JP6707794B2 - Dithienogelmol compound - Google Patents

Description

The present invention relates to a dithienogelmol compound that self-assembles into a spiral aggregate and exhibits circularly polarized light emission.

Silole, which is one of Group 14 metallols, is an organometallic compound having a structure in which one carbon of cyclopentadiene is replaced with silicon. A compound having a silole skeleton has been attracting attention as a light emitting material used in an organic electroluminescence (EL) device or the like, and self-assembly properties and light emission properties have been actively studied (for example, Patent Documents 1 and 2).

Another group 14 metalol is gelmol. Germol is an organometallic compound having a structure in which one carbon of cyclopentadiene is replaced with germanium. A compound having a germol skeleton is also known to exhibit luminescence, but there have been few reports on self-assembly properties and luminescence properties up to now. For example, Patent Document 3 describes an organic heteropolymer having a dithienogelmol skeleton, but does not describe the self-assembly property and the emission property in detail.

JP, 2013-60415, A JP, 2013-20996, A JP, 2014-221871, A

It is an object of the present invention to provide a dithienogelmol compound that self-assembles to form a spiral aggregate and exhibits circularly polarized light emission.

The present invention is a dithienogelmol compound represented by the following general formula (1). The present invention is described in detail below.

In the general formula (1), both or one of R ¹ and R ² is a group having an asymmetric center, and R ⁴ is hydrogen or OR ³ .

The present inventors produced a dithienogelmol compound represented by the above general formula (1) having a structure in which a dithienogelmol skeleton is modified with a plurality of phenylisoxazoles and having an asymmetric center in the structure. succeeded in. Furthermore, the present inventors have found that the resulting dithienogelmol compound self-assembles to form a spiral aggregate, and that the spiral aggregate exhibits circularly polarized light emission, The present invention has been completed.

The present invention is a dithienogelmol compound represented by the following general formula (1).

In the general formula (1), both or one of R ¹ and R ² is a group having an asymmetric center, and R ⁴ is hydrogen or OR ³ .

R ¹ and R ² are groups in which both or one has an asymmetric center. In addition, the plurality of R ^{1 s} in the general formula (1) may be the same or different, and the plurality of R ^{2 s} may be the same or different.
When R ¹ is a group having an asymmetric center, examples of R ¹ include a 2-ethylhexyl group, a citronellyl group, a perylyl group and a menthyl group having an asymmetric center. Of these, a 2-ethylhexyl group is preferable.
When R ¹ is a group having an asymmetric center, R ² is not particularly limited and may or may not have an asymmetric center, for example, methyl group, ethyl group, propyl group, butyl group. Group, pentyl group, hexyl group, heptyl group, octyl group, citronellyl group, geranyl group, farnesyl group, menthyl group, 3,7-dimethyloctyl group, 3,7-dimethyldecanyl group and the like. Of these, a 3,7-dimethyloctyl group is preferable.

When R ² is a group having an asymmetric center, R ¹ is not particularly limited and may have or may not have an asymmetric center, and examples thereof include an alkyl group having little steric hindrance. .. Examples of the alkyl group having less steric hindrance include a linear alkyl group, and the linear alkyl group is preferably a linear alkyl group having 2 to 12 carbon atoms such as n-octyl group and n-butyl group. ..
When R ² is a group having an asymmetric center, examples of R ² include an alkyl group having an asymmetric center, an amino acid derivative having an asymmetric center, and a cholesterol derivative having an asymmetric center. Of these, an alkyl group having an asymmetric center is preferable from the viewpoints of ease of production, steric hindrance, accumulating ability, and the like. Examples of the alkyl group having an asymmetric center include a 3,7-dimethyloctyl group and a 3,7-dimethyldecanyl group.

R ¹ and R ² may be groups having both or one of them having an asymmetric center, but from the viewpoint of ease of production, steric hindrance, accumulating ability, etc., R ¹ is an alkyl having less steric hindrance as described above. More preferably, it is a group having no asymmetric center such as a group, and R ² is a group having an asymmetric center such as an alkyl group having the above asymmetric center.

R ⁴ is hydrogen or OR ³ . R ³ is not particularly limited, and examples thereof include a linear alkyl group, an alkyl group having an asymmetric center, an amino acid derivative having an asymmetric center, and a cholesterol derivative having an asymmetric center. Of these, a linear alkyl group is preferable. In this case, both R ² and R ^{4 in} the above general formula (1) can be alkyl groups, that is, introducing a plurality of alkyl groups into the phenylisoxazole moiety in the above general formula (1). Therefore, the accumulating ability of the dithienogelmol compound can be further improved. In addition, the plurality of R ^{3 s} in the general formula (1) may be the same or different, and the plurality of R ^{4 s} may be the same or different.

The method of producing the dithienogelmol compound of the present invention is not particularly limited, but a method of producing a dithienogelmol skeleton and then modifying the dithienogelmol skeleton with a plurality of phenylisoxazoles is preferable.
More specifically, a modification method using a uniform coupling reaction of a dithienogermol skeleton substituted with bromine or iodine and phenylisoxazole having an ethynyl group is preferable.

The dithienogelmol compound of the present invention self-assembles to form a spiral aggregate. The method for evaluating the self-assembly property of the dithienogelmol compound of the present invention is not particularly limited, and examples thereof include proton NMR measurement, ultraviolet-visible absorption spectrum, and circular dichroism (CD) spectrum.
For example, in the proton NMR measurement, when the proton NMR measurement is performed while changing the concentration of the dithienogelmol compound, the peak of each proton of the aromatic ring shifts to a high magnetic field as the concentration of the dithienogelmol compound is increased. Thus, it can be determined that the molecules of the dithienogelmol compound form a laminated structure. Further, in the UV-visible absorption spectrum and the CD spectrum, by analyzing the change of the absorption band or the CD signal depending on the temperature in measuring the temperature change of each spectrum, the formation of the dithienogelmol compound aggregate, the presence of the helical structure Etc. can be confirmed.

The dithienogelmol compound of the present invention self-assembles to form a spiral aggregate, and the spiral aggregate exhibits circularly polarized light emission. Since the formation of the above-mentioned spiral aggregate and the expression of circularly polarized light emitting property by it depend on temperature, the expression of circularly polarized light emitting property can be controlled by temperature.
The method for evaluating the light emission characteristics of the dithienogelmol compound of the present invention is not particularly limited, and examples thereof include a fluorescence spectrum and circularly polarized light emission (CPL) spectrum.

The use of the dithienogelmol compound of the present invention is not particularly limited, and the circularly polarized light emitting property (particularly, the expression of the circularly polarized light emitting property is controlled by temperature) can be used to, for example, security ink, 3D glasses, The dithienogelmol compound of the present invention can be used as a light emitting material for a sensor, a light emitting intermediate film, a temperature sensor and the like. Further, by using the dithienogelmol compound of the present invention, it can be expected to reduce the number of constituent members of a liquid crystal display (LCD) panel.

According to the present invention, it is possible to provide a dithienogelmol compound which self-assembles to form a spiral aggregate and exhibits circularly polarized light emission.

The result of the proton NMR measurement which changed the density|concentration of the compound 12 is shown. 1 shows an ultraviolet-visible absorption spectrum of Compound 12 (S-form) in methylcyclohexane. 3 shows a circular dichroism (CD) spectrum of Compound 12 (S-form and R-form) in methylcyclohexane. The figure which plotted the change of the absorption and circular dichroism with respect to the temperature in 408 nm based on the obtained ultraviolet visible absorption spectrum and CD spectrum is shown. 3 shows a fluorescence spectrum of Compound 12 (S-form) in methylcyclohexane. The photograph which image|photographed the appearance of light emission in the 0.0049 mM methylcyclohexane solution of a compound 12 (S-form) and a 0.049 mM methylcyclohexane solution is shown. 3 shows a circularly polarized light emission (CPL) spectrum of Compound 12 (S-form and R-form) in methylcyclohexane.

Hereinafter, the embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
Compound 12, which is a dithienogelmol compound, was prepared according to the following scheme.

(1) Synthesis of compound 2

According to a conventionally known method, Compound 2 ( ¹ H-NMR: 1.43, 1.39-1.25, 0.92, 0.90, 0.88 ppm) with reference to Organometallics 2011, 30, 3233-3236 Was synthesized.

(2) Synthesis of compound 8

According to a conventionally known method, referring to Organometallics 2011, 30, 3233-3236, compound 8 ( ¹ H-NMR: 6.97, 1.45, 1.31-1.04, 0.91, 0.84, 0.79 ppm) was synthesized.

(3) Synthesis of compound 12

According to a conventionally known method, compound 11 ( ¹ H-NMR: 8.24, 7.98, 7.79, 6.99, 6.89, 4.05 with reference to Dalton Transactions 2015, 44, 13156-13162). 3.24, 1.90-1.81, 1.75-1.47, 1.42-1.10, 0.96, 0.88 ppm) were synthesized.
Then, compound 8 (149 mg) and compound 11 (425 mg) were dissolved in tetrahydrofuran (12 mL), diisopropylamine (0.5 mL), copper iodide (8 mg) and dichlorobistriphenylphosphine palladium (78 mg) were added, and then argon was added. Reflux for 11 hours under an atmosphere, extract with methylene chloride, concentrate and then purify by silica gel column chromatography to obtain compound 12 ( ¹ H-NMR: 8.22, 8.03, 7.82, 7.34, 7). 0.01, 6.93, 4.06, 1.85, 1.75-1.05, 0.96, 0.88, 0.83 ppm) were synthesized.

<Evaluation>
The dithienogelmol compound (Compound 12) obtained in Example 1 was evaluated by the following methods.

(1) Self-assembly property 1 (proton NMR measurement)
The self-assembly property of compound 12 in deuterated chloroform was evaluated by proton NMR measurement with varying concentration of compound 12. The concentration of compound 12 was 2.40 mML ^-1 , 3.59 mML ^-1 , 6.00 mML ^-1, and 12.0 mML ^-1 .
FIG. 1 shows the results of proton NMR measurement in which the concentration of compound 12 was changed. As shown in FIG. 1, as the concentration of compound 12 was increased, the peak of each proton of the aromatic ring was shifted to a high magnetic field. It is considered that this is because the molecules of the compound 12 form a layered structure and are affected by the ring current generated by the adjacent molecules to shield the protons. When the association constant of the molecule was determined by nonlinear analysis, it was 9±2 Lmol ⁻¹ .

(2) Self-assembly property 2 (UV-visible absorption spectrum and circular dichroism (CD) spectrum)
The self-assembly property of compound 12 in methylcyclohexane was evaluated using an ultraviolet-visible absorption spectrum and a circular dichroism (CD) spectrum. The concentration of compound 12 was 0.049 mM.
FIG. 2 shows an ultraviolet-visible absorption spectrum of Compound 12 (S-form) in methylcyclohexane. As shown in FIG. 2, in the temperature change measurement of the UV-visible absorption spectrum, the absorption band near 400 nm decreased as the temperature decreased, and a new absorption band appeared near 480 nm. This suggests that compound 12 exists as a monomer at high temperature and forms a J-aggregate by self-assembly at low temperature.
FIG. 3 shows a circular dichroism (CD) spectrum of Compound 12 (S-form and R-form) in methylcyclohexane. As shown in FIG. 3, in the temperature change measurement of the CD spectrum, the CD signal was not obtained at high temperature, but the CD signal appeared as the temperature was lowered, and the signal was inverted when the temperature was lowered from 10° C. to 0° C. .. Furthermore, for the S-form and the R-form, spectra having a mirror image relationship were given as shown in FIG. This suggests that compound 12 forms a spiral aggregate in methylcyclohexane, and the winding direction of the spiral is controlled by the chirality of the side chain.
Further, FIG. 4 shows a plot of changes in absorption and circular dichroism with respect to temperature at 408 nm, based on the obtained UV-visible absorption spectrum and CD spectrum. From this plot, it can be seen that the temperature at which the absorption in the UV-visible absorption spectrum changes significantly and the temperature at which the CD in the CD spectrum changes significantly.

From the above results, it was found that the compound 12 has two-stage association in methylcyclohexane, and shows a negative CD signal in the first stage association of the S-form and a positive CD signal in the second stage association. ..

(3) Emission characteristics (fluorescence spectrum and circularly polarized light emission (CPL) spectrum)
The emission characteristics of Compound 12 in methylcyclohexane were evaluated using a fluorescence spectrum and a circularly polarized light emission (CPL) spectrum. The concentration of compound 12 was 0.049 mM. The detection wavelength in the fluorescence spectrum was 420 nm, and the detection wavelength in the CPL spectrum was 400 nm.
FIG. 5 shows the fluorescence spectrum of Compound 12 (S-form) in methylcyclohexane. As shown in FIG. 5, in the temperature change measurement of the fluorescence spectrum, the emission intensity decreased as the temperature was lowered, but increased again at 0°C. When the quantum yield at 25° C. was measured, φ=0.29 in the 0.0049 mM methylcyclohexane solution and φ=0.17 in the 0.049 mM methylcyclohexane solution. From this, it was found that the quantum yield was reduced due to the aggregation of the compound 12. In addition, the photograph which image|photographed the light emission aspect in the 0.0049 mM methylcyclohexane solution of the compound 12 (S-form) and the 0.049 mM methylcyclohexane solution is shown in FIG. In FIG. 6, the right photograph is a 0.0049 mM methylcyclohexane solution, and the left photograph is a 0.049 mM methylcyclohexane solution.
FIG. 7 shows the circularly polarized light emission (CPL) spectrum of Compound 12 (S-form and R-form) in methylcyclohexane. As shown in FIG. 7, when the CPL spectrum was measured, CPL was inactive at 30° C., but at −10° C., a peak appeared with the formation of the aggregate. Further, the S body and the R body have mirror images as shown in FIG. 7.

According to the present invention, it is possible to provide a dithienogelmol compound that self-assembles to form a spiral aggregate and exhibits circularly polarized light emission.

Claims (1)

A dithienogelmol compound represented by the following general formula (1).
In the general formula (1), both or one of R ¹ and R ² is a group having an asymmetric center, and R ⁴ is hydrogen or OR ³ . When R ¹ is a group having an asymmetric center, R ¹ is a 2-ethylhexyl group, a citronellyl group, a perylyl group or a menthyl group having an asymmetric center. When R ² is a group having an asymmetric center , R ² is an alkyl group having an asymmetric center, an amino acid derivative having an asymmetric center or a cholesterol derivative having an asymmetric center. R ³ is a linear alkyl group, an alkyl group having an asymmetric center, an amino acid derivative having an asymmetric center, or a cholesterol derivative having an asymmetric center. A plurality of R ^{1 s} in the general formula (1) may be the same or different, a plurality of R ^{2 s} may be the same or different, and a plurality of R ^{3 s} may be the same or different. Of course, a plurality of R ^{4 s} may be the same or different.