A method for preparing curved carbon nanoribbons by Pd-catalyzed HCl removal

Abstract

The present invention discloses a method for preparing curved carbon nanobelts by removing HCl by Pd catalysis, wherein the structure of the curved carbon nanobelts is shown as follows: wherein R is hydrogen, C 1‑20 Alkyl, C 1‑20 Alkoxy, mesitylene, phenyl or its large π extension derivative, n is 1 or 3. The product prepared by the method of the present invention can be regarded as a sidewall fragment of a (m, m)-type carbon nanotube. The present invention uses a compound with a borate group and a compound with a halogen to undergo Suzuki-Miyaura cross-coupling reaction and reductive aromatization reaction to obtain a carbon nanocyclic compound, and then further undergoes a Suzuki-Miyaura cross-coupling reaction and Pd-catalyzed deHCl to obtain armchair-type carbon nanobelts of different sizes. The synthesis method of the present invention is unique, the structure is novel, it has good photophysical properties, and it has potential applications in bottom-up growth of single-walled carbon nanotubes.

Description

Technical Field

[0001] The invention belongs to the technical field of organic materials, and particularly relates to a method for preparing curved carbon nanobelts by removing HCl through Pd catalysis. Background Art

[0002] Since Iijima discovered and analyzed the structure of carbon nanotubes (CNTs) in 1991, 1 Due to its outstanding mechanical, electrical and optical properties, it has attracted widespread attention and has been successfully used as electric field emission materials, batteries, scanning electron microscope probes, chemical sensors, hydrogen storage materials, etc. 2-4 However, the traditional method of preparing carbon nanotubes still has many limitations, such as the disordered structure, which can only produce a series of CNTs mixtures with different lengths, diameters and chirality, and the high separation cost, which is not suitable for large-scale preparation. 5-6 Therefore, in the past few years, the bottom-up synthesis approach has become a promising synthetic strategy and has attracted extensive attention in exploring different types of bent or cyclic structures.

[0003] In 2008, Jasti's group synthesized the first armchair carbon nanotube cross-section repeating unit with a defined diameter and chirality - cycloparaphenylene (CPPs). 7 Afterwards, Itami's research group 8 , Yamago 9 Research groups such as

[15] used different synthesis strategies to obtain CNTs cross-cut units with different diameters and chirality, which can be called carbon nanorings.

[0004] Carbon nanobelts (CNBs) are a type of carbon nanoring, which is a closed cyclic compound composed of fully fused benzene rings. It requires the cleavage of at least two CC bonds to destroy their ring structure. 11 . CNBs can be regarded as fused ring sidewall segments of single-walled carbon nanotubes, so they can be divided into armchair, zigzag and chiral carbon nanobelts according to the chiral index (n, m) of single-walled carbon nanotubes (SWCNTs). The CNBs structure not only retains important structural information such as the diameter and pitch of the corresponding CNTs, but is also an ideal template for constructing structurally uniform CNTs. It also has very interesting photophysical properties, such as size quantum effects, supramolecular properties and chirality. Moreover, it reveals important concepts such as aromaticity, conjugation and strain, and plays a unique role in the bottom-up synthesis of chirality-specific SWCNTs. In recent years, Itami's research team 10 A (6,6) carbon nanoribbon was successfully synthesized by iterative Wittig reaction and intramolecular Yamamoto coupling. This was the first organic synthesis of armchair-shaped carbon nanotube segments. Subsequently, Miao's team 11The synthesis of armchair (12,12) carbon nanotubes and the first chiral (18,12) carbon nanotube sidewall fragments via Suzuki coupling, reductive aromatization, and Scholl reaction was reported. In 2020, the Chi and Itami research groups independently reported the synthesis of the first zigzag carbon nanoribbons. 12,13 However, the current nanoribbon synthesis strategies are severely limited, and the reported methods all have low yields, which cannot provide material and experimental support for subsequent functionalization and applications.

[0005] References

[0006] [1]Iijima,S.,Helical Microtubules of Graphitic Carbon.Nature 1991,354(6348),56-58.

[0007] [2] Dresselhaus, MS; Dresselhaus, G.; Charlier, JC; Hernández, E. Electronic, thermal and mechanical properties of carbon nanotubes. Philos. Trans. R. Soc. London, Ser. A2004, 362, 2065-2098.

[0008] [3] Terrones, M. Carbon nanotubes: Synthesis and Properties, Electronic Devices and Other Emerging Applications. Int. Mater. Rev. 2013, 49, 325-377.

[0009] [4]Schroeder, V.; Savagatrup, S.; He, M.; Lin, S.; Swager, TMCarbon NanotubeChemical Sensors.Chem.Rev.2019,119,599-663.

[0010] [5]Guo, T.; Nikolaev, P.; Thess, A.; Colbert, DT; Smalley, REcatalytic growth of single-walled manotubes by laser vaporization. Chem. Phys. Lett., 1995, 243, 49-54.

[0011] [6]José-Yacamán,M.;Miki-Yoshida,M.;Rendón,L.;Santiesteban,J.G.Catalytic growth of carbon microtubules with fullerenestructure.Appl.Phys.Lett.,1993,62,657-659.

[0012] [7]Jasti,R.;Bhattacharjee,J.;Neaton,J.B.;Bertozzi,C.R.,Synthesis,characterization,and theory of[9]-,

[12] -,and

[18] cycloparaphenylene:carbonnanohoop structures.J.Am.Chem.Soc.2008,130(52),17646-17647.

[0013] [8]Takaba,H.;Omachi,H.;Yamamoto,Y.;Bouffard,J.;Itami,K.,SelectiveSynthesis of

[12] Cycloparaphenylene.Angew.Chem.Int.Ed.2009,48(33),6112-6116.

[0014] [9]Yamago,S.;Watanabe,Y.;Iwamoto,T.,Synthesis of[8]cycloparaphenylenefrom a square-shaped tetranuclear platinum complex.Angew.Chem.Int.Ed.2010,49(4),757-759.

[0015]

[10] Povie,G.;Segawa,Y.;Nishihara,T.;Miyauchi,Y.;Itami,K.,Synthesis ofa carbon nanobelt.Science 2017,356(6334),172-175.

[0016]

[11] Cheung, KY; Gui, S.; Deng, C.; Liang, H.;

[0017]

[12] Cheung KY,Watanabe K.,Segawa Y.,Itami K.,Synthesis of a ZigzagCarbon Nanobelt[J].Nat.Chem.,2021,13(3):255-259.

[0018]

[13] Han Y.,Dong SQ,Shao JW,Fan W.,Chi CY,Synthesis of aSidewall Fragment of A(12,0)Carbon Nanotube[J].Angew.Chem.,Int.Ed.,2021,60(5):2658-2662. Summary of the Invention

[0019] In view of this, the present invention aims to provide a method for preparing curved carbon nanoribbons (or armchair carbon nanoribbons) by Pd-catalyzed HCl removal. The present invention adopts a novel method to prepare armchair carbon nanoribbons, which can obtain two armchair carbon nanoribbons at one time, such as (12,12) carbon nanoribbons and (16,16) carbon nanoribbons at the same time. The synthesis method of the present invention is unique, the product purification method is simple, the yield is high, the solubility is good, and it exhibits good photophysical properties. As a sidewall fragment of single-walled carbon nanotubes, it has potential application in the bottom-up growth of single-configuration single-walled carbon nanotubes. In addition, considering that carbon nanotubes and related structures have significant electrical properties, the present invention has an organic conjugated π-extended structure and can be regarded as a sidewall fragment of (12,12) and (16,16) carbon nanotubes, and can therefore be used as an electron transport material for electronic devices.

[0020] The present invention adopts a novel Pd-catalyzed HCl removal method to prepare curved carbon nanobelts, the structure of which is shown as follows:

[0021]

[0022] wherein R is selected from hydrogen, C 1-20 Alkyl, C 1-20 Alkoxy, mesityl, phenyl or their large π-extended derivatives; the value of n is 1 or 3.

[0023] In a preferred embodiment, we take R as mesitylene and n as 1 or 3 for illustration.

[0024] The method of preparing curved carbon nanoribbons by Pd-catalyzed HCl removal of the present invention comprises the following steps:

[0025] Step 1: In a mixed solvent, in the presence of a catalyst (10% to 30%, the same below), a ligand (50% to 80%, the same below), a base (12 to 20%, the same below) and a phase transfer catalyst (20% to 30%), a Suzuki-Miyaura cross-coupling reaction is carried out with the compound represented by formula (II) and the compound represented by formula (III) (molar ratio 1:1) at a certain temperature, and a reductive aromatization reaction is carried out under acidic conditions and at room temperature to obtain the compound represented by formula (IV);

[0026] Step 2: In a pure organic solvent at a temperature below -40°C, converting OBn in the structure of the compound represented by formula (IV) to OH and performing a sulfonylation reaction to obtain a compound represented by formula (V);

[0027] Step 3: In a mixed solvent, in the presence of a catalyst and a base, subjecting the compound represented by formula (V) and the compound represented by formula (VI) to a Suzuki-Miyaura cross-coupling reaction at a certain temperature to obtain a compound represented by formula (VII);

[0028] Step 4: In a pure organic solvent, in the presence of a catalyst, a ligand and a base, the compound represented by formula (VII) undergoes an intramolecular elimination reaction at a certain temperature to obtain the target product represented by formula (I).

[0029] In step 1, the catalyst is a palladium catalyst selected from tetrakis(triphenylphosphine)palladium or tris(dibenzylideneacetone)dipalladium; the ligand is a phosphorus-based ligand, such as 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl; the base is potassium carbonate or sodium carbonate; and the phase transfer catalyst is tetra-n-butylammonium bromide.

[0030] In step 1, the mixed solvent is composed of toluene and water in a ratio of 10:1 to 25:1, V / V. The acidic condition is provided by stannic acid prepared by stannous chloride and hydrochloric acid in tetrahydrofuran.

[0031] In step 1, the reaction temperature of the Suzuki-Miyaura cross-coupling reaction is 60-120° C., and the reaction time is 1-5 days.

[0032] In step 2, the structure of the OBn group is The reagent used to convert to OH is a dichloromethane solution of boron trichloride or boron tribromide, and the reaction time is 9 hours.

[0033] In step 2, the reagents used for the sulfonylation reaction are dry pyridine and trifluoromethanesulfonic anhydride, and the reaction time is 12 hours.

[0034] In step 2, the pure organic solvent is dry dichloromethane.

[0035] In step 3, the catalyst is tetrakistriphenylphosphine palladium; the base is potassium carbonate or sodium carbonate; the mixed solvent is toluene and water; the reaction temperature is 60-120° C., and the reaction time is 1 to 5 days.

[0036] In step 4, the catalyst is a palladium catalyst, such as palladium acetate or palladium dichloride; the ligand is a phosphorus-based ligand, such as di-tert-butylmethylphosphonium tetrafluoroborate or tricyclohexylphosphine; the base is 1,8-diazabicycloundec-7-ene (DBU), cesium carbonate or 2,2-dimethylpropionic acid; the pure organic solvent is dry N,N-dimethylacetamide; the reaction temperature is 60-120° C., and the reaction time is 1 to 5 days.

[0037] In step 4, the reaction vessel used in the reaction process is a coated explosion-proof thick-walled pressure-resistant bottle.

[0038] The reactions of steps 1 to 4 are carried out under an argon or nitrogen atmosphere.

[0039] The synthesis route of the armchair carbon nanobelt material of the present invention is as follows:

[0040]

[0041] Wherein R1 is a boronic acid group or a boronic ester group, R is hydrogen, C 1-20 Alkyl, C 1-20 Alkoxy, mesityl, phenyl or their large π-extended derivatives, n is 1 or 3.

[0042] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0043] 1. For the first time, Pd-catalyzed HCl removal was used to prepare curved carbon nanoribbon structures.

[0044] 2. Two macrocyclic precursors of different sizes can be obtained through a one-step reaction (step 1), and then two carbon nanobelts of different sizes can be obtained;

[0045] 3. The synthesis process of the present invention is simple and efficient. The two raw material molecules used are easy to prepare quickly and in large quantities. The synthesis process is short and the operation is convenient.

[0046] 4. The precursor molecules used are easy to functionalize, that is, their substituents R are easy to change, which can quickly enrich the structure of the target product, such as changing its different conjugated extension degrees, so that it exhibits different physical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The UV-Vis (curve) and fluorescence (FL) spectra (solid line) of the structure of formula (VII) in dichloromethane (DCM) provided in Example 1 of the present invention;

[0048] Figure 2 This is a fluorescence decay lifetime test spectrum of the structure of formula (VII) provided in Example 1 of the present invention in dichloromethane (DCM);

[0049] Figure 3 Matrix-assisted laser desorption tandem time-of-flight mass spectrometry (MALDI-TOF-MS) spectrum (solid line) and simulated data (dashed line) of the structure of formula (I) provided in Example 1 of the present invention;

[0050] Figure 4 The nuclear magnetic resonance hydrogen spectrum of the structure of formula (I) provided in Example 1 of the present invention in deuterated chloroform (CDCl3) ( 1 HNMR) spectrum;

[0051] Figure 5 The UV-Vis (curve) and fluorescence (FL) spectra (solid line) of the structure of formula (I) in dichloromethane (DCM) provided in Example 1 of the present invention are shown;

[0052] Figure 6 This is a fluorescence decay lifetime test spectrum of the structure of formula (I) provided in Example 1 of the present invention at 436 nm in dichloromethane (DCM);

[0053] Figure 7 This is a fluorescence decay lifetime test spectrum of the structure of formula (I) provided in Example 1 of the present invention at 464nm in dichloromethane (DCM).

[0054] Figure 8 J of the electron transport device ITO / ZnO / I / Ca / Al constructed with the structure of formula (I, CPP16-16 (ph-Mes)) provided in Example 1 of the present invention 1 / 2 -V fitting curve diagram, showing its electron transport performance in carrier transport devices. DETAILED DESCRIPTION

[0055] The present invention uses a method for preparing curved carbon nanobelt materials by Pd-catalyzed dehydrogenation, and the synthesis route thereof is as follows:

[0056]

[0057] Wherein R1 is a boronic acid group or a boronic ester group, R is hydrogen, C 1-20 Alkyl, C 1-20 Alkoxy, mesityl, phenyl or their large π-extended derivatives, n is 1 or 3.

[0058] In the present invention, C 1-20 The alkyl group may be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, or the like.

[0059] In the present invention, C 1-20 The alkoxy group may be methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy, n-hexoxy, isohexoxy, and the like.

[0060] In order to explain the present invention more clearly, the present invention is further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0061] Example 1: Synthesis of armchair carbon nanoribbons having the structure of formula (I) (wherein R1 is a pinacol borate group, R is a mesitylene group, and n is 3)

[0062]

[0063] 1. Synthesis of the structure of formula (IV) (n is 3): In a 500 mL flask equipped with a magnetic stirring device, 844 mg of the compound of formula (II) (wherein R1 is a pinacol borate group, the compound can be synthesized with reference to the article Angew. Chem. Int. Ed. 2021, 60, 17368-17372, and the raw material 1,4-dibromobenzene used is purchased from Inotech), 500 mg of the compound of formula (III) (the compound can be synthesized with reference to the article Org. Biomol. Chem., 2005, 3, 524-537, and the raw material hydroquinone used is purchased from Inotech), 108 mg of tetra(n-butyl)ammonium bromide, 138 mg of 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl and 153 mg of trisdibenzylideneacetone dipalladium are added to a mixed solvent of toluene (250 mL) and water (25 mL). The mixture was bubbled with argon for 25 minutes, and then the flask was sealed and heated to 85 ° C for 5 days. After the reaction was completed, the reaction mixture was cooled to room temperature, the solvent toluene was dried by rotary evaporator (purchased from Shanghai Yikai Instrument Equipment Co., Ltd., the same below), and then extracted with dichloromethane (3×100mL). The organic phases were combined, washed twice with brine, dried over anhydrous magnesium sulfate, and dried by rotary evaporator. The crude product was extracted in a vacuum drying oven for 4h. During this period, 1.631g of stannous chloride dihydrate was placed in a 250mL flask equipped with a magnetic stirring device, and 150mL of tetrahydrofuran was added. It was bubbled with argon for 15 minutes, and then 1.2mL of concentrated hydrochloric acid was added and reacted for more than 30 minutes to obtain stannic acid. The crude product was then degassed by evaporating the above mixture with an oil pump and backfilling with argon for 3 cycles. The prepared stannic acid was injected into the crude product and reacted at room temperature overnight. After the reaction, the solvent tetrahydrofuran was dried by rotary evaporation, and then extracted with dichloromethane (3×100 mL). The organic phases were combined, washed twice with brine, and then dried over anhydrous magnesium sulfate. The crude product was dried by rotary evaporation. The crude product was preliminarily purified on a silica gel column with petroleum ether and dichloromethane (volume ratio of 1:1) as eluent, and then recrystallized from pure methanol to obtain an off-white product, which is the compound of formula (IV) (n is 3), with a yield of 103 mg (3.2%).

[0064] The obtained compound of formula (IV) (n is 3) was characterized using a matrix-assisted laser desorption time-of-flight (MALDI-TOF) tandem mass spectrometer (Model: Autoflex Speed ​​TOF / TOF, Manufacturer: Bruker Corporation, USA, hereinafter the same): m / z theoretical value: 2913.1789, experimental value: 2913.7449. It was also characterized by proton nuclear magnetic resonance spectroscopy (Model: Bruker AVANCE AV400, Manufacturer: Bruker Corporation, Switzerland, hereinafter the same): 1H NMR (400MHz, CDCl3): δ7.64 (s, 32H), 7.30-7.33 (m, 80H), 7.07 (s, 16H), 5.01 (s, 32H).

[0065] 2. Synthesis of Formula (V) (n is 3): 80 mg of the compound of Formula (IV) (n is 4) and 412 mg of 1,2,4,5-tetramethylbenzene were placed in a 150 mL flask equipped with a magnetic stirrer. 50 mL of anhydrous dichloromethane was added and bubbling with argon was performed for 15 minutes. The mixture was then placed in an ethanol bath at -78°C and incubated for 30 minutes. 1.2 mL of a 1 M boron trichloride solution in dichloromethane was then added. After 9 hours of reaction, 0.7 mL of methanol was injected into the reaction flask to quench the reaction. The mixture was then extracted with water, the organic layer separated, and the aqueous layer was further extracted with diethyl ether (3 × 25 mL). The organic phases were combined and dried over anhydrous Na2SO4. After filtering to remove the Na2SO4, the solvent was dried using a rotary evaporator to obtain the crude product, which was used directly in the next step without further purification. To the crude product, 50 mL of anhydrous dichloromethane was added. The mixture was bubbled with argon in an ice-water bath for 15 minutes, followed by the addition of 0.9 mL of anhydrous pyridine. After a 5-second interval, 0.8 mL of trifluoromethanesulfonic anhydride was added. The reaction mixture was then allowed to warm to room temperature and allowed to react for at least 12 hours. After completion of the reaction, 40 mL of a 1 mol / L HCl solution was added to the reaction mixture, followed by extraction with dichloromethane (3 × 40 mL). The organic phases were combined, washed twice with brine, and dried over anhydrous Na₂SO₄. The crude product was purified by silica gel column chromatography using a 1:1 volume ratio of petroleum ether and dichloromethane as eluent. Recrystallization from pure methanol afforded the compound of formula (V) (n = 3) as a white solid in a yield of 61 mg (62%).

[0066] The obtained compound of formula (V) (n is 3) was characterized by hydrogen nuclear magnetic resonance spectroscopy: 1 HNMR (400MHz, CDCl3): δ7.65 (d, J = 9.4 Hz, 32H), 7.51 (d, J = 16.6 Hz, 16H).

[0067] 3. Synthesis of the structure of formula (VI) (R is mesitylene): In a 100 mL flask equipped with a magnetic stirring device, 2 g of 1-bromo-2-chloro-4-iodobenzene (purchased from Bethesda, MD), 1.03 g of mesitylene boronic acid (purchased from Bethesda, MD), 1.3 g of potassium carbonate and 72.8 mg of tetrakis(triphenylphosphine)palladium were added to a mixed solvent of tetrahydrofuran (30 mL) and water (6 mL) and placed in the flask. The mixture was bubbled with argon for 15 minutes, and then the flask was sealed and heated to 75°C for reaction for 48 hours. After the reaction is completed, the solvent is dried by rotary evaporation, extracted with dichloromethane (3×50 mL), the organic phases are combined, washed twice with brine, and then dried over anhydrous sodium sulfate. The crude product is purified on a silica gel column with petroleum ether as eluent to obtain a colorless transparent oily substance, which is the precursor of the structure of formula (VI) (R is mesitylene), 4'-bromo-3'-chloro-2,4,6-trimethyl-1,1'-biphenyl, with a yield of 1.86 g (95.3%). It is characterized by hydrogen nuclear magnetic resonance spectroscopy: 1 H NMR (400MHz, CDCl3): δ7.63 (dd, J=8.2, 1.0Hz, 1H), 7.28-7.24 (m, 1H), 6.96- 6.92(m,2H),6.91-6.87(m,1H),2.32(d,J=1.3Hz,3H),2.01(d,J=1.6Hz,6H). Next, 1.8 g of 4'-bromo-3'-chloro-2,4,6-trimethyl-1,1'-biphenyl was placed in a 100 mL flask equipped with a magnetic stirrer. The mixture was degassed using an oil pump vacuum and argon backfill for three cycles. 30 mL of anhydrous tetrahydrofuran was added to the mixture, and the mixture was placed in an ethanol bath at -78°C and incubated for 30 minutes. Then, 3.5 mL of a 2.5 M solution of n-butyl lithium in n-hexane was added dropwise. After reacting for two hours, 2.2 mL of trimethyl borate was added dropwise. The reaction continued for another two hours, then the mixture was gradually warmed to room temperature and allowed to react for at least 10 hours. Then, 20 mL of a 1 M HCl solution was added to the flask and stirred for at least one hour. Then, tetrahydrofuran was removed by rotary evaporation, and the mixture was extracted with dichloromethane (3×50 mL). The organic phases were combined and dried over anhydrous sodium sulfate. The crude product was washed with petroleum ether to precipitate a white solid, which is the compound of formula (VI) (R is mesitylene), with a yield of 1.53 g (95.8%).

[0068] The obtained compound of formula (VI) (R is mesitylene) was characterized by hydrogen nuclear magnetic resonance spectroscopy: 1HNMR (400MHz, CDCl3): δ8.00(d,J=7.6Hz,1H),7.17(d,J=1.5Hz,1H),7.12(dd,J=7.7,1.5Hz,1H),6.94(s,2H),5.50(s,2H),2.33(s,3H),2.00(s,6H).

[0069] 4. Synthesis of the structure of formula (VII) (R is mesityl, n is 3): In a 25 mL flask equipped with a magnetic stirring device, 150 mg of the compound of formula (V) (n is 3), 330 mg of the compound of formula (VI) (R is mesityl), 550 mg of potassium carbonate and 10 mg of tetrakis(triphenylphosphine)palladium were added to a mixed solvent of toluene (10 mL) and water (2 mL) and placed in the flask. The mixture was bubbled with argon for 20 minutes, and then the flask was sealed and heated to 110°C for reaction for 48 hours. After the reaction is completed, the solvent is dried by rotary evaporation, extracted with dichloromethane (3×30 mL), the organic phases are combined, and then dried over anhydrous sodium sulfate. The crude product is purified on a silica gel column with petroleum ether and dichloromethane (volume ratio of 2: 1) as eluent (obvious blue fluorescence can be seen on the silica gel column using a 365 nm fluorescent lamp), and then washed three times with methanol to obtain a white solid product with a yield of 128 mg (62.7%).

[0070] The obtained compound of formula (VII) (R is mesitylene, n is 3) was characterized by matrix-assisted laser desorption time-of-flight (MALDI-TOF) tandem mass spectrometry: m / z theoretical value: 4876.6283, experimental value: 4876.6524. It was also characterized by proton nuclear magnetic resonance spectroscopy: 1 H NMR (400 MHz, CDCl3): δ7.41 (s, 16H), 7.10 (s, 32H), 7.05 (d, J = 6.5 Hz, 32H), 6.83 (s, 48H), 2.20 (s, 48H), 1.98 (s, 96H). Characterization was performed by UV-Vis (model: UV-3802, manufacturer: Unicorn (Shanghai) Instrument Co., Ltd., China) and fluorescence spectroscopy (model: FluoroMax-4, manufacturer: HORIBA Group, Japan). UV-Vis (DCM solution) produces an absorption signal in the range of approximately 250-650 nm, with the largest absorption peaks located at 264 nm and 317 nm. FL (DCM solution) produces an emission signal in the range of approximately 340-660 nm, with the maximum emission peak located at 415 nm, see Figure 1The fluorescence decay lifetime was measured using a fluorescence lifetime spectrometer (model: Mini-Tau, manufacturer: Tianmei Instrument Laboratory Equipment (Shanghai) Co., Ltd.). The lifetime (τ) exhibited a single exponential decay characteristic at an excitation wavelength of 415 nm, and the fluorescence lifetime value was determined to be τ = 1.18 ns, see Figure 2 .

[0071] 5. Synthesis of the structure of formula (I) (R is mesityl, n is 3): 20 mg of the compound of formula (VII) (R is mesityl, n is 3), 1.7 mg of palladium dichloride bis(tricyclohexylphosphine), 0.5 mg of 2,2-dimethylpropionic acid, and 47 mg of cesium carbonate were added to 3 mL of ultra-dry N,N-dimethylacetamide and placed in a 15 mL coated explosion-proof thick-walled pressure bottle. The mixture was bubbled with argon for 20 minutes, and then the pressure bottle was sealed and heated to 150°C for reaction for 3 to 5 days. After the reaction was completed, it was directly extracted with dichloromethane (3×30 mL), the organic phases were combined, and then dried over anhydrous sodium sulfate. The crude product was purified on a silica gel column with petroleum ether and dichloromethane (volume ratio of 1:1) as eluent (obvious blue-green fluorescence could be seen on the silica gel column using a 365 nm fluorescent lamp), and then washed three times with methanol to obtain a yellow-green solid product with a yield of 7 mg (39.8%).

[0072] The obtained compound of formula (I) (R is mesitylene, n is 3) was characterized by using matrix-assisted laser desorption time-of-flight (MALDI-TOF) tandem mass spectrometry: m / z theoretical value: 4292.9833, experimental value: 4292.9114, see Figure 3 . And characterized by H NMR spectroscopy: 1 H NMR (400 MHz, CDCl3): δ 9.69 (s, 32H), 8.93 (s, 16H), 8.65 (s, 16H), 7.61 (s, 16H), 7.11 (s, 32H), 2.45 (s, 48H), 2.34 1.91 (m, 96H) Figure 4 Characterization was performed using UV-Vis (model: UV-3802, manufacturer: China Unico (Shanghai) Instrument Co., Ltd.) and fluorescence spectroscopy (model: FluoroMax-4, manufacturer: Japan HORIBA Group) spectrometers: UV-Vis (DCM solution) produces absorption signals in the range of approximately 250-650 nm, with the largest absorption peaks mainly located at 287 nm, 341 nm, 394 nm, and 421 nm; FL (DCM solution) produces emission signals in the range of approximately 340-660 nm, with the maximum emission peaks located at 436 nm and 464 nm, see Figure 5The fluorescence decay lifetime was measured using a fluorescence lifetime spectrometer (Model: Mini-Tau, Manufacturer: Tianmei Instrument Laboratory Equipment (Shanghai) Co., Ltd.). The lifetime (τ) exhibited a single exponential decay characteristic at an excitation wavelength of 436 nm. The fluorescence lifetime value was determined to be τ1 = 2.29 ns. Figure 6 , also exhibits a single exponential decay characteristic at 464 nm excitation wavelength, and the fluorescence lifetime value can be determined to be τ2 = 2.35 ns, see Figure 7 The electron mobility was tested using the space charge limited current model (SCLC method). Using (Ⅰ) as the electron transport layer, the structure of ITO / ZnO / Ⅰ / Ca / Al constituted a pure electron transport device; the electron mobility was calculated using the Mott-Gurney equation to be approximately 2.7×10 -4 cm 2 V -1 s -1 , see Figure 8 .

[0073] Example 2: Synthesis of armchair carbon nanoribbons having the structure of formula (I) (wherein R1 is a pinacol borate group, R is a mesitylene group, and n is 1)

[0074]

[0075] 1. Synthesis of Formula (IV) (n is 1): The crude product obtained in Example 1 was initially purified on a silica gel column using petroleum ether and dichloromethane (volume ratio of 3:1) as eluent, followed by recrystallization from pure methanol to obtain a yellow-green product, namely, the compound of Formula (IV) (n is 1), in a yield of 542 mg (16.8%). The remaining procedures were the same as in Example 1.

[0076] 2. Synthesis of Formula (V) (n is 1): The procedure was the same as in Example 1. The crude product was purified by silica gel column chromatography using petroleum ether and dichloromethane (volume ratio 2:1) as eluent. Recrystallization from pure methanol afforded a white solid, namely, the compound of Formula (V) (n is 1), in a yield of 32 mg (35%).

[0077] 3. Synthesis of the structure of formula (VI) (R is mesitylene): The operation process is the same as that of Example 1.

[0078] 4. Synthesis of the structure of formula (VII) (R is mesityl, n is 1): The operation process is the same as that of Example 1. The difference is that the obtained crude product is purified on a silica gel column using petroleum ether and dichloromethane (volume ratio of 3:1) as eluent.

[0079] 5. Synthesis of the structure of formula (I) (R is mesityl, n is 1): The operation process is the same as that of Example 1. The difference is that the crude product is purified on a silica gel column using petroleum ether and dichloromethane (volume ratio of 2:1) as eluent (obvious yellow-green fluorescence can be seen on the silica gel column using a 365 nm fluorescent lamp).

Claims

1. A method for preparing curved carbon nanobelts by Pd-catalyzed HCl removal, characterized in that The steps include: Step 1: In a mixed solvent, in the presence of a catalyst, a ligand, a base, and a phase transfer catalyst, the compound represented by formula (II) and the compound represented by formula (III) are subjected to a Suzuki-Miyaura cross-coupling reaction, followed by a reductive aromatization reaction under acidic conditions and at room temperature to obtain a compound represented by formula (IV); Step 2: In a pure organic solvent at a temperature below -40°C, converting OBn in the structure of the compound represented by formula (IV) to OH and performing a sulfonylation reaction to obtain a compound represented by formula (V); Step 3: In a mixed solvent, in the presence of a catalyst and a base, subjecting the compound represented by formula (V) and the compound represented by formula (VI) to a Suzuki-Miyaura cross-coupling reaction at a certain temperature to obtain a compound represented by formula (VII); Step 4: In a pure organic solvent, in the presence of a catalyst, a ligand and a base, subjecting the compound represented by formula (VII) to an intramolecular elimination reaction at a certain temperature to obtain the target product represented by formula (I); In step 1, the catalyst is a palladium catalyst selected from tetrakis(triphenylphosphine)palladium or tris(dibenzylideneacetone)dipalladium; the ligand is a phosphorus-based ligand; the base is potassium carbonate or sodium carbonate; the phase transfer catalyst is tetra-n-butylammonium bromide; the ligand is 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl; the mixed solvent is a mixture of toluene and water; and the acidic conditions are provided by stannic acid prepared by stannous chloride and hydrochloric acid in tetrahydrofuran. In step 3, the catalyst is tetrakistriphenylphosphine palladium; the base is potassium carbonate or sodium carbonate; In step 4, the catalyst is a palladium catalyst selected from palladium acetate or palladium dichloride; the ligand is a phosphorus-based ligand; the base is 1,8-diazabicycloundec-7-ene, cesium carbonate or 2,2-dimethylpropionic acid; The synthetic route is as follows: ； Wherein R1 is a boronic acid group or a boronic ester group, R is hydrogen, C 1-20 Alkyl, C 1-20 Alkoxy, mesityl or phenyl, n is 1 or 3.

2. The method according to claim 1, wherein: In step 1, the reaction temperature of the Suzuki-Miyaura cross-coupling reaction is 60-120° C., and the reaction time is 1-5 days.

3. The method according to claim 1, wherein: In step 2, the structure of the OBn group is , converted to OH using a dichloromethane solution of boron trichloride or boron tribromide, and the reaction time is 9 hours.

4. The method according to claim 1, wherein: In step 3, the reaction temperature is 60-120° C., and the reaction time is 1-5 days.

5. The method according to claim 1, wherein: In step 4, the reaction temperature is 60-120° C., and the reaction time is 1 to 5 days.

6. A curved carbon nanoribbon, prepared according to the preparation method according to any one of claims 1 to 5, wherein the structure thereof is as follows: ； wherein R is selected from hydrogen, C 1-20 Alkyl, C 1-20 Alkoxy, mesityl or phenyl; the value of n is 1 or 3.

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