JP2015071640A - Fullerene derivative solution and fullerene derivative film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fullerene derivative having solubility to an alkaline solvent in addition to high solubility to an ester solvent and capable of simply being manufactured only with inexpensive raw material, a solution thereof and a film thereof.SOLUTION: There is provided a fullerene derivative represented by the formula (I). (I), where Rrepresents a hydrocarbon group which contains 1 to 3 hydroxyl group(s), may have a substituent other than the hydroxyl group and has aromaticity with 6 to 18 carbon atoms, a represents an average addition number of Rof 1 to 15, b represents the average addition number of hydrogen atom (H) of 0 to 4 while satisfying a>b, and a structure represented by a circle represents a fullerene skeleton.

Description

  The present invention relates to a novel fullerene derivative, a solution thereof, and a membrane thereof.

Since the mass synthesis of C ₆₀ has been established in 1990, studies on fullerene has been energetically developed. As a result, many fullerene derivatives with controlled solubility, electron acceptability, light absorption properties, etc. have been synthesized and their various functions have been clarified. Along with this, developments are being made for various applications such as electronic materials such as organic semiconductors, functional optical materials, and coating materials that replace conventional amorphous hydrocarbon films.

By the way, in order to use fullerene derivatives as electronic materials, optical materials, metal complex ligands, or as intermediates of other fullerene derivatives, fullerene derivatives exhibit high solubility in organic solvents. It is preferable.
In order to impart solubility to fullerenes, several reactions for adding organic groups such as hydrocarbons have been reported. For example, Non-Patent Document 1 proposes a method of using an organometallic reagent such as a Grignard reagent and a copper complex as a reaction for adding an aryl group to a fullerene skeleton.

In addition, fullerene derivatives that are soluble in aromatic hydrocarbon solvents such as toluene, halogen solvents such as chloroform, aliphatic hydrocarbon solvents such as hexane, etc. have been developed by applying the reaction described in Non-Patent Document 1. Has been.
Furthermore, from the viewpoints of safety and volatility, propylene glycol-1-monomethyl ether-2-acetate (hereinafter sometimes referred to as “PGMEA” as appropriate) is easy to handle and is generally used in industrial applications. Fullerene derivatives exhibiting high solubility in ester solvents represented by the above have also been developed (see Patent Document 1).

  Also, as a method for synthesizing fullerene derivatives using only inexpensive reagents, a method by which a plurality of phenyl groups can be added to the fullerene skeleton by the action of aluminum chloride in a benzene solution has been reported by Orar et al. Patent Document 2), Nakamura et al. Improve the reaction and determine the structure (Non-Patent Document 3). Furthermore, by improving this reaction, in addition to high solubility in ester solvents such as PGMEA, it has solubility in alkaline solvents, and fullerene derivatives that can be easily produced only with inexpensive raw materials and solutions thereof And a film thereof can be provided (Patent Document 2).

  Further, as a fullerene synthesis method using only other inexpensive reagents, there has been reported a method capable of adding an aryl halide to a fullerene skeleton by acting iron (III) chloride (Patent Document 3). .

JP 2006-56878 A JP 2010-59110 A JP 2009-132680 A

J. et al. Am. Chem. Soc. , 1996, 118, 12850-12551 J. et al. Am. Chem. Soc. 1991, 113, 9387-9388. Angew. Chem. Int. Ed, 2007, 46, 3513

  However, in the method described in Patent Document 1, there are complicated steps including preparation of a Grignard reagent, and a large amount of expensive raw materials are used, which is not sufficient from the viewpoint of production cost. Moreover, although the method described in Patent Document 2 shows high solubility in an ester solvent or an alkaline solvent, it has a property that protons added to the fullerene derivative are easily oxidized, and thus there is a problem in stability under air. . In the method described in Patent Document 3, a halogen atom is introduced into the fullerene derivative. However, the presence of the halogen atom may cause chemical contamination in applications in the field of electronic materials such as organic semiconductors. Development of fullerene derivatives containing no halogen atom is desired. Furthermore, when an aromatic hydrocarbon which is not halogen-substituted is introduced using the method described in Patent Document 3, there is an interaction with a metal compound described later, and it is difficult to purify and isolate the product. It was.

  The present invention has been made in view of the above-described problems. That is, fullerene derivatives that exhibit high oxidation resistance in ester solvents such as PGMEA and alkaline solvents, are applicable to aromatic hydrocarbons that are not halogen-substituted, and can be easily produced using only inexpensive raw materials, and solutions thereof And a membrane thereof.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention acted on a specific metal compound and an aromatic hydrocarbon which is not substituted with a halogen and has a hydroxyl group or a hydroxyl group protector, and has a low oxidation resistance proton. Succeeded in reducing the introduction of. The fullerene derivative of the present invention is not introduced with a halogen atom, and not only exhibits high solubility in ester solvents such as PGMEA and alkaline solvents, but also has high oxidation resistance. Furthermore, the present inventors have found that this fullerene derivative can be easily produced with only inexpensive raw materials and can be applied to aromatic hydrocarbons not substituted with halogen by using a chelating agent after the reaction, thus completing the present invention.

  That is, the gist of the present invention resides in a fullerene derivative represented by the following formula (I) (claim 1).

(In the formula (I),
R ¹ represents a hydrocarbon group having 6 to 18 carbon atoms which contains 1 to 3 hydroxyl groups and may have a substituent other than hydroxyl groups,
a represents an average addition number of R ¹ of ^{1 to} 15,
b represents an average addition number of H (hydrogen atom) of 0 or more and 4 or less,
And a> b is satisfied,
A structure indicated by a circle represents a fullerene skeleton. )
Each R ¹ in the formula (I) preferably has 1 or more and 2 or less substituents (Claim 2).
The substituent contained in each R ¹ in the formula (I) preferably has an organic group having 1 to 20 carbon atoms (Claim 3).
The hydrocarbon group having aromaticity in each R ¹ in the formula (I) is preferably a phenyl group (Claim 4).
In the formula (I), a is preferably 4 or more and 12 or less (Claim 5).
The fullerene skeleton in the formula (I) is preferably fullerene C ₆₀ and / or fullerene C ₇₀ (Claim 6).
The fullerene derivative in which the fullerene skeleton in the formula (I) is fullerene C ₆₀ and / or fullerene C ₇₀ , and the fullerene in which the fullerene skeleton in the formula (I) is a fullerene other than fullerene C ₆₀ and fullerene C ₇₀ And a derivative thereof (Claim 7).
Another gist of the present invention resides in a fullerene derivative solution, wherein the above-mentioned fullerene derivative is dissolved in a solvent (claim 8).

At this time, the solvent is preferably an ester solvent.
Further, another gist of the present invention resides in a fullerene derivative film comprising the above-mentioned fullerene derivative (claim 10).
Another aspect of the present invention is to react a fullerene, at least one metal compound in Group 8, 9, or 10 of the periodic table and a compound represented by HR ¹ , and then react the reaction solution. The method for producing a fullerene derivative according to claim 1, wherein the metal compound is removed by adding a chelating agent having at least one amino group or carboxyl group. Item 11).

  According to the present invention, a fullerene derivative that exhibits not only high solubility in an ester solvent such as PGMEA and an alkaline solvent, but also high oxidation resistance, and that can be easily produced using only inexpensive raw materials, a solution thereof, and a membrane thereof Can be provided.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the scope of the invention.
[1. Fullerene derivative]
[1-1. Fullerene Derivative Structure]
(Fullerene skeleton)
The fullerene derivative of the present invention is represented by the formula (1).

Here, the “fullerene skeleton” represented by a circle in the formula (1) is a carbon cluster having a closed shell structure. The carbon number of the fullerene skeleton is usually an even number of 60 or more and 130 or less.
Specific examples of the fullerene skeleton include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ and higher carbon clusters having more carbon than these. Can be mentioned.

In the present specification, a fullerene skeleton having i carbon atoms (where i represents an arbitrary natural number) is appropriately represented by a general formula “C _i ”.
The “fullerene derivative” is a general term for compounds or compositions having a fullerene skeleton. That is, fullerene derivatives include those having a substituent on the fullerene skeleton, those containing a metal or a compound in the fullerene skeleton, and those having a complex formed with another metal atom or compound. Further, the fullerene derivative may contain only one compound represented by the above formula (1), and two or more compounds represented by the above (1) may be used in any ratio and combination. It may be included.

Although the fullerene skeleton which the fullerene derivative of the present invention has is not limited, fullerene C ₆₀ or fullerene C ₇₀ is preferable, and fullerene C ₆₀ is more preferable. Since fullerene C ₆₀ and fullerene C ₇₀ are obtained as main products during the production of fullerene, there is an advantage that they are easily available. That is, the fullerene derivative of the present invention is preferably a derivative of fullerene C ₆₀ or fullerene C _70, and more preferably a derivative of fullerene C _60.

Moreover, from the viewpoint of the production cost of the fullerene derivative, the fullerene derivative of the present invention includes a fullerene derivative in which the fullerene skeleton in the formula (I) is a fullerene C ₆₀ and / or fullerene C ₇₀ , and a fullerene in the formula (I). skeleton is preferably a composition of the fullerene derivative is other than fullerene C ₆₀ or fullerene C _70. In this case, the mixing ratio of the fullerene C ₆₀ derivative, fullerene C ₇₀ derivative, and fullerene skeleton derivatives other than fullerene C ₆₀ and fullerene C ₇₀ is arbitrary, and may be determined according to the use of the fullerene derivative of the present invention.

In the case where the fullerene derivative is the above composition, the fullerene skeleton other than the fullerene C ₆₀ and the fullerene C ₇₀ in the formula (I) is, for example, C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , _C96 etc. are mentioned. The fullerene skeleton derivatives other than fullerene C ₆₀ and fullerene C ₇₀ may be contained alone in the fullerene derivative of the present invention, or two or more may be contained in any ratio and combination. .

(Hydrocarbon group R ¹ and its average addition number a)
In the formula (I), R ¹ represents a hydrocarbon group having an aromaticity of 6 to 18 carbon atoms which contains a hydroxyl group of 1 to 3 and may have a substituent other than the hydroxyl group. This R ¹ is bonded to the fullerene skeleton. The bonding position with the fullerene skeleton in R ¹ is not particularly limited, and preferable bonding positions can be determined depending on the reactivity of the raw materials used. For example, when 2,6-dimethylphenol is used as a raw material for introducing R ¹ , it can be bonded to the fullerene skeleton at the para-position of the hydroxyl group.

The number of carbon atoms of the aromatic hydrocarbon group is usually 6 or more, and is usually 18 or less, preferably 16 or less, more preferably 12 or less.
Specific examples of the aromatic hydrocarbon group include phenyl group; vinylphenyl group such as vinylphenyl group, divinylphenyl group, and trivinylphenyl group; pentarenyl group, indenyl group, naphthyl group, azulenyl group, and heptaenyl. Group, biphenylenyl group, as-indacenyl group, s-indacenyl group, acenaphthylenyl group, fluorenyl group, phenalenyl group, phenanthrenyl group, anthracenyl group, fluoracenyl group, acephenanthrylenyl group, aceantienylenyl group, triphenylenyl group, pyrenyl group, chrysenyl group A condensed polycyclic hydrocarbon group such as a group and a tetracenyl group.

Among these, a phenyl group, a naphthyl group, an anthracenyl group, a phenalenyl group, and a pyrenyl group are preferable from the viewpoint of raw material procurement, and a phenyl group and a naphthyl group are particularly preferable from the viewpoint of ease of synthesis.
The number of hydroxyl groups bonded to the aromatic hydrocarbon group is an integer of 1 to 3. Among them, the number of hydroxyl groups is preferably 1 from the viewpoint of easy reaction control when performing further reactions and the ease of synthesis.

The hydroxyl group may be bonded to any position of the aromatic hydrocarbon group. Usually, the bonding position is appropriately determined according to the raw material and the like.
Moreover, in order to produce the fullerene derivative of the present invention at a low cost and more simply, it is preferable to omit the deprotection step described later in the production. Therefore, the interaction between iron (III) chloride as a raw material and a hydroxyl group is preferably low, and it preferably has a substituent other than the hydroxyl group in addition to the hydroxyl group.

  The type of the substituent is not particularly limited as long as it does not significantly impair the excellent physical properties of the fullerene derivative according to the present invention, but an organic group is usually preferable. In addition, there is no particular limitation on the bonding position of the substituent to the aromatic hydrocarbon group, but in particular, the positional relationship between the hydroxyl group and the substituent in the aromatic hydrocarbon group is the ortho position. It is preferable. Moreover, when there are two or more types of substituents, it is preferable that the substituents are respectively bonded to both ortho positions of the hydroxyl group.

When the substituent is an organic group, the carbon number thereof is arbitrary as long as the effects of the present invention are not significantly impaired, but it is usually 1 or more, and the upper limit is usually 20 or less, preferably 10 or less. . When there are too many carbon atoms, acquisition of raw materials may become difficult.
Moreover, the organic group which is a substituent may be linear, and may have a branch. The organic group may be a chain or a ring. Furthermore, the organic group may have only a saturated bond or may have an unsaturated bond.

  Specific examples of the substituent when the substituent is an organic group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, linear or branched chain alkyl groups such as sec-butyl group, iso-butyl group, tert-butyl group, tert-amyl group, 2-methylbutyl group, 3-methylbutyl group; cyclopropyl group, cyclobutyl group, cyclopentyl Group, cyclohexyl group, cycloheptyl group, norbornyl group, tricyclodecanyl group, adamantyl group and other cyclic alkyl groups; allyl group, crotyl group, cinnamyl group and other alkenyl groups; phenyl group, biphenyl group, naphthyl group and other aryl groups Group, alkoxy group such as methoxy group, ethoxy group, and aryloxy group such as phenoxy group It is.

Moreover, when the said substituent is an organic group, the said substituent may have a substituent further. However, when the said substituent further has a substituent, it is preferable that the sum total of all the carbon number in the said substituent containing a substituent satisfy | fills the said conditions. In addition, these substituents may be further substituted in multiple by one or more substituents.
Among these, from the viewpoint of raw material procurement and environmental load, the substituent is preferably a linear or branched alkyl group, a cyclic alkyl group, or an aryl group, and particularly preferably a methyl group.

The number of substituents in each R ¹ , that is, the number of substituents bonded to an aromatic hydrocarbon group is arbitrary, but is usually preferably 1 or more and 2 or less from the viewpoint of raw material procurement. In addition, when it has two or more substituents, the kind of substituent may be one kind, and two or more kinds of substituents may be substituted in any combination and ratio.
Specific examples of R ¹ include hydroxyphenyl group; alkylhydroxyphenyl such as methylhydroxyphenyl group, ethylhydroxyphenyl group, propylhydroxyphenyl group, butylhydroxyphenyl group, isopropylhydroxyphenyl group, and tert-butylhydroxyphenyl group. Groups: Cyclic alkylhydroxyphenyl groups such as cyclohexylhydroxyphenyl group, norbornylhydroxyphenyl group, adamantylhydroxyphenyl group; dimethylhydroxyphenyl group, diethylhydroxyphenyl group, dipropylhydroxyphenyl group, dibutylhydroxyphenyl group, diisopropylhydroxyphenyl group A dialkylhydroxyphenyl group such as ditert-butylhydroxyphenyl group; dicyclohexylhydroxypheny Groups, cyclic dialkylhydroxyphenyl groups such as dinorbornylhydroxyphenyl group, diadamantylhydroxyphenyl group; arylhydroxyphenyl groups such as phenylhydroxyphenyl group, naphthylhydroxyphenyl group, diphenylhydroxyphenyl group, dinaphthylhydroxyphenyl group; methoxyhydroxy Examples thereof include alkoxyhydroxyphenyl groups such as phenyl group, ethoxyhydroxyphenyl group, dimethoxyhydroxyphenyl group and diethoxyhydroxyphenyl group; aryloxyhydroxyphenyl groups such as phenoxyhydroxyphenyl group and diphenoxyhydroxyphenyl group.

  In addition, hydroxy naphthyl group; alkyl hydroxy naphthyl group such as methyl hydroxy naphthyl group, ethyl hydroxy naphthyl group, propyl hydroxy naphthyl group, butyl hydroxy naphthyl group, isopropyl hydroxy naphthyl group, tert-butyl hydroxy naphthyl group; cyclohexyl hydroxy naphthyl group, Cyclic alkylhydroxynaphthyl groups such as rubonylhydroxynaphthyl group and adamantylhydroxynaphthyl group; arylhydroxynaphthyl groups such as phenylhydroxynaphthyl group and naphthylhydroxynaphthyl group; alkoxyhydroxynaphthyl groups such as methoxyhydroxynaphthyl group and ethoxyhydroxynaphthyl group; phenoxy Examples also include aryloxyhydroxynaphthyl groups such as hydroxynaphthyl group.

Among these, from the viewpoint of raw material procurement, a hydroxyphenyl group, an alkylhydroxyphenyl group, a dialkylhydroxyphenyl group, a cyclic alkylhydroxyphenyl group, an arylhydroxyphenyl group, a hydroxynaphthyl group, and an alkylhydroxynaphthyl group are preferable.
When two or more R ¹ are bonded to the fullerene skeleton, each R ¹ may be the same or different.

In the formula (I), a represents the average addition number of R ¹ . From the viewpoint of solubility in an ester solvent, a is usually 1 or more, preferably 4 or more, more preferably 6 or more, and from the viewpoint of maintaining the original properties of fullerene, it is usually 15 or less, preferably 12 or less. Represents.
Here, the average addition number a represents an average value of the addition number of R ¹ with respect to one fullerene skeleton of a fullerene derivative existing in a certain system. The molecular composition formula of the fullerene derivative of the present invention can be measured by elemental analysis or the like, and can be derived from data such as MS and LC-MS.
R ¹ may be randomly added to the fullerene skeleton, and may be obtained as isomers having different addition positions even in the same addition number in the fullerene derivative.

(Hydrogen atom H and its average addition number b)
In the formula (I), a hydrogen atom (that is, a hydrogen group or a hydro group) H is bonded to the fullerene skeleton. At this time, the position at which the hydrogen atom is bonded to the fullerene is not limited and is arbitrary.

In formula (I), b represents the average addition number of H (hydrogen atom). The average addition number b represents the average value of the addition number of H with respect to one fullerene skeleton possessed by a fullerene derivative existing in a certain system. The average addition number b can be calculated in the same manner as the average addition number a.
From the viewpoint of oxidation resistance in the solution, the number of a and b is a relationship of a> b, and b is usually 4 or less, preferably 3 or less, and more preferably 2 or less. Since the presence of a hydrogen group (proton) decreases the stability, the smaller the number of b, the better the oxidation resistance. In addition, since a hydrogen group (proton) can be converted into another substituent after allowing various bases to act on it, from the viewpoint of a further intermediate for producing a derivative, hydrogen can be used within a range having oxidation resistance. Preferably there is a group.
In addition, when a fullerene derivative is a single compound, average addition number a and b show each addition number of the single compound.

[1-2. Properties of fullerene derivatives]
The fullerene derivative of the present invention is soluble in an ester solvent, that is, has high solubility in an ester solvent.

  In this specification, a fullerene derivative is “soluble in an ester solvent” means that a fullerene derivative is mixed with an ester solvent, subjected to ultrasonic irradiation for 10 minutes, and then a precipitate or an insoluble matter is detected visually. Means not. Specifically, at 25 ° C. and normal pressure (usually 1 atm), an ester solvent with respect to an ester solvent of either propylene glycol-1-monomethyl ether-2-acetate (ie, PGMEA) or ethyl lactate When the fullerene derivative is usually dissolved in an amount of 10 mg or more per unit volume (1 mL), it is judged that the fullerene derivative is soluble in the ester solvent, that is, highly soluble in the ester solvent.

  When the fullerene derivative of the present invention is used after being dissolved in an ester solvent, the type of the ester solvent is not limited as long as the fullerene derivative of the present invention is dissolved. Examples of ester solvents include methyl acetate, ethyl acetate, propyl acetate, phenyl acetate, methyl propionate, ethyl propionate, propyl propionate, phenyl propionate, methyl 3-methoxypropionate, methyl 3-ethoxypropionate, lactic acid Linear esters such as methyl and ethyl lactate; cyclic esters such as γ-butyrolactone and caprolactone; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol-1-monomethyl ether Examples thereof include ether esters such as acetate and propylene glycol-1-monoethyl ether acetate.

Among these, linear esters and ether esters are preferable, and specifically, propylene glycol-1-monomethyl ether-2-acetate (that is, PGMEA) and ethyl lactate are preferable.
In addition, any 1 type may be used for an ester solvent, and 2 or more types may be used together by arbitrary combinations and a ratio.

  These ester solvents are generally used as solvents for manufacturing optical disk materials such as DVD and CD, manufacturing semiconductor integrated circuits, manufacturing masks for manufacturing semiconductor integrated circuits, manufacturing integrated circuits for liquid crystals, and resist materials for manufacturing liquid crystal screens. It is an ester solvent that is commonly used. In addition to the KrF excimer laser and ArF excimer laser that have been developed in the past, the ester solvent is a photoresist that is suitable for shortening the wavelength of light sources such as EUV (extreme ultraviolet light) and EB (electron beam), It is a solvent suitably used for a photoresist, nanoimprint, and interlayer insulating film as a lower layer film material having a function of an antireflection film.

  Therefore, being soluble in the above ester solvent, that is, having high solubility in the above ester solvent means that the fullerene derivative of the present invention is dissolved in the above-mentioned widely used solvents in the industry. Indicates that it is possible. When the fullerene derivative is dissolved in the ester solvent, the fullerene derivative is often soluble in other organic solvents as well.

  Accordingly, the high solubility of the fullerene derivative of the present invention in an ester solvent means that the fullerene derivative of the present invention can be obtained by, for example, organic solar cells such as dye-sensitized solar cells and organic thin film solar cells, organic transistors and diodes, organic electric fields General organic devices such as light-emitting elements (organic EL elements) and nonlinear optical materials; resin additives; lubricants; battery substrates in batteries such as insulating films, Li secondary batteries, fuel cells, capacitors, and additives, surface modifications, etc. Coating materials, other materials and additives that constitute members such as separators; metal / ceramics additives; additives for sliding applications such as solid lubricants and lubricant additives, catalysts, and paints, inks, and pharmaceuticals・ It shows that it can be applied to various industrial fields such as cosmetics and diagnostics.

  Moreover, the preferable solubility value of the fullerene derivative with respect to the ester solvent described above varies depending on the use of the fullerene derivative. For example, in order to form a coating film for use as a resist material for semiconductor integrated circuit fabrication, semiconductor integrated circuit fabrication mask fabrication, liquid crystal integrated circuit fabrication, and liquid crystal screen fabrication using the fullerene derivative of the present invention, It is desirable that the fullerene derivative has a solubility of usually 10 mg / mL or more, preferably 50 mg / mL or more, more preferably 100 mg / mL or more with respect to the ester solvent.

Although fullerene derivative of the present invention is not clear why having high solubility in ester solvents, according to the place be inferred by the present inventors, in addition to the acidity of the hydroxyl groups of R ^1, added to the R ¹ fullerene skeleton It is presumed that there is a synergistic effect with the non-crystallization effect due to the decrease in the symmetry of the molecule. Therefore, it is considered that due to these factors, the fullerene derivative of the present invention expresses higher solubility in the ester solvent than expected.

In addition, the fullerene derivative of the present invention is usually soluble in an alkaline solvent, that is, has high solubility in an alkaline solvent.
In this specification, a fullerene derivative is “soluble in an alkaline solvent” means that a fullerene derivative is mixed with an alkaline solvent and subjected to ultrasonic irradiation for 10 minutes, and then a precipitate or an insoluble matter is detected visually. Means not. Specifically, when 50 mg or more of a fullerene derivative is dissolved per unit volume (1 mL) of an aqueous sodium hydroxide solution with respect to a 1N aqueous sodium hydroxide solution at 25 ° C. and normal pressure, the fullerene derivative is alkaline. It is judged that it is soluble in a solvent, that is, has high solubility in an alkaline solvent.

  When the fullerene derivative of the present invention is dissolved in an alkali solvent and used, the type of the alkali solvent is not limited as long as the fullerene derivative of the present invention is dissolved. Examples of the alkaline solvent include alkaline organic solvents such as pyridine, piperidine, triethylamine, tri-n-propylamine, methyldiethylamine, 1,8-diazabicyclo- (5,4,0) -7-undecene, dimethylethanolamine, and the like. Sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, calcium hydroxide aqueous solution, sodium carbonate aqueous solution, lithium carbonate aqueous solution, calcium carbonate aqueous solution, ammonia aqueous solution, tetramethylammonium hydroxide aqueous solution and the like. In the case of an alkaline aqueous solution, the concentration of the solute is arbitrary.

Among them, an alkaline aqueous solution is preferable as the alkaline solvent, and an aqueous solution such as an aqueous ammonia solution or an aqueous tetramethylammonium hydroxide solution, which is a nonmetallic alkaline aqueous solution, is preferable for applications where it is desirable to avoid metal contamination in the product.
In addition, any 1 type may be used for these alkaline solvents, and 2 or more types may be used together by arbitrary combinations and a ratio.

Further, the preferred solubility value of the fullerene derivative in the alkali solvent described above varies depending on the use of the fullerene derivative, but is usually 50 mg / mL or more, preferably 100 mg / mL or more, more preferably 200 mg / mL or more with respect to the alkali solvent. It is desirable to have a solubility of
The reason why the fullerene derivative of the present invention has high solubility in an alkaline solvent is not clear, but according to the inventor's inference, the non-crystallizing effect due to the decrease in the symmetry of the molecule due to the addition of R ¹ to the fullerene skeleton. And R ¹ which is a group containing a phenolic hydroxyl group is considered to have increased affinity for an alkaline solvent while having a hydrophobic fullerene skeleton due to a synergistic effect with R ¹ bonded to the fullerene skeleton. .

  Moreover, the fullerene derivative of the present invention has very high thermal stability. This is because the fullerene derivative of the present invention retains a large amount of π-electron conjugation of the fullerene skeleton and is bonded to the hydrocarbon group having the above aromaticity by a carbon-carbon bond. Then, even at the temperature at which thermal decomposition begins, it can exist stably without decomposition. Therefore, the fullerene derivative of the present invention can also be suitably used for applications requiring heat resistance that cannot be decomposed and used with ordinary organic substances.

  The thermal stability of the fullerene derivative of the present invention may be evaluated by a heat resistance test at a high temperature or by using TG-DTA (simultaneous differential thermothermal gravimetric measurement) that can be measured quickly. Absent. In addition, when evaluating by TG-DTA, the kind and quantity of gas to be circulated, the kind of bread, the heating rate, the measurement upper limit temperature, the amount of sample and the like can be arbitrarily selected according to the physical properties to be measured.

[2. Method for producing fullerene derivative]
There is no restriction | limiting in the method to manufacture the fullerene derivative of this invention, It can manufacture by arbitrary methods.
Conventionally, a general method for producing a fullerene derivative having an aromatic hydrocarbon group and hydrogen in a fullerene skeleton has already been established. For example, the method described in Patent Document 3 can be referred to.

However, when the group represented by R ¹ of the present invention is bonded to the fullerene skeleton, there is an interaction with the metal compound described later, and the product may not be purified and isolated. is there. By using a chelating agent after the reaction with the metal compound, it is possible to weaken the interaction between the metal compound and the hydroxyl group, and to produce an aromatic hydrocarbon which is not halogen-substituted by the method described in the above document. In addition, the fullerene derivative of the present invention can be produced by adding a fullerene skeleton using a raw material in which a hydroxyl group is protected with a methyl group or the like and then deprotecting the fullerene skeleton.

In this case, the conditions described in the above literature can be adopted as various conditions such as reaction temperature, solvent type, reagent mixing order, and reaction time.
The fullerene derivative according to the present invention is preferably produced by the production method exemplified below. However, the manufacturing method illustrated below is an example of the manufacturing method of the fullerene derivative of this invention, and is not limited to the following examples.

In the method for producing a fullerene derivative according to the present invention, fullerene; a metal compound; and a hydroxyl group represented by HR ¹ , having an aromaticity containing at least one hydrogen group having 6 to 18 carbon atoms. And a hydrocarbon compound (hereinafter referred to as “raw hydrocarbon compound” as appropriate). After reacting the raw material hydrocarbon compound and fullerene, by using a chelating agent, the interaction between the metal compound and the hydroxyl group is weakened, and the fullerene derivative of the present invention can be obtained. When purification of this fullerene derivative is difficult even if a chelating agent is used, a hydrocarbon compound having an aromaticity and containing at least one hydrogen group having 6 to 18 carbon atoms and protecting the hydroxyl group (hereinafter, An appropriate “protected raw material hydrocarbon compound”) is reacted instead of the raw material hydrocarbon compound and then reacted with a deprotecting agent to obtain the fullerene derivative of the present invention. At this time, a reaction solvent can be used separately, but the reaction can also proceed by using a raw material hydrocarbon compound or a protected raw material hydrocarbon compound as an alternative to the reaction solvent.

[2-1. Fullerene]
As the fullerene, [1. Various fullerenes listed as examples of the fullerene skeleton in the “fullerene derivative” column can be used. In addition, any 1 type may be used for fullerene, and 2 or more types may be used together by arbitrary combinations and a ratio.

[2-2. Metal compound]
The metal compound used here contains at least one transition metal (specifically, Fe, Co, Ni, Ru, Pd) belonging to group 8, 9 or 10 of the periodic table (hereinafter, these are simply referred to as “metal”). "Metal compound").
The metal compound is preferably a metal compound of the fourth period which is advantageous in terms of availability and cost, for example, a metal compound used as an oxidizing agent typified by iron (III) chloride, iron (III) bromide, etc. Is preferred. More preferably, iron halides such as iron (III) chloride and iron (III) bromide are used.
Moreover, this metal compound is not limited to the structure which consists of the transition metal and halogen which belong to the 8th, 9th, or 10th group of a periodic table. For example, iron (III) oxide, iron (III) nitrate, iron (III) sulfate, iron (III) sulfide, potassium hexacyanoferrate (III), or the like can be used. One or more alkyl groups or aryl groups may be included, or a complex containing two or more kinds of metals may be used. Or you may mix and use these. As these metal compounds, those containing a halogen atom are preferable, and metal halides are more preferably used from the viewpoint of availability and cost.

  The content of the metal compound in the reaction system is arbitrary as long as the above reaction proceeds. However, the ratio to the fullerene is usually at least 1 mol, preferably at least 3 mol, more preferably at least 10 mol, Usually, it is desirable that the amount be 200 times or less, preferably 100 times or less, more preferably 50 times or less. If the content of the metal compound is too large, the production cost increases, and separation from the fullerene derivative may be difficult. If the content is too small, the reaction may not be completed. In addition, when using 2 or more types of metal compounds together, it is desirable for those total amount to satisfy | fill the said range.

[2-3. Raw material hydrocarbon compound]
In the manufacturing method of this embodiment, it has a hydroxyl group in the reaction system, having 6 to 18 carbon atoms, containing at least one hydrogen group, a hydrocarbon compound having an aromatic H-R 1 ^(i.e., the raw material hydrocarbon compound) Make it exist. The kind of the raw material hydrocarbon compound may be arbitrarily selected according to the structure of the fullerene derivative to be produced.

As the raw material hydrocarbon compound to be present in the reaction system, only one kind may be used, or two or more kinds may be used in any combination and ratio.
Examples of feedstock hydrocarbon compounds H-R ¹ is phenol, cresol, ethylphenol, propylphenol, butylphenol, isopropyl phenol, tert- alkylphenols such as butylphenol, cyclohexylphenol, norbornyl Le phenol, cyclic alkyl phenols such as adamantyl phenol Dialkylphenols such as dimethylphenol, diethylphenol, dipropylphenol, dibutylphenol, diisopropylphenol and ditert-butylphenol; cyclic dialkylphenols such as dicyclohexylphenol, dinorbornylphenol and diadamantylphenol; phenylphenol, naphthylphenol, Arylphenols such as diphenylphenol and dinaphthylphenol Lumpur like; methoxyphenol, ethoxyphenol, dimethoxy phenol, alkoxy phenols such as diethoxy phenol; phenoxyphenol, aryloxy phenols diphenoxylate phenol, alkyl dihydroxybenzenes such as methyl dihydroxy benzene.

  In addition, alkyl naphthols such as methyl naphthol, ethyl naphthol, propyl naphthol, butyl naphthol, isopropyl naphthol, tert-butyl naphthol; cyclic alkyl naphthols such as cyclohexyl naphthol, norbornyl naphthol, adamantyl naphthol; phenyl naphthol, naphthyl naphthol, etc. Aryl naphthols; alkoxy naphthols such as methoxy naphthol and ethoxy naphthol; aryloxy naphthols such as phenoxy naphthol; and alkyl dihydroxy naphthalenes such as methyl dihydroxy naphthalene.

Among these, from the viewpoint of raw material procurement, phenol, alkylphenols, dialkylphenols, cyclic alkylphenols, arylphenols, and alkylnaphthols are preferable. Specifically, phenol, orthocresol, and 2,6-dimethylphenol are particularly preferable.
The content of the raw material hydrocarbon compound is arbitrary as long as the above reaction proceeds, but is usually 10 times mol or more, preferably 20 times mol or more, and usually 4000 times mol or less, preferably 1000 times in terms of the ratio to fullerene. It is preferable that the amount is not more than mol, more preferably not more than 100 times mol. If the content of the raw material hydrocarbon compound is too large, the production cost increases, and separation from the fullerene derivative may be difficult. If the content is too small, the reaction may not be completed.

[2-4. Protected raw material hydrocarbon compound]
In the production method of this example, it is preferable to directly react the raw material hydrocarbon compound and fullerene from the viewpoint of production cost. However, the purification and isolation can be performed even when the progress of the reaction is significantly inhibited or a chelating agent is used. If a raw material (that is, a protected raw material hydrocarbon compound) in which a hydroxyl group in the raw material hydrocarbon compound is protected with a protective group (for example, a methyl group) resistant to a metal compound such as iron chloride is used. Good.

In addition, as the protected raw material hydrocarbon compound to be present in the reaction system, only one kind may be used, or two or more kinds may be used in any combination and ratio.
Specific examples of the protected raw material hydrocarbon compound include compounds in which the hydroxyl group in the above-mentioned raw material hydrocarbon compound is protected with a protecting group in addition to anisole, methoxynaphthalene, methoxyanthracene, methoxypyrene, and the like. Of these, anisole and methoxynaphthalene are preferable from the viewpoint of reactivity.

The content of the protected raw material hydrocarbon compound is arbitrary as long as the above reaction proceeds, but is usually at least 10 times mol, preferably at least 20 times mol, and usually at most 4000 times mol, preferably in terms of the ratio to fullerene. Is preferably 1000 times mol or less, more preferably 100 times mol or less. If the content of the protected raw material hydrocarbon compound is too large, the production cost increases, and separation from the fullerene derivative may be difficult. If the content is too small, the reaction may not be completed.
In the reaction system, both the raw material hydrocarbon compound and the protected raw material hydrocarbon compound may be used in any combination and ratio.

[2-5. Reaction solvent]
In the production method of this example, for example, when the raw material hydrocarbon compound and the protected raw material hydrocarbon compound are in a solid state at room temperature, a reaction solvent may be used. When a reaction solvent is used, the type thereof is arbitrary as long as it can dissolve and / or disperse the above-mentioned fullerene, metal compound, and raw material hydrocarbon compound or protected raw material hydrocarbon compound suitably. is there.

Examples of the solvent include organic solvents. Of these, a solvent in which the fullerene derivative is soluble is preferable. Examples thereof include halogen-substituted aromatic hydrocarbons, aliphatic hydrocarbons, chlorinated hydrocarbons, and the like. These may be cyclic or acyclic.
Examples of the halogen-substituted aromatic hydrocarbon include orthodichlorobenzene (ODCB) and trichlorobenzene.

  As the aliphatic hydrocarbon, either cyclic or non-cyclic can be used. Examples of the cyclic aliphatic hydrocarbon include monocyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; derivatives thereof such as methylcyclopentane, ethylcyclopentane, methylcyclohexane, ethylcyclohexane, 1, 2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane, isopropylcyclohexane, n-propylcyclohexane, tert-butylcyclohexane, n-butylcyclohexane, isobutylcyclohexane, 1,2,4-trimethylcyclohexane, 1 , 3,5-trimethylcyclohexane, etc .; polycyclic aliphatic hydrocarbons such as decalin; n-pentane, n-hexane, n-heptane, n-octane, isooctane, n-nonane, n- Kang, n- dodecane, include acyclic aliphatic hydrocarbons n- tetradecane.

Examples of the chlorinated hydrocarbon include dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane (TCE), and the like.
Examples of other solvents include ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, 1,4-dioxane, and methylcyclopentyl ether.

Of these, halogen-substituted aromatic hydrocarbons and chlorinated hydrocarbons are preferred, and TCE is particularly preferred from the viewpoint that fullerene can be suitably dissolved.
In addition, any 1 type may be used for the reaction solvent, and 2 or more types may be used together by arbitrary combinations and a ratio.
When a reaction solvent is used, the amount used is usually 1 mg / mL or more, preferably 5 mg / mL or more, and usually 100 mg / mL or less, preferably 50 mg / mL or less, as a ratio to fullerene. If the amount of the reaction solvent used is too large, the concentration of the raw material becomes thin and the reaction rate may be slow. If the amount is too small, the raw material and the product cannot be dissolved, and the reaction may not proceed completely.

In addition, when using together 2 or more types of reaction solvent, it is desirable to make those total amount satisfy | fill the said range.
In the production method of this example, it is sufficient that at least the above-mentioned fullerene, metal compound and raw material hydrocarbon compound or protected raw material hydrocarbon compound can be reacted. Therefore, if the raw material hydrocarbon compound or the protected raw material hydrocarbon compound is liquid at the reaction temperature and pressure, the raw material hydrocarbon compound or the protected raw material hydrocarbon compound can be used as the reaction solvent.

[2-6. Chelating agent]
In the production method of this example, after reacting the raw material hydrocarbon compound and fullerene using a metal compound, if there is an interaction between the hydroxyl group of the fullerene derivative and the metal compound and purification is difficult, a chelating agent is used. It may be used to remove the metal compound. In the case of using a chelating agent, the type is arbitrary as long as it is a chelating agent capable of suitably removing the metal compound, but a chelating agent having at least one amino group or carboxyl group is preferable.

  Specific examples of chelating agents include pyridine, triphenylphosphine, ammonia, ethylenediamine, tetramethylethylenediamine (TMEDA), bipyridine, phenanthroline, acetylacetone (acac), hexafluoroacetylacetone (hfac), catechol, terpyridine, ethylenediaminetetraacetic acid. (EDTA) and salts thereof, diethylenamine pentaacetic acid (DTPA) and salts thereof, tetraazacyclododecanetetraacetic acid (DOTA and salts thereof), porphyrins, cyclams, salens, crown ethers and the like.

  Among these, pyridine, triphenylphosphine, ammonia, ethylenediamine, tetramethylethylenediamine (TMEDA), bipyridine, acetylacetone (acac), ethylenediaminetetraacetic acid (EDTA) and salts thereof are preferable from the viewpoint of raw material procurement. Moreover, from a viewpoint of affinity with a metal compound, a multidentate ligand is preferable, and specifically, tetramethylethylenediamine (TMEDA), ethylenediaminetetraacetic acid (EDTA) and salts thereof are particularly preferable.

In addition, as a chelating agent used for the removal of a metal compound, only any 1 type may be used independently and 2 or more types may be used together by arbitrary combinations and a ratio.
The amount of the chelating agent used is arbitrary as long as the metal compound can be removed after completion of the reaction, but is usually 1 times mol or more, preferably 5 times mol or more, more preferably 10 times mol or more, in the ratio to the fullerene. In addition, it is usually 200 times mol or less, preferably 100 times mol or less, more preferably 50 times mol or less. When the content of the chelating agent is too large, the production cost increases, and separation from the fullerene derivative may be difficult. When the content is too small, the metal compound may not be removed from the fullerene derivative.
In addition, when using 2 or more types of chelating agents together, it is desirable for those total amount to satisfy | fill the said range.

[2-6. Operation and reaction conditions]
The order and reaction conditions for mixing the above-mentioned fullerene, metal compound and raw material hydrocarbon compound or protected raw material hydrocarbon compound, and the reaction solvent used as necessary are arbitrary as long as the fullerene derivative of the present invention can be produced. The addition number of the hydrocarbon group R ¹ can be arbitrarily set by appropriately adjusting the amount of these reagents used. Further, the reaction system may contain components other than those described above as long as the progress of the reaction is not inhibited.

  For example, when a reaction solvent is used, the raw material hydrocarbon compound or the protected raw material hydrocarbon compound can be mixed after mixing the metal compound in a state where the fullerene is dissolved / suspended in the reaction solvent. For example, when a reaction solvent is not used, the metal compound can be mixed in a state where the fullerene is dissolved / suspended in the raw material hydrocarbon compound or the protected raw material hydrocarbon compound.

The temperature conditions during the reaction are not limited as long as the reaction proceeds, but the temperature of the reaction system after mixing the raw material hydrocarbon compound or the protected raw material hydrocarbon compound is usually 10 ° C or higher, preferably 20 ° C or higher, Further, it is usually 150 ° C. or lower, preferably 80 ° C. or lower.
Although the reaction time is not limited, after mixing the raw material hydrocarbon compound or the protected raw material hydrocarbon compound, it is usually 5 minutes or longer, preferably 2 hours or longer, and usually within 5 days, preferably within 24 hours, more preferably It is preferable to make it react within 12 hours.

  After completion of the reaction, the produced fullerene derivative of the present invention is usually isolated from the reaction solution by a conventional method. Moreover, the post-processing method using the above-mentioned chelating agent may be performed. The isolation operation varies depending on the type of each raw material. For example, the reaction solution is crystallized as it is with a poor solvent such as hexane, or ion-exchanged water is added to the reaction solution to stop the reaction, followed by extraction with an appropriate solvent. Then, liquid separation is performed, the solvent is distilled off, and crystallization is performed to isolate the product.

In the above reaction, when a protected raw material hydrocarbon compound is used, the fullerene derivative of the present invention produced by the reaction is in a state in which a protecting group is introduced into the hydroxyl group of R ¹ (hereinafter referred to as the following). Sometimes referred to as “hydroxyl-protected fullerene derivative”). Therefore, in this case, a deprotecting agent corresponding to the type of protecting group is allowed to act on the obtained hydroxyl-protected fullerene derivative to remove the protecting group (this reaction is sometimes referred to as “deprotection reaction”). ), The intended fullerene derivative of the present invention can be produced. Under the present circumstances, only 1 type may be used for a deprotecting agent and it may use 2 or more types together by arbitrary combinations and a ratio.

For example, when the protecting group is a methyl group, examples of the deprotecting agent include boron tribromide, boron trichloride, trimethylsilyl iodide, and the like. Among these, boron tribromide and trimethylsilyl iodide are preferable from the viewpoint of reactivity. In addition, when handling of these deprotecting agents is difficult, a method of generating in situ may be used.
The amount of these deprotecting agents to be used is arbitrary as long as the above-mentioned protecting group can be removed, but it is usually at least 1 mol, preferably 1.2 times in proportion to the corresponding protecting group (methyl group). It is desirable that the amount be not less than mol, more preferably not less than 1.4 times mol, and usually not more than 10 times mol, preferably not more than 5 times mol, more preferably not more than 3 times mol. If the amount of the deprotecting agent used is too large, it may be disadvantageous in terms of production costs, and if the amount of the deprotecting agent used is too small, the reaction may not be completed. In addition, when using 2 or more types of deprotecting agents together, it is desirable for those total amount to satisfy the said range.

  The deprotection reaction is usually performed in a state where the hydroxyl-protected fullerene derivative is dissolved or suspended in an organic solvent. The organic solvent used for the reaction may be arbitrarily selected as long as it does not inhibit the deprotection reaction or cause an undesirable reaction. Specific examples of the organic solvent include halogenated hydrocarbons such as chlorobenzene, orthodichlorobenzene, trichlorobenzene and methylene chloride; aromatic hydrocarbons such as toluene, xylene and trimethylbenzene; nitrile solvents such as acetonitrile and benzonitrile; Is mentioned. Any one of these organic solvents may be used, or two or more thereof may be used in any combination and ratio.

  The amount of the organic solvent used for the hydroxyl-protected fullerene derivative is arbitrary, but the concentration of the hydroxyl-protected fullerene derivative in the organic solvent is usually 1 mg / mL or more, preferably 10 mg / mL or more, more preferably 15 mg / mL. In addition, it is desirable that the amount is usually 1000 mg / mL or less, preferably 500 mg / mL or less, more preferably 100 mg / mL or less.

In any deprotection reaction, the order of mixing the hydroxyl-protected fullerene derivative, the deprotecting agent, the organic solvent, etc. is not limited as long as the reaction proceeds. Furthermore, if deprotection reaction advances, reaction conditions are also arbitrary.
However, although the temperature condition varies greatly depending on the type of deprotection reaction, it is usually 0 ° C or higher, preferably 15 ° C or higher, and usually 180 ° C or lower, preferably 120 ° C or lower.

The reaction time is usually 30 minutes or longer, preferably 2 hours or longer, and usually several tens of hours or shorter, preferably 10 hours or shorter.
After completion of the reaction, the produced fullerene derivative of the present invention is usually isolated from the reaction solution by a conventional method. The isolation operation varies depending on the type of each reaction. For example, the reaction solution is crystallized with a poor solvent such as hexane as it is, or the reaction solution is stopped by adding ion-exchanged water or an aqueous solution of sulfurous acid to the reaction solution. After extraction with a suitable solvent, the product can be isolated by liquid separation and evaporation of the solvent.

The obtained fullerene derivative of the present invention may be purified by a technique such as high performance liquid chromatography (HPLC), silica gel column chromatography, alumina column chromatography, recrystallization or the like as necessary.
In addition, the fullerene derivative of the present invention is usually a proton nuclear magnetic resonance spectrum method (hereinafter sometimes referred to as “ ¹ H-NMR” as appropriate) or a carbon nuclear magnetic resonance spectrum method (hereinafter referred to as “ ¹³ C-NMR” as appropriate). ), Infrared absorption spectroscopy (hereinafter sometimes referred to as “IR” as appropriate), mass spectrometry (hereinafter also referred to as “MS” as appropriate), and general organic analysis such as elemental analysis, Its structure can be confirmed. In addition, when the crystallinity of the fullerene derivative is good, the structure may be confirmed by an X-ray crystal diffraction method.

[3. Embodiment and Use of Fullerene Derivative of the Present Invention]
The fullerene derivative of the present invention can be used for any application in any known embodiment. Among them, the fullerene derivative of the present invention is dissolved in a solvent and used as a fullerene derivative solution (hereinafter referred to as “the solution of the present invention” as appropriate), or a fullerene derivative film containing the fullerene derivative of the present invention (hereinafter referred to as appropriate). It is preferably used as “a film of the present invention”).

  Hereinafter, the embodiment and use of the fullerene derivative of the present invention will be specifically described by using the fullerene derivative of the present invention as a fullerene derivative solution and a fullerene derivative film as an example. Applications are not limited to the following contents.

[3-1. Fullerene derivative solution]
The fullerene derivative of the present invention can be used in various applications by dissolving in a suitable solvent to obtain a fullerene derivative solution.
The type of the solvent in the solution of the present invention is arbitrary, but an organic solvent is preferably used as the solvent. Any organic solvent can be used as the organic solvent. Among them, the fullerene derivative of the present invention has a hydroxyl group and exhibits high solubility in a polar organic solvent such as an ester solvent. It is preferred to use a polar organic solvent). In addition, a solvent may be used individually by 1 type and may use 2 or more types by arbitrary ratios and combinations.

  The type of polar organic solvent is not limited, but, for example, alcohol (alcohol solvent) such as methanol, ethanol, isopropyl alcohol; ketones such as acetone, methyl ethyl ketone, methyl isoamyl ketone, methyl amyl ketone, cyclohexanone; methyl acetate, ethyl acetate, acetic acid Esters (ester solvents) such as propyl, butyl acetate, methyl propionate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, and γ-butyrolactone; tetrahydrofuran, dioxane, anisole, ethylene glycol dimethyl ether, Ethers such as diethylene glycol dimethyl ether; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl Ether, propylene glycol monomethyl ether, ether alcohol such as 3-methoxy-3-methyl-1-butanol; ether ester (ester solvent) which is an ester compound of the above ether alcohols such as PGMEA and acid such as acetic acid; N, Examples include amides such as N-dimethylformamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; dimethyl sulfoxide and the like.

Among these, from the viewpoint of being often used for industrial applications, it is preferable to use ketones such as methyl amyl ketone and cyclohexanone and ester solvents as the solvent in the solution of the present invention, and in particular, propylene glycol-1-monomethyl ether- It is preferable to use an ester solvent such as 2-acetate (PGMEA) or ethyl lactate.
An alkaline solvent is also preferably used as the solvent in the solution of the present invention. The type of the alkali solvent is not limited as long as the fullerene derivative of the present invention is soluble. For example, pyridine, piperidine, triethylamine, tri-n-propylamine, methyldiethylamine, 1,8-diazabicyclo- (5,4 , 0) -7-undecene, dimethylethanolamine, and other alkaline organic solvents; sodium hydroxide aqueous solution, lithium hydroxide aqueous solution, calcium hydroxide aqueous solution, sodium carbonate aqueous solution, lithium carbonate aqueous solution, calcium carbonate aqueous solution, ammonia aqueous solution, tetramethylammonium Examples include alkaline aqueous solutions such as hydroxide aqueous solutions. In the case of an alkaline aqueous solution, the concentration of the solute is arbitrary.

Furthermore, the concentration of the fullerene derivative of the present invention in the solution of the present invention is arbitrary. Further, in the solution of the present invention, the fullerene derivative of the present invention is preferably completely dissolved in a solvent, but may not be partially dissolved but may be suspended or precipitated.
As long as the excellent physical properties of the fullerene derivative of the present invention are not significantly impaired, the solution of the present invention may contain other components in addition to the fullerene derivative and the solvent of the present invention. Other components may contain only 1 type and may contain 2 or more types by arbitrary combinations and ratios.

As long as the fullerene derivative of the present invention can be dissolved in a solvent, the method for preparing the solution of the present invention is not limited. However, it is usually prepared by a method of dissolving with stirring in a predetermined apparatus, a method of irradiating ultrasonic waves, be able to. Further, the mixing order of the fullerene derivative of the present invention, the solvent, and other components used as necessary is not particularly limited.
The solution of the present invention is usually prepared at 25 ° C. from the viewpoints of stability, operability and the like, but can be dissolved and stored while heating as long as it is not higher than the boiling point of the solvent. Moreover, although the fullerene derivative of this invention may precipitate, it can also prepare and store under low temperature of 25 degrees C or less.

[3-2. Fullerene derivative film]
Since the fullerene derivative of the present invention exhibits high solubility in an ester solvent, it is usually possible to produce a fullerene derivative film by applying the solution of the present invention and removing the solvent (for example, heating and drying). The solution used in this case may contain any other compound in addition to the fullerene derivative and the solvent, as long as the excellent physical properties of the fullerene derivative of the present invention are not significantly impaired. In addition, the other component may contain only 1 type and may contain 2 or more types by arbitrary combinations and ratios.

Further, the fullerene derivative film of the present invention may have the same composition, or may be a multilayer film in which two or more constituent films having different compositions are laminated.
As a coating method, for example, an arbitrary method such as a spray method, a spin coating method, a dip coating method, or a roll coating method can be selected. A plurality of methods may be combined. The substrate to be coated is not limited, and examples thereof include organic coatings, silicon substrates, polysilicon films, silicon oxide films, silicon nitride films such as silicon nitride films, and inorganic coatings such as metal wiring. At this time, one type of substrate may be used alone, or two or more types of substrates may be used in any combination.

  The method for removing the solvent after application of the solution is arbitrary, but usually the coating film is subjected to heat drying treatment to remove the solvent. The heat drying treatment is preferably performed at a temperature of usually 80 ° C. or higher and 300 ° C. or lower and usually 10 seconds or longer and 300 seconds or shorter. Since the fullerene derivative of the present invention is excellent in thermal stability as compared with a normal organic compound, a stable film can be formed without thermal decomposition. Moreover, it is preferable to perform a heating in air | atmosphere or inert gas atmosphere, such as argon and nitrogen. In addition, an inert gas may be used individually by 1 type and may be used 2 or more types by arbitrary ratios and combinations.

The film thickness of the film of the present invention varies greatly depending on the application and cannot be uniformly limited, but is usually 10 nm or more, preferably 30 nm or more, and usually 1000 nm or less, preferably 500 nm or less, more preferably 300 nm or less.
By forming a uniform film, for example, using a spectroscopic ellipsometer, the refractive index (n value) and extinction coefficient (k value) of the film of the present invention (hereinafter, these are collectively referred to as “optical constant” as appropriate. Can be measured). Moreover, the dielectric constant, reflectance, etc. of the film of the present invention can be calculated using these measured values. These optical constants vary greatly depending on the use of the fullerene derivative film, and also in the same use, depending on the type of process and the type and amount of other components contained in the fullerene derivative film. Therefore, it is preferable to use the film of the present invention for applications in which the excellent physical properties of the film of the present invention can be effectively utilized. In particular, the film of the present invention is expected to have high etching resistance because the fullerene derivative, which is a component thereof, retains the π-electron conjugation of the fullerene skeleton and introduces an aromatic hydrocarbon group. Since it can be used, it is particularly suitably used for photoresist applications.

[3-3. Application]
The fullerene derivative of the present invention, the solution of the present invention, and the film of the present invention can be used for the aforementioned applications. Hereinafter, some examples of applications will be described in more detail. However, the applications in which the functions of the fullerene derivative of the present invention can be exhibited are not limited to the following descriptions.

[3-3-1. Photoresist application]
Conventionally, a photoresist is a composition in which a resin component such as a (meth) acrylic, polyhydroxystyrene, or novolak resin is combined as a film forming component with an acid generator or a photosensitizer that generates an acid upon exposure. Is widely used. Since the fullerene derivative of the present invention is usually highly soluble in a solvent used for a photoresist, it can be combined with the photoresist at a higher concentration without using a special solvent. Further, it is possible to form a resist film with a fullerene derivative alone. In addition to the conventionally developed KrF excimer laser and ArF excimer laser, EUV (extreme ultraviolet light), EB (electron beam), and the like can be applied as the exposure source for the photoresist.

  As described above, when the fullerene derivative of the present invention is used in the field of photoresist, having a fullerene skeleton has high heat resistance and high etching resistance as a superaromatic molecule, and can reduce edge roughness. High-resolution photoresist can be reproduced. Further, the resist film formed using the fullerene derivative of the present invention or the solution of the present invention also has a function as an antireflection film as apparent from the absorption spectrum. It is expected to exhibit an excellent function as a coating type mask material (hard mask).

[3-3-2. Semiconductor manufacturing applications]
In the field of semiconductor manufacturing and the like, a nanoimprint method has been studied as a method for forming a fine pattern of 500 μm or less with high production efficiency. The nanoimprint method is a method for forming a fine pattern in which a pattern of a mold having a fine pattern is transferred to a transfer layer.
Examples of such a nanoimprint method include a step of heating and softening a transfer layer made of a thermoplastic polymer, a step of pressing the transfer layer and a mold to form a pattern of the mold on the transfer layer, and a mold. A step of sequentially removing the transfer layer; a step of contacting the transfer layer made of a curable monomer with the mold; a step of curing the curable monomer; and a mold from a cured product of the curable monomer. And a method of sequentially performing the step of releasing the The fullerene derivative of the present invention is usually highly soluble in the thermoplastic polymer without using a special solvent because of its high solubility in the solvent used in the thermoplastic polymer and curable material. It is possible to fill.

  As described above, when the fullerene derivative of the present invention is used in the nanoimprint method, since the fullerene derivative of the present invention is highly soluble in a solvent, aggregation of the fullerene derivative of the present invention in the thermoplastic polymer is suppressed. Dispersion. For this reason, it is possible to realize high resolution. Furthermore, by using the fullerene derivative of the present invention or the solution of the present invention for the nanoimprint method, it is possible to improve the mechanical strength, heat resistance and etching resistance of the transfer layer. Significant improvement is possible.

[3-3-3. Low dielectric constant insulation materials]
In recent years, resin thin film wiring suitable for high-density and fine multilayer wiring using a resin thin film as an interlayer insulating film has been applied to a circuit board for a central processing unit (CPU) of a computer. In order to realize a computer having a higher processing speed in the future, development of a low dielectric constant insulating material that utilizes high-density and delicate multilayer wiring and is suitable for high-speed signal propagation is required. The fullerene derivative of the present invention can be complexed with other materials at a higher concentration without using a special solvent because the fullerene derivative of the present invention usually has a high solubility in the solvent used in the above-mentioned applications. It is also possible to form a film with a fullerene derivative alone. At this time, the fullerene derivative of the present invention retains the properties of high resistance and low dielectric constant inherently possessed by the fullerene structure, and has an effect of improving mechanical strength as a filler when used in combination. As a result, it is possible to realize an interlayer insulating film having a low dielectric constant and excellent performance that has never been obtained.

[3-3-4. Solar cell application]
Organic solar cells have many advantages over silicon-based inorganic solar cells, but have low energy conversion efficiency and often do not sufficiently reach a practical level. In order to overcome this problem, a bulk heterojunction organic solar cell having an active layer in which a conductive polymer as an electron donor and a fullerene and a fullerene derivative as an electron acceptor are recently proposed has been proposed. Yes. In this bulk heterojunction type organic solar cell, the conductive polymer and the fullerene derivative are mixed at the molecular level, and as a result, a very large interface is successfully created, and the conversion efficiency is greatly improved.

  Since the fullerene derivative of the present invention has high solubility in the solvent used in the above applications, it is easy to form an efficient bulk heterojunction structure with a p-type semiconductor. In addition, the fullerene derivative of the present invention essentially has the properties of fullerene as an n-type semiconductor. Therefore, by using the fullerene derivative of the present invention or the solution of the present invention, an extremely high performance organic solar cell can be realized. Furthermore, by utilizing this high solubility, it is possible to control layer separation from electron donor layers such as conductive polymers, and to control morphology such as alignment orientation and fine packing of derivative molecules, thereby improving characteristics. In addition, it provides great flexibility in device design. Also, in terms of production, it is possible to easily realize a large area at low cost by ordinary printing methods, ink jet printing, and spraying.

[3-3-5. Semiconductor application]
Research has been made on the use of fullerenes and fullerene derivatives as organic materials for field-effect transistors that can be expected to be applied to optical sensors, rectifiers, and the like. Generally, when a field effect transistor is manufactured using fullerene and a fullerene derivative as a semiconductor, it is known that the field effect transistor functions as an n-type transistor.
Since the fullerene derivative of the present invention has high solubility in the solvent used in the above-mentioned applications, film formation by coating is easy, and the essential properties of fullerene as an n-type semiconductor are retained. Thereby, the fullerene derivative of the present invention can be expected to be used as a low-cost, high-performance organic semiconductor.

[3-3-6. Use as raw material intermediate]
Using the fullerene derivative of the present invention as a starting material, a fullerene derivative having a new function can be produced through a step of introducing a specific organic group into the hydroxyl group in R ¹ in the above formula (I). Hereinafter, representative examples of the method for introducing the organic group will be described, but the present invention is not limited to the following examples.

Specific methods for introducing an organic group vary depending on the type of the organic group to be introduced. For example, the following may be mentioned.
(1) The fullerene derivative of the present invention is esterified by reacting with an esterifying agent.
(2) The fullerene derivative of the present invention is reacted with a carbonating agent to be carbonated.
(3) The fullerene derivative of the present invention is reacted with an etherifying agent to be etherified.
(4) The fullerene derivative of the present invention is reacted with a urethanizing agent to urethanize. In addition to the above methods (1) to (4), the conditions for introducing an organic group into the fullerene derivative of the present invention are as follows. For example, a method described in JP 2006-56878 A can be referred to.

  EXAMPLES Hereinafter, the present invention will be further described with reference to examples. However, the present invention is not limited to the following examples, and can be arbitrarily modified without departing from the gist of the present invention. . In the description of the present specification, TCE represents 1,1,2,2-tetrachloroethane, and DMSO represents dimethyl sulfoxide. Further, Me represents a methyl group, and Ph represents a phenyl group.

[Example 1: Production of C ₆₀ (C ₆ H ₄ OH) _a H _b ]
(Production of fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H)
Fullerene C ₆₀ (2.0 g, 2.78 mmol) and phenol (13.05 g, 138.7 mmol) were added and degassed TCE (50 mL) and iron trichloride (anhydrous) (22.5 g, 138.7 mmol) And stirred at 25 ° C. for 1 day. A saturated aqueous sodium hydrogen carbonate solution (200 mL) was added thereto to stop the reaction, and then ethyl acetate (200 ml) and ethylenediaminetetraacetic acid (8.12 g, 27.8 mmol) were added, followed by stirring for 30 minutes. Then, it filtered by celite and extracted with the separatory funnel. The organic layer was washed once with a saturated aqueous sodium hydrogen carbonate solution and three times with a saturated saline solution, dried over magnesium sulfate, and then subjected to a silica gel short pass.

The solution was concentrated, crystallized with ethyl acetate (10 ml) and toluene (200 ml), crystallized again with ethyl acetate (10 ml) and toluene (200 ml), and then vacuum dried at 50 ° C. for 3 hours. As a result, 1.45 g was obtained as a brown solid product.
¹ H-NMR, HPLC, and LC-MS were measured on the obtained product. ¹ H-NMR was measured at 400 MHz using DMSO-d6 as a solvent. Moreover, HPLC and LC-MS prepared the methanol solution of 500 ppm, and measured it on the following measuring conditions.

[HPLC, LC-MS conditions]
Column type: Octadecylsilyl (ODS) column Column size: 150 mm x 4.6 mmφ
Temperature: 40 ° C
Eluent: Methanol flow rate: 1.0 ml / min
Injection volume: 1 μl
Detector: UV290nm
[LC-MS conditions]
Ionization method: ESI (neg)
As a result of HPLC measurement, it was observed at 96.9 (Area%) at a retention time of 1.61 min.

  The measurement result of LC-MS was as follows.

[Calculation of average added number (a, b)]
From the results of LCMS measurement, the average addition number was calculated from the addition number and area% of each peak. When n molecular weights were observed in one peak, it was assumed that each existed equally, and the area% was estimated by 1 / n.
Therefore, it was estimated that 9.2 hydroxyphenyl groups (a) and 2.9 H (b) were added to the fullerene skeleton, and it was confirmed that a> b.

Moreover, the measurement result of < ¹ > H-NMR was as follows.
[ ¹ H-NMR (DMSO-d6, 400 MHz)]
Since 9.9 to 8.5 ppm (br, OH) and 8.0 to 5.5 ppm (br, Ph) were observed at an integration ratio of 1: 4, a structure in which a hydroxyphenyl group was added to the fullerene skeleton It was confirmed that. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product obtained was C ₆₀ (C ₆ H ₄ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H; a = 9.2; b = 2.9).
Further, the obtained product was dissolved in propylene glycol-1-monomethyl ether-2-acetate (PGMEA) at 25 ° C. and normal pressure, and the solubility was judged visually. The results are shown in Table 1 below.
Moreover, the solubility test with respect to alkali developing solution (2.3 weight% tetramethylammonium hydroxide (TMAH) aqueous solution) was done by the method similar to the solubility test of PGMEA. The results are shown in Table 1 below.

Example _{2: C 60 (CH 3 -C} 6 H 3 OH) preparation of a _{H b]
^{(Fullerene: C 60; R 1: CH}} 3 -C 6 H 3 OH; H: Production of H)
Fullerene C ₆₀ (1.0 g, 1.39 mmol) and orthocresol (3.0 g, 27.8 mmol) were added and degassed TCE (25 mL) and iron trichloride (anhydrous) (4.51 g, 27.8 mmol). ) And stirred at 25 ° C. for 24 hours. Methanol (40 mL) was added thereto to stop the reaction, and the solution was added dropwise to water (150 ml), followed by suction filtration. The obtained crude product was dissolved in ethyl acetate (100 ml), washed 3 times with saturated brine, and dried over magnesium sulfate. The solution was concentrated, ethyl acetate (30 ml) and toluene (200 ml) were added, and the amount of the solution was distilled off under reduced pressure to 100 ml. After suction filtration, vacuum drying at 50 ° C. for 3 hours resulted in a brown solid product (2 As a result, 1.69 g was obtained.
Further, the filtrate after suction filtration was distilled off under reduced pressure, crystallized with ethyl acetate (20 ml) and hexane (200 ml), and vacuum dried at 50 ° C. for 3 hours. As a result, a brown solid product (2-2 ) Was obtained as 0.72 g.

In the same manner as in Example 1, the obtained product was measured by HPLC, LC-MS, ¹ H-NMR (400 MHz).
For HPLC and LC-MS, the measurement was performed in the same manner as in Example 1 except that the eluent was changed to toluene / methanol = 20/80.
[Product (2-1)]
As a result of HPLC measurement, the retention time was 1.59 min, 85.4 (Area%), 2.10 min, 13.2 (Area%), 3.96 min, 0.34 (Area%), 4.82 min. , 0.32 (Area%).

From the LC-MS result of the product (2-2), the same retention time peaks are considered to be the same compound, and when the average addition number (a, b) is estimated in the same manner as in Example 1, the fullerene skeleton is It was confirmed that 8.1 methyl methyl phenyl groups (a) and 2.0 H (b) were added, and a> b.
Moreover, the measurement result of < ¹ > H-NMR was as follows.

[ ¹ H-NMR (DMSO-d6, 400 MHz)]
9.6-8.5 ppm (br, OH), 7.6-5.6 ppm (br, Ph), 2.4-1.1 ppm (br, Me) were observed at an integration ratio of 1: 3: 3. From this, it was confirmed that the structure was obtained by adding a methylhydroxyphenyl group to the fullerene skeleton. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product (2-1) obtained was C ₆₀ (CH ₃ -C ₆ H ₃ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : CH ₃ -C ₆ H ₃ OH; H: H; a = 8.1;
b = 2.0).

[Product 2-2]
As a result of HPLC measurement, the retention time was 1.59 min, 59.2 (Area%), 2.10 min, 33.8 (Area%), 3.96 min, 1.88 (Area%), 4.82 min. It was observed at 0.87 (Area%) at 2.40 (Area%) and 4.99 min.
The measurement result of LC-MS was as follows.

When the average addition number (a, b) was estimated in the same manner as in Example 1, 7.5 methylhydroxyphenyl groups (a) and 2.1 H (b) were added to the fullerene skeleton, and a> b was confirmed.
Moreover, the measurement result of < ¹ > H-NMR was as follows.
[ ¹ H-NMR (DMSO-d6, 400 MHz)]
9.6-8.5 ppm (br, OH), 7.6-5.6 ppm (br, Ph), 2.4-1.1 ppm (br, Me) were observed at an integration ratio of 1: 3: 3. From this, it was confirmed that the structure was obtained by adding a methylhydroxyphenyl group to the fullerene skeleton. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product (2-2) obtained was C ₆₀ (CH ₃ -C ₆ H ₃ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : CH ₃ -C ₆ H ₃ OH; H: H; a = 7.5; b = 2.1).
Furthermore, about the obtained product, it carried out similarly to Example 1, and judged the solubility visually.
The results are shown in Table 1 below.

Example _{3: C 60 (CH 3 -C} 6 H 3 OH) preparation of a _{H b]
^{(Fullerene: C 60; R 1: CH}} 3 -C 6 H 3 OH; H: Production of H)
Fullerene C ₆₀ (2.0 g, 2.78 mmol) and orthocresol (6.0 g, 55.6 mmol) were added and degassed TCE (50 mL) and iron trichloride (anhydrous) (13.5 g, 85.5 mmol). ) And stirred at 25 ° C. for 12 hours. A saturated aqueous sodium hydrogen carbonate solution (200 mL) was added thereto to stop the reaction, and then ethyl acetate (200 ml) and ethylenediaminetetraacetic acid (16.5 g, 55.6 mmol) were added, followed by stirring for 30 minutes. Then, it filtered by celite and extracted with the separatory funnel. The organic layer was washed once with a saturated aqueous sodium hydrogen carbonate solution and three times with a saturated saline solution, dried over magnesium sulfate, and then subjected to a silica gel short pass.

The solution was concentrated, crystallized with ethyl acetate (10 ml) and toluene (200 ml), and vacuum dried at 50 ° C. for 3 hours. As a result, 2.63 g of a brown solid product was obtained.
In the same manner as in Example 2, the obtained product was measured by HPLC, LC-MS, ¹ H-NMR (400 MHz).
As a result of the HPLC measurement, the retention time was observed at 86.2 (Area%) at 1.59 min, 12.1 (Area%) at 2.10 min, and 0.55 (Area%) at 3.96 min.

From the LC-MS result of the product (2-2), the same retention time peaks are considered to be the same compound, and when the average addition number (a, b) is estimated in the same manner as in Example 1, the fullerene skeleton is It was confirmed that 8.1 methyl methyl phenyl groups (a) and 2.0 H (b) were added, and a> b.
Moreover, the measurement result of < ¹ > H-NMR was as follows.

[ ¹ H-NMR (DMSO-d6, 400 MHz)]
9.7 to 8.3 ppm (br, OH), 8.0 to 5.5 ppm (br, Ph), and 2.5 to 1.0 ppm (br, Me) were observed at an integration ratio of 1: 3: 3. From this, it was confirmed that the structure was obtained by adding a methylhydroxyphenyl group to the fullerene skeleton. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product obtained was C ₆₀ (CH ₃ -C ₆ H ₃ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : CH ₃ -C ₆ H ₃ OH; H: H product A = 8.1; b = 2.0).
Furthermore, about the obtained product, it carried out similarly to Example 1, and judged the solubility visually.
The results are shown in Table 1 below.

[Example 4: Production of C ₆₀ ((CH ₃ ) ₂ -C ₆ H ₂ OH) _a H _b ]
(Production of fullerene: C ₆₀ ; R ¹ : (CH ₃ ) ₂ -C ₆ H ₂ OH; H: H)
Fullerene C ₆₀ (1.0 g, 1.39 mmol) and 2,6-dimethylphenol (3.40 g, 27.8 mmol) were added and degassed TCE (25 mL) and iron trichloride (anhydrous) (4.51 g 27.8 mmol) and stirred at 25 ° C. for 1 day. Saturated brine (100 mL) was added thereto to stop the reaction, ethyl acetate (200 ml) was added, and the mixture was extracted with a separatory funnel. Further, TMEDA (tetramethylethylenediamine) (2 ml) was added, washed twice with saturated saline, once with 1N dilute hydrochloric acid, twice with saturated saline, and dried over magnesium sulfate, followed by silica gel short path. Was done.

The solution was concentrated and crystallized with ethyl acetate (20 ml) and toluene (300 ml) to obtain 2.41 g of a brown solid product.
In the same manner as in Example 1, the obtained product was measured by HPLC, LC-MS, ¹ H-NMR (400 MHz).
For HPLC and LC-MS, the measurement was performed in the same manner as in Example 1 except that the eluent was changed to methanol.

As a result of HPLC measurement, it was observed at 97.2 (Area%) at a retention time of 1.64 min.
The measurement result of LC-MS was as follows.

When the average number of additions (a, b) was estimated in the same manner as in Example 1, 9.2 dimethylhydroxyphenyl groups (a) and 2.4 H (b) were added to the fullerene skeleton, and a> b was confirmed.
Moreover, the measurement result of < ¹ > H-NMR was as follows.
[ ¹ H-NMR (DMSO-d6, 400 MHz)]
8.9 to 7.1 ppm (br, OH), 7.1 to 6.2 ppm (br, Ph), and 2.5 to 1.0 ppm (br, Me) were observed at an integration ratio of 1: 2: 6. From these results, it was confirmed that the dimethylhydroxyphenyl group was added to the fullerene skeleton. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product obtained was C ₆₀ ((CH ₃ ) ₂ -C ₆ H ₂ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : (CH ₃ ) ₂ -C ₆ H ₂ OH; H: H; a = 9.2; b = 2.4).
Furthermore, about the obtained product, it carried out similarly to Example 1, and judged the solubility visually.
The results are shown in Table 1 below.

[Example 5: Production of C ₆₀ (C ₆ H ₄ OH) _a H _b ]
(Production of fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H)
Fullerene C ₆₀ (1.0 g, 1.39 mmol) and anisole (3.0 g, 27.8 mmol) were added and degassed TCE (25 mL) and iron trichloride (anhydrous) (6.76 g, 41.7 mmol) And stirred at 25 ° C. for 10 hours. Ion exchange water (100 mL) was added thereto to stop the reaction, toluene (100 ml) was added, celite filtration was performed, and extraction was performed with a separatory funnel. The organic layer was washed 3 times with ion exchange water, dried over magnesium sulfate, and then subjected to a silica gel short pass.

The solution was concentrated, crystallized with ethyl acetate (10 ml) and hexane (200 ml), and vacuum dried at 50 ° C. for 3 hours. As a result, 1.09 g was obtained as a brown solid product. When this product was measured by ¹ H-NMR, a structure in which a methoxyphenyl group and hydrogen were added to the fullerene skeleton (C ₆₀ (C ₆ H ₄ OMe) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OMe; product of H: H))).

Next, an ODCB solution (25 mL) of C ₆₀ (C ₆ H ₄ OMe) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OMe; product of H: H) (1.0 g) was prepared. After cooling to 5 ° C., a BBr ₃ -methylene chloride solution (1.0 mol / L, 6.1 mL) was added, and the temperature was raised to 25 ° C. After stirring at room temperature for 9 hours, the reaction was stopped with ion-exchanged water (14 mL), ethyl acetate (14 mL) was added, and the mixture was extracted with a separatory funnel. The organic layer was washed twice with ion exchange water, dried over magnesium sulfate, and then filtered. The solution was concentrated and crystallized with hexane (100 mL). In order to effectively remove ODCB as a residual solvent, it was dissolved again in ethyl acetate (5 mL), crystallized with hexane (100 mL), and vacuum-dried at 50 ° C. for 3 hours. As a result, an orange solid ( 0.71 g) of product.

In the same manner as in Example 1, the obtained product was measured by HPLC, LC-MS, ¹ H-NMR (400 MHz).
As a result of HPLC measurement, it was observed at 98.2 (Area%) at a retention time of 1.61 min.
From the LC-MS results of Example 1, the same retention time peaks are considered to be the same compound, and when the average addition number (a, b) is estimated in the same manner as in Example 1, a hydroxyphenyl group ( It was confirmed that 9.3 a), 2.9 H (b) were added, and a> b.

Moreover, the measurement result of < ¹ > H-NMR was as follows.
[ ¹ H-NMR (DMSO-d6, 400 MHz)]
Since 9.9 to 8.5 ppm (br, OH) and 8.0 to 5.5 ppm (br, Ph) were observed at an integration ratio of 1: 4, a structure in which a hydroxyphenyl group was added to the fullerene skeleton It was confirmed that. Protons bound to the C ₆₀ is broadening can not be observed intensely.

From the above results, the product obtained was C ₆₀ (C ₆ H ₄ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H product; a = 9.3 B = 2.9) was confirmed.
Furthermore, about the obtained product, it carried out similarly to Example 1, and judged the solubility visually.
The results are shown in Table 1 below.

[Comparative Example 1: Production of C ₆₀ (C ₆ H ₄ OH) _a H _b ]
(Production of fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H)
Fullerene C ₆₀ (3.0 g, 4.17 mmol) and aluminum trichloride (anhydrous) (5.56 g, 41.7 mmol) were added and degassed ODCB (75 mL) and anisole (9.00 mL, 83.4 mmol). And stirred at 25 ° C. for 2 days. Thereto was added 150 mL of ion exchange water to stop the reaction, ethyl acetate was added, and the mixture was extracted with a separatory funnel. The organic layer was washed twice with ion exchange water, dried over magnesium sulfate, and then filtered.

The solution was concentrated, crystallized with methanol (600 mL), and vacuum-dried at 50 ° C. for 3 hours to obtain C ₆₀ (C ₆ H ₄ OMe) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ 6.18 g of OMe; H: H product) as a brown solid product.
Next, an ODCB solution (75 mL) of C ₆₀ (C ₆ H ₄ OMe) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OMe; product of H: H) (3.00 g) was prepared. After cooling to 5 ° C., a BBr ₃ -methylene chloride solution (1.0 mol / L, 18.2 mL) was added, and the temperature was raised to 25 ° C. After stirring at room temperature for 6 hours, the reaction was stopped with ion-exchanged water (42 mL), ethyl acetate (42 mL) was added, and the mixture was extracted with a separatory funnel. The organic layer was washed twice with ion exchange water, dried over magnesium sulfate, and then filtered. The solution was concentrated and crystallized with hexane (300 mL).

In order to effectively remove the residual solvent ODCB, it was dissolved again in ethyl acetate (10 mL), crystallized with hexane (300 mL), and vacuum dried at 50 ° C. for 3 hours. As a result, an orange solid ( 2.63 g; yield 93.5%).
In the same manner as in Example 1, the obtained product was measured by ¹ H-NMR (400 MHz).

For HPLC and LC-MS, the measurement was performed in the same manner as in Example 1 except that the eluent was changed to toluene / methanol = 5/95.
As a result of HPLC measurement, a retention time of 1.71 min was observed at 59.24 (Area%), and 2.62 to 7.40 min at 37.0 (Area%).
The measurement result of LC-MS was as follows.

When the average addition number (a, b) was estimated in the same manner as in Example 1, 7.6 hydroxyphenyl groups (a) and 7.6 H (b) were added to the fullerene skeleton, and a = b It was confirmed that.
Moreover, the measurement result of < ¹ > H-NMR was as follows.
[ ¹ H-NMR (DMSO-d6, 400 MHz)]
9.8 to 9.0 ppm (br, OH), 7.8 to 6.0 ppm (br, Ph), 5.0 to 3.8 ppm (br, C ₆₀ -H) is an integration ratio of 1: 4: 1 As a result, it was confirmed that the fullerene skeleton had a structure in which a hydroxyphenyl group and hydrogen were added.

From the above results, the product obtained was C ₆₀ (C ₆ H ₄ OH) _a H _b (fullerene: C ₆₀ ; R ¹ : C ₆ H ₄ OH; H: H; average addition number a, b = 7 .6 product).
Furthermore, about the obtained product, it carried out similarly to Example 1, and judged the solubility visually.
The results are shown in Table 1 below.

  In Table 1 below, PGMEA represents propylene glycol-1-monomethyl ether-2-acetate, and the alkali developer represents a 2.3 wt% TMAH (tetramethylammonium hydroxide) aqueous solution. Moreover, (circle) shows that it melt | dissolved completely visually, x shows that the solubility to the solvent of a fullerene derivative is low, and shows that it did not melt | dissolve completely.

[Evaluation of oxidation resistance of fullerene derivatives in solution using elemental analysis]
Using the fullerene derivatives obtained in Example 1 and Comparative Example 1, the oxidation resistance in the solution was evaluated by the following procedure.
(I) The fullerene derivative was added to 0.66% by weight with respect to 15 g of ethyl acetate, and the mixture was stirred with a stirrer under normal pressure and air for 2 days.
(Ii) The ethyl acetate in the fullerene derivative solution was distilled off under reduced pressure and vacuum dried at 50 ° C. for 5 hours.
(Iii) Elemental analysis was performed on both samples stirred in ethyl acetate (samples exposed to air) and samples stored in a nitrogen atmosphere to increase the weight percent of oxygen in the samples before and after exposure to air. The oxidation resistance was evaluated from the rate.

[Elemental analysis of C, H, N]
CHN meter: Perkin Elmer 2400II
[Elemental analysis of O]
ON meter: LECO oxygen / nitrogen analyzer TC600
(Impulse furnace heating extraction under inert gas atmosphere-IR detection method)
The above results are summarized below.

<Fullerene derivative of Example 1>

  Although the weight percentage of oxygen increased by 0.2% before and after exposure to air, it is within the error range of elemental analysis of oxygen, and it is considered that there is no significant difference.

<Fullerene Derivative of Comparative Example 1>

Before and after exposure to air, the oxygen weight percentage increased by 1.6% from 12.1% to 13.7%, and oxygen is expected to be added by stirring in air under ethyl acetate. .
As is clear from the above elemental analysis results, the ester solution of the fullerene derivative of the present invention was more stable and higher in oxidation resistance than the comparative example 1 in the solution.

The fullerene derivative of the present invention can be used in any field. Among them, the fullerene derivative of the present invention has characteristics such as high solubility in an ester solvent such as PGMEA and high oxidation resistance, and can be easily produced at low cost. It can be preferably used for applications such as production of optical disc materials such as, production of semiconductor integrated circuits, production of masks for production of semiconductor integrated circuits, production of integrated circuits for liquid crystals, and resist materials for production of liquid crystal screens. In addition to KrF excimer lasers and ArF excimer lasers, it can be used as an underlayer film material that functions as a photoresist and antireflection film suitable for shortening the wavelength of light sources such as EUV (extreme ultraviolet light) and EB (electron beam). It can be particularly preferably used for applications of photoresist, nanoimprint, and interlayer insulating film.

  That is, the gist of one embodiment of the present invention is characterized in that a fullerene derivative not having a halogen atom introduced therein represented by the following formula (I) is dissolved in a solvent and does not include a fullerene derivative having a halogen atom introduced therein. In the fullerene derivative solution.

(In the formula (I),
R ¹ represents a hydrocarbon group having 6 to 18 carbon atoms that contains 1 to 3 hydroxyl groups and may have a substituent other than hydroxyl groups,
a represents an average addition number of R ¹ of 6 to 15,
b represents an average addition number of H (hydrogen atom) of 0 or more and 4 or less,
And a> b is satisfied,
A structure indicated by a circle represents a fullerene skeleton. )
Each R ¹ in the formula (I), it is not preferable having 1 to 2 substituents.
Substituents contained in each R ¹ in the formula (I) is not preferred to have 1 to 20 of the organic group having a carbon number.
Hydrocarbon group having aromaticity in each R ¹ in general formula (I) may, it is not preferable is a phenyl group.
Of the formula (I), it is not preferable a is 6 to 12.
Fullerene skeleton in the formula (I), it is not preferable a fullerene _{C 60} and / or fullerene _{C 70.}
The fullerene derivative in which the fullerene skeleton in the formula (I) is fullerene C ₆₀ and / or fullerene C ₇₀ , and the fullerene in which the fullerene skeleton in the formula (I) is a fullerene other than fullerene C ₆₀ and fullerene C ₇₀ it preferred to contain and derivatives.

At this time, the solvent is, it is not preferable is an ester solvent.
Another aspect of the present invention resides in a fullerene derivative film obtained by applying the above-described fullerene derivative solution and removing the solvent.

Claims (11)

A fullerene derivative represented by the following formula (I):

(In the formula (I),
R ¹ represents a hydrocarbon group having 6 to 18 carbon atoms which contains 1 to 3 hydroxyl groups and may have a substituent other than hydroxyl groups,
a represents an average addition number of R ¹ of ^{1 to} 15,
b represents an average addition number of H (hydrogen atom) of 0 or more and 4 or less,
And a> b is satisfied,
A structure indicated by a circle represents a fullerene skeleton. ) 2. The fullerene derivative according to claim 1, wherein each R ¹ in the formula (I) has 1 or more and 2 or less substituents. The fullerene derivative according to claim 1, wherein the substituent contained in each R ¹ in the formula (I) has an organic group having 1 to 20 carbon atoms. The fullerene derivative according to any one of claims 1 to 3, wherein the aromatic hydrocarbon group at each R ¹ in the formula (I) is a phenyl group.   The fullerene derivative according to any one of claims 1 to 4, wherein a in the formula (I) is 4 or more and 12 or less. 6. The fullerene derivative according to claim 1, wherein the fullerene skeleton in the formula (I) is fullerene C ₆₀ and / or fullerene C ₇₀ . The fullerene derivative in which the fullerene skeleton in the formula (I) is fullerene C ₆₀ and / or fullerene C ₇₀ , and the fullerene in which the fullerene skeleton in the formula (I) is a fullerene other than fullerene C ₆₀ and fullerene C ₇₀ The fullerene derivative according to claim 6, comprising a derivative.   A fullerene derivative solution, wherein the fullerene derivative according to any one of claims 1 to 7 is dissolved in a solvent.   The fullerene derivative solution according to claim 8, wherein the solvent is an ester solvent.   A fullerene derivative film comprising the fullerene derivative according to any one of claims 1 to 7. After allowing fullerenes, at least one metal compound in Group 8, 9 or 10 of the periodic table and a compound represented by HR ¹ to act, at least one amino group or carboxyl group is added to the reaction solution. The method for producing a fullerene derivative according to claim 1, wherein the acted metal compound is removed by adding at least one chelating agent.