KR101047976B1 - New Solvatochromic Dyes - Google Patents

Abstract

The present invention provides a solvatochromic dye of formula (I) in which a range of absorption wavelength and emission fluorescence wavelength is changed depending on the degree of polarity of the solvent. The present invention also provides a solvatochromic dye of the following formula II in which the ranges of the absorption wavelength and the emission fluorescence wavelength are changed according to the polarity of the solvent.

Solvent, Polarity, Absorption, Fluorescence, Luminescence, Wavelength, Solvatochromic Dye

Description

Novel solvatochromic dyes

The present invention relates to novel solvatochromic dyes. More specifically, the present invention relates to a novel solvatochromic dye in which the absorption wavelength and the range of the fluorescence emission wavelength change according to the degree of polarization of the solvent.

Solvatochromic dyes have attracted attention for their potential as probes in solvent polarity experiments and as colorants such as colorimetric systems for the analysis of volatile organic solvents. Solvatochromism may be defined as a phenomenon in which a compound changes color due to a spectral change caused by a difference in absorption or emission spectra when molecules are dissolved in different solvents. Recently, solvatochromic dyes such as pyridinim betaine, 2 ', 2-bithiophene, stilbazolium and Brooker's merocyanine dye have been studied.

These solvatochromic dye molecules and merocyanine dyes are expected to be used in various fields such as photographic photosensitizers, nonlinear lenses, and chemotherapy. Merocyanine dyes are considered to be a potent material for sorbatochromic dyes because of their electronic structure and have heterocyclic chromophores. The electronic structure of the ground state merocyanine dye with a push-pull system can be explained by a model in which two states are combined. This model predicts the resonance state between neutral and zwitterionic molecular structures and provides a useful analytical method for solbatochromism and bond length alternation.

In general, condensation reactions between N, N-dimethylamino benzaldehyde derivatives, Meldrum's acid and barbituric acid, or derivatives thereof, form merocyanine dyes, which are useful for spectroscopic analysis. Thus, meldmic acid and barbituric acid can be considered as potentially useful parts for designing solvatochromic merocyanine dyes.

In the present invention, the sorbatochromic merocyanine dye homologue is 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde and 5- (2,6-dimethyl-4H-pyran-4-ylidene). ) Was synthesized through the condensation of meldmic acid, 5- (2,6-dimethyl-4H-pyran-4-ylidene) barbituric acid. The absorbance and luminescence were measured by spectroscopic analysis of dye reactions in 22 different solvents by UV-Vis absorbance experiment. Solvatochromic properties of the various solvents showed notable color differences. This property shows applicability as a probe effective for the detection of volatile organics.

Therefore, the present inventors have completed the present invention by developing a solvatochromic dye whose color changes depending on the type of solvent. The solvatochromic dye of the present invention is expected to be applicable as an effective probe for the detection of volatile organic substances in various fields such as photographic photosensitizers, nonlinear lenses and chemotherapy.

The problem to be solved by the present invention is to develop a dye having a solvatochromic properties showing a noticeable color difference for various solvents. In the present invention, the sorbatochromic merocyanine dye analogue is a 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde and 5- (2,6-dimethyl-4H-pyran-4-ylidene) meldum. It was synthesized through condensation of acid, 5- (2,6-dimethyl-4H-pyran-4-ylidene) barbituric acid.

It is an object of the present invention to provide a solvatochromic dye of formula I, wherein the range of absorption wavelength and emission fluorescence wavelength is changed depending on the degree of polarity of the solvent.

Equation Ⅰ

On the other hand, another object of the present invention is to provide a solvatochromic dye of the following formula II in which the range of absorption wavelength and emission fluorescence wavelength is changed according to the degree of polarity of the solvent.

Equation II

On the other hand, another object of the present invention is a compound represented by the formula (4) by condensation polymerization of the compound represented by the formula (2) to the raw material represented by the formula (2,6-dimethyl-4H-pyran-4-one) (5- After obtaining (2,6-dimethyl-4H-pyran-4-ylidene) -1,3-dimethylpyrimidine-2,4,6 (1H, 3H, 5H) -trione) It is condensed with a compound (4-((2-hydroxyethyl) (methyl) amino) benzaldehyde) to provide a method for producing a sorbatochromic dye represented by the formula (I).

On the other hand, another object of the present invention is to condense the compound represented by the formula 3 to the raw material represented by the formula (2,6-dimethyl-4H-pyran-4-one) represented by the formula (3) (5- After obtaining (2,6-dimethyl-4H-pyran-4-ylidene) -2,2-dimethyl-1,3-dioxane-4,6-dione), the compound represented by formula 6 (4- ( It is a condensation with (2-hydroxyethyl) (methyl) amino) benzaldehyde) to provide a method for producing a solvatochromic dye represented by the formula (II).

In addition, the solvent is xylene, toluene, benzene, 1,2-dichlorobenzene, chloroform, dichloromethane, 1,2-dichloroethane, trichloroethylene, ethyl acetate, acetone, ethanol, methanol, propanol, n-butanol, THF , DMF, DMSO, pyridine, formamide, diethyl ether, 1,4-dioxane, acetonitrile.

In addition, the sorbatochromic dye of Formula I is characterized in that the absorption wavelength increases and the maximum vasochromic shift is possible up to 73 nm as the polarity of the solvent increases.

On the other hand, the sorbatochromic dye of Formula II is characterized in that the absorption wavelength increases as the polarity of the solvent increases and the maximum vasochromic shift is possible up to 81 nm.

The effect of the present invention is to provide dyes with solvatochromic properties that exhibit notable color differences for various solvents. In the present invention, the sorbatochromic merocyanine dye analogue is a 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde and 5- (2,6-dimethyl-4H-pyran-4-ylidene) meldum. Synthesis is provided through condensation of acid, 5- (2,6-dimethyl-4H-pyran-4-ylidene) barbituric acid.

Two forms of sorbatochromic merocyanine dyes derived from meldrumic acid or barbituric acid are 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde and 5- (2,6-dimethyl-4H It was synthesized by condensation reaction of pyran-4-ylidene) meldmic acid, 5- (2,6-dimethyl-4H-pyran-4-ylidene) barbituric acid. Solvatochromic reaction of merocyanine dyes in 22 different solvents with distinctly different polarities measured increased the maximum wavelength of fluorescence due to vasochromic shift as the polarity of solvents such as DMSO in xylene increased. Was observed. Such dyes can be used as effective probes in detecting volatile organic compounds.

The present invention is described in more detail below.

The following factors were considered in the design and design of the experiment. Firstly, meldmic acid (2,2, -dimethyl-1,3-dioxane-4,6-dione) and barbituric acid or derivatives of these dyes are condensed with ketones of various species to produce various kinds of merocyanine Dye can be produced. Secondly, these merocyanine dyes show excellent reactivity in spectroscopic analysis in transparent solvents, show various absorbance sensitivities and absorbances when tested in the visible range in various solvents, and excellent solubility in various organic solvents. Merocyanine dyes incorporating prominent electron donors and acceptors at both ends of the conjugated [pi] -system are known to induce absorbance and luminescence that varies sensitively with the solvent environment over a long wavelength range. Thirdly, 2,6-dimethyl-4H-pyran type dyes can be utilized as PL and electroluminescent material (EL) in the dye laser field, and their application as fluorescent sensors, logic memories, and OLEDs is attracting attention.

Dyes 1 and 2 is produced by the condensation reaction is barbie acid 2, 6-dimethyl -4H- pyran-4-one condensed with Meldrum's acid (2,2-dimethyl-1,3-dioxan -4 , 6-dione), and 3 5- (2,6-dimethyl--4H- of each reaction leading to intermediates pyran-4-ylidene) barbie acid 4 with 5- (2,6-dimethyl--4H- pyran- 4-ylidene) meldmic acid 5 was synthesized. These intermediates then condensed with 4-((2-hydroethyl) (methyl) amino) benzaldehyde. ¹ H nuclear magnetic resonance, mass spectrometry, and component analysis revealed the chemical structures of all intermediates and dyes 1 and 2 . Λ _max of dyes 1 and 2 exhibiting various solvents and solvent dependent absorption and fluorescence at E _T (30) λ _em values are listed in Table 1.

As shown in Table 1, the dyes 1 and 2 are dissolved in various solvents such as nonpolar solvents such as benzene. Dyes 1 and 2 showed obvious solvatochromic properties.

The standardized absorption and emission spectra of dye 1 in various solvents with different polarities are shown in FIG. 1. As the polarity of the solvent increased, the absorption band of the strong long wavelength range of the dye 1 exhibited a red shift. For example, as the polarity of the solvent increases from xylene to DMSO, an increase in wavelength of 21 nm appears. These results indicate that π-π * transitions are possible with the nature of charge transfer. The intermolecular charge transfer (ICT) interaction from the 2- (methylamino) ethanol group to the barbituric acid fragments was enhanced in the excited state with evidence indicating that the basochromic transfer of fluorescence maximums in polar solvents is maximized. As the polarity of the solvent changed from xylene to DMSO, the emission peak of dye 1 was observed up to 73 nm. This property indicates stabilization of the bipolar excited state in polar solvents. Maximum stroke shift was 161 nm in acetonitrile solvent. Figure 2 is a photograph showing the absorption and fluorescence in various solvents of the dye 1 shown in the UV-visible light, the difference in color and the degree of fluorescence in different solvents can be easily observed with the naked eye.

The present invention also investigated the solvatomic properties of dye 2 in various solvents. 3 shows normalized absorbance and emission spectra of dye 2 in a similar range of solvents. Dye 2 showed a red shift in both absorption and emission as the solvent polarity increased, indicating a large change in the excited state dipole moment due to intermolecular charge transfer. The maximum absorption band of dye 2 showed a large red shift as the solvent polarity increased. The maximum luminescence of Dye 2 showed a 81 nm transition as it moved to the red end of the spectrum. The maximum stroke shift in methanol solution was 139 nm. FIG. 4 is a UV-visible absorption and fluorescence photograph in a representative solvent of Dye 2. In these solvents, Dye 2 showed various colors and fluorescence.

A dye as compared to the dyes 1 and 2, merocyanine based on barbie acid dye 1 was deduced exhibit a consistently lower transition energy (higher λ _max) than the dyes of the dye 2 merocyanine based on Meldrum's acid . Depending on the molecular structure, dyes 1 and 2 are similarly bound to different receptor fragments and can be said to share the same donor group. Their relative transition energy depends on the relative electron affinity of the receptor fragment. The pyrimidinetrione moiety of dye 1 can more readily accept negative charges than the dioxanedione fragment of dye 2. The larger transition energy of dye 2 was linearized by this inference. If the dye molecule has a strong dipole when the excited state exhibits a greater polarity than the ground state, its stability is favored by more polar solvents. Reduction of transition energy and vasochromic shift appear in the spectrum.

Dimroth et al. Proposed the transition energy of the pyridinium-N-phenoxide betaine dye represented by kcal mol ^-1 as the polarity parameter. This figure can be expressed as an E _T value. Table 1 shows the E _T values of the solvent and the UV-visible spectral data of the dyes 1 and 2. As shown in FIG. 5, the values of λ _max with respect to the E _T values of the solvents of the dyes 1 and 2 were linearly derived by plotting. As the solvent polarity increased, an increase in the solvatochromic migration of Dye 1 and Dye 2 was observed.

This result is consistent with the theoretical estimates shown in FIG. 6. Theoretical calculations were performed with the DMol ³ program in Materials Studio 4.2 Package, a quantum mechanical code using density function theory. The Perdew-Burke-Ernzerhof (PBE) function of the generalized gradient approximation (GGA) to the double fractional polarization foundation set was used to calculate the energy values of the boundary molecular orbits. 6 is the predicted molecular structure and electron arrangement of HOMO and LUMO of dyes 1 and 2. Comparison of electron distribution in the boundary molecular orbital (MO) showed that HOMO-LUMO excitation shifted the electron distribution from the amino moiety to the Barbitur / meldrum and pyran moiety, indicating a strong shift of the intramolecular charge-transfer of the dye. Indicated. Electron density rearrangement during HOMO-LUMO affects color properties by affecting the effect of substituents or other factors of the dye, such as the interaction of the dye molecule with its environment, such as its solvent and composite substrate.

Two types of sorbatochromic merocyanine dyes based on barbituric acid and meldrumic acid were prepared. The dyes exhibited positive solvatochromic properties in various solvents. Of the two new solvatochromic merocyanine dyes, dye 2 showed greater sensitivity. These dyes can be usefully used in the development of sensors for the detection of volatile organic solvents.

The present invention will be described in more detail with reference to the following examples. However, these examples do not limit the scope of the present invention.

Melting points were measured using an Electrothermal IA 900 instrument. Component analysis was performed and recorded with the Carlo Elba Model 1106 analyzer. Mass spectra using FAB ion sources were recorded on a JMS-700 high resolution mass spectrometer. ¹ H nuclear magnetic resonance spectra were recorded on CDC1 ₃ using a Varian Inova 400 MHz FT-nuclear magnetic resonance spectrometer using TMS as an internal standard. UV-visible spectra and transmittance were measured with an Agilent 84575 UV-vis spectrophotometer. Fluorescence spectra were measured with a SHMADZU RF-5301 PC fluorescence spectrophotometer.

material

Aldrich's 1,3-dimethylpyrimidine-2,4,6 (1H, 3H, 5H) -trione, 2,2-dimethyl-1,3-dioxane-4,6-dione and 4-((2 -Hydroxyethyl) (methyl) amino) benzaldehyde was used and the other reagents were of high purity and used without further purification. All solvents were pure and used without drying or purification. Compound 5 was synthesized as described in the literature.

(Example 1) Synthesis of 5- (2,6-dimethyl-4H-pyran-4-ylidene) -1,3-dimethylpyrimidine-2,4,6 (1H, 3H, 5H) -trione ( 4 )

1.24 g, 0.01 mol of 2,6-dimethyl-4H-pyran-4-one 1 and 1.56 g, 0.01 mol of 1,3-dimethylpyrimidine-2,4,6 in 15 ml of acetaldehyde for 2 hours ( 1H, 3H, 5H) -trione 2 was refluxed. After cooling the condensed material was filtered off in methanol and recrystallized to yield 2.25 g yellow powder in 80% yield.

Mp 264 ° C. ¹ H NMR (400 MHz, CDCl ₃ , ppm) δ: 6.67 (s, 2H, pyran-H), 3.30 (s, 6H, NCH ₃ ), 1.56 (s, 6H, CH ₃ ), EI-MS, m elemental analysis: C, 59.49; H, 5. 30; N, 10.59%. C ₁₃ H ₁₄ N ₂ O ₄ requires: C, 59.54; H, 5. 38; N, 10.68%.

Example 2 Synthesis of 5- (2,6-dimethyl-4H-pyran-4-ylidene) -2,2-dimethyl-1,3-dioxane-4,6-dione ( 5 )

1.24 g, 0.01 mol of 2,6-dimethyl-4H-pyran-4-one 1 and 3,5-dimethyl-1,3,5-oxadiazinane-2,4,6-trione in a nitrogen-filled state The mixture of 3 was refluxed in 10 ml of acetaldehyde for 2.5 hours. After cooling the condensed material was filtered off in acetic acid and recrystallized to give 1.5 g of a pale yellow powder in a yield of 55.9.

Mp 219-226 ° C. ¹ H NMR (400 MHz, CDCl ₃ , ppm) δ: 6.68 (s, 2H, pyran-H), 2.23 (s, 6H, —NCH ₃ ), 1.58 (s, 6H, CH ₃ ), EI-MS, m / z = 250. Elemental analysis: C, 62.20; H; 5.50%. C ₁₃ H ₁₄ O ₅ requires: C, 62.39; H, 5.64%.

Example 3 5- (2- (4-((2-hydroxyethyl) (methyl) amino) styryl) -6-methyl-4H-pyran-4-ylidene) -1,3-dimethylpyri Synthesis of midine-2,4,6 (1H, 3H, 5H) -trione (dye 1 )

5 mmol, 1.31 g of 5- (2,6-dimethyl-4H-pyran-4-ylidene) -1,3-dimethylpyrimidine-2,4,6 (1H, 3H, 5H) -trione 4 5 mmol, 0.88 g of 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde 6 , 0.45 ml of piperidine solution mixed with 30 ml of acetonitrile for 8 hours using Dean-Stark trap Reflux and heated. After cooling the mixture of reactions at room temperature the crude product was separated and dried. The crude product was purified by column chromatography using a mixture of chloroform and methanol (v / v = 50: 1) as the mobile phase, and then recrystallized from ethanol to give a black red powder that was purified in 35% yield.

Mp 284 ° C. ¹ H NMR (400 MHz, CDCl ₃ , ppm) δ: 8.82 (d, 2H, Ar-H, J = 7.8 Hz), 7.46 (d, 1H, J = 9.0 Hz, Ar-H), 7.42 (d, 2H, J = 9.0 Hz, Ar-H), 6.77 (d, 1H, 〓CH), 6.75 (d, 1H, 〓CH), 6.67 (s, 1H, pyran-H), 6.62 (s, 1H, pyran -H), 4.54 (s, 1H, OH), 3.88 (m, 2H, -CH ₂ -O), 3.58 (m, 2H, -NCH _2- ), 3.35 (s, 6H, -NCH ₃ ), 3.0 (s, 3H, -NCH ₃ ), 1.55 (s, 3H, -CH ₃ ). EI-MS, m / z = 423.0. Elemental analysis: C, 65.20; H, 5. 90; N, 9.90%. Formula: C ₂₃ H ₂₅ N ₃ O ₅ Requires: C, 65.24; H, 5.95; N, 9.92%.

Example 4 5- (2- (4-((2-hydroxyethyl) (methyl) amino) styryl) -6-methyl-4H-pyran-4-ylidene) -2,2-dimethyl- Synthesis of 1,3-dioxane-4,6-dione (dye 2 )

5 mmol, 1.25 g of 5- (2,6-dimethyl-4H-pyran-4-ylidene) -2,2-dimethyl-1,3-dioxane-4,6-dione 5 with 5 mmol, 0.88 g of A 0.45 ml piperidine solution mixed with 4-((2-hydroxyethyl) (methyl) amino) benzaldehyde 6, 30 ml acetonitrile was heated to reflux for 8 hours using Dean-Stark trap. The reaction solution was cooled at room temperature and the crude product was separated and dried. The crude product was purified by column chromatography using a mixture of chloroform and methanol (v / v = 100: 1) as the mobile phase and then recrystallized from ethanol to give a black red powder which was purified in a yield of 30%.

Mp 190 ° C. ¹ H NMR (400 MHz, CDCl ₃ , ppm) δ: 8.89 (d, 1H, J = 7.58 Hz, Ar-H), 8.70 (d, 1H, J = 7.48 Hz, Ar-H), 7.74 (d, 1H, J = 9.0 Hz, Ar-H), 7.72 (d, 1H, J = 8.48 Hz, Ar-H), 7.42 (s, 1H, 〓CH), 6.69 (s, 1H, 〓CH), 6.67 ( s, 1H, pyran-H), 6.66 (s, 1H, pyran-H), 4.88 (s, 1H, OH), 3.72 (m, 2H, -CH ₂ -O), 3.54 (m, 2H, -NCH _2- ), 3.36 (s, 3H, -NCH ₃ ), 2.48 (s, 6H, -NCH ₃ ), 2.0 (s, 3H, -CH ₃ ). EI-MS, m = 411.0. Elemental analysis: C, 67.0; H, 6.0; N, 3.35%. Formula: C ₂₃ H ₂₅ NO ₆ Requires: C, 67.14; H, 6. 12; N, 3.40%.

1 shows normalized UV-visible absorbance (a) in xylene (1), acetone (2), CHCl ₃ (3) and DMSO (4) of dye 1 (ca. 10 ⁻⁵ molL ⁻¹ ), respectively; Fluorescence emission spectrum (b) is shown.

2 is a UV-vis absorption and fluorescence photograph of Dye 1 in various solvents.

3 shows normalized UV-visible light in xylene (1), acetone (2), CHCl ₃ (3), ethane (4) and DMSO (5) of dye 2 (ca. 10 ⁻⁵ molL ⁻¹ ), respectively. Absorbance (a) and fluorescence emission spectrum (b) are shown.

4 is a UV-Visible Absorption and Fluorescence Picture of Dye 1 in various solvents.

FIG. 5 shows a linear plot on λ _max (maximum absorbance) plotting for solvent parameter E _T of dye 1 and dye 2. FIG.

Figure 6 shows the electron distribution of HOMO and LUMO energy values of the dyes 1 and 2.

Claims (7)

Solvatochromic dyes of the following formula I in which the ranges of the absorption wavelength and the emission fluorescence wavelength vary depending on the polarity of the solvent:

Equation Ⅰ Solvatochromic dyes of the following formula II in which the ranges of absorption wavelengths and emission fluorescence wavelengths vary depending on the polarity of the solvent.

Equation II Compound (5- (2,6-dimethyl-4H) represented by the formula 4 by condensation polymerization of the compound represented by the formula 2 to the raw material represented by the formula (2,6-dimethyl-4H-pyran-4-one) -Pyran-4-ylidene) -1,3-dimethylpyrimidine-2,4,6 (1H, 3H, 5H) -trione) to obtain a compound represented by the formula (4-((2- Hydroxyethyl) (methyl) amino) benzaldehyde) condensation method for preparing sorbatochromic dye represented by formula (I)

Compound (5- (2,6-dimethyl-4H) represented by Formula 5 by condensation polymerization of the compound represented by Formula 3 to the raw material represented by Formula 1 (2,6-dimethyl-4H-pyran-4-one) -Pyran-4-ylidene) -2,2-dimethyl-1,3-dioxane-4,6-dione, followed by the compound represented by formula 6 (4-((2-hydroxyethyl) ( Method for preparing solvatochromic dye represented by formula II by condensation with methyl) amino) benzaldehyde)

The method of claim 1 or 2, wherein the solvent is xylene, toluene, benzene, 1,2-dichlorobenzene, chloroform, dichloromethane, 1,2-dichloroethane, trichloroethylene, ethyl acetate, acetone, ethanol, Solvatochromic dyes characterized in that the solvent is selected from methanol, propanol, n-butanol, THF, DMF, DMSO, pyridine, formamide, diethyl ether, 1,4-dioxane, acetonitrile 2. The solvatochromic dye according to claim 1, wherein the solvatochromic dye of formula I is characterized in that the absorption wavelength increases and the maximum vasochromic shift is possible up to 73 nm as the polarity of the solvent increases. The solvatochromic dye according to claim 2, wherein the solvatochromic dye of formula II is characterized in that the absorption wavelength increases and the maximum vasochromic shift is possible up to 81 nm as the polarity of the solvent increases.

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