JPH07113053B2 - Linear poly (2,5-pyridinediyl) polymer, method for producing the same, method for producing a film or filamentous material using the same, method for using the same, and semiconductor using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses a unit in which pyridine is bonded at the 2,5-position as a repeating unit, has excellent heat resistance, is soluble, and has a large polarization. The present invention relates to a linear poly (2,5-pyridinediyl) polymer having a degree of elimination, a method for producing the same, and a method for using the same.

[Problems of conventional technology and means for solving the problem]

Poly (arylene) having a structure in which aromatic rings are continuously bonded (for example, poly (p-phenylene), poly (2,
5-thienylene), poly (1,4-naphthalenediyl), etc.)
Generally has excellent heat resistance, and its electron acceptor (AsF ₅
Etc.) and an adduct with an electron donor (lithium, etc.) have excellent properties such as having conductivity and being usable as an active material for primary batteries and secondary batteries (eg, Macromolecules, 34, 848 (1985)). However, most poly (arylene) s have low solubility and are often infusible, so their usage may be limited.
It is a problem in drawing out the characteristic function.

For example, since poly (arylene) has a π-conjugated system along the main chain, it has a large polarizability in the direction of the main chain and is therefore considered to have a large degree of depolarization.
Due to its low solubility, such properties have not been fully elucidated. With regard to poly (arylene), it has been desired to develop a substance having physical properties not possessed by conventional poly (arylene) by devising a molecular structure. For example, if poly (arylene) having an oxidation / reduction potential different from that of conventional poly (arylene) can be obtained, it can be used as an active material or electrode material in a conventional polymer battery (eg, electrochemical and industrial physics, 54 Volume, 306
Page (1986)), and a polymer battery having characteristics different from the above is obtained.

Under the circumstances, the present invention was discovered by searching for poly (arylene) having a new molecular structure. INDUSTRIAL APPLICABILITY The linear poly (2,5-pyridinediyl) polymer of the present invention has heat resistance, is soluble in an organic solvent, and can be formed into a film using a solution obtained by dissolving it in an organic solvent. It has a very high degree of depolarization, and has excellent properties not found in conventional poly (arylene) such as showing a characteristic redox potential. In addition, in the text, "poly (arylene)"
(In English, poly (arylene)) is a polymer that has an aromatic ring as a repeating unit, such as poly (p-phenylene), and "aromatic ring" refers to aromatic hydrocarbon rings as well as pyridine and It includes a ring structure of a compound having aromaticity such as thiophene.

[Principle of production method] A zero-valent nickel compound takes halogen from a halogenated aromatic compound (including compounds showing aromaticity such as pyridine and thiophene in addition to aromatic hydrocarbons; hereinafter the same),
It causes a coupling reaction between aromatic groups (for example, Synthesis, p. 736 (1984)).

Ar−X + Ar′−X + NiLn → Ar−Ar ′ + NiX ₂ Ln ′ …… (1) (where Ar and Ar ′ are aromatic groups, X is halogen, L is a neutral ligand (thus NiLn is Therefore, a polymer is obtained by dehalogenation when an equimolar amount or more of a zero-valent nickel compound is added to an aromatic compound having two halogens in the molecule and reacted. .

nX-Ar "-X + nNiLm → >>Ar">> n + nNiX ₂ Lm '(2) (where X-Ar "-X represents an aromatic compound having two halogens in the molecule (X is a halogen) The polymerization method based on this principle can be applied to polymer synthesis from aromatic compounds having three or more halogens by using a larger amount of zero-valent nickel compound.

The production method of the present invention uses the polymerization method represented by the formula (2) as 2,5-
Dihalogenated pyridine (the following formula) To obtain a polymer.

As the zero-valent nickel compound, the one synthesized in the reaction system immediately before the polymerization reaction may be used as it is (so-called
Synthesized in situ), and those that have been previously synthesized and isolated are used.

〔Example〕

Example 1 To 40 ml of N, N-dimethylformamide (hereinafter abbreviated as DMF)
A zero-valent nickel compound Ni (PPh ₃ ) ₄ was prepared by adding 10 mmol of nickel chloride, 40 mmol of triphenylphosphine (hereinafter abbreviated as PPh ₃ ) and 11 mmol of zinc powder, and stirring (Synth
esis, 736 (1984)). After this, 10 mmol of this mixed system
2,5-Dibromopyridine was added and reacted at a reaction temperature of 60 ° C for 16 hours. By this reaction, a yellow powdery polymer (poly (2,5-pyridinediyl)) was obtained. After taking out this powdery polymer separately, in order to remove impurities such as nickel compounds, wash the powdery polymer several times in the following order with the substances (liquids) (a) to (f) below. did.

(A) hot toluene, (b) warm aqueous solution of ethylenediaminetetraacetic acid (pH adjusted to 3), (c) warm aqueous solution of ethylenediaminetetraacetic acid (pH adjusted to 9), (d) dilute aqueous NaOH solution at pH 9, ( (E) Warm water, (f) benzene After the above washing was completed, the powdery polymer was dried using a vacuum line.

Elemental analysis value of this polymer is carbon 76.0%, hydrogen 3.9%,
Nitrogen 16.9%, Bromine 0.6%, Calculated value of polymer with repeating unit (carbon 77.9%, hydrogen
3.9%, nitrogen 18.2%). The small difference between the observed and calculated values in elemental analysis is probably due to the high thermal stability of the polymer, which is not easy to burn completely in elemental analysis. The bromine obtained from the observed values is the end of the polymer at the end of the reaction. It is thought to be due to. The polymer yield in this example was 59%.

[Example 2] Polymerization reaction was carried out by the same operation as in Example 1, and post-treatment of the obtained polymer was carried out to obtain the results shown in Table 1. The results of Example 1 are also shown in No. 1 of Table 1.

In Table 1, the zero-valent nickel compound was added in an amount of about 1.0 to 1.1 mol based on 1 mol of 2,5-dibromopyridine. Further, the elemental analysis values of the polymers obtained in Table 1 were almost the same as the values calculated as poly (2,5-pyridinediyl).

Example 3 The polymers obtained in Examples 1 and 2 showed diffraction lines at 2θ = 15.7 ° and 25.4 ° in the powder X-ray diagram. The X-ray source was CuK _α .

[Example 4] The infrared absorption spectra of the polymers obtained in Examples 1 and 2 showed the following absorptions.

3040w, 3000w, 1584s, 1455vs, 1400w, 1345m, 1280w, 1220m, 1180w, 1120m, 1074s, 1024m, 1010s, 995m, 924w, 824vs, 787w, 740m, 694m, 642m, 562m (Numbers shown in cm ^-1 numbers W, s, m, vs each show weak absorption, strong absorption, medium absorption, and very strong absorption.) Depending on the obtained polymer, absorption around 790 cm ^-1 It was sometimes observed strongly.
All of the above measurement results are in KBr pellets.

[Example 5] The polymers obtained in Examples 1 and 2 were soluble in formic acid (HCOOH) and slightly soluble in concentrated hydrochloric acid. No difference in solubility depending on the degree of polymerization was observed. ^13C -NMR of polymer formic acid solutions.
(Nuclear magnetic resonance) spectrum is about 125 to 152 ppm (3-
(Trimethylsilyl) -sodium propanesulfonic acid (based on sodium salt) showed multiple absorptions roughly divided into three groups. These absorption positions are suitable as absorption positions based on carbon in the pyridine ring. Also, ¹³ C
-NMR showed that the polymer did not contain sp ³ carbon at all. Absorbent polymer that does not contain sp ³ carbon, in ¹ H-NMR obtained for a solution prepared by dissolving the polymer in a heavy water saturated with heavy hydrochloric acid, based on the hydrogen bonded to sp ³ carbon Was also confirmed by the fact that was not observed.

[Example 6] The polymers obtained in Examples 1 and 2 all showed high thermal stability. As a result of thermogravimetric analysis, a slight weight loss was observed at about 330 ° C for the first time. 0.4 mg for 11.9 mg sample (ratio to sample at heating at 450 ℃
Only 3.4%) weight loss was observed.

Example 7 The formic acid solutions of the polymers obtained in Examples 1 and 2 (containing about 4 mg of polymer per liter of solution) had a relatively sharp and clear chevron around 370 nm in the UV-visible spectrum. Shows the maximum absorption (absorbance often shows a value of about 0.8). Table 2 shows the positions of the absorption maximums (in max) obtained for the polymers obtained in each of the polymerizations in Table 1.

Also, in the same polymerization as No. 4 in Table 1, a polymer was prepared in the same manner as No. 4 in Table 1, except that maleic anhydride (equivalent mole to the zero-valent nickel compound) was added after the polymerization time of 13 hours. Obtained. This polymer showed an absorption maximum at 379 nm.

[Example 8] The molecular weight of the polymer was obtained by the laser light scattering method for the formic acid solutions of the polymers obtained in Examples 1 and 2 (Reference Biopolymers, vol. 22, p. 1461 (1983), etc. See). The results are shown in Table 3.

Also, in the same polymerization as No. 4 in Table 1, a polymer was prepared in the same manner as No. 4 in Table 1, except that maleic anhydride (equivalent mole to the zero-valent nickel compound) was added after the polymerization time of 13 hours. Obtained. The molecular weight of this polymer was 2,100.

Further, a polymer having a molecular weight of 650 was obtained by changing the reaction time under the same experimental conditions as in Example 1.

The molecular weight of each of the above polymers corresponds to a degree of polymerization of 9 to 32. By changing the mixing ratio of the 2,5-dihalogenated pyridine and the zero-valent nickel compound, it is possible to obtain a polymer having a wider degree of polymerization.

[Example 9] The degree of depolarization of the formic acid solutions of the polymers obtained in Examples 1 and 2 was determined by a laser light scattering method. The value of ρν in the depolarization degree ρ (also referred to as the degree of polarization reduction. For the definition, see Nobuhiko Saito “Polymer Physics (Revised Edition)”, published by Sokabo (1976, 7th edition), p. 181 And page 210)
Main polarizability of polymer by the following formula (also called main value of polarizability)
Of which the maximum polarizability (α ₁ ) and the other two axial main polarizabilities (α ₂ and α ₃ ) are associated.

Here, regarding the poly (2,5-pyridinediyl) of the present invention, if α ₁ >> α ₂ and α ₁ >> α ₃ , then δ ² ≈1, and thus ρν≈1 / 3. α ₁ >> α ₂ and α ₁ >> α
The condition of ₃ shows that the main polarizability along one direction is overwhelmingly larger than the main polarizabilities along the other two directions for the molecule, and in poly (2,5-pyridinediyl), It is considered that the major axis direction of the polymer is approximately coincident with the α ₁ direction. Also, α ₁ is larger than α ₂ and α ₃ ,
If the δ value does not change so much even if it is approximated to α ₂ ≈α ₃ , δ is calculated by the following equation (4). May be approximated by

For the polymers of Examples 1 and 2, as well as the polymer of Example 7 having an absorption maximum at 379 nm and the polymer of Example 8 having a molecular weight of 650, the value of ρν was between 0.20 and 0.33. showed that. Especially for No3 and No4 polymers in Table 1, the value of ρν is 0.33, which is close to the limit value (1/3). Thus, the fact that ρν is large indicates that the polarizability (α ₁ ) along the polymer main chain is very large. The measurement of ρν was carried out for each polymer formic acid solution.

[Example 10] The formic acid solutions of the polymers obtained in Examples 1 and 2 were spread on a platinum plate, and formic acid was removed by an evaporation method to obtain a polymer film (yellow). The infrared absorption spectrum of the substance obtained after removal of formic acid was in agreement with that of the polymer before addition of formic acid. Also, a filamentous substance could be obtained from the polymer formic acid solution.

[Example 11] Formic acid solutions of the polymers obtained in Examples 1 and 2 were spread on a platinum plate, and formic acid was removed by an evaporation method to obtain a polymer film on the platinum plate. About this polymer film,
The cyclic voltanogram was measured in a tetrahydrofuran solution containing 0.2 mol / l [N (C ₄ H ₉ ) ₄ ] [BF ₄ ] (the polymer was not dissolved in this solution). As a result, the polymer can be doped at about −2.5 V with respect to Ag / Ag ^{+ and} dedoped at about −2.2 V (potential with respect to Ag / Ag ⁺ ) in the reverse sweep. I understand. The color of the polymer changed from yellow to purple or magenta upon doping, and the opposite color was observed upon dedoping. Such an electrochemical discoloration phenomenon indicates that the polymer of the present invention can be used as a material exhibiting electrochromism.

Further, when the polymer of the present invention is immersed in a solution containing sodium naphthalide (a reaction product of naphthalene and sodium), the color changes from yellow to purple or magenta, which is the same color change as in electrochemical doping. It was observed. Sodium naphthalide is a typical compound for doping a π-conjugated polymer into an n-type, so it is considered that n-type doping occurs even in the above electrochemical doping. Reference)).

[Example 12] 53 mg of the polymer (powder) obtained in the polymerization shown in No. 4 of Table 1 of Example 2 was taken and exposed to iodine vapor at room temperature for 3 days using a vacuum line. As a result, a weight increase of about 41 mg was observed, and it was found that iodine was absorbed by the polymer to form an adduct. For this adduct, under pressure,
It was compression molded and the conductivity was measured by the two-terminal method. As a result, the solid obtained by compression molding the adduct under pressure was 4.3 × 10 ^-7 Scm ^-1 (Siemens / centimeter) at room temperature.
It was found to be a semiconductor having a conductivity of. Iodine is a typical electron-withdrawing compound (electron acceptor), and it is considered that adducts with other electron acceptors such as tetracyanoquinodimethane also show semiconductivity.

Claims (8)

[Claims] 1. The following equation And a linear poly (2,5-pyridinediyl) represented by
Polymer. 2. The ultraviolet / visible absorption spectrum at 367 nm.
To have a clear absorption maximum at any position in the range from 382 nm to 382 nm (here, the measurement of the UV-visible absorption spectrum is performed on a formic acid solution containing 5 mg of sample per liter of formic acid). The polymer according to claim 1, wherein 3. Depolarization degree (ρ) of the polymer in formic acid, for a solution obtained by dissolving the polymer in formic acid.
ν) is 0.28 or more (where, depolarization degree (ρν)
Is physically related to the maximum polarizability (α ₁ ) of the polymer's main polarizabilities and the other two axial main polarizabilities (α ₂ and α ₃ ) by the formula: ) The polymer according to claim 1 or 2, characterized in that 4. The following formula (In the formula, X represents halogen) 2,5-dihalogenated pyridine represented by the formula: is reacted with a zero-valent nickel compound. The linear poly (2,
Process for producing 5-pyridinediyl) polymer. 5. A solution obtained by dissolving the polymer (the linear poly (2,5-pyridinediyl) polymer according to any one of claims 1 to 3) in formic acid. A method for producing a film or filamentous material of the polymer by using. 6. A method of using the linear poly (2,5-pyridinediyl) polymer according to any one of claims 1 to 3 as a material exhibiting an electrochromic phenomenon. 7. A method of using the linear poly (2,5-pyridinediyl) polymer according to any one of claims 1 to 3 as an active material or an electrode material of a battery. 8. An electron acceptor is added to the linear poly (2,5-pyridinediyl) polymer according to any one of claims 1 to 3. semiconductor.