Room-temperature phosphorescent material of phenylacetylene node substituted pyrene derivative and preparation method of room-temperature phosphorescent material

Abstract

The invention discloses a room-temperature phosphorescent material of a phenylacetylene node substituted pyrene derivative and a preparation method of the room-temperature phosphorescent material, pyrene is used as a substrate, phenylacetylene substitution is selectively carried out at a node (2 position) of pyrene, compared with a pyrene derivative obtained by carrying out phenylacetylene substitution at an anti-node (1 position), the pyrene derivative obtained by carrying out phenylacetylene substitution at the anti-node (1 position) has the advantages that the conjugacy of a substitution site is destroyed; compared with the prior art, the room-temperature phosphorescent material has the advantages that the rotation degree of freedom between a substituent group and a pyrene core is maintained, so that spin-orbit coupling is enhanced, room-temperature phosphorescence of the pyrene derivative is started, and the obtained room-temperature phosphorescent material has the advantages of high luminous efficiency and long service life.

Description

Technical Field

[0001] This invention belongs to the field of organic room temperature phosphorescent materials technology, and particularly relates to a room temperature phosphorescent material of phenylacetylene node-substituted pyrene derivative and its preparation method. Background Technology

[0002] In recent years, the design and research of room-temperature phosphorescence systems have received widespread attention due to the unique photophysical phenomena of room-temperature phosphorescence and its potential applications in information encryption, organic light-emitting diodes, chemical sensing, biosensors, and bioimaging. However, the presence of precious metals such as iridium and platinum in traditional phosphorescent materials significantly increases manufacturing costs while improving device performance, hindering their application and widespread adoption.

[0003] Generally, for pure organic compounds, due to some inherent drawbacks such as thermal disturbance, intramolecular motion, and collisional quenching with oxygen or solvent molecules, the long-lived triplet state can easily return to the ground state through non-radiative transitions. In addition, the relatively tight electron binding in pure organic compounds is not conducive to the conversion of excited singlet states into excited triplet states. Therefore, phosphorescence is usually rare in pure organic compounds. Even if pure organic compounds can have room-temperature phosphorescence properties, their luminescence efficiency is generally low, and they are all limited to the range of photophosphorescent emission, which restricts their further applications. Summary of the Invention

[0004] Based on the above-mentioned technical problems, this invention discloses a room-temperature phosphorescent material of phenylacetylene node-substituted pyrene derivative and its preparation method. By using pyrene as a substrate, phenylacetylene is selectively substituted at its node (2-position). Compared with the pyrene derivative obtained by substituted phenylacetylene at the anti-node (1-position), the former destroys the conjugation of the substitution site, maintains the rotational degree of freedom between the substituent and the pyrene core, thereby enhancing spin-orbit coupling and enabling room-temperature phosphorescence of the pyrene derivative. The resulting room-temperature phosphorescent material has the advantages of high luminous efficiency and long lifetime.

[0005] The present invention proposes a room-temperature phosphorescent material with a phenylacetylene node-substituted pyrene derivative, the general formula of which is shown in structural formula I below:

[0006] R can be one or more, independently selected from hydrogen, electron-donating groups, or electron-withdrawing groups.

[0007] Preferably, R is hydrogen, C1-6 alkoxy, or cyano.

[0008] Preferably, the room-temperature phosphorescent material has one of the following structural formulas: , , .

[0009] This invention also proposes a method for preparing the above-mentioned phenylacetylene node-substituted pyrene derivative room temperature phosphorescent material, the synthetic route of which is shown below:

[0010] R can be one or more, independently selected from hydrogen, electron-donating groups, or electron-withdrawing groups; X is a halogen.

[0011] Preferably, R is hydrogen, C1-6 alkoxy, or cyano; X is bromine.

[0012] Preferably, the preparation method specifically includes: performing a Sonogashira coupling reaction between 2-bromopyrene shown in structural formula II and phenylacetylene shown in structural formula III to obtain the nodally substituted pyrene derivative of phenylacetylene shown in structural formula I.

[0013] Preferably, the catalyst for the Sonogashira coupling reaction includes a palladium catalyst, a monovalent copper catalyst, and an organic amine; The palladium catalyst is at least one of Pd(PPh3)4, Pd(PPh3)2Cl2 or Pd(dppf)Cl2, the monovalent copper catalyst is at least one of CuCl, CuBr or CuI, and the organic amine is at least one of triethylamine, diethylamine or diisopropylethylamine.

[0014] Preferably, the solvent for the Sonogashira coupling reaction is at least one of tetrahydrofuran, 1,4-dioxane, or N,N-dimethylformamide; the temperature of the Sonogashira coupling reaction is 70-90°C, and the time is 9-18 hours.

[0015] Preferably, the molar ratio of 2-bromopyrene shown in structural formula II to phenylacetylene shown in structural formula III is 1:1-1.5.

[0016] This invention also proposes the application of the above-mentioned room temperature phosphorescent material or the room temperature phosphorescent material prepared by the above-mentioned preparation method in anti-counterfeiting encryption.

[0017] In this invention, pyrene is used as a substrate, and selective phenylacetylene substitution at its node (position 2) yields pyrene derivatives exhibiting significant room-temperature phosphorescence. This demonstrates that node (position 2) and anti-node (position 1) substitutions determine the photophysical properties of the molecule. Comprehensive spectroscopic characterization reveals that anti-node substitution extends the π-conjugated system of pyrene, significantly reducing intersystem crossing and increasing non-radiative decay pathways, thereby suppressing room-temperature phosphorescence (RTP) intensity to undetectable levels. In contrast, node substitution disrupts the conjugation of the substitution site, preserving the rotational degree of freedom between the substituent and the pyrene core, thus enhancing spin-orbit coupling and enabling room-temperature phosphorescence of pyrene. Ultrafast spectroscopy further confirms that the charge-transfer state retains rotational degree of freedom due to the bonding effect at the node positions, which is beneficial for improving phosphorescence efficiency. Attached Figure Description

[0018] Figure 1 The above is the 1H NMR spectrum of the phenylacetylene nodally substituted pyrene derivative described in Example 1 of this invention; Figure 2 The carbon NMR spectrum of the phenylacetylene nodally substituted pyrene derivative described in Example 1 of this invention; Figure 3 This is a high-resolution mass spectrum of the phenylacetylene nodally substituted pyrene derivative described in Example 1 of the present invention; Figure 4 The UV-Vis absorption and steady-state emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives described in Example 1 and Comparative Example 1 of this invention in 2-methyltetrahydrofuran (m-THF) are shown. Figure 5 The steady-state emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives described in the embodiments and comparative examples of the present invention in different polar solvents; Figure 6 The delayed emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives in m-THF are shown in the embodiments and comparative examples of the present invention. Figure 7 The lifetime diagram of the two emission peaks of the phenylacetylene nodally substituted pyrene derivative described in the embodiments of the present invention in m-THF; Figure 8 The steady-state emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives in polymethyl methacrylate (PMMA) at room temperature and low temperature are shown in the embodiments and comparative examples of the present invention. Figure 9 The delayed emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives described in the embodiments and comparative examples of the present invention at low temperatures in PMMA; Figure 10 The delayed emission spectrum of the phenylacetylene nodally substituted pyrene derivative in PMMA at room temperature, as described in this embodiment of the invention; Figure 11The lifetime diagram of the two emission peaks of the phenylacetylene nodally substituted pyrene derivative described in the embodiments of the present invention in PMMA; Figure 12 These are room-temperature phosphorescent (RTP) encryption demonstration photos of phenylacetylene node / anti-node substituted pyrene derivatives as described in the embodiments and comparative examples of the present invention. Figure 13 This illustrates the design principles and Jablonski diagrams for the phenylacetylene node / anti-node substituted pyrene derivatives described in Embodiment 1 and Comparative Example 1 of the present invention. Figure 14 The molecular orbital wavefunction distributions of the phenylacetylene node / anti-node substituted pyrene derivatives described in Example 1 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0019] The present invention will now be described in detail through specific embodiments. However, these examples are clearly provided for illustrative purposes and are not intended to limit the scope of the invention.

[0020] Example 1 A nodally substituted pyrene derivative of phenylacetylene has the following structural formula:

[0021] The phenylacetylene nodally substituted pyrene derivative was prepared by the following method: 2-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing phenylacetylene (0.25 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred at 80 °C under a nitrogen atmosphere for 72 h, and finally quenched with dichloromethane. The mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent, yielding the phenylacetylene nodally substituted pyrene derivative (0.236 g, 36.5%), abbreviated as 2-H-Py.

[0022] 1 H NMR (400 MHz, Chloroform- d ) δ 8.34 (s, 2H), 8.19 (d, J = 7.6 Hz, 2H), 8.11 – 7.98 (m, 5H), 7.68–7.62 (m, 2H), 7.44–7.35 (m, 3H). Figure 1 The above is the 1H NMR spectrum of the phenylacetylene nodally substituted pyrene derivative described in this embodiment; Figure 2 The carbon NMR spectrum of the phenylacetylene nodally substituted pyrene derivative described in this embodiment; Figure 3 This is a high-resolution mass spectrum of the nodally substituted pyrene derivative of phenylacetylene described in this embodiment. Figure 1-3 The molecular structure of the phenylacetylene nodally substituted pyrene derivative described in this embodiment can be clearly defined.

[0023] Example 2 A nodally substituted pyrene derivative of phenylacetylene has the following structural formula:

[0024] The phenylacetylene nodally substituted pyrene derivative was prepared by the following method: 2-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing p-methoxyphenylacetylene (0.33 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred and reacted at 80 °C under a nitrogen atmosphere for 72 h. Finally, dichloromethane was added for quenching, and the mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent. This yielded the phenylacetylene nodally substituted pyrene derivative (0.318 g, 44.8%), abbreviated as 2-OME-Py.

[0025] 1 H NMR (400 MHz, Chloroform- d ) δ 8.32 (d, J = 1.1 Hz, 2H), 8.18 (dd, J = 7.7, 1.2 Hz, 2H), 8.11–7.97 (m, 5H), 7.63–7.55 (m, 2H), 6.97–6.90 (m,2H), 3.86 (s, 3H). Example 3

[0026] A nodally substituted pyrene derivative of phenylacetylene has the following structural formula:

[0027] The phenylacetylene nodally substituted pyrene derivative was prepared by the following method: 2-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing p-cyanophenylacetylene (0.32 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred and reacted at 80 °C under a nitrogen atmosphere for 72 h. Finally, dichloromethane was added for quenching, and the mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent. This yielded the phenylacetylene nodally substituted pyrene derivative (0.240 g, 34.3%), abbreviated as 2-CN-Py.

[0028] 1 H NMR (400 MHz, Chloroform- d ) δ 8.34 (s, 2H), 8.20 (d, J = 7.6 Hz, 2H), 8.11 (d, J = 9.0 Hz, 2H), 8.07–8.01 (m, 3H), 7.73–7.65 (m, 4H). Comparative Example 1 A phenylacetylene anti-node substituted pyrene derivative has the following structural formula:

[0029] The phenylacetylene anti-node substituted pyrene derivative was prepared by the following method: 1-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing phenylacetylene (0.25 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred and reacted at 80 °C under a nitrogen atmosphere for 72 h. Finally, dichloromethane was added for quenching, and the mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent. This yielded the phenylacetylene anti-node-substituted pyrene derivative (0.496 g, 76.8%), abbreviated as 1-H-Py.

[0030] 1 H NMR (400 MHz, Chloroform- d) δ 8.67 (d, J = 9.1 Hz, 1H), 8.26 –8.17 (m, 4H), 8.15–8.08 (m, 2H), 8.07–8.00 (m, 2H), 7.75–7.70 (m, 2H), 7.47–7.37 (m, 3H). Comparative Example 2 A phenylacetylene anti-node substituted pyrene derivative has the following structural formula:

[0031] The phenylacetylene anti-node substituted pyrene derivative was prepared by the following method: 1-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing p-methoxyphenylacetylene (0.33 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred and reacted at 80 °C under a nitrogen atmosphere for 72 h. Finally, dichloromethane was added for quenching, and the mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent. This yielded the phenylacetylene anti-node-substituted pyrene derivative (0.606 g, 85.4%), abbreviated as 1-OME-Py.

[0032] 1 H NMR (400 MHz, Chloroform- d ) δ 8.66 (d, J = 9.1 Hz, 1H), 8.25–8.15(m, 4H), 8.14–7.99 (m, 4H), 7.69–7.63 (m, 2H), 7.00–6.93 (m, 2H), 3.87 (s,3H). Comparative Example 3 A phenylacetylene anti-node substituted pyrene derivative has the following structural formula:

[0033] The phenylacetylene anti-node substituted pyrene derivative was prepared by the following method: 1-Bromopyrene (0.6 g, 2.1 mmol), bis(triphenylphosphine)palladium(II) dichloride Pd(PPh3)2Cl2 (0.075 g, 0.1 mmol), and cuprous iodide (0.020 g, 0.1 mmol) were added to a flask, followed by 3 mL of tetrahydrofuran solution containing p-cyanophenylacetylene (0.32 g, 2.5 mmol), then 7 mL of tetrahydrofuran and 10 mL of diisopropylamine. The resulting mixture was stirred and reacted at 80 °C under a nitrogen atmosphere for 72 h. Finally, dichloromethane was added for quenching, and the mixture was purified by column chromatography using petroleum ether and ethyl acetate in a 6:1 ratio as the eluent. This yielded the phenylacetylene anti-node-substituted pyrene derivative (0.439 g, 62.8%), abbreviated as 1-CN-Py.

[0034] 1 H NMR (400 MHz, Chloroform- d ) δ 8.58 (d, J = 9.1 Hz, 1H), 8.27–8.17(m, 4H), 8.15–8.09 (m, 2H), 8.07–8.01 (m, 2H), 7.77–7.63 (m, 4H). The phenylacetylene nodal / anti-nodal substituted pyrene derivatives described in Example 1 and Comparative Example 1 were dissolved in m-THF and subjected to spectral analysis at room temperature. The results are as follows: Figure 4 As shown, Figure 4 The UV-Vis absorption and steady-state emission spectra of the phenylacetylene nodal / anti-nodal substituted pyrene derivatives described in Example 1 and Comparative Example 1 in m-THF are shown (λex = 350 nm, c = 1 × 10⁻⁶). -5 mol / L).

[0035] Depend on Figure 4 It can be seen that the absorption spectrum of 2-H-Py is blue-shifted compared to 1-H-Py; the UV-Vis spectrum of 1-H-Py shows an additional absorption band near 375 nm, while that of 2-H-Py is not, that is, the substitution of the anti-node (1-position) disrupts the original high symmetry of the pyrene ring, thereby allowing new electronic transitions; the steady-state emission spectrum shows that both 1-H-Py and 2-H-Py exhibit two main emission vibration peaks at 391 nm and 411 nm.

[0036] To investigate the existence of intramolecular charge transfer (ICT) states, the phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples were dissolved in solvents of different polarities (m-THF, DMF, DMSO), and spectroscopic measurements were performed at room temperature. The results are as follows: Figure 5 As shown, Figure 5The steady-state emission spectra of the phenylacetylene nodal / anti-nodal substituted pyrene derivatives described in the examples and comparative examples in different polar solvents (λex = 350 nm, c = 1 × 10⁻⁶). -5 mol / L).

[0037] Depend on Figure 5 It is evident that increasing solvent polarity leads to a redshift of approximately 10 nm in the emission peak of 2-H-Py (from 391 nm to 401 nm), resulting in the disappearance of its fine vibrational structure. In contrast, 1-H-Py exhibits only a slight redshift (from 391 nm to 395 nm and from 411 nm to 416 nm), preserving its vibrational structure. In m-THF, with the introduction of substituents, the emission peaks of the 1- and 2-position derivatives gradually redshift, with the cyano-substituted compounds showing the most significant shifts (30 nm for 1-CN-Py and 26 nm for 2-CN-Py). The phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples were dissolved in m-THF (c=1×10⁻⁶). - 5 (mol / L), and spectroscopic measurements were performed at 77 K. The results are as follows: Figure 6 As shown, Figure 6 The images show the delayed emission spectra (λex = 298 nm, delay time = 5 ms) of the phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples in m-THF. The insets are photographs taken under UV light irradiation and after the UV lamp was turned off.

[0038] Depend on Figure 6 It can be seen that although the anti-node (1-position) and node (2-position) substituted pyrene derivatives show some similarities in steady-state luminescence, their phosphorescence behavior is significantly different: all three node-type 2-substituted derivatives exhibit obvious red phosphorescence emission in m-THF solution at low temperature (77 K), characterized by two main emission vibration peaks located at 587 nm and 648 nm, respectively.

[0039] Figure 7 The image shows the lifetime of the two emission peaks of the phenylacetylene nodally substituted pyrene derivative described in the examples in m-THF. The insets are photographs taken under UV light irradiation and after the UV lamp is turned off, respectively. Figure 7 It can be seen that the lifetime of 2-H-Py is = 0.54 s; After substitution at the para-position of the alkynyl group with methoxy and cyano groups, the phosphorescence brightness and duration of the former increased compared to 2-H-Py. Specifically, the lifetime of the 587 nm emission peak increased to 0.69 s (2-OME-Py) and 0.74 s (2-CN-Py), respectively. In m-THF solution at 77 K, 2-CN-Py with the strongest electron-withdrawing cyano group exhibited the brightest phosphorescence and the longest lifetime, which is attributed to the enhanced ICT properties, which promote intersystem crossing (ISC) and stabilize the triplet state through a highly distorted donor-acceptor geometry. In contrast, no phosphorescence emission was observed in the three 1-substituted derivatives in glassy solution at 77 K, indicating low ISC efficiency and significant non-radiative decay.

[0040] The phenylacetylene nodal / anti-nodal substituted pyrene derivatives described in the examples and comparative examples were doped into PMMA at a mass fraction of 0.5%, and spectroscopic measurements were performed at room temperature and 77 K. The results are as follows: Figure 8 As shown, Figure 8 Steady-state emission spectra (λex = 350 nm) of the phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples in PMMA.

[0041] Depend on Figure 8It can be seen that at room temperature (left), the steady-state emission of all anti-node (1-position) substituted pyrene derivatives in PMMA films exhibits a significant red shift with increasing substituent polarity, while node (2-position) substituted pyrene derivatives show a slight blue shift and loss of fine spectral structure; for example, when the phenyl group is substituted with a cyano group at the 1-position, the maximum emission value shifts from 418 nm to 457 nm, a red shift of 39 nm, while the spectrum broadens and the vibrational electronic structure disappears; for the 2-position substituted pyrene derivatives in PMMA, 2-H-Py retains three vibrational peaks (the main peaks are located at 427 nm and 44 nm). The emission peak position did not follow the same redshift trend as in m-THF solution (7 nm); this observation can be explained by the rigid color change effect; in polar solvents such as m-THF, the fluorescence state of pyrene can be stabilized by nearby dielectric groups such as OMePh- and CNPh-, while in rigid media such as PMMA, the transition is vertical (no dielectric stabilization), and the substitution of nodal positions by more polar groups will increase the curvature of the wavefunction at position 2 to a greater extent; the overall effect is that the substitution of OMePh- and CNPh- increases the emission state, thus causing a blue shift. At 77 K (right), the steady-state emission spectrum of 1-H-Py shows a more pronounced fine structure, with its peaks redshifted at 417 nm, 426 nm, and 454 nm. The spectra of the nodal (2-position) pyrene derivatives are more complex: 2-H-Py exhibits three main vibrational peaks at 424 nm, 446 nm, and 465 nm, similar to its room-temperature spectrum; while 2-OME-Py shows a new shoulder peak at 408 nm, and the emission wavelength of 2-CN-Py is close to 435 nm. Notably, in the longer wavelength region, the 2-position pyrene derivatives exhibit a broad emission band between 550 nm and 680 nm.

[0042] The phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples were doped into PMMA at a mass fraction of 0.5%, and spectroscopic measurements were performed at 77 K. The results are as follows: Figure 10 As shown, Figure 10 The delayed emission spectra of the phenylacetylene node / anti-node substituted pyrene derivatives in PMMA for the examples and comparative examples are shown (λex = 298 nm, delay time = 5 ms).

[0043] Depend on Figure 9 It can be seen that in PMMA films, the anti-node (1-position) pyrene derivative again exhibits an undetectable level of phosphorescence emission; in contrast, the RTP spectrum of the node (2-position) pyrene derivative remains essentially unchanged, consistent with the spectrum observed in m-THF solution.

[0044] The phenylacetylene nodally substituted pyrene derivative described in the examples was doped into PMMA at a mass fraction of 0.5%, and spectroscopic measurements were performed at room temperature. The results are as follows: Figure 10As shown, Figure 10 The delayed emission spectrum (λex = 298 nm, delay time = 5 ms) of the phenylacetylene nodally substituted pyrene derivative described in the examples is shown in PMMA. The insets are photographs taken under UV irradiation and after the UV lamp is turned off.

[0045] Depend on Figure 10 It is known that all three 2-substituted pyrene derivatives (2-H-Py, 2-OME-Py, 2-CN-Py) exhibit significant phosphorescence behavior at room temperature and 77 K; multiple vibrational peaks were observed at approximately 587 nm, 648 nm and 710 nm, with the peak at 587 nm being the most significant; the introduction of electron-withdrawing substituents enhances the room temperature phosphorescence (RTP) phenomenon, with 2-CN-Py exhibiting the most significant RTP.

[0046] Figure 11 This is a lifetime plot of the two emission peaks of the phenylacetylene nodally substituted pyrene derivative described in the examples in PMMA. Figure 11 It can be seen that 2-CN-Py has the longest lifetime in PMMA at 77 K and room temperature, while 2-OME-Py has the shortest lifetime (0.29s and 74.70ms, respectively).

[0047] The phenylacetylene node / anti-node substituted pyrene derivatives described in Example 1 and Comparative Example 1 were dissolved in DCM and then doped into polymethyl methacrylate (PMMA) at a mass fraction of 1%. The resulting image was then coated on filter paper with the number "1958" (the founding year of the University of Science and Technology of China) and irradiated under 365 nm ultraviolet light. Figure 12 As shown. Figure 12 This is a room-temperature phosphorescent (RTP) encryption demonstration image (λex = 365 nm) of the phenylacetylene node / anti-node substituted pyrene derivatives described in the examples and comparative examples. Figure 12 It is known that the phenylacetylene nodally substituted pyrene derivative described in the examples emits blue fluorescence under 365 nm ultraviolet light, and produces obvious red afterglow after the ultraviolet light is removed.

[0048] Regarding the differences in room-temperature phosphorescence properties of the phenylacetylene node / non-node substituted pyrene derivatives described in the above embodiments and comparative examples, the inventors offer the following explanation based on molecular orbital (MO) theory: For those skilled in the art, introducing electron-donating or electron-withdrawing groups at the antinode position (i.e., the position where the orbital wavefunction amplitude is maximum) of an aromatic molecule can extend the π-conjugation length, which typically leads to an increase in the transition dipole moment (TDM) of the substituted compound, according to the following formula:

[0049] Where i = initial is the initial state, and f = final is the final state. It is the transition dipole moment (vector). For operators The expected value between the initial state and the final state. and These are the wave functions of the initial and final states. It is the electric dipole moment operator. It is a spatial volume element.

[0050] According to this equation, with the enhancement of effective conjugation, or the increase of average r, and the decrease of wavefunction symmetry, the transition dipole moment (TDM) of the molecule is expected to increase sharply; this effect is particularly significant when the core structure is highly symmetric, because anti-node substitution destroys the symmetry during electronic transitions, thus leading to an increase in TDM by several orders of magnitude; therefore, the effect of anti-node substitution is twofold: (1) The increase in TDM inevitably reduces intersystem crossing (ISC) efficiency; (2) Extended π conjugation promotes the increase of molecular motion degrees of freedom.

[0051] The combined effect is expected to lead to a decrease in room temperature phosphorescence (RTP) efficiency; conversely, substitution at the node position will minimize the perturbation of the aromatic core electronic structure, which means that the ground state electronic conjugation effect is negligible, and therefore the rotational degree of freedom of the substituent group at room temperature is also small; in this case, RTP will be enhanced when the substituent and the core exhibit a certain degree of charge transfer properties, because this will mix the spin multiplicity of the singlet and triplet states.

[0052] like Figure 13 As shown, orbital phase analysis reveals how substitution positions on pyrene (substitution at the 1-position and 2-position) affect the exciton spin state. When a substituent is introduced at the 1-position, the fluorescence decay rate increases significantly, accompanied by nonradiative decay competition of the triplet exciton. In contrast, substitution at the node (i.e., the 2-position) reverses the symmetry-induced slow fluorescence decay of pyrene, and the π-electron system of the substituent can promote an intramolecular "intermolecular-like" charge transfer (CT) state. This CT state with rotational degrees of freedom can greatly enhance spin-orbit coupling (SOC), thereby enhancing room-temperature phosphorescence (RTP).

[0053] As previously described, in the synthesis of phenylacetylene node / non-node substituted pyrene derivatives via palladium-catalyzed Sonogashira coupling reaction according to the embodiments and comparative examples of this invention, the reaction yield decreases with increasing electron-withdrawing ability of the substituents, and the yield of anti-node substituted pyrene derivatives is higher than that of their node-substituted isomers. However, there is a significant yield difference between the C-C coupling reactions at the node and anti-node sites; in the Sonogashira reaction, the key step involves the nucleophilic attack of the acetylene anion (the highest occupied molecular orbital (HOMO) of the alkyne) on the electrophilic carbon of the aryl halide (characterized by its lowest unoccupied molecular orbital (LUMO)).

[0054] like Figure 14 As shown, the bromination sites on the pyrene core in the substrate (i.e., the sites where the coupling reaction occurs) exhibit different frontier orbital properties; when the coupling reaction occurs at the antinode, the overlap between the acetylene HOMO and the pyrene LUMO reaches its maximum; this efficient orbital interaction lowers the activation energy of the reaction, thereby increasing the yield; when the reaction occurs at the node of the LUMO, the amplitude of the orbital wavefunction near carbon is essentially zero, and there is no overlap between the acetylene HOMO and the pyrene LUMO; the reaction may proceed via a higher LUMO (such as LUMO+1), where the overlap is optimal; however, this pathway requires additional energy and is less stable due to the rapid relaxation from LUMO+1 to LUMO, ultimately resulting in a much lower yield as observed.

[0055] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A room-temperature phosphorescent material of a phenylacetylene node-substituted pyrene derivative, characterized in that, Its general formula is shown in structural formula I below: ； R can be one or more, independently selected from hydrogen, electron-donating groups, or electron-withdrawing groups.

2. The room-temperature phosphorescent material of the phenylacetylene nodally substituted pyrene derivative according to claim 1, characterized in that, R is hydrogen, C1-6 alkoxy, or cyano.

3. The room-temperature phosphorescent material of a phenylacetylene node-substituted pyrene derivative according to claim 1 or 2, characterized in that, Its structural formula is shown in one of the following: 、 、 。 4. A method for preparing a room-temperature phosphorescent material with a phenylacetylene node-substituted pyrene derivative, characterized in that, The synthetic route is shown below: ； R can be one or more, independently selected from hydrogen, electron-donating groups, or electron-withdrawing groups; X is a halogen.

5. The method for preparing the room-temperature phosphorescent material of the phenylacetylene node-substituted pyrene derivative according to claim 4, characterized in that, R is hydrogen, C1-6 alkoxy, or cyano; X is bromine.

6. The method for preparing the room-temperature phosphorescent material of the phenylacetylene node-substituted pyrene derivative according to claim 4 or 5, characterized in that, Specifically, it includes: The 2-bromopyrene shown in structural formula II and the phenylacetylene shown in structural formula III were subjected to a Sonogashira coupling reaction to obtain the nodally substituted pyrene derivative of phenylacetylene shown in structural formula I.

7. The method for preparing the room-temperature phosphorescent material of the phenylacetylene nodally substituted pyrene derivative according to claim 6, characterized in that, The catalysts for the Sonogashira coupling reaction include palladium catalysts, monovalent copper catalysts, and organic amines; The palladium catalyst is at least one of Pd(PPh3)4, Pd(PPh3)2Cl2 or Pd(dppf)Cl2, the monovalent copper catalyst is at least one of CuCl, CuBr or CuI, and the organic amine is at least one of triethylamine, diethylamine or diisopropylethylamine.

8. The method for preparing the room-temperature phosphorescent material of the phenylacetylene nodally substituted pyrene derivative according to claim 6, characterized in that, The solvent for the Sonogashira coupling reaction is at least one of tetrahydrofuran, 1,4-dioxane, or N,N-dimethylformamide; the Sonogashira coupling reaction is carried out at a temperature of 70-90°C for 9-18 hours.

9. The method for preparing the room-temperature phosphorescent material of the phenylacetylene nodally substituted pyrene derivative according to claim 6, characterized in that, The molar ratio of 2-bromopyrene shown in structural formula II to phenylacetylene shown in structural formula III is 1:1-1.

5.

10. The application of a room-temperature phosphorescent material according to any one of claims 1-3 or a room-temperature phosphorescent material prepared by the preparation method according to any one of claims 4-9 in anti-counterfeiting encryption.

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