction potential and the second reduction potential becomes smaller in the order of compound 3a (monomer), compound 3b (dimer), and compound 3c (trimer). That's what I found out. Specifically, the respective reduction potential differences were narrowed to 0.31V, 0.15V, and 0V. This result suggested that in the oligomer according to the present invention, even dianions are particularly likely to be generated. Regarding the formation of dianions, we also conducted a study using quantum chemical calculations, as described later.

FIG. 10 shows the results of cyclic voltammetry (CV) measurements for Compound 8. FIG. 10 also shows the measurement results for the monomer corresponding to Compound 8.

As shown in FIG. 10, an increase in the first reduction potential was also observed in Compound 8 compared to the corresponding monomer. Moreover, it was found that reversible reduction of 2n=4 electrons was also observed for compound 8.

[Quantum chemical calculation]
Geometric optimization was performed using Gaussian 16 Revision B. The PBE0/6-31+G(d) level of the theory implemented in 01 was performed using default thresholds and algorithms. The stationary points were optimized without any symmetry assumption and identified by frequency analysis at the same theoretical level (the number of imaginary frequencies is 0).

FIG. 11 shows changes in calculated values of carbon-carbon bond distances in the dianion structures of compounds 3b and 3c. Specifically, in FIG. 11, structural optimization is performed for compounds 3b and 3c and their dianions, and the distances between carbon atoms in the main chain are plotted in order from the left. In addition, in the example shown in FIG. 11, for simplicity, the calculation was performed assuming that R=trimethylsilyl group.

As shown in FIG. 11, the tendency of bond alternation was reversed between the dianion and the neutral species. Furthermore, in the dianion, the change in bond distance between the five-membered ring portions at both ends was particularly small. This result shows that in the dianion of the oligomer mentioned above, the dianion structure is stabilized because the negative charges are separated and localized at the ends to acquire aromaticity and the repulsion between negative charges is suppressed. It is assumed that there are. In addition, as the chain length increases, the separation of charges within the molecule becomes larger, and the repulsion between negative charges becomes smaller. Therefore, as the number of oligomer units increases, the difference between the first and second reduction potentials increases. is considered to have become smaller. This tendency is a characteristic of expanding the pentafulvalene structure into a one-dimensional (chain-like) structure, and the design concept explained earlier with reference to Figure 1 confirms the difference from fullerene _C60 , etc. It is suggested that it is produced by

FIG. 12 shows changes in the calculated value of the carbon-carbon bond distance in the dianion structure of Compound 8. Specifically, in FIG. 12, structure optimization is performed for Compound 8 and its dianion, and distances between carbon atoms in the main chain are plotted in order from the left. As shown in FIG. 12, it was found that a similar tendency was observed in Compound 8 as well.

FIG. 13 shows an example of calculating the frontier orbital level of a chain trimer according to one embodiment of the present invention. FIG. 13 also shows calculated values for fullerene C ₆₀ and the hypothetical cyclic trimer described above with reference to FIG. 1. The chain trimer shown in FIG. 13 corresponds to formula (I) in which R ¹ = hydrogen atom, A = hydrogen atom, and n = 3.

As can be seen from FIG. 13, the linear trimer has a higher HOMO compared to fullerene _C60 . Also, linear trimers have lower LUMOs compared to corresponding cyclic trimers. Furthermore, linear trimers have smaller HOMO-LUMO gaps compared to fullerene C ₆₀ and the corresponding cyclic trimers. These calculation results are in good agreement with the above-mentioned observation results of the oligomer's light absorption on the long wavelength side and high electron affinity.

FIG. 14 shows calculation results of frontier orbital levels and their orbital distributions for compounds 3b and 3c. FIG. 14 also shows the measurement results for Compound 3a and Fullerene C ₆₀ . In addition, in the example shown in FIG. 14, for simplicity, the calculation was performed assuming that R=trimethylsilyl group.

As shown in FIG. 14, the LUMO decreases and the HOMO increases in the order of compound 3a (monomer), compound 3b (dimer), and compound 3c (trimer). This calculation result suggests that the oligomer according to the present invention typically has a LUMO as low as fullerene C ₆₀ and a higher HOMO than fullerene C ₆₀ . It is also suggested that the oligomer according to the present invention typically has a narrower HOMO-LUMO gap than fullerene _C60 .

Furthermore, in Figure 14, if we pay attention to the distribution of orbitals, we can see that in the above oligomer, both HOMO and LUMO have delocalized π orbitals and π ^* orbitals along the main chain direction. . This calculation result suggests that the oligomer according to the present invention typically has a delocalized electronic structure like polyacetylene.

Furthermore, as described for the case of n = 3 in Figure 14, the oscillator strength of the lowest energy transition of the trimer obtained from the TD-DFT calculation is a very high value of 1.93. Ta. It is thought that such high oscillator strength corresponds to the delocalized HOMO-LUMO transition.

FIG. 15 shows an example of calculating the frontier orbital level of an oligomer according to one embodiment of the present invention. FIG. 15 also shows calculation results for the corresponding monomers and corresponding oligoenes.

As shown in FIG. 15, in both the oligomer according to one embodiment of the present invention and the corresponding oligoene, as the number n of repeating units increases, the LUMO decreases and the HOMO increases. However, the above oligomers have significantly lower LUMOs compared to the corresponding oligoenes. In particular, in this calculation example, when n is 3 or more, the above oligomer has a LUMO lower than fullerene C ₆₀ . The oligomers described above also have narrower HOMO-LUMO gaps compared to the corresponding oligoenes. These calculation results suggest that the above oligomer has an electronic structure similar to that of the corresponding oligoene (that is, an electronic structure similar to that of polyacetylene) and also has excellent electron-accepting properties.

Claims (15)

An oligomer containing an n-mer (n is a natural number from 2 to 5) of 1,1'-biindenylidene or its derivative. The oligomer according to claim 1, which is represented by the following formula (I).
In formula (I),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of A is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5. 2. Each of A is independently selected from the group consisting of an aryl group, an alkenyl group, an alkynyl group, an alkyl group, an alkoxy group, an amino group, a silyl group, a boryl group, a stannyl group, and a halogen atom. Oligomers described in. The oligomer according to claim 2 or 3, which is represented by the following formula (II).
In formula (II),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ² is independently a hydrogen atom or an arbitrary substituent,
n is a natural number from 2 to 5. Each of R ² is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate. 5. The oligomer according to claim 4, wherein the oligomer is selected from the group consisting of amide groups, amino groups, phosphoryl groups, and boryl groups. Each of R ¹ independently represents a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, an alkylthio group, an arylthio group, an acyl group, an acyloxy group, a carbamate group, The oligomer according to any one of claims 2 to 5, wherein the oligomer is selected from the group consisting of an amide group and a silyl group, or wherein adjacent R ^1s are bonded to each other to form a ring structure. The oligomer according to any one of claims 2 to 6, wherein each R ¹ is the same or adjacent R ^1s are bonded to each other to form a symmetrical ring structure. A compound represented by the following formula (III).
In formula (III),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
Each of R ³ is independently selected from the group consisting of an aryl group, an alkyl group, an alkenyl group, an alkynyl group, a silyl group, a boryl group, and a stannyl group, and at least one of the two R ³ is a silyl group, It is a boryl group or a stannyl group, and two ^R3s are not trimethylsilyl groups at the same time. The compound according to claim 8, which is represented by the following formula (III-A).
In formula (III-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of silyl group, boryl group, and stannyl group,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, It is selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group. A compound represented by the following formula (IV).
In formula (IV),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
R ³ is selected from the group consisting of aryl group, alkyl group, alkenyl group, alkynyl group, silyl group, boryl group, and stannyl group,
X is a halogen atom. The compound according to claim 10, which is represented by the following formula (IV-A).
In formula (IV-A),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
^R4 is a hydrogen atom, an alkyl group, a perfluoroalkyl group, an alkoxy group, a polyalkylene glycol group, an aryloxy group, a siloxy group, a silyl group, an alkylthio group, an arylthio group, a sulfonyl group, an acyl group, an acyloxy group, a carbamate group, selected from the group consisting of an amide group, an amino group, a phosphoryl group, and a boryl group,
X is a halogen atom. 12. A compound according to any one of claims 8 to 11, used for the production of an oligomer according to any one of claims 1 to 7. A step of preparing at least one compound selected from the group consisting of the compound according to any one of claims 8 to 12 and the compound represented by the following formula (V),
performing a coupling reaction using the at least one compound;
The method for producing an oligomer according to any one of claims 1 to 7, comprising:
In formula (V),
Each of R ¹ is independently a hydrogen atom or an arbitrary substituent, or adjacent R ¹ are bonded to each other to form a ring structure,
X is a halogen atom. 13. The step of preparing the at least one compound comprises synthesizing the compound according to any one of claims 8 to 12 using the compound represented by formula (V). The manufacturing method described in. An electron-accepting material comprising the oligomer according to any one of claims 1 to 7.