JP7341470B2 - Material having cocrystal containing fullerene, triarylamine derivative, and toluene, and method for producing the same - Google Patents

Description

The present invention relates to a material having a cocrystal containing fullerene, a triarylamine derivative, and toluene, and a method for producing the same.

Since the establishment of a method for synthesizing carbon clusters (hereinafter also referred to as "fullerenes"), which are formed by arranging carbon atoms in a spherical or rugby ball shape, research has been conducted on fullerenes with various functions. .

For example, Patent Document 1 describes a fullerene derivative having a predetermined structure as a compound that can absorb light in a wide range.

Japanese Patent Application Publication No. 2010-270018

The present inventor has found that the compound described in Patent Document 1 does not have sufficient absorbance of visible light, and there is room for improvement.
Therefore, an object of the present invention is to provide a fullerene-derived material that can absorb light in a wide range. Another object of the present invention is to provide a method for manufacturing the material.

As a result of intensive studies to achieve the above object, the inventors of the present invention found that the above object could be achieved by the following configuration.

[1] A material having a cocrystal containing fullerene, a triarylamine derivative, and toluene.
[2] The material according to [1], wherein the molar ratio of fullerene, triarylamine derivative, and toluene in the co-crystal is 1:1:1.
[3] The material according to [1] or [2], wherein the fullerene is a C ₆₀ fullerene.
[4] The material according to any one of [1] to [3], wherein the triarylamine derivative is a compound represented by formula 1 described below.
[5] The material according to [4], wherein the aryl group is at least one group selected from the group consisting of formulas 2a to 2h described below.
[6] Mixing toluene and fullerene to prepare a saturated fullerene solution; Adding a triarylamine derivative to the saturated fullerene solution to prepare a mixed solution; and allowing the mixed solution to stand still. The method for producing the material according to [1], comprising: precipitating crystals.

According to the present invention, a fullerene-derived material that can absorb light in a wide range can be provided. Further, according to the present invention, a method for manufacturing the material can also be provided.

1 is an image of the co-crystal of Example 1. 2 is a schematic diagram of the molecular structures of C60 fullerene, TPD, and toluene, and the structure of the cocrystal of Example 1. FIG. 1 is an infrared absorption spectrum of the co-crystal of Example 1, fullerene C ₆₀ , N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD), and toluene. ^13C -NMR spectrum of the co-crystal of Example 1. 1 is an ultraviolet-visible absorption spectrum of the co-crystal of Example 1, TPD, and C ₆₀ .

The present invention will be explained in detail below.
Although the description of the constituent elements described below may be made based on typical embodiments of the present invention, the present invention is not limited to such embodiments.
In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the lower limit and upper limit.

[Co-crystal]
A material according to an embodiment of the present invention (hereinafter also referred to as "this material") has a cocrystal containing fullerene, a triarylamine derivative, and toluene.
As used herein, the term "cocrystal" refers to a solid that is a crystalline, single-phase material in which two or more different molecules are bonded to each other in a certain stoichiometric ratio through interactions other than ionic and covalent bonds. do.
Note that this material may contain other components as long as it contains the above-mentioned co-crystal, but it is preferable that it consists of the above-mentioned co-crystal because a material having more excellent effects of the present invention can be obtained.
Each component in the co-crystal will be explained in detail below.

The fullerene in the co-crystal is not particularly limited, but includes, for example, C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , and C ₉₆ , and the number of carbon atoms in one molecule. Examples include higher-order fullerenes having a particle size of more than 96 and a maximum aggregate diameter of 30 nm or less. Among them, C ₆₀ , C ₇₀ , C ₇₆ , and C ₈₂ are preferable, and C ₆₀ or C ₇₀ is preferable. preferable.

These fullerenes can be synthesized by known methods. for example,
J. Phys. Chem. , 94, 8634 (1990) discloses a manufacturing method using an arc discharge method. Further, higher fullerenes having a carbon number of more than 96 in one molecule and a maximum agglomerate diameter of 30 nm or less can be obtained as a by-product of the arc discharge method.

The triarylamine derivative in the co-crystal is not particularly limited, but compounds having hole transport properties are preferred, such as compounds represented by the following formula.

Among these, the compound represented by the following formula 1 is preferable as the triarylamine derivative since co-crystals can be easily obtained.

In formula 1, Ar ₁ to Ar ₄ each independently represent an aryl group, and the aryl group is not particularly limited, but for example, at least one group independently selected from the group consisting of the following formulas 2a to 2h. preferable.

Specific examples of triarylamine derivatives include N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD: C ₃₈ H ₃₂ N ₂ ), 2,7-bis[N- (1-naphthyl)anilino]-9,9-dimethylfluorene (NPB: C ₄₇ H ₃₆ N ₂ ), N,N'-di-2-naphthyl-N,N'-diphenylbenzidine (β-NPB: C ₄₇ H ₃₆ N ₂ ), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-2,7-diamino-9,9-spirobifluorene (spiroTPD: C ₅₁ H ₃₈ N ₂ ), 2,7-bis[N-(1-naphthyl)anilino]-9,9'-spirobi[9H-fluorene] (spiroNPB: C ₅₇ H ₃₈ N ₂ ), 9,9-dimethyl-2,7 -bis[N-(m-tolyl)anilino]fluorene (DMFL-TPD: C ₄₁ H ₃₆ N ₂ ), 2,7-bis[N-(1-naphthyl)anilino]-9,9-dimethylfluorene (DMFL -NPB: C ₄₇ H ₃₆ N ₂ ), N,N'-bis-(3-methylphenyl)-N,N'-bis(phenyl)-9,9-d (DPFL-TPD: C ₅₁ H ₄ 0N ₂ ), N,N'-di(1-naphthyl)-N,N',9,9-tetraphenyl-9H-fluorene-2,7-diamine (DPFL-NPB), 2,2',7,7 '-tetrakis(diphenylamino)-9,9'-spirobi[9H-fluorene] (spiro-TAD: C ₇₃ H ₅₂ N ₄ ) and 9,9-bis[4-(N,N-bis-biphenyl) -4-yl-amino)phenyl]-9H-fluorene (BPAPF: C ₇₃ H ₅₂ N ₂ ) and the like, with TPD or NPB being preferred.

The content of fullerene, triarylamine derivative, and toluene in the co-crystal is not particularly limited, but the molar content of fullerene in the co-crystal [A], the molar content of the triarylamine derivative [A], B], and the content molar ratio ([A]/ ([A]+[B]+[C])) is preferably 0.29 to 0.37, more preferably 0.30 to 0.36, even more preferably 0.31 to 0.35, and 0. Particularly preferred is 32 to 0.34.

In addition, the sum of the molar-based content [A] of fullerene, the molar-based content [B] of triarylamine derivatives, and the molar-based content [C] of toluene ([A] + [B] + The content molar ratio ([B]/([A]+[B]+[C])) of the molar content [B] of the triarylamine derivative to [C]) is 0.29 to 0.37. is preferable, 0.30 to 0.36 is more preferable, 0.31 to 0.35 is even more preferable, and 0.32 to 0.34 is particularly preferable.

In addition, the sum of the molar-based content [A] of fullerene, the molar-based content [B] of triarylamine derivatives, and the molar-based content [C] of toluene ([A] + [B] + The content molar ratio ([C]/([A]+[B]+[C])) of toluene content [C] on a molar basis to [C]) is preferably 0.29 to 0.37, 0.30 to 0.36 is more preferred, 0.31 to 0.35 is even more preferred, and 0.32 to 0.34 is particularly preferred.
Among them, a material having more excellent effects of the present invention can be obtained when the molar ratio [A]:[B]:[C] of fullerene, triarylamine derivative, and toluene in the co-crystal is 1: Preferably, the ratio is 1:1. The above molar ratio is determined from X-ray crystal structure analysis.

The method for preparing the above material is not particularly limited, but a method including the following steps is preferred.
・Step of dissolving fullerene in toluene to prepare a saturated fullerene solution (Step A)
・Step of adding a triarylamine derivative to a saturated fullerene solution to prepare a mixed solution containing toluene, fullerene, and a triarylamine derivative (step B)
・Step of letting the mixed liquid stand still to precipitate co-crystals (Step C)
Each step will be explained in detail below.

The method for preparing the saturated fullerene solution in Step A is not particularly limited, but includes a method of adding an excess amount of fullerene to toluene and dissolving it, and filtering out insoluble matter. Among these, it is preferable to dissolve fullerene by ultrasonic stirring because fullerene is more easily dissolved.

The method for preparing the mixed solution in Step B is not particularly limited, but examples include a method of adding a triarylamine derivative to a saturated fullerene solution and stirring the mixture.
At this time, the amount of the triarylamine derivative added is not particularly limited, but in order to obtain cocrystals more efficiently, the molar ratio of the content of the triarylamine derivative to the content of fullerene in the mixed liquid is , 1 to 50 are preferred.

In step C, the temperature at which the mixed solution is allowed to stand is not particularly limited, but is preferably 10 to 40°C. Further, the time for leaving to stand is not particularly limited, but is preferably from 1 hour to 1 week. Note that the precipitated crystals may be washed and dried.

The present invention will be explained in more detail below based on Examples. The materials, usage amounts, proportions, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the Examples shown below.

[Example 1]
28 mg of C ₆₀ fullerene (manufactured by MTR Ltd., purity 99.95%) was added to 10 ml of toluene (manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., dehydrated toluene), dissolved, and then ultrasonically stirred for 30 minutes. Thereafter, it was filtered to prepare a saturated fullerene solution.
Next, 100 mg of TPD (manufactured by Sigma-Aldrich) was added and dissolved in 5 ml of the above saturated fullerene solution to prepare a toluene/C60 fullerene/TPD mixture.
Next, the mixed solution was allowed to crystallize at room temperature for one day, and the crystals were taken out, washed with water, and then dried to obtain cocrystal 1 shown in FIG.

Co-crystal 1 is black and plate-shaped. From the composition analysis described below, the chemical formula of the co-crystal of Example 1 is C ₁₁₅ H ₄ 0N ₂ , and from the results of crystal structure analysis by X-ray diffraction, it is found that C60 fullerene and TPD (C ₃₈ H ₃₂ N ₂ ) and toluene (C ₆ H ₅ CH ₃ ) was found to be 1:1:1. FIG. 2 shows a schematic diagram of the molecular structures of C60 fullerene, TPD, and toluene, and the structure of the co-crystal of Example 1.

In FIG. 2, (a) shows the structure of C ₆₀ fullerene, (b) shows the structure of TPD, (c) shows the structure of toluene, and (d) shows the structure of cocrystal 1.
Cocrystal 1 is a C ₆₀ /TPD cocrystal in which toluene is intercalated, and one molecule each of C ₆₀ , TPD, and toluene exists in the unit cell. However, since each molecule exists so that the center of symmetry of the molecule and the center of symmetry of the crystal coincide, approximately half of the molecules exist in independent regions (asymmetric units).

[evaluation]
(composition analysis)
Elemental analysis was performed at Atlantic Microlabs (Norcross, GA, USA) and yielded results regarding the carbon, hydrogen, and nitrogen contents in Cocrystal 1.
As a result, it was found that cocrystal 1 was expressed as C ₁₀₅ N ₄₀ H ₂ .

(Infrared absorption spectrum analysis)
Infrared absorption spectrum analysis was performed using the ATR method (Attenuated Total Reflection, total reflection measurement method) using FT/IR-6200 (with attachment for total reflection measurement "ATRPRO 410-S", manufactured by JASCO). The results are shown in Table 1 and FIG. 3.

In FIG. 3, "(a) Co-Crystal" indicates the infrared absorption spectrum of co-crystal 1, and "(b) C ₆₀ ,""(c)TPD," and "(d) Toluene" indicate the infrared absorption spectrum of co-crystal 1. These are infrared absorption spectra of C ₆₀ fullerene, TPD, and toluene alone.

In FIG. 3, the circled peaks indicate peaks originating from C ₆₀ fullerene, TPD, and toluene, respectively.

In Table 1, "Toluene intercalated C ₆₀ TPD co-crystal" represents the wave number (cm ^-1 ) of the peak top in the infrared absorption spectrum of the co-crystal.
Furthermore, “C ₆₀ ”, “TPD”, and “Toluene” represent the wave number (cm ⁻¹ ) of the peak top in the infrared absorption spectrum of C ₆₀ fullerene, TPD, and toluene alone.

Furthermore, to the right of "Toluene intercalated C ₆₀ TPD co-crystal", "C ₆₀ ", "TPD", and "Toluene" are listed as subcategories to the right of "Toluene intercalated C ₆₀ TPD co-crystal". It is classified into those derived from toluene, and the wave number of the peak top of each peak is described.

That is, "C ₆₀ 1539, 1426, 1181, 577, 526" indicates the wave number of the top of the peak derived from C ₆₀ fullerene in cocrystal 1. Further, "C ₆₀ 1537, 1427, 1181, 961, 574, 522" in the lower row indicates the wave number of the peak top of the single C ₆₀ fullerene. The same applies to TPD and toluene.

( ^13C -MAS-NMR analysis)
¹³ C-MAS-NMR was performed using a CMX300 MNR spectrometer manufactured by Chemagnetics. FIG. 4 shows the ¹³ C-NMR spectrum of the co-crystal of Example 1.
From the results shown in FIG. 4, the chemical shift derived from C ₆₀ fullerene was confirmed at 143.9 ppm. Chemical shifts of the quaternary carbon atom bonded to N (nitrogen atom) of TPD and the quaternary carbon atom bonded to -CH ₃ were confirmed to be 147.5 ppm and 140.4 ppm, respectively.
The quaternary carbon atoms of TPD and toluene and the -CH= carbon atoms of the benzene ring were confirmed to be 115 to 135 ppm, and the methyl groups of TPD and toluene were confirmed to be 23.7 ppm and 22.3 ppm.

(UV-visible absorption spectrum)
The ultraviolet-visible absorption spectrum was analyzed using an ultraviolet-visible near-infrared spectrophotometer "V-570" (manufactured by JASCO Corporation, Rev. 1.00). The results are shown in Figure 5.
From the results shown in FIG. 5, the absorption spectrum of cocrystal 1 (indicated as "C ₆₀ /TPD Co-crystals" in FIG. 5) is different from the absorption spectrum of C ₆₀ fullerene (indicated as "(c) C _{60 Co} -crystals" in FIG. 5). It was found that the material had a higher absorption rate even in the long wavelength region (600 nm or more) compared to the material described in the following. This was also different from the characteristics of the absorption spectrum of TPD (indicated as "(b) TPD" in FIG. 5).

(Crystal structure analysis)
Crystal structure analysis was performed using Rigaku's RU-H2R (rotating anode cathode type) (Mo Kα ray), and SHELXL-97 (complete matrix least squares method) was used as a structural refinement method.
As a result of the analysis, the crystal system of cocrystal 1 is triclinic, the space group is P(-1) (No. 2), and the lattice constant is a = 12.752 (7) angstroms (Å, 10 ^-10 m). , b=13.539(5) Å, c=10.005(3) Å, α=92.75(2)°, β=95.54(3)°, γ=64.11(3)° was. The volume in the unit cell was V=1546.7(11) Å ³ and the number of molecules in the unit cell was Z=1. The density of the crystal (calculated value) was D=1.427 g/cm ³ . The R factor was R1(F)=0.131 (I>2σ(I)), wR(F ² )=0.439. The results are summarized in Table 2.

The co-crystal according to the embodiment of the present invention is a co-crystal of fullerene, which is an n-type organic semiconductor, and a triarylamine derivative having hole-transporting properties, and can absorb light in a wide range. It can be used for luminescence, organic solar cells, polymer solar cells, hydrogen storage, etc.

Claims (6)

It has a co-crystal containing fullerene, a triarylamine derivative, and toluene,
The sum of the mole-based content [A] of the fullerene in the co-crystal, the molar-based content [B] of the triarylamine derivative, and the molar-based content [C] of the toluene ([A ]+[B]+[C]),
The content molar ratio ([A]/([A] + [B] + [C])) of the molar content [A] of the fullerene is 0.29 to 0.37,
The content molar ratio ([B]/([A] + [B] + [C])) of the molar content [B] of the triarylamine derivative is 0.29 to 0.37,
The material, wherein the content molar ratio ([C]/([A]+[B]+[C])) of the toluene content [C] on a molar basis is 0.29 to 0.37. The material according to claim 1, wherein the molar ratio of fullerene, triarylamine derivative, and toluene in the co-crystal is 1:1:1. The material according to claim 1 or 2, wherein the fullerene is a C60 fullerene. The material according to any one of claims 1 to 3, wherein the triarylamine derivative is a compound represented by the following formula 1.
(In Formula 1, Ar ₁ to Ar ₄ each independently represent an aryl group.) The material according to claim 4, wherein the aryl group is at least one group selected from the group consisting of the following formulas 2a to 2h.
(In formulas 2a to 2h, * represents the bonding position.) A method for producing a material having a cocrystal containing fullerene, a triarylamine derivative, and toluene, the method comprising:
Mixing toluene and fullerene to prepare a saturated fullerene solution;
Adding a triarylamine derivative to the saturated fullerene solution to prepare a mixed solution;
A method for producing a material, the method comprising: allowing the mixed solution to stand still to precipitate a co-crystal.