Rare earth up-conversion luminescent material, preparation method and application thereof

Abstract

This application discloses a rare-earth upconversion luminescent material, which comprises a multi-component complex; the multi-component complex comprises a rare-earth metal ion center and an organic ligand chelated and coordinated with the rare-earth metal ion center; the rare-earth metal ion center comprises at least two Yb atoms. 3+ Sensitizer; the upconversion luminescence excitation wavelength of the rare earth upconversion luminescent material is 980 nm; the multi-component complex contains less than or equal to 20408 cm⁻¹ ‑1 The energy levels of the excited state; the rare earth upconversion luminescence is the Yb 3+ Upon excitation, the sensitizer co-transfers energy to the excited state of the organic ligand, which then undergoes upconversion luminescence. This application represents the first realization of upconversion luminescence in rare-earth molecular cages, potentially enabling lanthanide organic components to become novel upconversion luminescent materials for biological applications.

Description

Technical Field

[0001] This application relates to a rare earth upconversion luminescent material, its preparation method and application, and belongs to the technical field of upconversion luminescent materials. Background Technology

[0002] Rare-earth ion upconversion luminescence refers to the process by which rare-earth ions with stepped energy levels generate higher-energy photons through radiative transitions by successively absorbing two or more low-energy photons. In rare-earth upconversion luminescent materials, rare-earth ions with near-infrared absorption are generally selected as sensitizers, with Yb being the most common. 3+ (980 nm) and Er 3+ (808 nm) This is because low-energy near-infrared light has lower optical damage and a greater penetration depth in tissues. At the same time, upconversion luminescence can avoid autofluorescence interference and light scattering in biological samples. Therefore, upconversion luminescent materials are a more suitable luminescent material for biological applications, including but not limited to bioimaging, drug delivery, and cancer cell diagnosis and treatment.

[0003] Compared to upconversion nanoparticles, molecular upconversion luminescent materials offer advantages such as controllable synthesis of desired sizes, precise molecular structures, and high reproducibility, thus holding greater promise for applications in biological organisms and experiencing rapid development in the last decade or so. Currently, the main published upconversion luminescence mechanisms include: excited-state reabsorption (ESA), energy transfer upconversion (ETU), co-luminescence (CL), co-sensitization (CS), and photon avalanche (PA). A common issue with these mechanisms is that they only focus on the direct energy transfer process between metal ions, often neglecting other factors in the energy transfer process. For example, whether organic ligands coordinated with rare-earth ions participate in the energy transfer process, or whether ligand-ligand interactions can form new electronically coupled excited states that participate in the upconversion energy transfer process. These factors directly affect the material design of upconversion luminescent systems and even the improvement of the brightness and quantum yield of molecular upconversion. Summary of the Invention

[0004] In existing technologies for upconversion luminescence materials, most are based on direct energy transfer between metal ions. Therefore, the closer the distance between two rare earth ions, the better for upconversion research. The distance between lanthanide ions must be limited to a few angstroms to effectively achieve upconversion luminescence. However, in most multi-component rare earth cages, the shortest distance between the two rare earth ions is on the nanometer scale. Those skilled in the art often hold the bias that a large distance between lanthanide ions prevents upconversion luminescence. Therefore, there have been no reported technical solutions for upconversion luminescence technologies and materials using rare earth cages in this field. However, the advantage of multi-component rare earth complex luminescent materials lies in their ability to fully coordinate the advantages of each component, exhibiting assembly-induced luminescence characteristics. This is beneficial for exploring whether the excited state of ligands participates in the energy transfer process during rare earth upconversion luminescence, a process that has been largely overlooked by researchers.

[0005] According to one aspect of this application, a rare earth upconversion luminescent material is provided, which breaks the limitation in the prior art that the distance between lanthanide ions must be limited to a few angstroms to effectively achieve upconversion luminescence. By using the rigid framework of organic ligands and saturated coordination with the rare earth center to eliminate the non-radiative quenching of the rare earth center, rare earth upconversion luminescence is achieved.

[0006] The technical solution adopted in this application is as follows:

[0007] A rare-earth upconversion luminescent material, the rare-earth upconversion luminescent material comprising a multi-component complex;

[0008] The multi-component complex includes a rare earth metal ion center and an organic ligand chelated and coordinated with the rare earth metal ion center.

[0009] The rare earth metal ion center includes at least two Yb atoms. 3+ Sensitizer;

[0010] The upconversion luminescence excitation wavelength of the rare-earth upconversion luminescent material is 980 nm;

[0011] The multi-component complex contains less than or equal to 20408 cm⁻¹ -1 The energy levels of the excited states;

[0012] The rare earth upconversion luminescence is Yb 3+ After the sensitizer is excited, it transfers energy to the excited state of the organic ligand, and the organic ligand then undergoes upconversion luminescence.

[0013] The excited state of the organic ligand is selected from at least one of the singlet state, triplet state, and excited polymeric state.

[0014] The multi-component complex contains less than or equal to 20408 cm⁻¹ -1 The excited state energy levels include two cases: the excited state energy levels of the organic ligand are less than or equal to 20408 cm⁻¹.-1 Or, the energy level of the ligand is greater than 20408 cm⁻¹. -1 At that time, rare earth complex upconversion luminescent materials contain less than or equal to 20408 cm⁻¹ -1 The energy levels of the excited states;

[0015] The rare earth complex refers to a complex formed by the self-assembly and chelation coordination of rare earth metal ions and organic ligands.

[0016] Rare earth ions are excited at 980 nm, and energy is transferred to organic ligands, realizing upconversion luminescence of organic ligands. At the same time, organic ligands can also act as a bridge for energy transfer, transferring energy to another rare earth metal ion, realizing upconversion emission of another rare earth ion.

[0017] Optionally, the rare earth metal ion center further includes an activator;

[0018] Optionally, the activator is selected from Sm 3+ Eu 3+ 、Tb 3+ Dy 3+ Ho 3+ Er 3+ Tm 3+ At least one trivalent rare earth metal ion;

[0019] Optionally, the activator undergoes upconversion luminescence via ligand-mediated energy transfer;

[0020] The energy transfer is Yb 3+ The sensitizer, after being excited, transfers energy to the excited state of the organic ligand, and then the excited state of the organic ligand is transferred to the activator via an energy transfer process.

[0021] Optionally, the rare earth metal ion center includes 2 to 100 Yb atoms. 3+ Sensitizer;

[0022] Optionally, the coordination number of each rare earth metal ion center in the multi-component complex is independently 6 to 12.

[0023] In the technical solution of this application, the singlet state, triplet state and excited multiply state are mediated by the same method and principle, and all achieve upconversion luminescence of organic ligands through the excited state of organic ligands in multi-component complexes.

[0024] To achieve supramolecular upconversion luminescence, additional requirements are placed on the excited state energy levels of the ligands: at 980 nm excitation, the two Yb 3+ The virtual energy level that can be co-excited by each sensitizer absorbing one photon is ~20408 cm⁻¹. -1(Corresponding to a wavelength of 490 nm), therefore, the emission position of the ligand is best less than or equal to 490 nm to facilitate energy transfer. If the excited state energy level of the ligand is greater than or equal to 20408 cm⁻¹, the energy transfer is less likely. -1 In this case, the energy level of the excited multimer state, which is induced by weak interactions (such as π-π stacking) between ligands in the supramolecular assembly, must be less than or equal to 20408 cm⁻¹. -1 .

[0025] Optionally, the chemical formula of the multi-component complex is Ln. x (L) y Among them, at least one of the trivalent rare earth metal ions Ln, L is an organic ligand, and x and y are independently greater than or equal to 2.

[0026] Optionally, the multi-component complex is selected from at least one of the structures shown in Formula I-1 to Formula I-9:

[0027]

[0028] In this context, spheres represent trivalent rare earth metal ions, and the faces composed of edges in a polygon or polyhedron represent organic ligands.

[0029] The multi-component complex does not necessarily have to be a regular polyhedral structure, as long as it conforms to the above general chemical formula.

[0030] Optionally, the organic ligand includes a chelating unit and a linking unit.

[0031] Optionally, the chelating unit is a 2-4 toothed chelating group.

[0032] Optionally, the 2-4 toothed chelating groups are compounds containing N / O rare earth-loving functional groups, wherein the N / O rare earth-loving functional groups are selected from at least one of β-diketone, triazole-pyridine-amide, triazole-pyridine-triazole, amide-pyridine-amide, amide-pyridine-triazole, amide-pyridine-oxazoline, amide-pyridine-benzimidazole, pyridine-bisbenzimidazole, pyridine-bistetrazole, 8-hydroxyquinoline-amide, and amide-terpyridine.

[0033] Optionally, the connecting unit is a polycyclic aromatic hydrocarbon compound.

[0034] Optionally, the polycyclic aromatic hydrocarbon compound is selected from at least one of meta-substituted benzene, para-substituted benzene, 1,5-disubstituted naphthalene, 1,6-disubstituted naphthalene, disubstituted naphthaleneimide, disubstituted pyrene, tetrasubstituted pyrene, disubstituted porphyrin, tetrasubstituted porphyrin, disubstituted peryleneimide, tetrasubstituted peryleneimide, trisubstituted triphenylbenzene, trisubstituted triphenyltriazine, and trisubstituted N-heterotrimoninden.

[0035] Optionally, the organic ligand has a rigid framework structure.

[0036] When selecting organic ligands that chelate with rare earth ion centers, choosing structures with rigid frameworks avoids interference from nonradiative quenching caused by high-energy molecular vibrations, which is more conducive to luminescence regulation.

[0037] The connecting units are all polycyclic aromatic hydrocarbon compounds, exhibiting good conjugation rigidity and planarity, which can effectively reduce the non-radiative vibrational quenching of rare earth centers. Furthermore, the rare earth cage formed by these connecting units possesses suitable excited-state energy levels, which is beneficial for energy relay in the upconversion process.

[0038] Optionally, the rare earth upconversion luminescent material is a rare earth cage-like upconversion luminescent material.

[0039] Multiple organic ligands self-assemble and chelate with rare earth ions to form a cage-like structure.

[0040] Optionally, the rare-earth upconversion luminescent material has a rhombohedral or concave octahedral structure.

[0041] Optionally, the connection unit is: .

[0042] Although the singlet emission of the 1,5-naphthalene unit is at 370 nm, the maximum emission of the excited multi-state induced by the ligand in the assembly formed by self-assembly is at 500 nm, which meets the requirements of this application.

[0043] Optionally, the chelating group is .

[0044] Optionally, the chelating group is .

[0045] The chelating unit is a tridentate chelate, and both the rare earth ions are saturated nine-coordinated, which hinders the possibility of solvent molecules and counter ions participating in coordination, thus promoting upconversion luminescence.

[0046] According to another aspect of this application, a method for preparing the above-mentioned rare-earth upconversion luminescent material is provided, comprising the following steps:

[0047] Obtaining organic ligands;

[0048] The rare-earth upconversion luminescent material is obtained by self-assembling a mixture containing trivalent rare-earth metal salts and organic ligands.

[0049] Optionally, obtaining the organic ligand includes:

[0050] The mixture of raw materials containing connecting unit precursors and chelating unit precursors is reacted to obtain the product.

[0051] Optionally, the molar ratio of the connecting unit precursor to the chelating unit precursor is 1:2 to 4.

[0052] Optionally, the reaction is selected from at least one of click reaction, amide condensation reaction, Suzuki coupling reaction, carbocation reaction, and Schiff base condensation reaction.

[0053] Optionally, the reaction conditions are: a reaction temperature of 25~110℃ and a reaction time of 12~48h.

[0054] Optionally, the reaction conditions are: a reaction temperature of 25~90℃ and a reaction time of 12~36h.

[0055] Optionally, the reaction conditions are: a reaction temperature of 50~70℃ and a reaction time of 12~36h.

[0056] Optionally, the linker precursor is a linker substituted with R1, wherein R1 is selected from at least one of azide, amino, bromine, acetone, and hydrazide.

[0057] Optionally, the chelating unit precursor contains a chelating unit with an R2 group, wherein R2 is selected from at least one of alkynyl, carboxylic acid, borate ester, trifluoro / trimethylethyl acetate, and aldehyde.

[0058] The chelating unit precursor used in this application reacts with the linking unit via relatively mature reaction methods such as click reaction, amide condensation reaction, Suzuki coupling reaction, carbanion reaction, and Schiff base condensation reaction to obtain the desired ligand. The reaction conditions are relatively mild, and the yield is high, ranging from 40% to 80%.

[0059] Optionally, the trivalent rare earth metal salt is Ln(OTf)3;

[0060] Where Ln is Yb 3+ Or, Yb 3+ With Sm 3+ Eu 3+ 、Tb 3+ Dy 3+ Ho 3+ Er 3+ Tm 3+ A combination of at least one of them.

[0061] Optionally, the molar ratio of rare earth metal elements to organic ligands in the trivalent rare earth metal salt is 1:0.67~2.

[0062] Optionally, the mixture may further comprise at least one solvent selected from acetonitrile, methanol, and nitromethane.

[0063] Optionally, the self-assembly conditions are: a reaction temperature of 40~60℃ and a time of 0.5~1h.

[0064] Optionally, the raw material mixture may further contain ketone sulfate and sodium ascorbate.

[0065] Optionally, the molar ratio of the sulfate ketone to the linker precursor is 0.8 to 1:1.

[0066] Optionally, the molar ratio of sodium ascorbate to the precursor of the connecting unit is 1.5 to 2.5:1.

[0067] Optionally, the raw material mixture further comprises at least one solvent selected from N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide / methanol.

[0068] According to another aspect of this application, an application is also provided for at least one of the above-described rare-earth upconversion luminescent materials or rare-earth upconversion luminescent materials prepared according to the above-described preparation method in the fields of bioimaging, drug delivery, or cancer cell diagnosis and treatment.

[0069] The beneficial effects that this application can produce include:

[0070] The rare-earth upconversion luminescent material provided in this application addresses the problem of achieving upconversion luminescence in polynuclear lanthanide supramolecular assemblies. It achieves supramolecular upconversion luminescence through an assembly-induced excited multi-merging state-mediated approach. Specifically: 1. Previous reports indicated that co-sensitized upconversion luminescence systems, whether molecular clusters or nanoparticles, require a distance of <5 Å between rare-earth ions. This application breaks the limitation that the distance between lanthanide ions must be limited to a few Å to effectively achieve upconversion luminescence. It utilizes an excited multi-merging state-mediated approach to achieve an effective long-range (>1.3 nm) energy transfer process between rare-earth ions; 2. It fills the gap in the ability of excited states of organic ligands to participate in energy transfer during upconversion luminescence, providing a new approach for the design of novel upconversion luminescent materials; 3. The novel design strategy for upconversion luminescent materials developed in this application is crucial for developing the photofunctionality of multi-component lanthanide organic complexes, and is expected to make lanthanide organic components novel upconversion luminescent materials for biological applications, enriching the broader application prospects of the rare-earth supramolecular field. Attached Figure Description

[0071] Figure 1 The ligands L1 and L2 in Example 1 of this application S Self-assembly process and assembly Ln8(L1) 12 and Ln8(L2) S ) 12 Its single-crystal structure.

[0072] Figure 2This is the concentration-dependent emission spectrum of test example 1 in this application, where (a) is the emission spectrum of ligand L2. S Concentration-dependent emission spectrum (chloroform, λ) ex = 305 nm), (b) is Gd8(L2) S ) 12 (acetonitrile, λ) ex Concentration-dependent emission spectrum (335 nm).

[0073] Figure 3 This is the change in upconversion luminous intensity with power density in Test Example 2 of this application, where (a) is solid-state Yb8(L2) S ) 12 (a) The upconversion emission intensity varies with power density; (b) is the upconversion emission intensity (I) at 500 nm. up (a) is a log-log plot of laser power density (P); (b) is a diagram of the co-sensitization upconversion mechanism from Ln to excited multi-state, where E* and E represent the unrelaxed and relaxed excited multi-states, respectively.

[0074] Figure 4 This is the change in upconversion luminescence intensity with power density in Test Example 2 of this application, where (a) is the solid-state (Yb / Eu)8(L1). 12 The graph shows the change in upconversion luminous intensity as a function of power density. (b) represents (Yb / Eu)⁸(L²) S ) 12 (b) Graph showing the change of upconversion emission intensity with power density; (c) Graph showing the log-log graph of upconversion emission intensity with laser power density; (d) Graph showing the mechanism of co-sensitization upconversion mediated by excited multi-state. Detailed Implementation

[0075] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0076] Unless otherwise specified, all chemical reagents and solvents used in the embodiments of this application are commercially available and have not been further purified before use. The deuterated solvents were purchased from Adamas and Bailingwei Technology Co., Ltd.

[0077] The organic ligands described in this application can all be obtained by reacting the linker precursor and chelate precursor described in this application, wherein the linker precursor and chelate precursor can be synthesized by existing technology.

[0078] The analysis method in the embodiments of this application is as follows:

[0079] One-dimensional and two-dimensional NMR spectra were measured using a Bruker Biospin Avance III (400 MHz) NMR analyzer. The chemical shift values ​​in the proton NMR spectrum were determined based on the residual peaks of the deuterated solvent. High-resolution mass spectrometry (ESI-TOF-MS) was performed using a Bruker Impact II UHR-TOF mass spectrometer. UV-Vis spectroscopy was performed using a Shimadzu UV-2700 UV-Vis spectrophotometer. Excitation and emission spectra were performed using an Edinburgh FS5 spectrometer. Fluorescence quantum yield was determined using an Edinburgh SC-30 integrating sphere. Upconversion spectral data were obtained using an Edinburgh FLS980 and FLS1000 spectrometer.

[0080] Example 1: Preparation of ligands L1 and L2 S

[0081] In this embodiment, ligand L2 S Obtained through the following methods:

[0082] .

[0083] The specific preparation process is as follows: 1,5-diazidonaphthalene (250 mg, 1.19 mmol) and S-6-ethynyl-N-(1-phenylethyl)pyridine amide (626 mg, 2.50 mmol) are added to sodium ascorbate (476 mg, 2.5 mmol) and CuSO4. The reaction mixture was added to a 50 mL solution of DMF containing 268 mg (1.07 mmol) of 5H₂O. The reaction mixture was stirred at 60 °C for 24 hours. The reaction mixture was filtered, and the filtrate was distilled under reduced pressure and further separated by column chromatography (eluent: V(dichloromethane) / V(methanol) = 100:1) to give a pale yellow solid powder (520 mg, yield 62%). NMR results were as follows: 1H NMR (400 MHz, CDCl3,298 K) δ = 8.52 (s, 2H), 8.47 (d, J = 7.8, 2H), 8.25 (d, J = 7.8, 2H), 8.20(d, J = 8.4 Hz, 2H), 8.05 (t, J1= 15.6 Hz, J2= 7.8 Hz, 2H), 7.93 (d, J = 8.0Hz, 2H), 7.80 (d, J = 8.0 Hz, 2H), 7.73 (t, J1= 16.0 Hz, J2= 8.0 Hz, 2H), 7.41(d, J = 7.2 Hz, 4H), 7.34 (t, J1= 14.4 Hz, J2= 7.2 Hz, 4H), 7.27 (d, J = 7.2Hz, 2H), 5.42 – 5.35 (m, 2H), 1.64 (d, J = 6.8 Hz, 6H). 13 C NMR (101 MHz, CDCl3, 298 K) δ = 163.3, 150.0, 148.5, 148.0, 143.2, 138.7, 134.0, 129.7,128.8, 127.5, 127.3, 126.4, 125.5, 125.1, 125.1, 123.3, 122.2, 48.8, 21.9.ESI-TOF-MS for C 42 H 34 N 10 O2[M + Na] + : calcd, m / z = 733.2758; found 733.2751.

[0084] In this embodiment, ligand L1 is obtained in the following manner:

[0085] .

[0086] The specific preparation process is as follows: 1,5-diazidonaphthalene (120 mg, 0.57 mmol) and 6-ethynyl-N-isopropylpyridine amide (226 mg, 1.20 mmol) are added to sodium ascorbate (228 mg, 1.2 mmol) and CuSO4. The reaction mixture was added to a 50 mL solution of DMF containing 130 mg of 5H₂O (0.52 mmol). The reaction mixture was stirred at 60 °C for 24 hours. The reaction mixture was filtered, and the filtrate was distilled under reduced pressure and further separated by column chromatography (eluent: V(dichloromethane) / V(methanol) = 50:1) to give a pale yellow solid powder (152 mg, yield 45%). NMR results were as follows: 1 H NMR (400 MHz, CDCl3, 298 K) δ= 8.59 (s, 2H), 8.44 (d, J = 7.8 Hz, 2H), 8.23 ​​(d, J = 7.8 Hz, 2H), 8.03 (t, J 1 = 15.6 Hz J 2 = 7.8 Hz, 2H), 7.94 (d, J = 8.4 Hz, 2H), 7.81 (dd, J 1 = 8.4 Hz J 2 = 8.4Hz, 4H), 7.74 (t, J 1 = 16.8 Hz J 2= ​​8.4 Hz, 2H), 4.35 – 4.24 (m, 2H), 1.28 (d, J =6.4 Hz, 12H). 13 C NMR (101 MHz, CDCl3, 298 K) δ = 163.2, 150.2, 148.4, 148.1,138.7, 134.1, 129.8, 127.4, 125.5, 125.2, 125.1, 123.1, 122.1, 41.6, 22.9.ESI-TOF-MS for C 32 H 30 N 10 O2[M + Na] + : calcd, m / z = 609.2445; found, 609.2424.

[0087] Examples 2-5 are lanthanide polynuclear complexes Ln8(L2) S ) 12 Synthesis of (Ln=Eu, Gd, Yb, Yb / Eu)

[0088] Example 2: Concave octahedron Eu8(L2) S ) 12 (OTf) 24 Synthesis

[0089] L2 S (15.0 mg, 21.1 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 1 mL), and then Eu(OTf)3 (8.4 mg, 14.1 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. Tetrahydrofuran vapor was slowly diffused into the solution, and after two weeks, colorless rod-shaped crystals (13.0 mg, yield 56%) were obtained. L2 S The tridentate chelating group on the rare earth ion Eu 3+ The three-strand spiral nine-coordinate pattern is as follows: Figure 1 As shown. The single crystal was dissolved in a CD3CN / CD3OD mixed solution (v / v = 4 / 1, 500 μL) for characterization. Due to signal overlap and low signal-to-noise ratio, 1 The H NMR spectrum (400 MHz, 298 K) was too complex to be assigned. 13 The 12C NMR signal was too weak to be detected. However, the presence of a single species was confirmed by two-dimensional DOSY spectra. Eu8(L2) S ) 12 (OTf) 24 The ESI-TOF-MS detection result is: m / zcalcd for [Eu8(L2) S ) 12 (OTf) 19 ] 5+ 2515.3809, found 2515.3817; calcd for [Eu8(L2 S ) 12 (OTf) 18 ] 6+ 2071.3253, found 2071.3266; calcd for [Eu8(L2 S ) 12 (OTf) 17 ] 7+ 1754.1428,found 1754.1442; calcd for [Eu8(L2 S ) 12 (OTf) 16 ] 8+ 1516.2559, found 1516.2571;calcd for [Eu8(L2 S ) 12 (OTf) 15 ] 9+1331.2328, found 1331.2341; calcd for [Eu8(L2 S ) 12 (OTf) 14 ] 10+ 1183.2143, found 1183.2153.

[0090] Example 3: Concave octahedron Gd8(L2) S ) 12 (OTf) 24 Synthesis

[0091] L2 S (11.2 mg, 15.7 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Gd(OTf)3 (6.3 mg, 10.5 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. DCM was slowly diffused into the solution, and after one week, a white amorphous powder (12.6 mg, yield 72%) was obtained. The powder was dissolved in a CH3CN / CH3OH mixed solution for characterization. Gd8(L2) S ) 12 (OTf) 24 The ESI-TOF-MS detection result is: m / z calcd for [Gd8(L2) S ) 12 (OTf) 19 ] 5+ 2523.9865, found 2523.9841; calcd for [Gd8(L2 S ) 12 (OTf) 18 ] 6+ 2078.3299, found 2078.3276; calcd for [Gd8(L2 S ) 12 (OTf) 17 ] 7+ 1760.1467, found 1760.1451; calcd for [Gd8(L2 S ) 12 (OTf) 16 ] 8+ 1521.5093, found1521.5083; calcd for [Gd8(L2 S ) 12 (OTf) 15 ]9+ 1335.9025, found 1335.9020; calcd for[Gd8(L2 S ) 12 (OTf) 14 ] 10+ 1187.4170, found 1187.4169.

[0092] Example 4: Concave octahedron Yb8(L2) S ) 12 (OTf) 24 The synthesis will L2 S (13.3 mg, 18.7 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Yb(OTf)3 (7.7 mg, 12.5 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. DCM was slowly diffused into the solution, and after one week, a white amorphous powder (17.8 mg, yield 85%) was obtained. The powder was dissolved in a mixed solution of CH3CN / CH3OH for characterization. Yb8(L2) S ) 12 (OTf) 24 The ESI-TOF-MS detection result is: m / z calcd for [Yb8(L2) S ) 12 (OTf) 17 ] 7+ 1778.1628, found 1778.1622; calcd for [Yb8(L2 S ) 12 (OTf) 16 ] 8+ 1537.2734, found1537.2731; calcd for [Yb8(L2 S ) 12 (OTf) 15 ] 9+ 1349.9150, found 1349.9162; calcd for[Yb8(L2 S ) 12 (OTf) 14 ] 10+ 1200.0283, found 1200.0285; calcd for [Yb8(L2 S ) 12 (OTf) 13 ] 11+1077.3937, found 1077.3964; calcd for [Yb8(L2 S ) 12 (OTf) 12 ] 12+ 975.1982, found975.1987.

[0093] Example 5: Hybrid assembly Yb 8-x Eu x (L2 S ) 12 (OTf) 24 ( x Synthesis of (= 0~8)

[0094] L2 S (25.0 mg, 35.2 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Eu(OTf)3 (1.8 mg, 2.9 μmol) and Yb(OTf)3 (12.7 mg, 20.5 μmol) were added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. DCM was slowly diffused into the solution, and after one week, a white amorphous powder (31.3 mg, yield 79%) was obtained. The powder was dissolved in a mixed solution of CH3CN / CH3OH for characterization. ESI-TOF-MS confirmed the presence of the mixed assembly, and the detection result was: m / z calcd for [Yb8(L2 S ) 12 (OTf) 17 ] 7+ 1778.1628,found 1778.1623; calcd for [Yb8(L2 S ) 12 (OTf) 16 ] 8+ 1537.2734, found 1537.2734;calcd for [Yb8(L2 S ) 12 (OTf) 15 ] 9+ 1349.9150, found 1349.9144; calcd for [Yb8(L2 S ) 12 (OTf) 14 ] 10+ 1200.0283, found 1200.0271; calcd for [Yb8(L2 S )12 (OTf) 13 ] 11+ 1077.3937,found 1077.3940; calcd for [Yb8(L2 S ) 12 (OTf) 12 ] 12+ 975.1982, found 975.1974; calcdfor [Yb8(L2 S ) 12 (OTf) 11 ] 13+ 888.7251, found 888.7245. m / z calcd for [Yb7Eu1(L2 S ) 12 (OTf) 17 ] 7+ 1775.1603, found 1775.1596; calcd for [Yb7Eu1(L2 S ) 12 (OTf) 16 ] 8+ 1534.6463,found 1534.6437; calcd for [Yb7Eu1(L2 S ) 12 (OTf) 15 ] 9+ 1347.5797, found 1347.5787;calcd for [Yb7Eu1(L2 S ) 12 (OTf) 14 ] 10+ 1197.9265, found 1197.9261; calcd for [Yb7Eu1(L2 S ) 12 (OTf) 13 ] 11+ 1075.4830, found 1075.4817; calcd for [Yb7Eu1(L2 S ) 12 (OTf) 12 ] 12+ 973.4467, found 973.4474; calcd for [Yb7Eu1(L2 S ) 12 (OTf) 11 ] 13+887.1083, found887.1081. m / z calcd for [Yb6Eu2(L2 S ) 12 (OTf) 17 ] 7+ 1772.1578, found 1772.1522;calcd for [Yb6Eu2(L2 S ) 12 (OTf) 16 ] 8+ 1532.0191, found 1532.0198; calcd for [Yb6Eu2(L2 S ) 12 (OTf) 15 ] 9+ 1345.2445, found 1345.2453; calcd for [Yb6Eu2(L2 S ) 12 (OTf) 14 ] 10+ 1195.8248, found 1195.8260; calcd for [Yb6Eu2(L2 S ) 12 (OTf) 13 ] 11+ 1073.5723, found1073.5762; calcd for [Yb6Eu2(L2 S ) 12 (OTf) 12 ] 12+ 971.6953, found 971.6976; calcd for[Yb6Eu2(L2 S ) 12 (OTf) 11 ] 13+ 885.4916, found 885.4934. m / z calcd for [Yb5Eu3(L2 S ) 12 (OTf) 17 ] 7+ 1769.1553, found 1772.1554; calcd for [Yb5Eu3(L2 S ) 12 (OTf) 16 ] 8+1529.3919,found 1529.3955; calcd for [Yb5Eu3(L2 S ) 12 (OTf) 15 ] 9+ 1342.9092, found 1342.9104;calcd for [Yb5Eu3(L2 S ) 12 (OTf) 14 ] 10+ 1193.7230, found 1193.7280; calcd for [Yb5Eu3(L2 S ) 12 (OTf) 13 ] 11+ 1071.6623, found 1071.6663; calcd for [Yb5Eu3(L2 S ) 12 (OTf) 12 ] 12+ 969.9438, found 969.9497; calcd for [Yb5Eu3(L2 S ) 12 (OTf) 11 ] 13+ 883.8749, found883.8813.

[0095] Examples 6-9 are lanthanide polynuclear complexes Ln8(L1). 12 Synthesis of (Ln=Eu, Gd, Yb, Yb / Eu)

[0096] Example 6: Rhombohedral Eu8(L1) 12 (OTf) 24 Synthesis

[0097] L1 (12.8 mg, 21.8 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 1 mL), and then Eu(OTf)3 (8.7 mg, 14.6 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. Dichloromethane vapor was slowly diffused into the solution, and after two weeks, colorless flaky crystals (15.8 mg, 74% yield) were obtained. The single crystals were dissolved in a mixed solution of CD3CN / CD3OD / CDCl3 (v / v / v = 4 / 1 / 1, 500 μL) for characterization. 1The HNMR spectrum (400 MHz, 298 K) shows a set of peaks containing 60 protons. 13 The 12C NMR signal was too weak to be detected. However, the existence of a single species was confirmed by two-dimensional DOSY spectra. Eu8(L1) 12 (OTf) 24 The ESI-TOF-MS detection results are: m / z calcd for [Eu8(L1)] 12 (OTf) 19 ] 5+ 2217.5050, found 2217.5067; calcd for[Eu8(L1) 12 (OTf) 18 ] 6+ 1823.0954, found 1823.0978; calcd for [Eu8(L1) 12 (OTf) 17 ] 7+ 1541.3743, found 1541.3769; calcd for [Eu8(L1) 12 (OTf) 16 ] 8+ 1330.0835, found1330.0861; calcd for [Eu8(L1) 12 (OTf) 15 ] 9+ 1165.7462, found 1165.7486; calcd for[Eu8(L1) 12 (OTf) 14 ] 10+ 1034.1762, found 1034.1784.

[0098] Example 7: Rhombohedral Gd8(L1) 12 (OTf) 24 Synthesis

[0099] L1 (10.0 mg, 17.1 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Gd(OTf)3 (6.9 mg, 11.37 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. Dichloromethane vapor was slowly diffused into the solution, and after one week, a white amorphous powder (8.8 mg, yield 52%) was obtained. The powder was dissolved in a CH3CN / CH3OH mixed solution for characterization. Gd8(L1)12 (OTf) 24 The ESI-TOF-MS detection results are: m / z calcd for [Gd8(L1)] 12 (OTf) 19 ] 5+ 2225.9104, found 2225.9087; calcdfor [Gd8(L1) 12 (OTf) 18 ] 6+ 1830.0999, found 1830.0988; calcd for [Gd8(L1) 12 (OTf) 17 ] 7+ 1547.3782, found 1547.3774; calcd for [Gd8(L1) 12 (OTf) 16 ] 8+ 1335.3369, found1335.3370; calcd for [Gd8(L1) 12 (OTf) 15 ] 9+ 1170.4158, found 1170.4161; calcd for[Gd8(L1) 12 (OTf) 14 ] 10+ 1038.4790, found 1038.4796; calcd for [Gd8(L1) 12 (OTf) 13 ] 11+ 930.5307, found 930.5318; calcd for [Gd8(L1) 12 (OTf) 12 ] 12+ 840.4904, found840.4912.

[0100] Example 8: Rhombohedral Yb8(L1) 12 (OTf) 24 Synthesis

[0101] L1 (10.7 mg, 18.3 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Yb(OTf)3 (7.5 mg, 12.2 μmol) was added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. Dichloromethane vapor was slowly diffused into the solution, and after one week, a white amorphous powder (2.5 mg, yield 14%) was obtained. The powder was dissolved in a CH3CN / CH3OH mixed solution for characterization. Yb8(L1) 12 (OTf) 24 The ESI-TOF-MS detection results are: m / z calcd for [Yb8(L1)] 12 (OTf) 19 ] 5+ 2251.1330, found 2251.1300; calcdfor [Yb8(L1) 12 (OTf) 18 ] 6+ 1851.1188, found 1851.1164; calcd for [Yb8(L1) 12 (OTf) 17 ] 7+ 1565.3943, found 1565.3936; calcd for [Yb8(L1) 12 (OTf) 16 ] 8+ 1351.1010, found1351.1009; calcd for [Yb8(L1) 12 (OTf) 15 ] 9+ 1184.4284, found 1184.4285; calcd for[Yb8(L1) 12 (OTf) 14 ] 10+ 1051.0903, found 1051.0906; calcd for [Yb8(L1) 12 (OTf) 13 ] 11+ 941.9956, found 941.9957; calcd for [Yb8(L1) 12 (OTf) 12 ] 12+ 851.0832, found851.0842.

[0102] Example 9: Rhombohedron Yb 8-x Eu x (L1) 12 (OTf) 24 ( x Synthesis of (= 0~8)

[0103] L1 (10.2 mg, 17.4 μmol) was suspended in a mixed solution of CH3CN / CH3OH (v / v = 4 / 1, 500 μL), and then Eu(OTf)3 (0.9 mg, 1.5 μmol) and Yb(OTf)3 (6.3 mg, 10.2 μmol) were added. The suspension was heated at 50 °C for 1 hour to obtain a clear yellow solution. Dichloromethane vapor was slowly diffused into the solution, and after one week, a white amorphous powder (8.0 mg, yield 46%) was obtained. The powder was dissolved in a CH3CN / CH3OH mixed solution for characterization. ESI-TOF-MS confirmed the presence of the mixed assembly, and the detection results were: m / z calcd for [Yb8(L1)]. 12 (OTf) 19 ] 5+ 2251.1330, found 2251.1323; calcd for [Yb8(L1) 12 (OTf) 18 ] 6+ 1851.1188, found1851.1174; calcd for [Yb8(L1) 12 (OTf) 17 ] 7+ 1565.3943, found 1565.3939; calcd for[Yb8(L1) 12 (OTf) 16 ] 8+ 1351.1010, found 1351.1011; calcd for [Yb8(L1) 12 (OTf) 15 ] 9+ 1184.4284, found 1184.4290; calcd for [Yb8(L1) 12 (OTf) 14 ] 10+ 1051.0903, found1051.0911; calcd for [Yb8(L1) 12 (OTf) 13 ] 11+941.9956, found 941.9967. m / z calcdfor [Yb7Eu1(L1) 12 (OTf) 19 ] 5+ 2246.9295, found 2246.9287; calcd for [Yb7Eu1(L1) 12 (OTf) 18 ] 6+ 1847.6159, found 1847.6149; calcd for [Yb7Eu1(L1) 12 (OTf) 17 ] 7+ 1562.3918,found 1562.3916; calcd for [Yb7Eu1(L1) 12 (OTf) 16 ] 8+ 1348.4738, found 1348.4742;calcd for [Yb7Eu1(L1) 12 (OTf) 15 ] 9+ 1182.0931, found 1182.0941; calcd for [Yb7Eu1(L1) 12 (OTf) 14 ] 10+ 1048.9886, found 1048.9891; calcd for [Yb7Eu1(L1) 12 (OTf) 13 ] 11+ 940.0849, found 940.0862. m / z calcd for [Yb6Eu2(L1) 12 (OTf) 19 ] 5+ 2242.7260, found2242.7267; calcd for [Yb6Eu2(L1) 12 (OTf) 18 ] 6+ 1844.1129, found 1844.1120; calcdfor [Yb6Eu2(L1) 12 (OTf) 17 ] 7+ 1559.3893, found 1559.3889; calcd for [Yb6Eu2(L1) 12(OTf) 16 ] 8+ 1345.8466, found 1345.8470; calcd for [Yb6Eu2(L1) 12 (OTf) 15 ] 9+ 1179.7578,found 1179.7588; calcd for [Yb6Eu2(L1) 12 (OTf) 14 ] 10+ 1046.8868, found 1046.8882;calcd for [Yb6Eu2(L1) 12 (OTf) 13 ] 11+ 938.1742, found 938.1756. m / z calcd for [Yb5Eu3(L1) 12 (OTf) 19 ] 5+ 2238.5225, found 2238.5193; calcd for [Yb5Eu3(L1) 12 (OTf) 18 ] 6+ 1840.6100, found 1840.6078; calcd for [Yb5Eu3(L1) 12 (OTf) 17 ] 7+ 1556.3868, found1556.3868; calcd for [Yb5Eu3(L1) 12 (OTf) 16 ] 8+ 1343.2194, found 1343.2194; calcdfor [Yb5Eu3(L1) 12 (OTf) 15 ] 9+ 1177.4217, found 1177.4236; calcd for [Yb5Eu3(L1) 12 (OTf) 14 ] 10+ 1044.7851, found 1044.7868; calcd for [Yb5Eu3(L1) 12 (OTf) 13 ] 11+ 936.2635,found 936.2652。

[0104] Test Example 1: Ligands L1 and L2 S Down-transfer luminescence performance test of assemblies from Examples 2-9

[0105] L2 ligand S In a diluted chloroform solution (10 μM), UV-Vis spectra showed absorptions at 250 nm and 300 nm that could be assigned to ligand monomer π-π* transitions. However, with increasing concentration, a low-energy absorption tail appeared in the 380–500 nm range due to spontaneous aggregation of the ligand in solution. With increasing concentration, L2… S The changes in fluorescence spectra were more pronounced, with not only the expected singlet emission observed at 370 nm, but also dimer emission observed in the 450-700 nm range. The isoemission point at 407 nm confirmed the conversion between monomer and dimer. Figure 2 a). For Gd8(L2) S ) 12 Besides the residual fluorescence of the ligand monomer observed at 370 nm, a broad emission of the excited multimer was observed at 500 nm. The absence of an isoabsorption point with varying concentration indicates that the excited multimer is an excited state formed by electronic coupling between ligands in the concave octahedral cage through π-π interactions. Figure 2 b). Eu8(L2) S ) 12 Characteristic emission peaks are located at 580, 594, 616, 650, and 693 nm, corresponding to [missing information]. 5 D0→ 7 F J Absorption of transitions (J = 0, 1, 2, 3, 4) with a quantum yield as high as 75.2%. Yb8(L2) S ) 12 The emission spectrum showed ligand monomer fluorescence at 370 nm, assembly-induced multimer emission at 500 nm, and Yb-centered fluorescence at 978 nm. 2 F 5 / 2 → 2 F 7 / 2 The coexistence of three luminescent centers. Furthermore, a long-wavelength excitation window (up to 450 nm) can promote Yb transitions. 3+ The emission indicates the sensitization pathway of the excited multiplying state induced by assembly.

[0106] With L2 SSimilarly, in a diluted chloroform solution (10 μM), the UV-Vis spectrum of ligand L1 showed absorptions at 250 nm and 300 nm that could be allocated to ligand monomer π-π* transitions. However, with increasing concentration, the fluorescence spectrum of L1 only observed singlet emission at 370 nm, with no dimer emission. For Gd8(L1)... 12 At room temperature, only residual fluorescence of the ligand monomer at 370 nm was observed, with no obvious emission signal from the excited multimer. Eu8(L1) 12 Characteristic emission peaks are located at 580, 594, 616, 650, and 693 nm, corresponding to [missing information]. 5 D0→ 7 F J The absorption of the transition (J=0,1,2,3,4) has a higher fluorescence quantum yield than Eu8(L2). S ) 12 The highest was 79.9%. Yb8(L1) 12 The emission spectrum only showed ligand monomer fluorescence at 370 nm and Yb center fluorescence at 978 nm. 2 F 5 / 2 → 2 F 7 / 2 Leap forward.

[0107] The emission positions of all assemblies obtained from both CH3CN solution and solid powder were consistent. The quantum yield and upconversion luminescence performance were significantly improved under solid-state conditions, particularly for the lanthanide polynuclear complex Ln8(L2) under solid-state conditions. S ) 12 and Ln8(L1) 12 The down-transfer optical data are shown in Table 1, where λ ex The wavelength τ represents the maximum excitation wavelength, and τ represents the emission lifetime. This represents the quantum yield of rare earth center luminescence.

[0108] Table 1. Measurement data of downtransfer optical properties of lanthanide polynuclear complexes under solid conditions.

[0109]

[0110] via Ln8(L2) S ) 12 and Ln8(L1) 12 In comparing the down-transfer luminescence properties, the applicant found that minute changes in the substituents around the ligands led to different topological structures in the two assemblies, namely Ln8(L2). S ) 12 The concave octahedral structure and Ln8(L1) 12 The rhombohedral structure. It is precisely because of the different topological structures that the Ln8(L2) structure...S ) 12 Within the molecular cage, ligands exhibit distinct excited multipolymer characteristics through multiple weak interactions (primarily π-π stacking). Therefore, substituent effects and assembly-induced configurational and topological changes jointly determine the composition of Ln8(L2). S ) 12 The significant characteristics of excited multi-state polymers.

[0111] Test Example 2: Ligands L1 and L2 S Upconversion luminescence performance test of assemblies from Examples 2-9

[0112] In Ln8(L2) S ) 12 The average distance between the two lanthanide ions was 13.99 ± 0.52 Å. Yb8(L2) was observed to be fused with a 980 nm continuous-wave laser at room temperature. S ) 12 Broadband emission from the excited multiplying state is evident in the solid state, with a maximum emission wavelength of 500 nm. Figure 3 a). The quadratic dependence of upconversion luminescence intensity on laser power density is consistent with the mechanism of two-photon upconversion ( Figure 3 b). To prove that it is an upconversion emission of the excited multiphase state ( Figure 3 c) Rather than a mechanism of co-luminescence by two Yb molecules, the upconversion lifetime was tested to be 3.6 µs, which is not the lifetime of the Yb molecules. 3+ The lifetime was half that of the previous one (12.35 μs), ruling out co-luminescence. This significant lifetime increase, compared to the excited multiphase lifetime observed in the downconversion (2.87 ns), is associated with the slow population of the excited multiphase energy levels during the upconversion process. The energy transfer process can be represented as: (Yb * +Yb * → Excite the multi-state ( * (Indicates an excited state).

[0113] Part of Yb 3+ Eu with better luminescence properties 3+ This alternative method avoids energy loss caused by energy backflow and more effectively transfers the energy of the excited multiphase state to Eu. 3+ The excited state. Therefore, in the mixed assembly Yb 8-x Eu x (L2 S ) 12 ( x = 0 In 8), Eu was observed under 980 nm continuous laser excitation. 3+Characteristic red light emission and characteristic green light emission of the 500 nm excited multi-state polymer, dual emission centers ( Figure 4 b). The slopes at 618 nm and 500 nm are close to 2, consistent with the two-photon upconversion mechanism. Figure 4 c). The energy transfer process in this process is as follows: (Yb * +Yb * → Excited multi-state → Eu * ( Figure 4 d).

[0114] Yb8(L1) is excited at room temperature by a continuous laser at 980 nm. 12 No upconversion signal was observed. Based on experimental analysis, Yb8(L1) 12 Compared to Yb8(L2) S ) 12 The higher sensitization efficiency and weaker residual polymer emission indicate that L1 is effective for Yb. 3+ The excited state of ions exhibits better energy transfer, which is beneficial for efficient antenna sensitization processes. Therefore, it can lead to unfavorable energy backpropagation during upconversion, resulting in Yb8(L1) degradation. 12 There is no upconversion signal.

[0115] Part of Yb 3+ Eu with better luminescence properties 3+ This alternative method avoids energy loss caused by energy backflow and more effectively transfers energy to Eu. 3+ Therefore, in the mixed assembly Yb 8-x Eu x (L1) 12 ( x = 0 In 8), although the distance between two neighboring lanthanide ions is 14.33 ± 0.08 Å, 980 nm laser excitation still achieved Eu. 3+ Characteristic red light emission ( Figure 4 a) Due to the "saturation effect," when the excitation light power density is greater than 24.06 W·cm², -2 At that time, the slope of the upconversion luminescence intensity at 618 nm changes from 2 to 1 with respect to power density. Figure 4 c).

[0116] Although the distance between lanthanide ions in both cases exceeded 1.3 nm, which is theoretically very unfavorable for upconversion luminescence, good upconversion luminescence signals were observed in both cases, and the discussion of the mechanism is crucial: (1) Under 980 nm excitation, Eu8(L1) 12 and Eu8(L2) S ) 12No upconversion emission was observed, ruling out the two-photon absorption upconversion mechanism at the ligand center. (2) 7 equivalents of Yb8L 12 and 1 equivalent of Eu8L 12 Eu was not observed in the physical mixture of the assembled components. 3+ The upconversion launch at the center confirmed Yb 3+ →Eu 3+ Energy transfer is an intramolecular process, not an intermolecular process. (3) Tb 3+ ( 5 D4→ 7 The band gap of F0 is greater than that of Eu. 3+ ( 5 D0→ 7 F6), which makes the former less susceptible to quenching by high-energy vibrations of organic ligands than the latter. Therefore, in lanthanide organic materials, the upconversion efficiency of (Yb)2→Tb is usually higher than that of Eu. 3+ However, in this embodiment and comparative example, Tb was not observed. 3+ Co-sensitized luminescence centered on Ln indicates that 3+ Direct energy transfer between ions is not possible in our system. (4) Most importantly, with (Yb / Eu)8(L2) S ) 12 Eu 3+ With increasing doping ratio, the time-resolved upconversion lifetime at 500 nm gradually decreases, indicating a transition from the excited multiphase state to the Eu phase. 3+ The energy transfer efficiency increases accordingly. All of the above evidence clearly points to an excited multi-state-mediated cooperative sensitization upconversion mechanism, rather than the traditional two Ln... 3+ Direct energy transfer between ions.

[0117] The design concept of the upconversion luminescent material in this application is that, under the condition of satisfying the requirements of multi-component complexes and suitable excited state energy levels of organic ligands, multi-component rare earth complex luminescent materials can fully coordinate the advantages of each component, and have the characteristics of assembly-induced new excited state luminescence and even luminescence enhancement. This provides a unique advantage for exploring how the excited state of ligands participates in the energy transfer process during rare earth upconversion luminescence. The energy levels of the organic ligands that meet the excited state energy level requirements described in this application are related to the two Yb... 3+ The energy levels of the ion-coordinated energy transfer are matched to fully meet the design and upconversion luminescence conditions of the upconversion luminescent material of this application. Therefore, in addition to the L1 and L2 ligands described in the embodiments, other organic ligands described or defined in this application, after being assembled into rare earth complexes, satisfy the requirement of having an excited state energy level of less than or equal to 20408 cm-1, have the same effect as the L1 and L2 ligands and can all achieve the upconversion luminescent material performance of the multi-component complex of this application.

[0118] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A rare-earth upconversion luminescent material, characterized in that, The rare earth upconversion luminescent material comprises a multi-component complex Ln8L 12 ; Ln is selected from one or a mixture of two of Eu, Gd, and Yb; L is L1or L2 S ; The upconversion luminescence excitation wavelength of the rare-earth upconversion luminescent material is 980 nm; The multi-component complex Ln8L 12 comprises an energy level of the excited state less than or equal to 20408 cm -1 -1; The rare earth upconversion luminescence is Yb 3+ After the sensitizer is excited, it transfers energy to the excited state of the organic ligand, and the organic ligand then undergoes upconversion luminescence. The excited state of the organic ligand is selected from at least one of the singlet state, triplet state, and excited polymeric state.

2. The rare-earth upconversion luminescent material according to claim 1, characterized in that, The multi-component complex Ln8L 12 The structural formula is shown in Equation I-8: Formula I-8 Among them, the sphere represents the trivalent rare earth metal ion Ln. 3+ In an edge or polyhedron, the face composed of edges represents the organic ligand L.

3. The rare-earth upconversion luminescent material according to claim 1, characterized in that, The rare earth upconversion luminescent material is a rare earth cage-like upconversion luminescent material.

4. A method for preparing the rare-earth upconversion luminescent material according to any one of claims 1 to 3, characterized in that, Includes the following steps: Obtain the organic ligand L; The rare-earth upconversion luminescent material is obtained by self-assembling a mixture containing trivalent rare-earth metal salt Ln(OTf)3 and organic ligand L.

5. The preparation method according to claim 4, characterized in that, The acquisition of organic ligands includes: The mixture of feedstock containing 1,5-diazidonaphthalene and chelating unit precursors was reacted to obtain the following: The chelating unit precursor is selected from at least one of S-6-ethynyl-N-(1-phenylethyl)pyridine amide and 6-ethynyl-N-isopropylpyridine amide.

6. The preparation method according to claim 5, characterized in that, The molar ratio of 1,5-diazidonaphthalene to the chelating unit precursor is 1:2~4.

7. The preparation method according to claim 5, characterized in that, The reaction conditions are: reaction temperature of 25~110℃ and reaction time of 12~48h.

8. The preparation method according to claim 4, characterized in that, The molar ratio of rare earth metal element Ln to organic ligand L in the trivalent rare earth metal salt Ln(OTf)3 is 1:0.67~2.

9. The preparation method according to claim 6, characterized in that, The self-assembly conditions are: reaction temperature of 40~60℃ and time of 0.5~1h.

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