JPH0686457B2 - Thiophene derivative, complex containing the same, and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is characterized by a highly conductive charge transfer complex, an electron donor as a component thereof, a method for producing the same, and electrolytic polymerization of the electron donor. The present invention relates to a method for producing a conductive polymer.

(Problems to be developed by the prior art and the invention) Organic high-conductivity substances are lighter than metal materials such as copper and aluminum, and are not corrosive or can use abundant organic resources as manufacturing raw materials. It has been attracting attention in recent years because it has excellent advantages.

Generally, an organic substance is an electrical insulator, but in order to impart conductivity to it, it is preferable to form a charge transfer complex or to use a polymer having a structure in which the main chain is conjugated through an unsaturated bond. Has been done. For example, in a charge transfer complex, perylene-
It is known that halogen charge transfer complexes exhibit high conductivity. (H. Akamatu et al., Nature 173 , 168 (1954)).

Furthermore, if a heteroatom is introduced instead of the carbon atom of perylene, which has a carbon skeleton, the ionization potential will be lowered, which will not be advantageous as an electron donor. From the viewpoint of forming aggregates, it is expected to be advantageous as a high electric conductor. For example, 3,4 ';4,3'-bibenzo [b] thiophene (formula (A)) in which two carbon atoms of perylene are replaced by sulfur atoms And its iodine complex were synthesized, and it was found that the complex showed conductivity similar to that of the perylene-iodine complex (F. Wu
dl et al., J. Org. Chem .44, 2491 (1979)), but their electric conductivity was as low as 0.025 to 0.008 Scm ^-1 .

On the other hand, in the case of a polymer having a conjugated main chain, a method of electrolytically polymerizing an aromatic compound containing a hetero atom has recently attracted particular attention, and among them, a thiophene polymer is well known. However, since thiophene has only two polymerization active points, only a one-dimensional linear polymer was obtained by the polymerization reaction.

(Means for Solving the Problem) The present inventors further increased the number of sulfur atoms in the perylene homologue having two sulfur atoms shown in F. Wudl et al. By 2 to increase electron donation having a total of 4 sulfur atoms. The present invention has completed the present invention by discovering that the charge transfer complex formed from this and an electron acceptor as another component has high conductivity.

That is, the present invention relates to 3,4; 3 ', 4' represented by the formula (I).
-Vitieno [2,3-b] thiophene (I) And a method for producing the same, and a method for producing a highly conductive polymer by electrolytic polymerization of a charge transfer complex formed of compound (I) and an electron acceptor as another component, and compound (I).

The compound of formula (I) of the present invention can be synthesized by the following reaction formula.

0.2 to 2 moles of bis (triphenylphosphine) nickel (II) with respect to the above compounds (II) and (II)
A mixture of chloride, 2.5 to 40 moles of zinc and 1.5 to 20 moles of tetraethylammonium iodide in a solvent at 0 ° C or higher, preferably 20 ° C to 130 ° C.
Compound (I) is obtained by heating at the temperature of 0.5 to 50 hours.

Zinc may be in the form of powder, granules, or strips, and as the solvent, aliphatic hydrocarbons such as pentane, hexane, cyclohexane, aromatic hydrocarbons such as benzene, toluene, chlorobenzene, diethyl ether, tetrahydrofuran, dioxane, diglyme, In addition to ether compounds such as triglyme, ketone compounds such as acetone, methyl ethyl ketone, and cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, hexamethylphosphoramide, acetonitrile, chloroform, dichloromethane and the like can be mentioned.

The charge transfer complex of the present invention is usually prepared by subjecting compound (I) to an organic solvent.
And an electron acceptor are mixed in a molar ratio of 1: 0.5 to 10 to synthesize. Examples of the organic solvent include benzene, toluene, chlorobenzene, tetrahydrofuran, acetonitrile, benzonitrile, dichloromethane and the like. In addition to the above method, the compound (I) can be synthesized by thoroughly mixing it in a mortar or the like with a considerable amount of compound (I) without using an organic solvent. Examples of the electron acceptor used here include 7,7,8,8-tetracyanoquinodimethane, tetrafluorotetracyanoquinodimethane, dichlorodicyanoquinodimethane, hexacyanobutadiene, iodine and the like.

The polymer can be synthesized by electrolytic polymerization of the compound (I) as follows. Compound (I) is dissolved in a solution containing a supporting salt at a concentration of 0.01 to 1 M, and a platinum electrode is used for both the anode and the cathode to perform a constant potential reaction at 0.1 to 10 V for 0.1 to 500 hours, or at 10 ^-6 to 10 A for 0.1 to A polymer can be obtained on the anode side by conducting a constant current reaction for 500 hours.

Benzonitrile is used as the solvent.

As the supporting electrolyte, tetra-n-butylammonium perchlorate, tetra-n-butylammonium borofluorate, tetra-n-butylammonium hexafluorophosphate, etc. are used.

The molecular weight of the thiophene polymer of the present invention that can be synthesized by the above-mentioned electrolytic polymerization is usually 2000 to 110,000.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Example 1 0.5 g (1.68 mmol) of compound (II) and 0.54 g (0.84 mmo) of bis (triphenylphosphine) nickel (II) chloride
l), activated zinc 1.42 g (21.7 mmol), and tetraethylammonium iodide 2.76 g (10.7 mmol) containing 15 ml of benzene were refluxed for 28 hours for reaction.

The activated zinc used here was prepared by immersing ordinary zinc in dilute hydrochloric acid, washing it in the order of water and alcohol, and then drying it. After passing the reaction, the solution was concentrated under reduced pressure, passed through a silica gel column with carbon disulfide as an eluent, and then collected by high performance liquid chromatography to give compound (I) of 31.4%.
mg was obtained (yield 13.6%). This was recrystallized from carbon disulfide to obtain pale yellow needle crystals.

Spectral data of compound (I) ¹³ C-NMR (67.8 MHz, DMSO-d ₆ ) δ = 121.95,125.15,132.98,150.17 ¹ H-NMR (60 MHz, CS ₂ ) δ = 7.23 (s) IR (KBr) 3100 , 1421,819,740,719,693cm ^-1 MS (70eV) m / z (strength) M ⁺ 276 (100), 277 (16), 278 (19), 279 (2.7), 280
(1.5) UV / VIS (tetrahydrofuran) λmax = 252nm (ε = 46400), 254 (34200), 330 (2200
0) In cyclic voltammography, compound (I) is Ag / AgC
l The half-wave reduction potential of 1.01V was shown with respect to the standard electrode.

Example 2 7 mg of compound (I) was dissolved in about 0.7 ml of chlorobenzene to give 6 m
g of iodine is dissolved in as little chlorobenzene as possible, and this is mixed with a solution of compound (I) and left to stand 1:
Crystals of 1 complex were deposited, collected and dried.

Elemental analysis of the complex Measured value C; 27.50, H; 0.64% Calculated value as C ₁₂ H ₄ S ₄ · I ₂ C; 27.18, H; 0.76% The measured electrical conductivity was 0.11 Scm ^-1 .

Example 3 Compound (I) was dissolved in a benzonitrile solution containing 0.1 M tetrabutylammonium perchlorate as a supporting salt until saturation, and electrolysis was performed at a constant potential of 1.05 V for 2 days to obtain a black powder on the anode side. It was Elemental analysis of this product was C; 45.57, H; 1.05%. The theoretical value of a structure in which 0.45 of ClO ₄ is doped per polymer unit 1 represented by the following general formula is C; 45.15, H; 0.63%.

The electrical conductivity of the pellet obtained by compression-molding this black powder was 0.06 Scm ^{-1 when} measured at room temperature using the four-point method.

Comparative Example Compound (II) 0.30 g (1 mmol), bis (triphenylphosphine) nickel (II) chloride 0.064 g (0.1 mmo
l), benzene containing 0.98 g (1.5 mmol) of activated zinc and 0.25 g (1 mmol) of tetraethylammonium iodide 10
When m1 was refluxed for 30 hours to cause a reaction, and after-treatment was carried out in the same manner as in Example 1 below, compound (I) was not obtained, but compound (formula (B)) was obtained. Similar results were obtained when tetrahydrofuran was used as the solvent instead of benzene.

(Effects of the Invention) The compound (I) of the present invention is excellent as an electron donor constituting a charge transfer complex, and the charge transfer complex obtained therefrom has a very high conductivity as compared with a conventional complex of this type. have. Also, when the compound (I) is electropolymerized, a polymer is obtained, which has high conductivity.

Claims (5)

[Claims] 1. A compound represented by the following formula (I): 3,4; 3 ', 4'-
Vitieno [2,3-b] thiophene. 2. A 3,4-dibromothieno [2,3-b] thiophene represented by the following formula (II) and the compound (II),
0.2 to 2 mole times bis (triphenylphosphine) nickel (II) chloride, 2.5 to 40 mole times zinc and 1.5 to 2
3. The 3,4; 3 ', 4'- according to claim 1, wherein 0 mole times tetraethylammonium iodide is reacted.
Method for producing bithieno [2,3-b] thiophene. 3. The 3,4; 3 ', 4'-bithieno [2,3-b] thiophene according to claim 1 is used as an electron donor, and 7,7,8,8-tetracyanoquinodimethane, tetra A charge transfer complex derived from an electron acceptor selected from fluorotetracyanoquinodimethane, dichlorodicyanoquinodimethane, hexacyanobutadiene and iodine. 4. The molar ratio of electron donor to electron acceptor is 1: 0.5.
The charge transfer complex according to claim 3, wherein 5. A 3,4; 3 ', 4'-bithieno [2,3-b] thiophene polymer having a structural unit represented by the following formula (III): In the production of 3,4 represented by the following formula (I):
3 ', 4'-Bitieno [2,3-b] thiophene As a solvent, benzonitrile as a solvent, tetra-n-butylammonium perchlorate as a supporting electrolyte, tetra-
n-butylammonium borofluorate or tetra-
n-butylammonium hexafluorophosphate,
A method for producing a 3,4; 3 ', 4'-bithieno [2,3-b] thiophene polymer, characterized in that a platinum electrode is used as an electrode to carry out electrolytic polymerization at a potential of 1.05V.