JP2010129832A - Fullerene derivative and organic piezoelectric material containing the compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel material that is effectively used as piezoelectric material by allowing a fullerene derivative to replace a polarization radical of large dipole moment. <P>SOLUTION: An organic piezoelectric material is constituted to contain a compound represented by a formula (1). In the formula, Ck represents fullerene, and Z represents 3-6 member ring to be condensed into a ring for forming fullerene frame. W represents a linking group of single bond or bivalent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fullerene derivative having a polarizing group, and more particularly to a piezoelectric material containing the compound.

  Conventionally, acoustic devices such as microphones and speaker diaphragms, various thermal sensors, pressure sensors, measuring devices such as infrared detectors, ultrasonic probe, vibration sensors that detect mutations such as genes and proteins with high sensitivity, etc. Organic piezoelectric materials having piezoelectricity and pyroelectricity that can be used to convert heat and mechanical stimulation into electrical energy are known.

As the pyroelectric material, a so-called inorganic material in which a single crystal such as quartz, LiNbO ₃ , LiTaO ₃ , KNbO ₃ , a thin film such as ZnO or AlN, or a sintered body such as Pb (Zr, Ti) O ₃ is subjected to polarization treatment. Piezoelectric materials are widely used. These inorganic piezoelectric materials have characteristics such as high elastic stiffness, high mechanical loss coefficient, high density and high dielectric constant.

  On the other hand, organic piezoelectric materials such as polyvinylidene fluoride (hereinafter abbreviated as “PVDF”) and polycyanovinylidene (hereinafter abbreviated as “PVDCN”) have also been developed (for example, see Patent Document 1). This organic piezoelectric material is excellent in workability such as thin film and large area, can be made in any shape and form, and has characteristics such as low elastic modulus and low dielectric constant, so as a sensor It has the feature that enables high-sensitivity detection when the use of is considered. On the other hand, organic piezoelectric materials have low thermostability and lose their pyroelectric properties at high temperatures, and their physical properties such as elastic stiffness are greatly reduced, so that the usable temperature range is limited.

  In contrast to these limitations, polyurea resin compositions composed of urea bonds have a large dipole moment of urea bonds and are excellent in temperature characteristics as resins. Therefore, various studies have been made as organic piezoelectric materials. . For example, there is a so-called vapor deposition polymerization method in which a polyurea film is formed by simultaneously evaporating a diisocyanate compound such as 4,4′-diphenylmethane diisocyanate (MDI) and a diamine compound such as 4,4′-diaminodiphenylmethane (MDA). It is disclosed (for example, see Patent Documents 2 and 3). However, since the polyurea resin composition prepared by the vapor deposition polymerization method described in these documents has a non-uniform molecular weight of the oligomer or high molecular weight product to be produced, when the molecular weight is increased while performing polarization treatment, In this state, the polyurea resin composition is formed. For this reason, the dipole moment of the urea bond cannot be fully utilized, and further improvement has been demanded as an organic piezoelectric material.

On the other hand, fullerene is a spherical grain-shaped carbon molecules, including C ^60, since it was discovered by Kroto and Smalley in 1985, its unique structure has been noted, a large amount synthesis of C ⁶⁰ in 1990 Since its establishment, research on fullerene has been energetically developed. As a result, many fullerene derivatives have been synthesized and their various functions have been clarified. Along with this, various applications such as electron conducting materials, semiconductors, and physiologically active substances using fullerene derivatives have been developed (see Non-Patent Document 1). However, polar groups such as urea groups that have a large dipole moment are used as fullerenes. There have been no reports of examples of functional materials that have been replaced or examples that have been developed as piezoelectric materials.
JP-A-6-216422 JP-A-2-284485 Japanese Patent Laid-Open No. 5-31399 Chemical Reviews, 1998, Vol. 98, p. 2527-2547

  The present invention has been made in view of the above problems and circumstances, and an object thereof is to provide a novel material that can be effectively used as a piezoelectric material by substituting a fullerene derivative with a polarizing group having a large dipole moment. It is in.

  The above object of the present invention is achieved by the following means.

  1. An organic piezoelectric material comprising a compound represented by the following general formula (1):

[Wherein, Ck represents fullerene, and Z represents a 3- to 6-membered ring condensed with a ring forming a fullerene skeleton. W represents a single bond or a divalent linking group. L is urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), amide (—NR _e CO— or —CONR _e —), carbamate (—NR _f COO—), carbonate (—OCOO). -) or sulfonyl (-SO ₂ - represents a) a divalent group represented by. Here, R _{a to} R _f represent a hydrogen atom or a substituent. A represents a substituent. ]
2. 2. The organic piezoelectric material according to 1, wherein the general formula (1) is any one of the following general formula (2), general formula (3), and general formula (4).

[Wherein, Ck represents fullerene, and W represents a single bond or a divalent linking group. L is urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), amide (—NR _e CO— or —CONR _e —), carbamate (—NR _f COO—), carbonate (—OCOO). -) or sulfonyl (-SO ₂ - represents a) a divalent group represented by. Here, R _{a to} R _f represent a hydrogen atom or a substituent. A represents a substituent. ]
3. 3. The organic piezoelectric material as described in 1 or 2 above, wherein L in the general formulas (1) to (4) is urea or thiourea.

  4). Any of the above 1 to 3, comprising a film containing a compound represented by any one of the general formulas (1) to (4) and a thermoplastic resin, a thermosetting resin, or a photocurable resin. 2. The organic piezoelectric material according to item 1.

  5. 4. The organic piezoelectric element according to any one of 1 to 3 above, comprising a film containing a compound represented by any one of the general formulas (1) to (4) and a ferroelectric polymer. material.

  6). A fullerene derivative represented by the following general formula (1):

[Wherein, Ck represents fullerene, and Z represents a 3- to 6-membered ring condensed with a ring forming a fullerene skeleton. W represents a single bond or a divalent linking group. L represents a divalent group represented by urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), carbamate (—NR _f COO—) or carbonate (—OCOO—). Here, R _a , R _b , R _c , R _d , and R _f each represents a hydrogen atom or a substituent. A represents a substituent. ]
7). A fullerene derivative represented by any one of the following general formulas (2) to (4).

[Wherein, Ck represents fullerene, and W represents a single bond or a divalent linking group. L represents a divalent group represented by urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), carbamate (—NR _f COO—) or carbonate (—OCOO—). Here, R _a , R _b , R _c , R _d , and R _f each represents a hydrogen atom or a substituent. A represents a substituent. R represents a hydrogen atom or a substituent. ]

  The present invention has been made in view of the above-mentioned problems and situations, and its purpose is excellent in piezoelectric properties capable of converting heat and mechanical stimulation into electric energy, in particular, high orientation and thermally. It is to provide a stable organic piezoelectric material.

  Next, the best mode for carrying out the present invention will be described, but the present invention is not limited thereto.

  First, the compound represented by the general formula (1) will be described.

<Compound represented by formula (1)>
In the formula, Ck represents fullerene. In the present invention, fullerene is a carbon molecule composed of a carbon 5-membered ring and a 6-membered ring and having various polyhedral structures closed in a spherical shape, and is a third carbon allotrope following graphite and diamond. A typical molecule includes C ^{60 in} which ⁶⁰ carbon atoms form a spherical truncated icosahedron composed of 12 five-membered rings and 20 six-membered rings, and similarly C ⁷⁰ , Further, there are higher order fullerenes such as C ⁷⁶ , C ⁷⁸ , C ⁸² , C ⁸⁴ , C ⁸⁶ , C ⁹⁰ and the like having a larger number of carbon atoms. These fullerenes exhibit very special properties due to their structure, and are, for example, soluble in organic solvents such as benzene and toluene, regardless of the carbon allotrope. In addition, due to its highly symmetric structure, a large feature appears in the internal electronic state, and its application to superconductors, semiconductors, optical functional materials, pharmaceuticals and catalysts has been reported. Furthermore, various similar compounds have been obtained by encapsulating metal atoms in the interior or performing chemical modifications such as hydroxylation and halogenation.

The fullerene represented by Ck is preferably C ⁶⁰ or C ⁷⁰ , and particularly preferably C ⁶⁰ .

  Z represents a 3- to 6-membered ring that is condensed to a ring that forms a fullerene skeleton. Specific examples include cyclopropane, cyclobutane, cyclopentane, cyclohexane, pyrrolidine, pyrazolidine, imidazolidine, isoxazolidine, isothiazolidine, piperidine and the like. These rings may be substituted with an alkyl group, an aromatic group, a halogen atom, or the like, and other aromatic rings, heterocycles, or cycloalkanes may be condensed to form two or more condensed rings. .

  The 3- to 6-membered ring represented by Z is preferably cyclopropane, cyclohexane, or pyrrolidine, and more preferably cyclopropane or pyrrolidine.

  W represents a single bond or a divalent linking group. Specific examples of the divalent linking group represented by W include an alkylene group, a phenylene group, an oxyethylene group, an oxypropylene group, an imino group, an oxy group, and a thio group. W is preferably a single bond, a phenylene group or an alkylene group.

L represents urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), amide (—NR _e CO— or —CONR _e — as shown in the following (L-1) to (L-6). ), Carbamate (—NR _f COO—), carbonate (—OCOO—) or sulfonyl (—SO ₂ —).

Here, R _{a to} R _f represent a hydrogen atom or a substituent.

  L is preferably amide, urea, thiourea or carbamate, and more preferably urea or thiourea.

In (L-1) to (L-4), R _a , R _b , R _c , R _d , R _e and R _f represent a hydrogen atom or a substituent. Specific examples of the substituent include carbon number 1 to 25 alkyl groups (methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, cyclohexyl group, etc.), halogenated alkyl groups (trifluoromethyl group, perfluorooctyl group, etc.) ), Cycloalkyl group (cyclohexyl group, cyclopentyl group etc.), alkynyl group (propargyl group etc.), glycidyl group, acrylate group, methacrylate group, aromatic group (phenyl group etc.), heterocyclic group (pyridyl group, thiazolyl group, Oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, trisyl group Horanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group etc.), halogen atom (chlorine atom, bromine atom, iodine atom, fluorine atom etc.), alkoxy group (methoxy group, ethoxy group, propyloxy group, pentyloxy group, cyclopentyloxy) Group, hexyloxy group, etc.), aryloxy group (phenoxy group etc.), alkoxycarbonyl group (methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group etc.), aryloxycarbonyl group (phenyloxycarbonyl group etc.), Sulfonamide group (methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group, etc.), sulfamoyl group (aminosulfonyl group, methylaminosulfonyl group, dimethyl group) Ruaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group) , 2-pyridylureido group, etc.), acyl group (acetyl group, propionyl group, butanoyl group, hexanoyl group, cyclohexanoyl group, benzoyl group), carbamoyl group (aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group) Propylaminocarbonyl group, pentylaminocarbonyl group, phenylaminocarbonyl group, etc.), amide group (acetamide group, propionamide group, butanamide group, hexaneamide group, benza Group), sulfonyl group (methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (amino group, ethylamino group, dimethylamino group, Butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), cyano group, nitro group, sulfo group, carboxyl group, hydroxyl group, oxamoyl group and the like. Further, these groups may be further substituted with these groups.

R _a , R _b , R _c , R _d , R _e and R _f are preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, and an aromatic group, and more preferably a hydrogen atom, 1 to carbon atoms. 4 alkyl group and phenyl group.

A represents a substituent. Specific examples of the substituent represented by A include the examples given as specific examples of the substituent represented by R _{a to} R _f . The substituent represented by A is preferably an alkyl group or an aromatic group, more preferably an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted by an alkoxy group, or an alkoxy group. Is a substituted aromatic group.

  In the present invention, the fullerene derivative represented by the general formula (1) is preferably a compound represented by the general formula (2), the general formula (3), or the general formula (4).

In the general formulas (2) to (4), Ck, W, L, and A are synonymous with Ck, W, L, and A in the general formula (1). In General formula (3), R represents a hydrogen atom or a substituent. Specific examples of the substituent represented by R include the examples given as specific examples of the substituent represented by R _{a to} R _f . R is preferably a hydrogen atom, an alkyl group, or an aromatic group, and more preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

  Specific examples of the compounds represented by the general formulas (1) to (4) are given below, but the present invention is not limited to these.

  The compounds represented by the general formulas (1) to (4) can be synthesized by a known method. For example, it can be synthesized with reference to the methods described in JP-A-2002-88354, JP-A-2004-256708, and the like.

<Organic piezoelectric material>
The organic piezoelectric material of the present invention can be obtained by forming a film containing the compounds represented by the general formulas (1) to (4) or by subjecting the film to further polarization treatment. A body membrane can be formed.

  In the organic piezoelectric film, when stress is applied to the piezoelectric film, charges of opposite signs appear in proportion to both ends of the piezoelectric film, that is, an electric polarization phenomenon occurs. It has the property (piezoelectric performance) that a distortion proportional to that occurs when it is put into (applying an electric field). In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, a large piezoelectric effect is generated by polarization due to orientation freezing of the dipole moment of the polymer main chain or side chain.

  On the other hand, when energy (heat) is applied to the piezoelectric film, the magnitude of spontaneous polarization in the piezoelectric film changes accordingly. At this time, the surface charge existing on the surface of the piezoelectric film so as to neutralize the spontaneous polarization cannot respond to the energy change as quickly as the spontaneous polarization. There is a charge corresponding to the change in spontaneous polarization. The generation of electricity associated with this energy change is called pyroelectricity. In particular, in the organic piezoelectric film made of the organic piezoelectric material of the present invention, polarization due to orientation freezing of the dipole moment of the main chain or side chain of the polymer Results in greater pyroelectric performance.

(Method of forming organic piezoelectric film)
The organic piezoelectric film is preferably formed by coating. Examples of the coating method include spin coating, solvent casting, melt casting, melt press, roll coating, flow coating, printing, dip coating, and bar coating.

  In the present invention, preferably, when the compounds represented by the general formulas (1) to (4) are applied or formed into a film, the formed film may be further subjected to a polarization treatment described later.

  When the compounds represented by the general formulas (1) to (4) are formed on the organic piezoelectric film, an arbitrary polymer compound may be further mixed to improve the film formability. As the polymer compound to be mixed, specifically, a thermoplastic resin, a thermosetting resin, or a photocurable resin having a number average molecular weight of 1500 or more is used.

  As the thermoplastic resin, any resin having a number average molecular weight of 1500 or more, preferably 1500 to 100,000 can be used without particular limitation. If the number average molecular weight of the thermoplastic resin is less than 1500, the glass transition temperature is too low, and the mechanical stability of the organic piezoelectric film may be lowered.

  Specific examples of the thermoplastic resin suitably used in the present invention include polyvinyl chloride, polyvinyl bromide, polyvinyl fluoride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene. Copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-styrene-acrylonitrile terpolymer , Vinyl chloride-vinylidene chloride-vinyl acetate copolymer, polyvinylidene chloride, polytetrafluoroethylene, polytetrafluorochloroethylene, polyvinylidene fluoride, and other halogenated vinyl polymers or copolymers; polyvinyl alcohol, polyallyl alcohol, Polyvinyl ether, polyallyl A Polymers or copolymers of unsaturated alcohols or ethers such as ruthenium; Polymers or copolymers of unsaturated carboxylic acids such as acrylic acid or methacrylic acid; Polyvinyl esters such as polyvinyl acetate, Polyallyl such as polyphthalic acid Polymers or copolymers of unsaturated residues in alcohol residues such as esters; acid residues or acid residues such as polyacrylic acid esters, polymethacrylic acid esters, maleic acid esters or fumaric acid ester polymers Or copolymers having an unsaturated bond in the alcohol residue; polymers or copolymers of acrylonitrile or methacrylonitrile; unsaturated nitriles such as polymers or copolymers of polycyanide vinylidene, malononitrile or fumaronitrile Polymer or copolymer; polystyrene , Polymers of aromatic vinyl compounds such as poly α-methyl styrene, poly p-methyl styrene, styrene-α-methyl styrene copolymer, styrene-p-methyl styrene copolymer, polyvinyl benzene, polyhalogenated styrene, or Copolymers; Polymers or copolymers of heterocyclic compounds such as polyvinyl pyridine, poly-N-vinyl pyrrolidine, poly-N-vinyl pyrrolidone; polyester condensates such as polycarbonate, nylon 6, nylon 6, 6, etc. Polyamide condensate; polymer or copolymer containing maleic anhydride, fumaric anhydride and imidized product thereof; heat resistance of polyamideimide, polyetherimide, polyimide, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, etc. Organic polymer And the like. Of these, polycarbonate, polystyrene, polyacrylate, polymethacrylate, nylon and the like are preferably used.

  As a thermosetting resin, various things including what is marketed, such as an epoxy adhesive and an acrylic adhesive, can be used. As the photo-curable resin, various kinds of resins including those that are commercially available such as an adhesive that is cured by visible light, UV light, electron beam, or the like can be used. These non-liquid crystalline polymer substances may be appropriately selected from the manufacturing method of the organic piezoelectric film and the required durability.

  Specific examples of the heat or photocurable resin suitably used in the present invention include, for example, an epoxy adhesive, an acrylic adhesive, an unsaturated polyester adhesive, a polyurethane adhesive, a hot melt adhesive, and an elastomer type. Mention may be made of adhesives.

  As an example of the epoxy adhesive, a bisphenol A type is preferable as the main agent. A main agent in which the bisphenol A portion is a bisphenol compound as shown below can also be used.

  Examples of polyurethane adhesives include methylene bis (p-phenylene diisocyanate), tolylene diisocyanate, hexamethylene diisocyanate, 1-chlorophenyl diisocyanate, 1,5-naphthylene diisocyanate, thiodipropyl diisocyanate, ethylbenzene-α- as an isocyanate component. Examples include 2-di-isocyanate, 4,4,4-triphenylmethane triisocyanate, and the components that react with them include ethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, glycerol, hexanetriol, and xylylene diene. All, lauric acid monoglyceride, stearic acid monoglyceride, oleic acid monoglyceride, polyethylene glycol, polypro Glycol, polyesters, polyamides, and the like.

  The mixing amount of the resin compound is 10 to 80% by mass, preferably 20 to 80% by mass with respect to the compounds represented by the general formulas (1) to (4). When the amount of the resin compound is less than 10% by mass, the film forming property of the liquid crystal layer may be deteriorated and the mechanical strength may be insufficient. On the other hand, when it exceeds 80 mass%, unnecessary light scattering may occur, and the performance of the organic piezoelectric film may be deteriorated.

  Further, the compounds represented by the general formulas (1) to (4) may be used by mixing with other ferroelectric polymers. Specifically, polyvinylidene fluoride (PVDF), vinylidene fluoride / ethylene trifluoride copolymer P (VDF / TrFE), vinylidene fluoride / tetrafluoroethylene copolymer P (VDF / TeFE), cyanide To vinylidene / vinyl acetate copolymer P (VDCN / VA), vinyl fluoride / ethylene trifluoride copolymer P (VF / TrFE), and vinyl fluoride / ethylene trifluoride copolymer P (VF / TrFE) Copolymer added with vinylidene fluoride, tetrafluoroethylene, hexafluoroacetone and hexafluoropropylene as the third component, amide polymer such as nylon 7 or nylon 11, aliphatic polyurea, aliphatic polyurethane, etc. Can be used.

(Polarization treatment)
As a polarization processing method in the polarization processing according to the present invention, various conventionally known methods can be applied.

  For example, in the case of the corona discharge treatment method, the corona discharge treatment can be performed by using a commercially available device comprising a high voltage power source and electrodes.

  Since the discharge conditions vary depending on the equipment and processing environment, it is preferable to select the conditions as appropriate. However, the voltage of the high voltage power source is −1 to −20 kV, the current is 1 to 80 mA, and the distance between the electrodes is 1 to 10 cm. The applied voltage is preferably 0.5 to 2.0 MV / m.

  As the electrodes, needle-like electrodes, linear electrodes (wire electrodes), and mesh-like electrodes that have been conventionally used are preferable, but the invention is not limited thereto.

  In addition, since heating is performed during corona discharge, it is necessary to install a heater via an insulator under the electrode in contact with the substrate manufactured according to the present invention.

  In the present invention, when the corona discharge treatment is performed as the polarization treatment in the state where the solvent of the coating solution remains, it is sufficient to remove the volatile components of the solvent in order to avoid the danger of flammable explosion. It is necessary for safety to carry out with ventilation.

(substrate)
As the substrate, the selection of the substrate differs depending on the application and use method of the organic piezoelectric film of the present invention. It may be a plastic plate or film such as polyimide, polyamide, polyimide amide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate resin, cycloolefin polymer. The surface may be covered with aluminum, gold, copper, magnesium, silicon or the like. A single crystal plate or film of aluminum, gold, copper, magnesium, silicon simple substance, or rare earth halide may also be used.

  Further, it may be formed on a multilayer piezoelectric element. As a method of using a multilayer for stacking piezoelectric elements, there is a method in which the organic piezoelectric film of the present invention is superposed on a ceramic piezoelectric element via an electrode. PZT is used as the ceramic piezoelectric element, but in recent years, one containing no lead has been recommended.

PZT is preferably within the range of the formula Pb (Zr _1-X Ti _X ) O ₃ (0.47 ≦ X ≦ 1). As deleading, natural or artificial quartz, lithium niobate (LiNbO ₃ ), potassium niobium tantalate [K (Ta, Nb) O ₃ ], barium titanate (BaTiO ₃ ), lithium tantalate (LiTaO ₃ ), or strontium titanate (SrTiO ₃ ). The composition of various ceramic materials can be selected as appropriate in terms of performance.

  EXAMPLES Hereinafter, although a synthesis example and an Example are given and this invention is demonstrated, this invention is not limited to these.

  Synthesis Example 1 Synthesis of Compound 3

7.2 g of fullerene and 15.0 g of 1- [4- (dodecyloxybutylurea)] were dissolved in 50 ml of toluene and stirred at room temperature while irradiating with 60 W incandescent light. After stirring for 24 hours, the solvent was distilled off under reduced pressure, and the resulting solid was washed with heptane and recrystallized with toluene to obtain 9.1 g of Compound 3 (yield 89%).
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.88 (m, 3H), 1.28-1.54 (m, 24H), 3.02 (m, 2H), 6.31 (m, 1H) )
IR spectrum (ATR method, cm ⁻¹ ): 3345, 2934, 1645, 1435, 1257, 1035, 858, 794, 695
Mass spectrum (API method, m / e (relative intensity)): 1022 ((25) MH ⁺ )
Synthesis Example 2 Synthesis of Compound 29

Fullerene (14.4 g), 1- (4-formylphenyl) -3-tetradecylthiourea (7.5 g) and N-methylglycine (8.9 g) were dissolved in toluene (200 ml), and the mixture was heated to reflux for 20 hours. After allowing to cool, the reaction crude product was purified by silica gel chromatography (heptane: toluene = 2: 1). The obtained crystals were recrystallized from tetrahydrofuran to obtain 5.6 g (yield 25%) of Compound 29.
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.85 (m, 3H), 1.29-1.31 (m, 22H), 1.53 (m, 2H), 2.25 (s, 3H) ), 3.57-3.65 (m, 4H), 5.21 (s, 1H), 6.37 (d, 2H), 6.97 (d, 2H)
IR spectrum (ATR method, cm ⁻¹ ): 2920, 1640, 1432, 1245, 1030, 795, 700
Mass spectrum (API method, m / e (relative intensity)): 1025 ((40) MH ⁺ )
Synthesis Example 3 Synthesis of Compound 41

After dissolving 7.2 g of fullerene and 3.5 g of 1- [3- (5,8-dihydronaphthalen-2-yl) phenyl] -3-hexylurea in 80 ml of toluene and stirring for 10 minutes at room temperature, 60 W incandescent lamp Stirring while irradiating the light. After stirring for 36 hours, the solvent was distilled off under reduced pressure, and the resulting solid was washed with heptane and recrystallized with toluene to obtain 8.1 g of Compound 41 (yield 73%).
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.87 (m, 3H), 1.27-1.32 (m, 6H), 1.52 (m, 2H), 3.04 (t, 2H) ), 3.41 (m, 4H), 7.26 (m, 1H), 7.38 (m, 1H), 7.41 (m, 1H), 7.54 (m, 1H), 7.68 (M, 1H)
IR spectrum (ATR method, cm ⁻¹ ): 3345, 2930, 1648, 1432, 1259, 1028, 850, 798, 752
Mass spectrum (API method, m / e (relative intensity)): 1044 ((20), MH ⁺ )
Synthesis Example 4 Synthesis of Compound 61

Fullerene 7.2 g and 1-tridecanamide 3.2 g were dissolved in 50 ml of toluene, and the mixture was stirred at room temperature while irradiating with 60 W incandescent light. After stirring for 20 hours, the solvent was distilled off under reduced pressure, and the resulting solid was washed with heptane and recrystallized with toluene to obtain 7.7 g of Compound 61 (yield 82%).
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.85 (t, 3H), 1.26 to 1.33 (m, 18H), 1.54 (m, 2H), 2.14 (t, 2H) ), 6.15 (m, 1H)
Mass spectrum (API method, m / e (relative intensity)): 973 ((40), MH ⁺ )
Synthesis Example 5 Synthesis of Compound 68

Fullerene (14.4 g), dodecyl-3-formylphenylcarbamic acid (6.7 g) and N-methylglycine (8.9 g) were dissolved in toluene (180 ml), and the mixture was heated to reflux for 36 hours. After allowing to cool, the reaction crude product was purified by silica gel chromatography (heptane: toluene = 2: 1). The obtained crystals were recrystallized from tetrahydrofuran to obtain 4.7 g (yield 22%) of Compound 68.
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.84 (m, 3H), 1.27-1.44 (m, 18H), 1.63 (m, 2H), 2.25 (s, 3H) ), 3.55-3.67 (m, 4H), 5.20 (s, 1H), 7.11 (m, 1H), 7.32 (m, 1H), 7.43 (m, 1H) , 7.75 (s, 1H)
Mass spectrum (API method, m / e (relative intensity)): 1081 ((55), MH ⁺ )
Synthesis Example 6 Synthesis of Compound 75

7.2 g of fullerene and 4.4 g of 5,8-dihydronaphthalen-2-yl-octadecyl carbonate were dissolved in 100 ml of toluene, stirred for 15 minutes at room temperature, and then stirred for 24 hours while irradiating with 60 W incandescent light. After that, the solvent was distilled off under reduced pressure, and the resulting solid was washed with heptane and recrystallized with toluene to obtain 7.7 g of Compound 75 (yield 68%).
¹ H-NMR spectrum (CDCl ₃ , ppm): 0.85 (m, 3H), 1.25-1.46 (m, 30H), 1.63 (m, 2H), 3.93 (m, 8H) ), 4.25 (m, 2H), 6.98 (m, 1H), 7.14 (m, 1H), 7.29 (m, 1H)
Mass spectrum (API method, m / e (relative intensity)): 1137 ((35), MH ⁺ )
Example 1
<Measurement of spontaneous polarization>
The spontaneous polarization was measured for the compound represented by the general formula (1). In this measurement, a glass substrate on which 1 cm × 1 cm of ITO (Indium-Tin-Oxide) is formed is arranged so as to oppose an interval of 5 μm, and a compound represented by the general formula (1) is injected between the glass substrates. A cell was prepared, and a triangular wave voltage (amplitude ± 20 V / μm, 6 Hz cycle) was applied to the liquid crystal cell. The results of this measurement are shown in Table 1 (the temperature when this spontaneous polarization was measured was 120 ° C.).

Example 2
<Evaluation of piezoelectric e characteristics and thermal stability of organic piezoelectric film>
The compound represented by the general formula (1) shown in Tables 2 and 3 and the resin compound or the ferroelectric polymer are dissolved in tetrahydrofuran or dimethylformamide, and then cast on a glass plate to a thickness of about 100 μm. Membranes were performed and dried at 100 ° C. under reduced pressure for 12 hours. This film was peeled from the glass plate and then pressed to a thickness of about 40 μm to prepare organic piezoelectric films -1 to 24. The organic piezoelectric films 1 to 24 are fixed on a hot plate, a tungsten needle is placed 1.5 cm away from the upper part of the organic piezoelectric film, and a voltage of 4.0 kV is applied thereto to perform polarization treatment by corona discharge. went. The temperature of the organic piezoelectric film was kept at 120 ° C. during the corona discharge treatment.

  Similarly, Comparative Organic Piezoelectric Films A to C were produced using Comparative-A, Comparative-B and Comparative-C shown in Table 3 instead of the compound represented by the general formula (1).

  The piezoelectric e constants of the organic piezoelectric films 1 to 24 and the comparative piezoelectric films A to C created above were evaluated while being heated to room temperature and 100 ° C. The piezoelectric e constant was measured by a resonance-antiresonance method using an impedance analyzer (manufactured by Agilent, 4194A). The results are shown in Tables 2 and 3. The piezoelectric e constant is shown as a relative value with the value measured at room temperature for the comparative piezoelectric film-C as 100%.

  As is clear from the results shown in Tables 2 and 3, it can be seen that the piezoelectric e constant of the organic piezoelectric film formed of the compound of the present invention is superior to that of the comparative example.

Claims (7)

An organic piezoelectric material comprising a compound represented by the following general formula (1):

[Wherein, Ck represents fullerene, and Z represents a 3- to 6-membered ring condensed with a ring forming a fullerene skeleton. W represents a single bond or a divalent linking group. L is urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), amide (—NR _e CO— or —CONR _e —), carbamate (—NR _f COO—), carbonate (—OCOO). -) or sulfonyl (-SO ₂ - represents a) a divalent group represented by. Here, R _{a to} R _f represent a hydrogen atom or a substituent. A represents a substituent. ] The organic piezoelectric material according to claim 1, wherein the general formula (1) is any one of the following general formula (2), general formula (3), and general formula (4).

[Wherein, Ck represents fullerene, and W represents a single bond or a divalent linking group. L is urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), amide (—NR _e CO— or —CONR _e —), carbamate (—NR _f COO—), carbonate (—OCOO). -) or sulfonyl (-SO ₂ - represents a) a divalent group represented by. Here, R _{a to} R _f represent a hydrogen atom or a substituent. A represents a substituent. R represents a hydrogen atom or a substituent. ] The organic piezoelectric material according to claim 1 or 2, wherein L in the general formulas (1) to (4) is urea or thiourea. It consists of a film | membrane containing the compound represented by either of said general formula (1)-(4), and a thermoplastic resin, a thermosetting resin, or a photocurable resin, The characterized by the above-mentioned. The organic piezoelectric material according to any one of the above. The organic material according to any one of claims 1 to 3, comprising a film containing a compound represented by any one of the general formulas (1) to (4) and a ferroelectric polymer. Piezoelectric material. A fullerene derivative represented by the following general formula (1):

[Wherein, Ck represents fullerene, and Z represents a 3- to 6-membered ring condensed with a ring forming a fullerene skeleton. W represents a single bond or a divalent linking group. L represents a divalent group represented by urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), carbamate (—NR _f COO—) or carbonate (—OCOO—). Here, R _a , R _b , R _c , R _d , and R _f each represents a hydrogen atom or a substituent. A represents a substituent. ] A fullerene derivative represented by any one of the following general formulas (2) to (4).

[Wherein, Ck represents fullerene, and W represents a single bond or a divalent linking group. L represents a divalent group represented by urea (—NR _a CONR _b —), thiourea (—NR _c CSNR _d —), carbamate (—NR _f COO—) or carbonate (—OCOO—). Here, R _a , R _b , R _c , R _d , and R _f each represents a hydrogen atom or a substituent. A represents a substituent. R represents a hydrogen atom or a substituent. ]