JP5797497B2 - Tridentate rhodium complex, substituted acetylene polymerization initiator, and method for producing substituted polyacetylene derivative using the same - Google Patents

Description

  The present invention relates to a tridentate ligand rhodium complex, a method for producing the same, a substituted acetylene polymerization initiator, and a method for producing a substituted polyacetylene derivative using the same.

  Substituted polyacetylene has a conjugated polyethylene structure specific to the main chain. By controlling the three-dimensional structure of the main chain and the substituents on the side chain, various forms such as formation of conductivity, electroluminescence, and helical structure It is known to express various characteristics and functions.

  Polymers having a helical structure are materials that are particularly attracting attention for uses such as chiral sensors and optical resolution agents (see, for example, Patent Documents 1 to 3 below).

  As a method for producing a substituted polyacetylene having a helical structure, for example, a method using a rhodium-based polymerization initiator has been proposed (see Non-Patent Document 1). However, according to the method of Non-Patent Document 1, a chiral amine-based cocatalyst must be used in addition to the polymerization initiator, and the direction in which the helix is wound slightly changes depending on the amount of the cocatalyst added. However, there is a problem that it is difficult to control the reaction itself.

The present inventors have previously found that the tridentate ligands represented by the following general formulas (A1) and (A2) exhibit high catalytic activity for the polymerization of monosubstituted acetylene monomers. Reported (see Non-Patent Document 2).

JP 2003-292538 A JP 2008-291207 A JP 2008-273898 A

Journal of the American Chemical Society, (2003), 125 (21), 6346-6347 Proceedings of the Society of Polymer Science (CD-ROM) Vol.60 No.1 Disk1 Page.ROMBUNNO.1PB034

  While further studying a novel substituted acetylene polymerization initiator, the present inventors used a specific tridentate ligand rhodium complex as a substituted acetylene polymerization initiator, without using it together with a promoter. The inventors have found that a substituted polyacetylene derivative having a helical structure can be obtained, and have completed the present invention.

  That is, the first object of the present invention is to provide a novel tridentate rhodium complex useful as a polymerization initiator for a substituted acetylene, in which a substituted polyacetylene derivative having a helical structure can also be obtained. The second object of the present invention is to provide the tridentate ligand rhodium complex in an industrially advantageous manner. A third object of the present invention is to provide a method for producing a substituted polyacetylene derivative using the tridentate ligand rhodium complex, particularly a substituted polyacetylene derivative having a helical structure.

A first invention to be provided by the present invention is a tridentate rhodium complex represented by the following general formula (1).
(In the formula, R ¹ represents a linear or branched alkyl group having 1 to 5 carbon atoms and an aryl group. R ² and R ³ represent a linear or branched alkyl group having 1 to 5 carbon atoms. , And an aryl group, provided that R ² and R ³ are not the same group, Z represents an alkylene group having 3 to 6 carbon atoms, X represents NH or O, and * represents an asymmetric carbon. Indicates an atom.)

The second invention to be provided by the present invention is the following general formula (2).
(In the formula, R ² and R ³ represent a linear or branched alkyl group having 1 to 5 carbon atoms and an aryl group, provided that R ² and R ³ are not the same group. Z Represents an alkylene group having 3 to 5 carbon atoms, X represents NH or O, * represents an asymmetric carbon atom, and the following chemical formula (3):
Is reacted with a chlorobis (ethylene) rhodium dimer represented by the following general formula (4):
(In the formula, R ² , R ³ , Z, X and * are as defined above), and then the following general formula (5)
(In the formula, R ¹ represents an alkyl group or an aryl group.) A reaction with a boric acid compound represented by the following general formula (1)
(Wherein R ¹ , R ² , R ³ , Z, X and * are as defined above).

  The third invention to be provided by the present invention is a polymerization initiator of substituted acetylene comprising the tridentate rhodium complex of the first invention.

The fourth invention to be provided by the present invention is the following general formula (6).
(Wherein A represents an alkoxy group or an alkyl group, n1 represents an integer of 0 to 3, and n2 represents 0 or 2), the substituted acetylene polymerization initiator of the third invention The following general formula (7), wherein the polymerization reaction is carried out in the presence of
(In the formula, A, n1, and n2 have the same meanings as described above.) A method for producing a substituted polyacetylene derivative having a repeating unit represented by:

  According to the present invention, a substituted polyacetylene derivative having a helical structure can also be obtained. In particular, a novel tridentate ligand rhodium complex useful as a polymerization initiator for a substituted acetylene can be provided. Moreover, according to this invention, this tridentate ligand rhodium complex can be provided by an industrially advantageous method. Also, by using the tridentate ligand rhodium complex of the present invention as a polymerization initiator for substituted acetylene, a substituted polyacetylene derivative having a helical structure can be produced without using a cocatalyst, and the helical winding direction As for, a helical structure having a desired winding direction can be obtained by appropriately selecting the type of polymerization initiator used.

The CD spectrum figure (upper part) and UV-vis spectrum figure (lower part) of the substituted polyacetylene derivative obtained in Example 3 and Example 4. FIG.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
The tridentate ligand rhodium complex according to the present invention is represented by the following general formula (1).

R ¹ in the general formula (1) represents a linear or branched alkyl group or aryl group having 1 to 5 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, and iso-pentyl. Groups and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. In the present invention, R ¹ in the formula is particularly preferably a phenyl group.

R ² and R ³ in the formula (1) are groups selected from linear or branched alkyl groups and aryl groups having 1 to 5 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, and iso-pentyl. Groups and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group.
R ² and R ³ are different groups and do not become the same group. The most preferred combination of R ² and R ³ are either R ² and R ³ is a methyl group, it is preferably the other is a phenyl group.

  Z in the general formula (1) represents a linear alkylene group having 3 to 6 carbon atoms, and examples thereof include a propylene group, a butylene group, a pentylene group, and a hexylene group. An alkylene group having 4 to 5, particularly preferably 4 carbon atoms is preferred.

X in the formula of the general formula (1) represents NH or O. Moreover, * in a formula shows an asymmetric carbon atom. Regarding the stereo of the tridentate rhodium complex of the present invention, either the S-form or the R-form may be used.
The tridentate rhodium complex of the present invention has a chiral amine moiety when X in the formula of the general formula (1) is NH, and has a chiral ether moiety when X in the formula is O. It becomes like this.

  Subsequently, the manufacturing method of the tridentate ligand rhodium complex represented by the said General formula (1) of this invention is demonstrated.

  The method for producing a tridentate rhodium complex of the present invention comprises reacting the norbornadiene compound represented by the general formula (2) with the chlorobis (ethylene) rhodium dimer represented by the chemical formula (3). It has a first step of obtaining a rhodium complex represented by the formula (4), and then a second step of reacting the obtained rhodium complex with the boric acid compound represented by the general formula (5).

^{R 2, R} 3, X and Z in the formula of norbornadiene compound represented by the general formula of the raw material (2) in the first step, ^{R 2, R} 3 in the formula of the general formula (1), It is a group corresponding to each of X and Z. Specifically, R ² and R ^{3 in the} general formula (2) are groups selected from linear or branched alkyl groups and aryl groups having 1 to 5 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, and iso-pentyl. Groups and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. R ² and R ³ are different groups and do not become the same group. The most preferred combination of R ² and R ³ are either methyl groups R ² and R ³ as described above, the other is a phenyl group. Z in the formula of the general formula (2) represents a linear alkylene group having 3 to 6 carbon atoms, and examples thereof include a propylene group, a butylene group, a pentylene group, a hexylene group, and the like. An alkylene group having 4 to 5, particularly preferably 4 carbon atoms is preferred. In addition, * in the formula of the general formula (2) represents an asymmetric carbon atom as described above.
The norbornadiene compound represented by the general formula (2) according to the present invention is a novel compound and useful as a ligand.

Of the norbornadiene compounds represented by the general formula (2), a compound in which R ² which is a preferred compound in the present invention is a methyl group and R ³ is a phenyl group is prepared according to, for example, the following reaction scheme 1 Can do.
(In the formula, Z and * are as defined above.)

In the reaction scheme 1, the bromonorbornadiene compound (a) and the chiral amine compound (b1) are reacted with each other in a solvent such as acetonitrile at 100 to 150 ° C. for 5 hours or more, and represented by the general formula (2a). The norbornadiene compound obtained can be obtained.
On the other hand, the bromonorbornadiene compound (a) and the chiral alcohol compound (b2) are reacted in a solvent such as N, N-dimethylformamide at 30 to 100 ° C. for 3 hours or more in the presence of a base such as NaH. By doing so, a norbornadiene compound represented by the general formula (2b) can be obtained.

The bromonorbornadiene compound (a) is a known compound and can be easily produced by reacting 2,5-norbornadiene (a ′) with the dibromo compound (a ″) according to the following reaction scheme 2, for example. (See J. Am. Chem. Soc. 1995, 117, 10276-10291 etc.).
(In the formula, Z is as defined above.)

  In the reaction according to the first step, the addition amount of the chlorobis (ethylene) rhodium dimer is 0.3 to 0.7, preferably 0.4 to the molar ratio with respect to the norbornadiene compound represented by the general formula (2). 0.6.

  The reaction of the norbornadiene compound represented by the general formula (2) and the chlorobis (ethylene) rhodium dimer in the first step is performed in a solvent. The solvent that can be used is not particularly limited as long as it can dissolve the raw material and is inert to the product. For example, tetrahydrofuran, toluene, dichloromethane, acetonitrile, ethyl alcohol, methyl alcohol, hexane, diethyl ether, N, N-dimethylformamide, chloroform, chlorobenzene and the like can be used, and these can be used alone or in combination.

  The reaction conditions for the first step are a reaction temperature of 50 to 200 ° C., preferably 100 to 150 ° C., and a reaction time of 5 hours or more, preferably 5 to 15 hours.

  After completion of the reaction, for example, the reaction solution is distilled under reduced pressure to remove the solvent, and if necessary, purification such as recrystallization is performed to obtain the target rhodium complex represented by the general formula (4). Can do.

  In the second step, the rhodium complex represented by the general formula (4) obtained in the first step is reacted with the boric acid compound represented by the general formula (5) in a solvent.

R ¹ in the boric acid compound represented by the general formula (5) of the raw material in the second step is a group corresponding to R ¹ in the formula of the general formula (1). Specifically, R ¹ in the formula (5) represents a linear or branched alkyl group or aryl group having 1 to 5 carbon atoms. Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl, and iso-pentyl. Groups and the like. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. In the present invention, R ^{1 in} the formula is particularly preferably a phenyl group.

  The addition amount of the boric acid compound represented by the general formula (5) is 1 to 2, preferably 1 to 1.2 in terms of a molar ratio to the rhodium complex represented by the general formula (4).

  As the solvent that can be used in the reaction of the second step, any solvent can be used without particular limitation as long as it can dissolve the raw materials and is inert to the product. For example, tetrahydrofuran, toluene, dichloromethane, acetonitrile, ethyl alcohol, methyl alcohol, hexane, diethyl ether, N, N-dimethylformamide, chloroform, chlorobenzene and the like can be used, and these can be used alone or in combination.

  The reaction conditions for the second step are a reaction temperature of 0 to 40 ° C., preferably 20 to 30 ° C., and a reaction time of 5 hours or longer, preferably 10 to 20 hours.

  After completion of the reaction, for example, the reaction solution is distilled under reduced pressure to remove the solvent and, if necessary, purification such as recrystallization is performed, whereby the target tridentate ligand represented by the general formula (1) is obtained. A rhodium complex can be obtained.

  The tridentate rhodium complex represented by the general formula (1) according to the present invention is preferably used as a polymerization initiator for substituted acetylene, particularly a polymerization initiator for obtaining a substituted polyacetylene derivative having a helical structure. Can do.

  The method for producing a substituted polyacetylene derivative according to the present invention uses a tridentate ligand rhodium complex represented by the general formula (1) as a polymerization initiator of a substituted acetylene (hereinafter referred to as “polymerization initiator”). In the presence of the polymerization initiator, the substituted acetylene represented by the general formula (6) is polymerized to obtain a substituted polyacetylene having a repeating unit represented by the general formula (7).

The substituted acetylene used for the polymerization reaction is represented by the following general formula (6).
A in the general formula (6) is an alkoxy group or an alkyl group. The alkoxy group is preferably an alkoxy group having 1 to 16 carbon atoms, particularly 8 to 14 carbon atoms. The alkyl group is preferably an alkyl group having 1 to 16 carbon atoms, particularly 8 to 14 carbon atoms.
Moreover, n1 in the formula of General formula (6) shows the integer of 0-3, n2 in a formula shows the integer of 0 or 2.

In the present invention, as the substituted acetylene represented by the general formula (6), those represented by the following general formula (6a) or (6b) are particularly preferably used.

  In the present invention, when a polymerization reaction is carried out using the substituted acetylene represented by the general formula (6b), it undergoes an asymmetric induction from a polymerization initiator having an asymmetric moiety, and the optically active helix is produced from the achiral monomer. A substituted polyacetylene derivative having a structure can be produced.

In the main polymerization reaction, the polymerization initiator of the present invention described above is used.
The addition amount of the polymerization initiator in the main polymerization reaction is 10 to 1000, preferably 50 to 100 in terms of the molar ratio of the substituted acetylene to the polymerization initiator.

  The solvent that can be used is not particularly limited as long as it can dissolve the raw materials and is inert to the product. For example, tetrahydrofuran, toluene, dichloromethane, acetonitrile, ethyl alcohol, methyl alcohol, hexane, diethyl ether, N, N-dimethylformamide, chloroform, chlorobenzene and the like can be used, and these can be used alone or in combination.

  The reaction temperature of the polymerization reaction is preferably appropriately selected depending on the type of substituted acetylene to be polymerized, but in many cases it is 0 to 60 ° C, preferably 20 to 40 ° C. Moreover, although reaction time changes with kinds of substituted acetylene to superpose | polymerize, in many cases, it is 5 hours or more, Preferably it is 10 to 30 hours.

After completion of the polymerization reaction, the reaction solvent is removed by a conventional method, and if necessary, purification such as precipitation into a poor solvent is carried out to obtain the following general formula (7)
A substituted polyacetylene derivative having a repeating unit represented by the formula (wherein A, n1, and n2 are as defined above) can be obtained.

  The substituted polyacetylene derivative obtained by this production method has a number average molecular weight (Mn) of 5,000 or more, preferably 10,000 to 1,000,000. Further, the weight average molecular weight (Mw) is 10,000 or less, preferably 20,000 to 2,000,000.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
{Example 1}
(Synthesis of norbornadiene compound (2a-1))
Bromonorbornadiene compound (a-1) (300 mg, 1.32 mmol) was dissolved in 10 ml of acetonitrile, and (R) -1-phenylethylamine (b1) (0.50 ml, 3.92 mmol) was added thereto. Next, the reaction was carried out under reflux at 110 ° C. for 10 hours with stirring.
After completion of the reaction, the reaction solution was cooled to room temperature, and the reaction solution was distilled under reduced pressure to remove the solvent. The obtained residue was dissolved in ethyl acetate, and the organic layer was washed with a saturated aqueous solution of sodium bicarbonate. The organic layer was separated, and the organic layer was dehydrated with anhydrous sodium sulfate. Then, anhydrous sodium sulfate was removed, and the solvent was removed by distillation under reduced pressure. Subsequently, the obtained residue was purified using column chromatography to obtain an oily norbornadiene compound (2a-1) (yield 89%).
(Identification data of norbornadiene compound (2a-1))
Elemental analysis Calculated value (C ₁₉ H ₂₅ N): C, 85.34%; H, 9.42%; N, 5.24% measured value: C, 85.46%; H, 9.42%; N, 5.02%
・¹ H NMR (CDCl ₃ ) d: 7.27-7.15 (m, 5H), 6.66 (s, 2H), 6.02 (s, 1H), 3.68 (q, 1H, J = 6.8 Hz), 3.41 (s, 1H ), 3.18 (s, 1H), 2.45 (m, 1H), 2.40 (m, 1H), 2.15 (m, 2H), 1.93 (m, 2H), 1.40 (m, 4H), 1.33 (d, 3H, J = 6.8 Hz), 1.15 (brs, 1H).
・¹³ C NMR (CDCl ₃ ) d: 158.6, 145.8, 143.8, 142.3, 133.3, 128.3, 126.7, 126.5, 73.4, 58.3, 53.4, 50.0, 47.7, 31.3, 30.0, 25.0, 24.4.
Specific rotation [α] _D = + 36.8 (measured in chloroform at room temperature, c = 0.10 g / dL)

(Synthesis of rhodium complex (4a-1))
Chlorobis (ethylene) rhodium dimer (3) (185 mg, 0.48 mmol) was dissolved in 4.0 ml of dichloromethane, and 4.0 ml of dichloromethane in which norbornadiene compound (2a-1) (280 mg, 1.09 mmol) was dissolved was added thereto. The reaction was performed at room temperature (25 ° C.) for 15 hours in an argon atmosphere.
After completion of the reaction, the reaction solution was distilled under reduced pressure to remove the solvent, and the residue was purified by recrystallization from a dichloromethane-pentane mixed solvent to obtain a rhodium complex (4a-1) (yield 83%).
(Identification data of rhodium complex (4a-1))
Elemental analysis Calculated value (C ₁₉ H ₂₅ NClRh): C, 56.24%; H, 6.21%; N, 3.45% measured value: C, 56.31%; H, 6.39%; N, 3.35%

(Synthesis of tridentate rhodium complex (1a-1))
A Schlenk tube was charged with rhodium complex (4a-1) (60 mg, 0148 mmol) and sodium tetraphenylborate (5a-1) (55.8 mg, 0.163 mmol) and replaced with argon gas. Next, 5.5 ml of dichloromethane was charged, and the reaction was performed overnight at room temperature (25 ° C.).
After completion of the reaction, filtration was performed to remove sodium tetraphenylborate (5a-1), and then the filtrate was distilled under reduced pressure to remove the solvent. The residue was purified by recrystallization from a dichloromethane-pentane mixed solvent to obtain a tridentate rhodium complex sample (1a-1) (yield 89%).
(Identification data of tridentate rhodium complex (1a-1))
· Analysis Calculated _{(C 43 H 45 BNRh):} C, 74.9%; H, 6.59%; N, 2.03% measured value: C, 74.60%; H, 6.31%; N, 1.94%
・¹ H NMR (CDCl ₃ ) d: 7.37-7.00 (m, 20H), 6.60 (m, 2H), 6.38 (m, 1H), 6.25 (m, 1H), 5.84 (m, 1H), 3.80 (s , 1H), 3.71 (m, 1H), 3.66 (m, 1H), 3.46 (m, 1H), 3.31 (m, 1H), 3.14 (m, 1H), 2.42 (brs, 1H), 2.31 (brs, 1H), 2.06 (m, 1H), 1.38-1.29 (m, 7H), 1.09-1.00 (m, 4H).

{Example 2}
(Synthesis of norbornadiene compound (2a-2))
Bromonorbornadiene compound (a-1) (676.8 mg, 2.98 mmol) was dissolved in 8 ml of N, N-dimethylformamide, and (R) -1-phenylethanol (b2) (364 mg, 2.28 mmol) was dissolved therein. added. Next, NaH (content 50%, 184.7 mg, 5.54 mmol) was added, and the reaction was performed at 60 with stirring for 6 hours.
After completion of the reaction, the reaction solution was cooled to room temperature, saturated aqueous sodium carbonate solution was added to the reaction solution, and then extracted with diethyl ether. The organic layer was separated, and the organic layer was dehydrated with anhydrous sodium sulfate. Then, anhydrous sodium sulfate was removed, and the solvent was removed by distillation under reduced pressure. Subsequently, the obtained residue was purified using HPLC to obtain an oily norbornadiene compound (2a-2) (yield 38%).
(Identification data of norbornadiene compound (2a-2))
Elemental analysis: calculated _{(C 19 H 24 O):} C, 83.03%; H, 9.01% measured value: C, 84.99%; H, 8.72%
・¹ H NMR (CDCl ₃ ) d: 7.33-7.30 (m, 5H), 6.73 (s, 2H), 6.09 (s, 1H), 4.38 (q, 1H, J = 6.4 Hz), 3.48 (s, 1H ), 3.27 (m, 3H), 2.16 (m, 2H), 1.94 (m, 2H), 1.52 (m, 4H), 1.42 (d, 3H, J = 6.0 Hz).
・¹³ C NMR (CDCl ₃ ) d: 158.7, 144.3, 143.8, 142.4, 133.5, 128.4, 127.3, 126.1, 77.9, 73.4, 68.5, 53.4, 50.0, 31.2, 29.6, 24.2, 23.8.
Specific rotation [α] _D = −66 (measured in chloroform at room temperature, c = 0.10 g / dL)

(Synthesis of rhodium complex (4a-2))
Dissolve chlorobis (ethylene) rhodium dimer (3) (160 mg, 0.41 mmol) in 5.0 ml of dichloromethane, and add 3.0 ml of dichloromethane in which norbornadiene compound (2a-2) (243 mg, 0.91 mmol) was dissolved. The reaction was performed at room temperature (25 ° C.) for 19 hours in an air atmosphere.
After completion of the reaction, the reaction solution was distilled under reduced pressure to remove the solvent, and the residue was purified by recrystallization at -78 ° C. with a dichloromethane-pentane mixed solvent to obtain a rhodium complex (4a-2) (yield). 66%).

(Synthesis of tridentate ligand rhodium complex (1a-2))
A Schlenk tube was charged with rhodium complex (4a-2) (30 mg, 0.073 mmol) and sodium tetraphenylborate (5a-1) (26.5 mg, 0.077 mmol), and replaced with argon gas. Next, 2.0 ml of dichloromethane was charged, and the reaction was performed overnight at room temperature (25 ° C.).
After completion of the reaction, filtration was performed to remove sodium tetraphenylborate (5a-1), and then the filtrate was distilled under reduced pressure to remove the solvent. The residue was purified by recrystallization from a dichloromethane-pentane mixed solvent to obtain a tridentate rhodium complex (1a-2) (yield 79%).
(Identification data of tridentate rhodium complex (1a-2))
Elemental analysis calculated value (C ₄₃ H ₄₄ BORh): C, 74.79%; H, 6.42% measured value: C, 73.17%; H, 6.16%
・¹ H NMR (CDCl ₃ ) d: 7.41-7.03 (m, 20H), 6.67 (m, 1H), 6.50 (m, 1H), 6.43 (m, 1H), 6.20 (m, 1H), 5.79 (m , 1H), 4.35 (q, 1H, J = 6.8 Hz), 3.77 (brs, 1H), 3.63 (brs, 1H), 3.46 (brs, 1H), 3.33 (brs, 1H), 3.21 (m, 2H) , 3.15 (brs, 1H), 2.07 (m, 2H), 1.43-1.01 (m, 9H).

{Examples 3 to 4}
(Synthesis of a substituted polyacetylene derivative (7b) having a helical structure)
The substituted acetylene (6b) is dissolved in tetrahydrofuran so as to have a concentration of 0.2 M, the polymerization initiator sample is added so that the molar ratio of the substituted acetylene to the polymerization initiator sample is 100, and the polymerization reaction is performed at 30 ° C. for 24 hours. went. After completion of the reaction, the polymerization solution was poured into methanol, and the precipitated polymer was isolated.
(Identification data of substituted polyacetylene derivative (7b) having a helical structure)
¹ H NMR (CD ₂ Cl ₂ ) δ 0.81-1.80 (m, 23H), 3.87 (broad, 2H), 4.30 (broad, 2H), 4.37 (broad, 4H), 6.70-7.20 (broad, 3H).

<Evaluation of physical properties of substituted polyacetylene derivative (7b) having a helical structure>
(Evaluation 1): For the substituted polyacetylene derivative (7b) obtained in Example 3 and Example 4, the number average molecular weight (Mn) and the weight average molecular weight (Mw) were determined. Further, PDI (Mw / Mn) was calculated from the average molecular weight (Mn) and the weight average molecular weight (Mw). The results are shown in Table 1 together with the yield.
The number average molecular weight (Mn) and the weight average molecular weight (Mw) were evaluated by gel permeation chromatography (GPC; JASCO PU-980 / RI-930 chromatography, polystyrene conversion).
(Evaluation 2); Specific rotation and UV-vis spectrum of the substituted polyacetylene (7b) obtained in Example 3 and Example 4 were measured in CHCl ₃ at 20 ° C. The monomer unit concentration of the substituted polyacetylene in CHCl ₃ was 0.10 mM.
The obtained CD spectrum and UV-vis spectrum are shown in FIG.

From the results shown in FIG. 1, the substituted polyacetylene derivatives obtained in Example 3 and Example 4 show a large specific rotation in CHCl ₃ dissolution, and the CD signal and UV-visible signal based on the main chain polyacetylene are shown in the literature. It agrees with the value (Journal of the American Chemical Society, (2003), 125 (21), 6346-6347) and shows a peak near 300 nm, confirming that the main chain forms a helical structure. .
Moreover, it was revealed that the produced substituted polyacetylene derivative (7b) exhibited a clear cotton effect in the absorption region of the main chain and formed a helical structure with a biased winding direction. The stereo-coordination of the amine site and the ether site of the polymerization initiator used was (R), but the cotton effect of the obtained substituted polyacetylene (7b) was positive and negative.

  According to the present invention, a substituted polyacetylene derivative having a helical structure can also be obtained. In particular, a novel tridentate ligand rhodium complex useful as a polymerization initiator for a substituted acetylene can be provided. Moreover, according to this invention, this tridentate ligand rhodium complex can be provided by an industrially advantageous method. Also, by using the tridentate ligand rhodium complex of the present invention as a polymerization initiator for substituted acetylene, a substituted polyacetylene derivative having a helical structure can be produced without using a cocatalyst, and the helical winding direction As for, a helical structure having a desired winding direction can be obtained by appropriately selecting the type of polymerization initiator used.

Claims (8)

A tridentate rhodium complex represented by the following general formula (1):
(In the formula, R ¹ represents a linear or branched alkyl group having 1 to 5 carbon atoms and an aryl group. R ² and R ³ represent a linear or branched alkyl group having 1 to 5 carbon atoms. And an aryl group, wherein R ² and R ³ are not the same group, Z represents an alkylene group having 3 to 6 carbon atoms, X represents NH or O, and * represents an asymmetric carbon. Indicates an atom.)   The tridentate rhodium complex according to claim 1, wherein Z in the formula (1) is an alkylene group having 4 carbon atoms. The tridentate rhodium complex according to any one of claims 1 and 2 , wherein R ¹ in the formula (1) is a phenyl group. The tridentate ligand according to any one of claims 1 to 3 , wherein R ² and R ³ in the formula (1) are groups selected from a methyl group and a phenyl group. Rhodium complex. A norbornadiene compound represented by the following general formula (2):
(In the formula, R ² and R ³ represent a linear or branched alkyl group having 1 to 5 carbon atoms and an aryl group, provided that R ² and R ³ are not the same group. Z Represents an alkylene group having 3 to 5 carbon atoms, X represents NH or O. * represents an asymmetric carbon atom.)   A polymerization initiator of a substituted acetylene comprising the tridentate ligand rhodium complex according to any one of claims 1 to 4. The following general formula (6)
(In the formula, A represents an alkoxy group or an alkyl group. N1 represents an integer of 0 to 3, and n2 represents 0 or 2.) The substituted acetylene represented by the polymerization initiator for substituted acetylene according to claim 6 , The following general formula (7), wherein the polymerization reaction is carried out in the presence of
(Wherein A, n1 and n2 are as defined above). A method for producing a substituted polyacetylene derivative having a repeating unit represented by: The method for producing a substituted polyacetylene derivative according to claim 7, wherein the produced substituted polyacetylene derivative has a helical structure.