1. An organic material capable of absorbing near infrared light, characterized in that: the organic material comprises 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt shown as formula (1):

2. the method for preparing the near-infrared light absorbing organic material according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

dissolving 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt shown in formula (2) and 6-hydroxy-2, 3-dihydroxanthene-4-formaldehyde shown in formula (3) in n-butanol, mixing, heating for reaction, cooling to room temperature, performing rotary evaporation to remove the n-butanol, and purifying the obtained solid by silica gel column chromatography to obtain 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt shown in formula (1);

3. the method of claim 2, wherein: the temperature of the heating reaction is 118-122 ℃.

4. The method of claim 2, wherein: the heating reaction time is 10-12 h.

5. The method of claim 2, wherein: the mol ratio of the 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt to the 6-hydroxy-2, 3-dihydroxanthene-4-formaldehyde is 1: (1-1.2).

6. The method of claim 2, wherein: the dosage ratio of the 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt to the n-butanol is as follows: 1mmol (10-12) mL.

7. Use of the near-infrared absorbent organic material of claim 1 in an optical filter.

Background

The low-light-level night vision technology is a photoelectric technology for converting low-brightness light which cannot be sensed by human eyes into high-brightness visible images of the human eyes through a photoelectric imaging device, and is widely applied to the fields of aviation, military affairs and the like. At present, the commonly used low-light night vision device is a third-generation night vision mirror, GaAs with high sensitivity is used as a photocathode image enhancement tube, and the maximum spectral response interval is 625nm-930 nm. However, such night vision devices are susceptible to interference from portions of the red and near infrared light emitted by the illumination device, causing an abnormal response of the intensifier tube, resulting in a reduced imaging quality. In order to realize the mutual compatibility of the low-light night vision system and the illumination system, a near-infrared absorption filter is mainly adopted to filter near-infrared radiation light generated by an illumination device, and the most important component of the near-infrared filter is a material capable of absorbing near-infrared light. Therefore, the development of a novel near-infrared light absorption organic material has important significance for the wide application of the near-infrared filter in the low-light night vision technology.

The near-infrared absorption filters developed at home and abroad up to now are mainly classified into two main types, one is a conventional glass-based near-infrared absorption filter, and the other is a newly developed plastic-based near-infrared absorption filter made of a polymer material. The glass type near infrared absorption filter is prepared by mixing some metal oxides capable of absorbing near infrared light, such as Fe, in glass melting₂O₃CoO, and the like. The near-infrared absorption filter has the advantages of corrosion resistance and high temperature resistance, and the surface property of the near-infrared absorption filter is improved by easily performing surface modification. However, the glass type near infrared absorption filter has a short absorption wavelength, low absorption intensity, and poor material elasticity. And because the processing performance is poor, complex devices are difficult to manufacture, the density of finished materials is high, the finished materials are easy to damage, the service life of the materials is short, and the defects also restrict the application of the materials as near infrared absorption filters. The plastic type near-infrared absorption filter is prepared by doping some organic dyes capable of absorbing near-infrared light, such as anthraquinone dyes, metal complex dyes, cyanine dyes and the like, into transparent optical plastic. Compared with glassThe plastic near-infrared absorption filter can absorb near-infrared light in a wider range, and has stronger absorption intensity and higher visible light transmittance. And the material has lower cost, is not easy to damage and has higher reliability, and meanwhile, the polymer material has good forming and processing performance and is easy to process into a complex device. Moreover, the plastic type near-infrared filter is lighter in weight and better in practicability than the glass type near-infrared filter, and therefore the near-infrared filter used in the night vision compatible lighting device is mainly a plastic type near-infrared filter.

Currently, some near-infrared absorbing materials for near-infrared filters have been developed. Chinese patent CN109422460A discloses a glass for a near-infrared absorption filter, which has good visible light transmission characteristics and certain polishing processability, but is a glass-based near-infrared filter, and therefore, the glass has the disadvantages of short absorption wavelength, narrow range, low strength, poor elasticity, and the like, and severely limits the application range. Chinese patent CN103270019A prepares a diimine-based compound and a near infrared absorption filter using the same, although the absorption wavelength range of the material can reach 750nm-1000nm, the material structure is complex, and the defects also limit the industrial popularization of the material. Chinese patent CN112239463A prepared an organic small molecule material 2- (2- (8- (4- (bis (4-methoxyphenyl) amino) phenyl) -6- ((3, 3-dimethyl-3- (2,4, 5-trimethyl-3, 6-dioxocyclohex-1, 4-dien-1-yl) propionyl) oxy) -2, 3-dihydroxanthen-4-yl) vinyl ] -1,3, 3-trimethylindole salt with near infrared absorption, the material introduced indole as an electron withdrawing group, quinone propionate group as a strong fluorescence quenching group, although the material can absorb near infrared light in the wavelength range of 650nm-800nm, the absorption intensity of the material is low, only 0.01-0.11, therefore, the material has low near infrared absorption efficiency, and is not beneficial to application in a near infrared filter.

Although there have been some advances in the research for near-infrared absorbing materials, particularly for near-infrared filters, there are few near-infrared absorbing organic materials that have all of the following excellent properties at the same time: the material has obvious absorption effect on light in a near infrared region; a wide spectral absorption band; simple synthesis, low cost and good industrialization prospect. Therefore, a novel near-infrared light absorbing organic material is urgently needed in the field, which not only can well absorb the near-infrared light in a wider wavelength range, but also has a simple preparation process and meets the requirements of practical application.

Disclosure of Invention

In order to overcome the problems of the prior art, it is an object of the present invention to provide an organic material that can absorb near infrared light; the second purpose of the invention is to provide a preparation method of the organic material capable of absorbing near infrared light; the invention also aims to provide application of the organic material capable of absorbing near infrared light.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the first aspect of the present invention provides an organic material that can absorb near-infrared light, the organic material including 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinolinate represented by formula (1):

a second aspect of the present invention provides a method for preparing the near-infrared light absorbing organic material according to the first aspect of the present invention, comprising the steps of:

dissolving 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt shown in formula (2) and 6-hydroxy-2, 3-dihydroxanthene-4-formaldehyde shown in formula (3) in n-butanol, mixing, heating for reaction, cooling to room temperature, performing rotary evaporation to remove the n-butanol, and purifying the obtained solid by silica gel column chromatography to obtain 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt shown in formula (1);

preferably, in the preparation method of the near-infrared light absorbable organic material, the temperature of the heating reaction is 118-122 ℃; further preferably, the temperature for heating the reaction is 120 ℃.

Preferably, in the preparation method of the near-infrared light absorbable organic material, the heating reaction time is 10h-12 h.

Preferably, in the preparation method of the near-infrared light absorbing organic material, the molar ratio of the 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt to the 6-hydroxy-2, 3-dihydroxanthene-4-formaldehyde is 1 (1-1.2).

Preferably, in the preparation method of the near-infrared light absorbing organic material, the ratio of the 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt to n-butanol is as follows: 1mmol (10-12) mL.

A third aspect of the present invention provides a use of the near-infrared light absorbing organic material according to the first aspect of the present invention in an optical filter.

The invention has the beneficial effects that:

1. the invention provides an organic material capable of absorbing near infrared light, which has a structure comprising xanthene and quinoline salt groups and diphenylamine groups containing two pentoxy groups, so that two strong electron-donating groups (dianilino and xanthene groups containing dipentoxy groups) and a strong electron-withdrawing group (quinoline salt) exist in a molecule at the same time to form an electron donor-electron acceptor-electron donor structure; the charge push-pull effect is obviously enhanced under the action of the double electron donors, and the energy band gap between the ground state and the excited state is reduced; diphenylamine groups containing two pentoxy groups in the molecular structure can be used as rotor elements to promote the rapid dissipation of the energy of the absorbed near-infrared light.

2. The organic material capable of absorbing near infrared light provided by the invention is simple, convenient and quick to synthesize, low in manufacturing cost and good in industrialization prospect.

3. The organic material capable of absorbing near infrared light provided by the invention has good light stability, no toxicity, good near infrared light absorption performance and wider absorption band, and can generate higher-intensity absorption effect on the near infrared light with the wave band of 620nm-800 nm.

Drawings

FIG. 1 is a synthesis route diagram of an organic material capable of absorbing near infrared light according to the present invention.

FIG. 2 is a NMR chart of the product obtained in example 1.

FIG. 3 is a NMR chart of the product obtained in example 1.

FIG. 4 is a mass spectrum of the product obtained in example 1.

FIG. 5 is an absorption spectrum of the product obtained in example 1.

Detailed Description

The following description of the embodiments of the present invention is provided in connection with the accompanying drawings and examples, but the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available through commercial purchase.

The synthetic route of the near-infrared light absorbable organic material 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt prepared by the invention is shown in figure 1. A specific synthesis method of examples 1 to 3 of the present invention will be described below with reference to FIG. 1.

Example 1

The preparation steps of the organic material capable of absorbing near infrared light in the embodiment are as follows:

319.12mg of iodine-containing counterion 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt (0.50mmol) and 114.04mg of 6-hydroxy-2, 3-dihydroxanthene-4-carbaldehyde (0.50mmol) were placed in a single-neck flask, and 5mL of n-butanol were added and mixed well. The mixed solution was heated to 118 ℃ and stirred under reflux for 10 h. After the reaction was completed, the temperature was lowered to room temperature, the organic solvent was removed by rotary evaporation, and the obtained solid was purified by silica gel column chromatography (eluent used was dichloromethane/ethyl acetate, V/V ═ 20:1) to obtain 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt as a product.

The resulting product was characterized by means of nuclear magnetic resonance hydrogen spectroscopy:¹H NMR(600MHz,CDCl₃) δ 8.88(s,1H), 8.22-8.13 (m,2H),7.99(d, J ═ 9.2Hz,1H),7.59(d, J ═ 9.7Hz,1H), 7.40-7.34 (m,2H),7.09(d, J ═ 8.8Hz,4H),6.96(d, J ═ 2.7Hz,1H),6.92(d, J ═ 8.9Hz,4H),6.86(d, J ═ 8.4Hz,1H),6.59(d, J ═ 8.3Hz,1H),6.55(s,1H),6.47(d, J ═ 14.7Hz,1H),4.80(d, J ═ 7.2Hz,2H),3.98(t, J ═ 5, 4.5, 56 (t, 2H), 6.47(d, J ═ 14.7Hz,1H),4.80(d, J ═ 7.2Hz,2H),3.98(t, 5, 3.5 (m, H),8, 1H), 3, 1H, 1,3, 1H, 3, 1H), 3, 1H. The NMR spectrum is shown in FIG. 2.

The resulting product was characterized by nuclear magnetic resonance carbon spectroscopy:¹³c NMR (151MHz, DMSO-d6) delta 160.37,156.94,155.29,154.15,151.18,148.09,140.34,139.87,138.76,132.68,129.27,128.35,128.17,128.00,126.22,126.11,121.12,119.75,116.33,114.23,113.12,112.71,111.84,111.33,102.79,68.17,63.27,45.61,40.43,40.29,40.15,40.01,39.87,39.74,39.60,29.51,29.17,28.90,28.22,24.65,22.57,22.38,20.79,14.41,13.98, 0.57. The NMR spectrum is shown in FIG. 3.

The molecular formula of the organic material 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt capable of absorbing near infrared light is C₄₈H₅₃N₂O₄The relative molecular mass was 721.4. Further validation was performed by high resolution mass spectrometry testing: HR-MS (ESI) M/z 721.4008[ M ═ M]⁺(ii) a The mass spectrum is shown in FIG. 4. The synthesized product can be determined as a target product by nuclear magnetic and mass spectrometry.

Example 2

The preparation steps of the organic material capable of absorbing near infrared light in the embodiment are as follows:

1.276g of iodine-containing counterion 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt (2.00mmol) and 547.39mg of 6-hydroxy-2, 3-dihydroxanthene-4-carbaldehyde (2.40mmol) were taken in a single-neck flask, and 24mL of n-butanol were added and mixed well. The mixed solution was heated to 122 ℃ and stirred under reflux for 12 h. After the reaction was completed, the temperature was lowered to room temperature, the organic solvent was removed by rotary evaporation, and the obtained solid was purified by silica gel column chromatography (eluent used was dichloromethane/ethyl acetate, V/V ═ 20:1) to obtain 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt as a product.

The final product characterization of example 2 is the same as the results in example 1.

Example 3

The preparation steps of the organic material capable of absorbing near infrared light in the embodiment are as follows:

638.24mg of iodine-containing counterion 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt (1.00mmol) and 250.89mg of 6-hydroxy-2, 3-dihydroxanthene-4-carbaldehyde (1.10mmol) were taken in a single-neck flask, 11mL of n-butanol were added and mixed well. The mixed solution was heated to 120 ℃ and stirred under reflux for 11 h. After the reaction was completed, the temperature was lowered to room temperature, the organic solvent was removed by rotary evaporation, and the obtained solid was purified by silica gel column chromatography (eluent used was dichloromethane/ethyl acetate, V/V ═ 20:1) to obtain 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt as a product.

The final product characterization of example 3 is the same as the results in example 1.

The iodide counterion-containing 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2-methylquinoline salt used in examples 1-3 is reference Mao, m.; zhang, x.; zhu, b.; wang, j.; wu, g.; yin, y.; (iii) by the method reported in Song, Q.comprehensive students of organic dyes with a quinazoline or a quinazoline as pi-conjugated bridges for dye-sensitized solar cells, dyes and pigments2016,124, 72-81. The 6-hydroxy-2, 3-dihydroxanthene-4-carbaldehyde used in examples 1 to 3 is the reference Qi, y.; huang, y.; li, B.; zeng, f.; wu, S.real-Time Monitoring of endogenesis Cysteine Levels In Vivo by near-isolated tube Probe with Large Stokes Shift. anal Chem2018,90, 1014-.

The 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt prepared in examples 1 to 3 was a dark blue odorless solid powder, soluble in water, and easily soluble in organic solvents such as dimethyl sulfoxide and methanol.

The absorption spectrum test is carried out on the organic material 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt capable of absorbing near infrared light, and the absorption spectrum test solution sample is prepared by the following steps:

2.54mg of 6- (bis (4- (pentyloxy) phenyl) amino) -1-ethyl-2- (2- (6-hydroxy-2, 3-dihydroxanthene) vinyl) quinoline salt containing an iodine counter ion was dissolved in 3mL of dimethyl sulfoxide to prepare a compound mother liquor having a concentration of 1 mM. For testing, the test solution was diluted with dimethyl sulfoxide to a concentration of 10. mu.M, and the total amount of the test solution was 3 mL. The absorption spectrum test result is shown in fig. 5, and it can be seen from fig. 5 that the near-infrared light-absorbable organic material prepared by the invention can generate high-efficiency absorption for the near-infrared light of 620nm-800 nm.

The organic material capable of absorbing near infrared light prepared by the invention is applied to the optical filter, and the optical filter has excellent absorption effect on the near infrared light.

The above examples are preferred embodiments of the present invention, but the present invention is not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and they are included in the scope of the present invention.