CN104673275B - A kind of activation luminescent material and preparation method thereof - Google Patents

Abstract

The present invention relates to fluorescent material technical field, especially relate to a kind of activation luminescent material and preparation method thereof, activate in luminescent material structure and on tetraphenyl ethylene, combine different biological molecules by condensation reaction, obtain the biocompatible activation luminescent material with AIE/AEE characteristic, these biomolecule have the activation light emitting molecule of splendid biocompatibility and water soluble high-fluorescence quantum yield when being included in solution state and solid state, and the crystalline polymer of Nano lamellite can be formed in water-soluble medium, the activation luminescent material prepared may be used for the aspects such as live cell fluorescent dyeing and sensitive detection explosive.

Description

A kind of activated luminescent material and preparation method thereof

technical field

The invention relates to the technical field of fluorescent materials, in particular to an activated luminescent material and a preparation method thereof.

Background technique

Organic luminescent materials have attracted more and more attention because of their wide range of applications. Currently, organic luminescent materials are mainly used in bioimaging (Chem.Sci., 2012, 3, 984), electronic technology (Adv. .Sci.,2011,2,2402; Chem.Rev.2007,107,1011), optical technology (Adv.Master.,2012,24,1703-1708) and storage media (Adv.Master.,2012,24, 1255-1261) and other fields, but due to the phenomenon of aggregation-caused quenching (ACQ) caused by energy transfer and the formation of excimers and exciplexes, the traditional planar dyes The luminescence is weak in the solid state, which will seriously limit the application of planar dyes in the engineering industry.

In 2001, some inventors discovered a new type of activated luminescent molecule. The aggregation of this molecule plays a positive role in the luminescent process rather than destroying it, so it is called "aggregation-induced emission" (aggregation-induced emission, AIE) molecule. AIE molecules emit light weakly in the solution state, but can effectively emit light in the aggregated state (Chem. . Lett. 2007, 91, 011111.). The mechanism of restriction of intramolecular motions (RIM) has been proposed to explain the AIE phenomenon. The energy of the excited electrons is annihilated through the active intramolecular motion in the solution state; while the RIM process is activated by the intrinsic nature of the space in the aggregated state, resulting in Exciting electrons decayed by radiation in large numbers (J.Phys.Chem.B2005, 109, 10061, J.Am.Chem.Soc.2005, 127, 6335).

AIE-activated luminescence exploits the aggregation process to activate luminescence, opening a new way for creating luminescent materials that can be used in solid state or aggregated state. So far, based on the RIM mechanism, a large number of AIE dyes have been widely developed and widely used in many fields, such as organic light-emitting diodes (OLEDs) (J.Mater.Chem., 2011, 21, 7210-7216; J.Mater.Chem. ,2012,22,11018-11021), chemical sensors (J.Am.Chem.Soc.,2010,132,13951-13953; J.Am.Chem.Soc.,2011,133,18775-18784) and other fields, But there is no report about AIE dyes with good biocompatibility for cell imaging, which may be due to the complexity of living cells (Adv.Mater., 2011, 23, 3298-3202; J.Am Chem. Soc., 2012, 134, 9569-9572). In fact, useful knowledge about the commonality of AIE dyes in cell imaging is still lacking, thus there is an urgent need to develop biocompatible AIE dyes to expand their applications in the field of bioengineering.

On the other hand, the detection of explosives plays an important role in preventing terrorist attacks. In recent years, terrorist attacks based on explosives have become increasingly rampant, mainly because explosives are easy to prepare and can cause mass casualties. The detection of explosives faces many challenges. Such as low vapor pressure of explosives and frequent introduction of new explosive components. The detection of explosives includes two steps of gas collection and analysis. At present, explosives can be detected by mass spectrometry and ion mobility spectrometry, but these devices are expensive, bulky and time-consuming to operate, and cannot achieve online detection. Sensitivity detection methods are of great significance to prevent terrorist attacks, and there are no related reports on the use of AIE to activate luminescent materials for the detection of explosives.

Contents of the invention

The purpose of the present invention is to provide an activated luminescent material and a preparation method thereof, so as to solve the problem in the prior art that a biocompatible AIE activated luminescent material is urgently needed for cell imaging and for detecting explosives.

The technical solution adopted by the present invention to solve the technical problem is: a kind of activated luminescent material, its structural formula is as follows:

Wherein, the R ₁ group is cyclodextrin or polyε-caprolactone, and the polyε-caprolactone has 28-156 repeating units; R ₂ , R ₃ and R ₄ groups are respectively selected from C _n H _2n+1 , C ₁₀ H ₇ , C ₁₂ H ₉ , OC ₆ H ₅ , OC ₁₀ H ₇ , OC ₁₂ H ₉ , C _n H _2n NCS, C _n H _2n N ₃ , C _n H _2n NH ₂ , C _n H _2n Cl, C _n H _2n Br, C _n H _2n I, wherein n=0-20.

In the activated luminescent material of the present invention, the R ₁ group is cyclodextrin, and the activated luminescent material can be used to prepare a fluorescent visualization agent for staining living cells.

In the activated luminescent material of the present invention, the R ₁ group is polyε-caprolactone, and the activated luminescent material can be used to detect explosives.

The present invention also provides a method for preparing an activated luminescent material, comprising the following steps:

A. In a nitrogen environment, under low temperature conditions, dissolve the compound of R ₁ group, tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) and N,N-dicyclohexylcarbodiimide in anhydrous di In methylformamide; it should be noted that the compound of R ₁ group, tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) and N,N-dicyclohexylcarbodiimide can be added simultaneously to no Dissolve in water dimethylformamide; it is also possible to dissolve the compound of R ₁ group, tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) in anhydrous dimethylformamide, and then add N , N-dicyclohexylcarbodiimide is dissolved; it can also be a compound of R ₁ group and tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) dissolved in anhydrous dimethylformamide, and N, N-dicyclohexylcarbodiimide is dissolved in anhydrous dimethylformamide, and the two solutions are mixed again;

B, in a nitrogen environment, warm to room temperature and stir the reaction until the reaction is complete;

C, filter, the filtrate obtained is added dropwise in a large amount of ether under the condition of vigorous stirring, and the solid is separated out;

D. Filtrating and separating the solid again, and drying the solid under vacuum to obtain an activated luminescent material.

In the preparation method of the activated luminescent material of the present invention, in step A, the compound of the R ₁ group is cyclodextrin, and the cyclodextrin, tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) The molar ratio of cyclodextrin to N,N-dicyclohexylcarbodiimide is 1:1:1, and the molar volume ratio of cyclodextrin in anhydrous dimethylformamide is 1:30, that is, 1mol:30L.

In the preparation method of the activated luminescent material of the present invention, in step A, the R ₁ group compound is polyε-caprolactone, and the polyε-caprolactone, tetraphenylethylene-CO ₂ H (TPE The molar ratio of -CO ₂ H) and N,N-dicyclohexylcarbodiimide is 1:8:2, and the molar volume ratio of the polyε-caprolactone in anhydrous dimethylformamide is 1 : 150, that is, 1mol: 150L.

In the preparation method of the activated luminescent material of the present invention, in step A, the low temperature condition is 0°C.

In the preparation method of the activated luminescent material of the present invention, in step B, in a nitrogen environment, the reaction is stirred for 3 days under the condition of warming to room temperature.

In the preparation method of the activated luminescent material of the present invention, in step D, the drying temperature is 40°C.

Implementing the activated luminescent material of the present invention and its preparation method has the following beneficial effects: in the structure of the activated luminescent material of the present invention, different biomolecules are combined on tetraphenylethylene (TPE) through a condensation reaction to obtain an AIE/AEE (aggregation- induced/enhanced emission) characteristics of biocompatible activated luminescent materials, these biomolecules include activated luminescent molecules with excellent biocompatibility and water-soluble high fluorescence quantum yield in solution state and solid state, and in water-soluble A crystalline polymer that can form nanosheet crystals in a neutral medium, and the prepared activated luminescent material can be used for fluorescent dyeing of living cells and sensitive detection of explosives.

Description of drawings

Figure 1 is the 2D ROESY NMR spectrum of TPE-β-CD in DMSO-d ₆ , TPE-β-CD concentration: 2mM;

Figure 2 is the 2D ROESY NMR spectrum of TPE-α-CD in DMSO-d ₆ , TPE-α-CD concentration: 2mM;

Figure 3 is the 2D ROESY NMR spectrum of TPE-γ-CD in DMSO-d ₆ , TPE-γ-CD concentration: 2mM;

Figure 4A is the optimized chemical structure of TPE-CDs in rod and rod mode. For clarity, methyl is used to represent cyclodextrin;

Figure 4B shows the optimized chemical structure of TPE-CDs in the spatial fitting mode. For clarity, methyl is used to represent cyclodextrin:

Figure 5 is a schematic diagram of the structure of TPE trapped in the CD cavity;

Figure 6 is the ¹ H NMR control spectrum of TPE-β-CD in DMSO-d ₆ with 2mM and 40mM concentrations respectively;

Figure 7 is the ¹ H NMR control spectrum of TPE-β-CD in DMSO-d ₆ without adding chilled steel grains and adding 2 equimolar chilled steel grains, the concentration of TPE-β-CD is 40mM;

Figure 8 is the ¹ H NMR control spectrum of TPE-α-CD in DMSO-d ₆ with 2mM and 40mM concentrations respectively;

Fig. 9 is the ¹ H NMR control spectrum of TPE-γ-CD in DMSO-d ₆ with 2mM and 40mM concentrations respectively;

Figure 10 is the UV-Vis spectrophotometric spectrum of TPE-CDs, TPE-C2 and β-CD respectively in DMSO, the concentration of which is 0.1mM;

Figure 11 is the circular dichroism spectrum of TPE-CDs in DMSO, the concentration is 1mM;

Figure 12A is the fluorescence spectrum of TPE-CDs, TPE and TPE/CD mixture (molar ratio is 1:1) in DMSO respectively, the concentration is 5mM;

Figure 12B shows the quantum yields of TPE-CDs, TPE and TPE/CD mixture (molar ratio 1:1) in DMSO, respectively, and inserted TPE-CDs, TPE and TPE/CD mixture (molar ratio 1:1 ) respectively in DMSO under ultraviolet irradiation fluorescence photos, the concentration is 5mM;

Figure 13 is the standard emission spectrum of TPE-CDs, TPE and TPE/CD mixture in DMSO, the concentration is 5mM;

Figure 14 is the time-resolved fluorescence spectrum of TPE-CDs and TPE in DMSO;

Figure 15A is a bright field observation photo of HeLa cells cultivated by TPE-β-CD;

Figure 15B is a fluorescent imaging photo of HeLa cells cultivated by TPE-β-CD;

Figure 16 is the DSC spectrum of PCL and PCL3k-TPE during the cooling scan and thermal scan, the heating and cooling rate is 10°C/min;

Figure 17A is the DSC spectrum of PCL-TPE during the cooling scan process;

Figure 17B is the DSC spectrum of PCL-TPE during thermal scanning;

Figure 18A is the PL spectrum of PCL-TPE in THF/water mixed solvents with different water contents;

Figure 18B is a graph showing the variation of fluorescence intensity of PCL-TPE in a THF/water mixed solvent with different water contents, and the radiation wavelength is 350nm;

Figure 19A is a height imaging photo of PCL-TPE's tapping mode AFM with a resolution of 5 μm×5 μm;

Figure 19B is a cross-sectional profile diagram of the white dotted line in Figure 19A;

Fig. 20 is the XRD graph of PCL3k-TPE nano plate crystal;

Figure 21 is the DSC spectrum of PCL3k-TPE nanoplatelets in the first thermal scanning process;

Figure 22 is the TOF-SIMS spectrum of PCL-TPE with C ₆₀ ⁺ as the primary ion beam;

Figure 23 is the TOF-SIMS spectrum of PCL-TPE with Bi ₃ ⁺ as the primary ion beam;

Figure 24 is the TOF-SIMS spectrum of PCL-TPE with C ₆₀ ⁺ as the primary ion beam at 65°C;

25 is a schematic diagram of the crystallization process induced by nanoplatelets of fluorescent polymers;

Figure 26 is the XPS spectrum of PCL-TPE at an emission angle of 45°;

Figure 27 is the XPS spectrum of PCL-TPE at an emission angle of 25°;

Fig. 28A is the PL spectrum of adding different amounts of PA (picricacid) in the PCL-TPE nanoplatelet suspension;

Fig. 28B is a correlation curve between the I ₀ /I value and the concentration of PA in the PCL-TPE solution, and the static quenching constant of the PCL-TPE nanoplatelets is 380,000L mol ^-1 ;

Figure 29 shows the addition of PA, toluene, 2,4-dinitrotoluene, 4-nitrophenol, 4-nitrobenzene, 2-bromotoluene, 1,2 dichlorobenzene, 1,2 , Change diagram of fluorescence intensity (I ₀ /I) after 4-tribromobenzene, bromo-2-nitrobenzene, and 3,5-dinitrophenylethanol, and insert the above-mentioned different explosions into the PCL-TPE suspension digital imaging of analogues;

Figure 30 is a correlation curve between the I ₀ /I value and different concentrations of PA in the solution of PCL5k-TPE and THF/H ₂ O mixed solvent (volume ratio 1:99), the correlation coefficient R=0.9933; the static state of PCL5k-TPE The quenching constant (K) is 122,000L mol ^-1 ;

Figure 31 is the correlation curve of I ₀ /I value and different concentrations of PA in the solution of PCL10k-TPE and THF/H ₂ O mixed solvent (volume ratio 1:99), the correlation coefficient R=0.9944; the static state of PCL5k-TPE The quenching constant (K) is 102,000L mol ^-1 ;

Figure 32 is a correlation curve of I ₀ /I value and different concentrations of PA in the solution of PCL20k-TPE and THF/H ₂ O mixed solvent (volume ratio 1:9), the correlation coefficient R=0.9899; the static state of PCL20k-TPE The quenching constant (K) is 61,000L mol ^-1 ;

Figure 33 is a graph of the variation of the static quenching constant (K) of PCL with different numbers of repeating units.

detailed description

The activated luminescent material of the present invention and its preparation method will be further described below in conjunction with the accompanying drawings and examples:

The present invention prepares tetraphenylethylene-CO ₂ H (TPE-CO ₂ H) through the following reaction formula and forms TPE-CDs clathrate (TPE-CDs) by condensation reaction of TPE-CO ₂ H and cyclodextrin (CD) Activated luminescent materials, including TPE-β-CD, TPE-α-CD and TPE-γ-CD clathrates. The intermediate products and final products in the reaction process are purified, and these intermediate products and final products are characterized by nuclear magnetic resonance (NMR) spectrum and a large number of other spectra, so as to confirm their expected molecular structures. The above three TPE-CDs are all soluble in water, dimethylsulfoxide (DMSO) and dimethylformamide (DMF).

Example 1:

(1) The structural formula of TPE-β-CD

(2) Preparation of TPE-β-CD inclusion compound activated luminescent material

In a nitrogen atmosphere at 0°C, in a 50ml round bottom flask, 0.188g (0.5mmol) of TPE-CO ₂ H and 0.5675g (0.5mmol) of β-CD were dissolved in 10ml of anhydrous dimethylformamide (DMF ), after dissolving, add 5ml of anhydrous DMF containing 0.103g (0.5mmol) of N,N-dicyclohexylcarbodiimide (dicyclohexylcarbodiimide, DCC); 3 days; filter, add the filtrate dropwise to a large amount of diethyl ether under the condition of vigorous stirring, and precipitate a solid; then filter again to obtain the solid, and dry the solid overnight at 40°C under vacuum to produce rate of 70%. ¹ H NMR(400MHz,DMSO-d ₆ ),δ(TMS,ppm):3.28(d,7H,H ₄ ),3.33(d,7H,H ₂ ),3.55(d,7H,H ₅ ),3.60 (d,12H,H ₆ ),3.64(br,7H,H ₃ ),4.44(t,6H,O ₆ H),4.80(d,7H,H ₁ ),5.65(s,7H,O ₃ H) ,5.70(d,7H,O ₂ H),7.93(s,2H,Ar-H). ¹³ C NMR(400MHz,DMSO-d ₆ ),δ(TMS,ppm):59.7(C ₆ ),71.8( C ₂ ), 72.3(C ₅ ), 72.9(C ₃ ), 81.3(C ₄ ), 101.7(C ₁ ), 130.4(Ar), 156.7(C=C), 162.2(C=O).HRMS(MALDF -TOF): m/z 1492.65 (M ⁺ , calcd 1492.51).

Example 2:

(1) The structural formula of TPE-α-CD:

(2) Preparation of TPE-α-CD inclusion compound activated luminescent material

In a nitrogen atmosphere, at 0°C, 0.188g (0.5mmol) of TPE-CO ₂ H and 0.486g (0.5mmol) of α-CD were dissolved in 15ml of anhydrous dimethylformamide (DMF), and 0.103 g (0.5mmol) DCC as a catalyst; in a nitrogen environment, stirred and reacted for 3 days from warm to room temperature; filtered, the filtrate was added dropwise to a large amount of diethyl ether under vigorous stirring, and a solid was precipitated; then again The solid was isolated by filtration, and the solid was dried overnight at 40° C. under vacuum, with a yield of 60%. ¹ H NMR(400MHz,DMSO-d ₆ ),δ(TMS,ppm):3.30(m,6H,H ₄ ),3.36(m,6H,H ₂ ),3.56(d,6H,H ₅ ),3.61 (m,10H,H ₆ ),3.75(t,6H,H ₃ ),4.46(t,5H,O ₆ H),4.77(d,6H,H ₁ ),5.41(d,6H,O ₃ H) ,5.50(d,6H,O ₂ H),7.93(s,2H,Ar-H). ¹³ C NMR(400MHz,DMSO-d ₆ ),δ(TMS,ppm):59.7(C ₆ ),71.8( C ₂ ), 72.3(C ₅ ), 72.9(C ₃ ), 81.3(C ₄ ), 101.7(C ₁ ), 130.4(Ar), 156.7(C=C), 162.2(C=O).HRMS(MALDF -TOF): m/z 1330.63 (M ⁺ , calcd 1330.45).

Example 3:

(The structural formula of 1TPE-γ-CD:

(2) Preparation of TPE-γ-CD inclusion compound activated luminescent material

In a nitrogen atmosphere at 0°C, dissolve 0.188g (0.5mmol) of TPE-CO ₂ H, 0.648g (0.5mmol) of γ-CD and 0.103g (0.5mmol) of DCC in 15ml of anhydrous dimethylformamide (DMF); in a nitrogen environment, stirred and reacted for 3 days from warming to room temperature; filtered, and the filtrate was added dropwise to a large amount of ether under vigorous stirring, and a solid was precipitated; then filtered again to obtain a solid The solid was dried overnight at 40° C. under vacuum, and the yield was 52%. ¹ HNMR (400MHz, DMSO-d ₆ ), δ (TMS, ppm): 3.28 (d, 8H, H ₄ ), 3.33 (d, 8H, H ₂ ), 3.55 (d, 8H, H ₅ ), 3.60 ( d,16H,H ₆ ),3.64(br,8H,H ₃ ),4.44(t,7H,O ₆ H),4.80(d,8H,H ₁ ),5.65(s,8H,O ₃ H), 5.70(d,8H,O ₂ H),6.9-7.1(m,4H,Ar-H),7.93(s,2H,Ar-H). ¹³ C NMR(400MHz,DMSO-d ₆ ):δ(TMS ,ppm):59.7(C ₆ ),71.8(C ₂ ),72.3(C ₅ ),72.9(C ₃ ),81.3(C ₄ ),101.7(C ₁ ),130.4(Ar),156.7(C＝C ), 162.2 (C=O). HRMS (MALDF-TOF): m/z 1654.40 (M ⁺ , calcd 1654.56).

Example 4: Experimental research on the confirmation of the structure of TPE-CDs and its application

As shown in Figure 1, in the 2D ROESY NMR spectrum of TPE-β-CD, the NOE (nuclear overhauser enhancement) cross peak between the TPE protons and the internal protons of the CD cavity can be seen, indicating that the TPE protons are closely related to the CD cavity. The internal protons are tightly coupled to each other, which also shows that most of the benzene rings in TPE are fixed in the CD cavity. On the other hand, no NOE peak signal can be detected between the resonance peak at δ7.9 position and the internal protons of the β-CD cavity, which is due to the distance between them. As shown in Figures 2 and 3, it can be seen that the spectra of TPE-α-CD and TPE-γ-CD structure confirmation are similar to those of TPE-β-CD. Combining the above results, the geometric structure of TPE-β-CD and the optimized chemical structure of TPE are schematically shown by the structures of Figures 4A, 4B and 5.

The ¹ H NMR signal of the TPE-β-CD structure is concentration-dependent. As shown in Figure 6, the absorption peaks at the positions of δ7.1 and δ6.9 disappear in high-concentration solutions, indicating the formation of intermolecular clathrates. In order to further confirm, the NMR measurement was repeated in the presence of cold-cast steel grains. As shown in Figure 7, after mixing in cold-cast steel grains, the absorption peaks at δ7.1 and δ6.9 positions were significantly enhanced, which was due to the The strong and specific interaction between cast steel grains and CD led to the extrusion of some benzene rings from the cavity of β-CD.

Then, the effect of CD cavity size on the restriction of intramolecular motions (RIM) process was studied. Similar to TPE-β-CD, as shown in Figure 8, the dilute solution of TPE-α-CD showed two broad peaks at the positions of δ7.1 and δ6.9, when the TPE-α-CD solution was thickened These two peaks disappear. On the contrary, as shown in Figure 9, the peaks at the positions of δ7.1 and δ6.9 can still be observed in the concentrated solution of TPE-γ-CD, indicating that γ-CD has less restrictions on the movement of TPE. Taking the signal peak at δ7.9 as a reference, TPE-α-CD has the weakest absorption peaks at δ7.1 and δ6.9, and TPE-γ-CD has the strongest absorption peaks at δ7.1 and δ6.9 . See Table 1. Compared with the larger size of the γ-CD cavity, the smaller size of the α-CD cavity restricts the movement of the TPE benzene ring to a large extent, which weakens the signal of aromatic hydrocarbons.

Table 1: Cavity dimensions of cyclodextrins ^a

^a Depth of cyclodextrin: 0.78nm.

As shown in Figure 10, the ultraviolet (UV) spectrum of the TPE-CDs clathrate-activated luminescent material shows that it has a broad absorption band at 314 nm, which occurs relative to the TPE derivative (TPE-C2) without CD substituents. The blue shift indicates that TPE adopts more twisted conformation and then drives TPE into the CD cavity through the hydrophobic interaction between TPE and CD. The above-mentioned hydrophobic interaction has been confirmed using circular dichroism spectroscopy. As shown in Figure 11, a positive signal appears in the absorption region of TPE in the circular dichroism spectrum of the TPE-CDs clathrate-activated luminescent material, indicating that CD induces TPE to compress into a helical structure.

Figure 12A and Figure 12B show the fluorescence (FL) spectrum of the TPE-CDs clathrate activated luminescent material, the dilute solution of TPE in dimethyl sulfoxide (DMSO) makes the luminescence weak at 470nm due to the intramolecular movement of the benzene ring, benzene The intramolecular motion of the ring can effectively consume the energy of the excited state through nonradiative relaxation channels. In sharp contrast, as shown in Figure 13, TPE-β-CD shows strong fluorescence at 410nm, which is blue-shifted by 60nm compared to the fluorescence spectrum of unsubstituted TPE, and the fluorescence enhancement indicates that benzene in TPE-β-CD The motion of the rings will be somewhat restricted from clathrate formation. The TPE inside the CD cavity has a more twisted conformation, thus causing a blue shift in fluorescence. Compared with TPE-α-CD, TPE-β-CD showed weaker fluorescence at 410 nm, but more luminescent than TPE-γ-CD. Under the same experimental conditions, the physical mixture solution of TPE and CD dissolved in DMSO emits weakly at 470nm. By using quinine sulfate as a control to measure the quantum yield of TPE-CDs clathrate-activated luminescent material and TPE and CD physical mixture, the unsubstituted TPE showed a low quantum yield (0.5%) in DMSO, while TPE - The quantum yield of β-CD composites is 20 times higher than that of unsubstituted TPE, and this value can be even higher by mixing with chilled steel shot, which is presumably due to the larger volume of cold cast steel shot. Further activate the restriction of intramolecular motions (RIM) process. Compared with the larger γ-CD cavity, the smaller sized α-CD cavity will restrict the movement of the benzene ring more effectively, so in the TPE-CDs clathrate-activated luminescent material, the fluorescence of TPE-α-CD has the highest quantum yield. Since the quantum yields of physical mixtures of TPE and various CDs are all low, it indicates that the covalent bonding between TPE and CDs is crucial for the formation of clathrates. TPE and CD are fused into one molecule, and the two are close to each other, making it easier for the benzene ring to be included in the CD cavity.

To further confirm the mechanism of luminescence enhancement, a time-resolved fluorescence measurement experiment was performed. As shown in Figure 14 and Table 2, the luminescence intensity of unsubstituted TPE decreases exponentially, and the luminescence lifetime is 1.41 ns; in contrast, the luminescence intensity of TPE-β-CD excited state mainly decreases gradually along the slow path, and the luminescence lifetime is 1.41 ns. is 8.23ns. In the unsubstituted TPE solution, the active intramolecular motion effectively annihilates the energy of the excited state, resulting in a significantly shortened luminescence time; on the other hand, in the TPE-β-CD inclusion complex, the motion of TPE is restricted, which The non-radiative mitigation path will be blocked and the excited electrons subject to radiative decay will be blocked, thus resulting in a longer luminescence lifetime. The time-resolved fluorescence spectrum of TPE-α-CD is similar to that of TPE-β-CD, and the luminescence lifetime of TPE-γ-CD is shorter than that of unsubstituted TPE.

Table 2. Luminescence lifetime of TPE-CDs clathrate and unsubstituted TPE dissolved in DMSO a

^a is determined by I, I=A ₁ exp(-t/τ ₁ )+A ₂ exp(-t/τ ₂ ).

Utilizing the high quantum yield of TPE-CDs clathrate and the better biocompatibility of TPE and CD itself, the TPE-CDs clathrate was applied to the biological field. As shown in Figures 15A and 15B, the cytoplasm of HeLa cells incubated with TPE-β-CD emitted UV light, indicating that TPE-β-CD can penetrate into the cell membrane and can be used as a fluorescent visualization agent for intracellular imaging.

The present invention forms PCL-TPE nano-lamellae-activated luminescent materials through the condensation reaction of TPE-CO ₂ H and polyε-caprolactone (PCL) through the following reaction formula, including PCL3k-TPE, PCL5k-TPE, PCL10k-TPE and PCL20k -TPE. The intermediate and final products in the reaction process were purified and characterized by nuclear magnetic resonance (NMR) spectrum and gel permeation chromatography (GPC) to confirm their expected molecular structures. PCL-TPE polymers are all soluble in common solvents such as THF, acetone, DCM, DMSO and DMF.

Example 5:

(1) The structural formula of PCL3k-TPE:

(2) Method for preparing PCL3k-TPE polymer-activated luminescent material

Dissolve 0.302g (0.8mmol) of TPE-CO ₂ H and 0.32g (0.1mmol) of PCL3k in 10ml of anhydrous dimethylformamide (DMF) in a 50ml round bottom flask under nitrogen atmosphere at 0°C After dissolving, add 5ml of anhydrous DMF containing 0.041g (0.2mmol) of N,N-dicyclohexylcarbodiimide (DCC); in a nitrogen environment, stir and react for 3 days at warm to room temperature ; Filtration, the filtrate was added dropwise to a large amount of diethyl ether under the condition of vigorous stirring, and the solid was precipitated; then the solid was separated by filtration again, and the solid was dried overnight under vacuum at 40°C, with a yield of 82%. ¹ H NMR (400MHz, CDCl ₃ ), δ(TMS, ppm): 1.37(m, 56H, COOCH ₂ CH ₂ CH ₂ ), 1.64(d, 112H, COOCH ₂ CH ₂ CH ₂ CH ₂ ), 2.30(t ,56H,COCH ₂ ),3.64(t,3H,CH ₂ OH),4.05(t,53H,OCH ₂ ),4.26(s,4H,OCH ₂ from initiator).6.9-7.1(s,1H,Ar- H), 7.93 (br, 8H, Ar-H). Embodiment 6:

(1) The structural formula of PCL5k-TPE:

(2) Preparation method of PCL5k-TPE polymer activated luminescent material:

Dissolve 0.302g (0.8mmol) of TPE-CO ₂ H and 0.46g (0.1mmol) of PCL5k in 10ml of anhydrous dimethylformamide (DMF) in a 50ml round bottom flask under nitrogen atmosphere at 0°C After dissolving, add 5ml of anhydrous DMF containing 0.041g (0.2mmol) of N,N-dicyclohexylcarbodiimide (DCC); in a nitrogen environment, stir and react for 3 days at warm to room temperature ; Filtration, the filtrate was added dropwise to a large amount of diethyl ether under the condition of vigorous stirring, and the solid was precipitated; then the solid was separated by filtration again, and the solid was dried overnight under vacuum at 40°C, with a yield of 87%. ¹ H NMR (400MHz, CDCl ₃ ), δ(TMS, ppm): 1.37(m, 80H, COOCH ₂ CH ₂ CH ₂ ), 1.64(d, 160H, COOCH ₂ CH ₂ CH ₂ CH ₂ ), 2.30(t ,80H,COCH ₂ ),3.64(t,4H,CH ₂ OH),4.05(t,76H,OCH ₂ ),4.26(s,4H,OCH ₂ from initiator),6.9-7.1(s,1H,Ar- H), 7.93 (br, 8H, Ar-H).

Embodiment 7:

(1) The structural formula of PCL10k-TPE:

(2) Preparation method of PCL10k-TPE polymer activated luminescent material:

Dissolve 0.302g (0.8mmol) of TPE-CO ₂ H and 0.93g (0.1mmol) of PCL10k in 10ml of anhydrous dimethylformamide (DMF) in a 50ml round bottom flask under nitrogen atmosphere at 0°C After dissolving, add 5ml of anhydrous DMF containing 0.041g (0.2mmol) of N,N-dicyclohexylcarbodiimide (DCC); in a nitrogen environment, stir and react for 3 days at warm to room temperature ; Filtration, the filtrate was added dropwise to a large amount of diethyl ether under the condition of vigorous stirring, and the solid was precipitated; then the solid was separated by filtration again, and the solid was dried overnight under vacuum at 40°C, with a yield of 89%. ¹ H NMR (400MHz, CDCl ₃ ), δ(TMS, ppm): 1.37(m, 164H, COOCH ₂ CH ₂ CH ₂ ), 1.64(d, 328H, COOCH ₂ CH ₂ CH ₂ CH ₂ ), 2.30(t ,164H,COCH ₂ ),3.64(t,4H,CH ₂ OH),4.05(t,160H,OCH ₂ ),4.26(s,4H,OCH ₂ from initiator),6.9-7.1(s,1H,Ar- H), 7.93 (br, 8H, Ar-H).

Embodiment 8:

(1) The structural formula of PCL20k-TPE:

(2) Preparation method of PCL20k-TPE polymer activated luminescent material:

Dissolve 0.302g (0.8mmol) of TPE-CO ₂ H and 1.78g (0.1mmol) of PCL20k in 10ml of anhydrous dimethylformamide (DMF) in a 50ml round bottom flask under nitrogen atmosphere at 0°C After dissolving, add 5ml of anhydrous DMF containing 0.041g (0.2mmol) of N,N-dicyclohexylcarbodiimide (DCC); in a nitrogen environment, stir and react for 3 days at warm to room temperature ; Filtration, the filtrate was added dropwise to a large amount of diethyl ether under the condition of vigorous stirring, and the solid was precipitated; then the solid was separated by filtration again, and the solid was dried overnight under vacuum at 40°C, with a yield of 85%. ¹ H NMR (400MHz, CDCl ₃ ), δ(TMS, ppm): 1.37(m, 312H, COOCH ₂ CH ₂ CH ₂ ), 1.64(d, 624H, COOCH ₂ CH ₂ CH ₂ CH ₂ ), 2.30(t ,312H,COCH ₂ ),3.64(t,4H,CH ₂ OH),4.05(t,308H,OCH ₂ ),4.26(s,4H,OCH ₂ from initiator),6.9-7.1(s,1H,Ar- H), 7.93 (br, 8H, Ar-H).

Example 9: Relevant physical and chemical properties of PCL-TPE, as well as structural confirmation and application aspects

Experimental Study

See Table 3, which shows the molecular weight and molecular weight distribution of PCL and the

The mass percentage of TPE.

Table 3: Molecular weight and molecular weight distribution of PCL and the mass percentage of TPE in PCL-TPE

Wherein, ^a is determined by ¹ H NMR;

^c is calculated by GPC measurement with polystyrene as a contrast;

^d DP represents the degree of polymerization, determined by the ¹ H NMR spectrum of PCL, and calculated by the formula DP=2n=2I _c /I _a , where I _a and I _c represent 4.26 and 2.30 in the hydrogen nuclear magnetic resonance spectrum, respectively Integral of the resonance peak at;

^e T represents the final ratio of PCT to TPE (termination ratio of PCL with TPE), calculated and determined by T=I _a /I _c , where I _a and I _c represent the integration of the resonance peaks at 7.93 and 4.26 in the proton nuclear magnetic resonance spectrum, respectively ;

^f W represents the mass percentage of TPE in PCL-TPE, calculated by W=2T·M _TPE /(M _PCL +2M _TPE ), where M _TPE and M _PCL are the molecular weights of TPE and PCL, respectively.

As shown in Figures 16, 17A and 17B, and referring to Table 4, the crystallization and melting behavior of PCL-TPE was investigated by differential scanning calorimetry (DSC). The obvious exothermic peak is considered to be PCL crystallization; in the following thermal scanning process, the PCL crystallization melts, and a sharp endothermic peak can be observed at 52.3°C. The crystallinity of PCL-TPE was estimated to be 55.9%, these data show that PCL-TPE is crystallizable as expected.

Table 4: Crystallization temperature, melting temperature, melting enthalpy and crystallinity of PCL-TPE

The ΔH of the ideal PCL crystal is 142.9J/g; the crystallinity (X _c ) of PCL-TPE is calculated by X _c = ΔH/[142.9*(1-W)], where W represents the content of TPE in PCL-TPE % by mass.

PCL-TPE can emit light efficiently in a solid state, but the radiation becomes weaker when dissolved in a solvent, such as dissolved in THF. Therefore, the fluorescence behavior of PCL-TPE in a THF/water mixed solvent is investigated, as shown in Figures 18A and 18B , when the volume ratio of water in THF/water mixed solvent is ≤80%, PCL-TPE emits weakly; when the volume ratio of water increases to 99%, the luminescence intensity of PCL-TPE suddenly increases at 480nm, showing typical polymerization-induced luminescence (AIE )Phenomenon.

The morphology of PCL-TPE suspended in aqueous medium was characterized by atomic force microscopy (AFM). The height image of tapping mode AFM in Figure 19A shows the lamella structure of PCL-TPE; the cross-section of Figure 19B The contour plot shows that its thickness is about 7nm, which is close to the thickness of PCL lamellar. In order to further investigate the microstructure of PCL-TPE nanoplatelets, the PCL-TPE suspension solution is centrifuged and filtered to obtain PCL-TPE nanoplatelet powders, as shown in Figure 20, the X-ray diffraction (XRD) spectrum is between 21.3 ° and 23.6° shows two distinct diffraction peaks, which are respectively related to the 110 diffraction plane and 200 diffraction plane of PCL orthorhombic crystallization, indicating that PCL has been crystallized. As shown in Figure 21, the DSC spectrum during the first thermal scan showed a sharp endothermic peak, further confirming the crystallization of PCL.

The surface composition of the PCL-TPE lamella was analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS), as shown in Figure 22, the TOF-SIMS spectrum shows that C ₆₀ ⁺ is used as An ion beam was used to detect the PCL backbone and the TPE end group located at the end of the PCL backbone, see Table 5, the C ₃ H ₃ O fragment positive ion m/z=55 of the PCL backbone; the TPE end group m/z=357.

Table 5: Peak assignments of TOF-SIMS spectra of PCL-TPE nanosheets

In order to determine the distribution of TPE along the depth direction, Bi ₃ ⁺ smaller than C ₆₀ ⁺ is used as the primary ion beam. Generally, it is believed that the penetration depth under the same ion dose is related to the size of the primary ion beam, and small cluster ions penetrate deeper. As shown in Figure 23, the TOF-SIMS spectrum of PCL-TPE using Bi ₃ ⁺ as the primary ion beam is similar to the TOF-SIMS spectrum using C ₆₀ ⁺ as the primary ion beam, but it is interesting to use Bi ₃ ⁺ as the primary ion beam The ratio of the peak intensity of m/z=357 to the peak intensity of m/z=55 in the ion beam is 5×10 ^-3 , which is much lower than the ratio of 22.9×10 ^-3 when using C ₆₀ ⁺ as the primary ion beam , which shows that the content of TPE decreases sharply with the increase of penetration depth, indicating that TPE is located on the surface of PCL-TPE nanoplatelets.

Since the structure of PCL-TPE nanoplatelets is related to temperature, TOF-SIMS detection was carried out at 65°C higher than the melting temperature of PCL-TPE (52.3°C). As shown in Figure 24, at 65°C, PCL- The ratio of the peak intensity of m/z=357 to the peak intensity of m/z=55 of TPE is 4.4×10 ^-3 , which is much lower than the ratio of 22.9×10 ^-3 at room temperature, indicating that it is located in the nanometer The TPE on the surface of the lamellae will diffuse inward, and the PCL lamellae will melt under conditions higher than the melting temperature of PCL-TPE. Driven by the concentration gradient, TPE will migrate inward, so it is verified that the PCL-TPE shown in Figure 25 TPE nano plate structure.

In order to further confirm the distribution of TPE in the PCL-TPE lamellae, see Table 6 and Figure 26, using X-ray photoelectron spectroscopy (XPS) for verification, as expected, PCL-TPE lamellae detected carbon and oxygen element, the oxygen content (oxygen fraction) in PCL-TPE was detected at 45° takeoff angle (takeoff angle) to be 20.1%; Oxygen TPE remained on the surface of the PCL-TPE platelets. In addition, the emission angle decreased from 45° to 25°, and the ^sp2 carbon content increased from 40.1% to 64.5%, indicating that the TPE is located at the polymer/air interface.

Table 6: Oxygen content and sp ² carbon content of PCL-TPE nanosheets detected at different injection angles

The results of TOF-SIMS and XPS spectra both imply that during the crystallization of PCL, the TPE end groups are repelled outside the PCL crystal, making it hang on the surface due to the covalent binding of TPE to the polymer. There are three possible reasons for the exposed TPE on the polymer platelets: (1) low miscibility between the hydrophobic aromatic TPE and the hydrophilic aliphatic caprolactone segment; (2) the size of the bulky TPE and The PCL unit cells do not match (a=0.748nm, b=0.498nm, c=1.726nm); (3) TPE has high mobility as a terminal group, and cannot be trapped in the lamellae during polymer crystallization. In fact, so far there is no relevant report on the ability of terminal groups to be trapped in polymer lamellae, even small terminal groups, such as mercapto, hydroxyl, carboxyl, benzyl, etc., cannot enter into the lamellae and Positioned on the lamellar surface, the TPE is much larger than the aforementioned groups. This also confirms the structure shown in Figure 25 that the TPE is exposed outside the PCL-TPE lamellae.

Explosives can be detected using PCL-TPE nanoplatelets with TPE suspended on the surface. The PCL-TPE nanoplatelets suspended in the aqueous medium emit light efficiently based on the radiation at 350nm, and the luminescence gradually weakens after adding trinitrophenol (picric acid, PA). As shown in Figures 28A and 28B, the ratio of I ₀ /I decreases linearly with increasing PA concentration, and the quenching of PCL-TPE with the addition of trinitrophenol follows the Stern-Volmer Formula: I ₀ /I=1+K[Q], where I ₀ and I are the fluorescence intensity in the steady state without adding the quencher and adding the quencher respectively; K represents Stern-Wolmer (Stern -Volmer) constant, which represents the sensitivity of the fluorescent material to the quencher, and the larger the K value, the higher the sensitivity to the quencher. The K value of PCL-TPE nanoplatelets is 380000L/mol, which is much larger than that of linear polysiloles-based fluorescent chemical sensors (K<20000L/mol). The high static quenching constant of PCL-TPE is related to the new structure of nanoplatelet TPE exposed on its surface.

The fluorescence response of PCL-TPE nanoplatelets to explosive analogues was further studied. Blank PCL-TPE emits strong blue light under 365nm radiation, and the blue light is quenched after adding equimolar PA. However, equimolar PA analogs such as toluene (Tol), 2,4-dinitrotoluene (DNT), 4-nitrophenol (NP), 4-nitrobenzene (NB), 2-bromotoluene (BT), 1,2-dichlorobenzene (DCB), 1,2,4-tribromobenzene (TBB), bromo-2-nitrobenzene (BNB), 3,5-dinitrophenylethanol (DNBA ), etc., the luminescence of the PCL-TPE suspension can still be observed with the naked eye. Figure 29 shows the ratio of I ₀ /I when PA and its analogues are added to PCL-TPE. The ratio of I ₀ /I when PA is added is much greater than that of other analogues, indicating that PCL-TPE nanoplatelets have excellent properties. Selectivity against the properties of PA analogs, so PCL-TPE can specifically recognize PA.

Study the effect of PCL-TPE molecular weight on the quenching constant (K), as shown in Figure 30-33, with the increase of PCL-TPE molecular weight, the K value decreases, the possible reason is the grafting between TPE and PCL lamella The density is related to the molecular weight of PCL-TPE. Low molecular weight PCL-TPE has a high TPE graft density due to the high content of TPE and then forms fluorescent nanoplatelets. After adding PA, PA molecules quench the light of some adjacent TPE molecules, resulting in higher detection sensitivity. ; For high molecular weight PCL-TPE, due to the low content of TPE, TPE is isolated on the surface of polymer platelets alone, in order to quench the light of individual TPE, this requires more PA molecules, which leads to Quenching constant is low.

It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements or changes should fall within the protection scope of the appended claims of the present invention.

Claims (1)

1. An activated luminescent material, its structural formula is as follows: Wherein, the R ₁ group is cyclodextrin or polyε-caprolactone, and the polyε-caprolactone has 28-156 repeating units; R ₂ , R ₃ and R ₄ groups are respectively selected from C _n H _2n+1 , C ₁₀ H ₇ , C ₁₂ H ₉ , OC ₆ H ₅ , OC ₁₀ H ₇ , OC ₁₂ H ₉ , C _n H _2n NCS, C _n H _2n N ₃ , C _n H _2n NH ₂ , C _n H _2n Cl, C _n H _2n Br, C _n H _2n I, wherein n=0～20; When the R group is cyclodextrin, the activated luminescent material is TPE _- β-CD, TPE-α-CD or TPE-γ-CD, The structural formula of the TPE-β-CD is: The structural formula of the TPE-α-CD is: The structural formula of the TPE-γ-CD is: When the R group is _polyε -caprolactone, the activated luminescent material is PCL3k-TPE, PCL5k-TPE, PCL10k-TPE or PCL20k-TPE, The structural formula of the PCL3k-TPE is: The structural formula of the PCL5k-TPE is: The structural formula of the PCL10k-TPE is: The structural formula of the PCL20k-TPE is: