Efficient and simple synthesis method of dibenzotetrathiafulvalene derivative

Abstract

The invention discloses an efficient and simple synthesis method of a dibenzotetrathiafulvalene derivative, which is characterized in that benzene-1, 2-thiophenol or a derivative of benzene-1, 2-thiophenol is subjected to dimerization in a solvent containing acetic acid under a solvothermal reaction condition to obtain the dibenzotetrathiafulvalene or the derivative of dibenzotetrathiafulvalene. The solvothermal reaction conditions are mild, the operation is simple, and the method is suitable for large-scale preparation and environment-friendly. No toxic by-product is generated in the reaction, the reaction product does not need to be purified, the high-purity crystal compound can be obtained, the product efficiency is improved, and the selectivity is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to an efficient and simple method for synthesizing dibenzotetrathiofulvalene derivatives. Background Technology

[0002] Tetrathiafulvalene (TTF) is a class of organic functional molecules with unique redox activity and electron-donating properties. Due to their excellent charge transport capabilities, TTF derivatives show great promise for applications in organic semiconductors, conductive materials, electrochemical sensors, molecular switches, and organic field-effect transistors (OFETs). Since the charge-transfer complex formed by tetrathiafulvalene and 7,7,8,8-tetracyano-p-benzoquinone dimethane (TCNQ) exhibits metal-like conductivity, researchers have developed various methods for preparing sulfur-containing donor molecules (TTF derivatives). This research encompasses the synthesis of related analogs, especially dibenzotetrathiafulvalene (DBTTF) derivatives, which possess a more extended conjugated π-electron system.

[0003] To date, the main synthetic routes for the TTF backbone are as follows:

[0004]

[0005] Route 1: Dimerization of 1,3-dithionium salts as carbene precursors under the catalysis of bases (such as amines); Route 2: Cross-coupling of two 1,3-dithiol-2-thioketones promoted by phosphine; Route 3: Coupling of organotin dithiolates with 1,3-dithiols containing ester groups at the 2-position under the catalysis of trimethylaluminum (AlMe3), forming a tetrathiofulvalene skeleton through two carbon-sulfur bond formations; Route 4: Reaction of electron-deficient alkynes with carbon disulfide under the catalysis of trialkylphosphine to prepare the corresponding tetrathiofulvalene derivatives.

[0006] A typical method for synthesizing DBTTF derivatives is the dimerization of the 1,3-benzodithionylpentene ring, as shown in the following equation:

[0007]

[0008] Specifically, it involves the dimerization of carbene derivatives generated by the capture of 2-lithium-1,3-dithioheterocyclic anions by hydride anions (route 5); and the dimerization of 1,3-benzodithioheterocyclic cations in the presence of bases such as triethylamine (route 6); Hurtley and Smiles reported that benzene-1,2-dithiophenol reacts with substrates containing two carbon atoms (such as oxalyl chloride or tetrachloroethylene) under base-promoted conditions to prepare DBTTF derivatives (route 7).

[0009] However, the above reaction process has several shortcomings;

[0010] 1) Extremely harsh operating conditions (such as temperature and environmental requirements): ultra-low temperature dependence, requiring -78℃ to stabilize the active intermediate, significantly increasing equipment and energy costs; high temperature and high pressure operation, requiring reaction at temperatures >150℃, resulting in high energy consumption and significant safety hazards; strict anhydrous and oxygen-free conditions, cumbersome operation and difficult industrial scale-up; dependence on highly corrosive reagents, requiring strong acid / base systems, which severely corrode reaction vessels; highly toxic catalysts: trimethylaluminum (AlMe3) or organotin reagents, residual metals are difficult to remove and contaminate the product.

[0011] 2) Highly toxic and selectively uncontrolled byproducts: The generation of highly toxic gases, releasing phosgene (COCl2) and hydrogen sulfide (H2S), endangers operational safety and the environment; sulfur oxide impurities: sulfur atoms are oxidized to form sulfoxide / sulfone byproducts, which are difficult to separate due to their similar polarity to the target analyte; chemical selectivity defects: sulfur-sulfur coupling competition and poor sulfur / selenium atom selectivity.

[0012] 3) Product purification bottlenecks are prominent and impurity separation is difficult: polarity similarity limits sublimation purification; multi-step scale-up obstacles: intermediates are unstable, sensitive to air and have large yield fluctuations; low overall yield: multi-step reaction.

[0013] Existing technologies suffer from inherent limitations in reaction pathways, resulting in significant bottlenecks in operational safety, environmental compatibility, and product purity. Therefore, the preparation and large-scale application of DBTTF derivatives still face considerable obstacles. Summary of the Invention

[0014] For the reasons mentioned above, the purpose of this invention is to provide an efficient and simple method for synthesizing dibenzotetrathiofulvalene derivatives. Benzene-1,2-thiophenol and its derivatives can be reacted in a mixed solvent under solvothermal conditions with the aid of acid to efficiently and greenly prepare BDTTF derivatives in one step, without generating toxic byproducts. No purification is required after the reaction; high-purity crystalline compounds can be obtained through simple post-treatment.

[0015] The objective of this invention can be achieved by adopting the following technical solutions:

[0016] An efficient and simple method for synthesizing a dibenzotetrathiofulvalene derivative is disclosed, wherein benzene-1,2-thiophenol or its derivative undergoes dimerization in a solvent containing acetic acid under solvothermal reaction conditions to obtain the dibenzotetrathiofulvalene or its derivative.

[0017] Furthermore, benzo-1,2-thiophenol and its derivatives, and dibenzotetrathiofulvalene derivatives are shown in Formula I and Formula II:

[0018] ;

[0019] R1, R2, R3, and R4 are independently selected from H and C1-C5 alkyl groups.

[0020] Furthermore, the solvent containing acetic acid is a mixed solution of acetonitrile, water, and acetic acid.

[0021] Further, the volume ratio of acetonitrile, water and acetic acid is (1-5):1:(0.5-1.2).

[0022] Furthermore, the volume ratio of acetonitrile, water and acetic acid is (1.5-3):1:(0.7-1).

[0023] Furthermore, the mass-to-volume ratio of benzene-1,2-thiophenol and its derivatives to the solvent is 2.5 mg: (0.5-1) ml.

[0024] Furthermore, the conditions for the solvothermal reaction are: a reaction temperature of 110-120℃ and a reaction time of 18-72h.

[0025] Furthermore, the reaction is carried out in an inert gas atmosphere; the inert gas atmosphere is a nitrogen atmosphere.

[0026] Furthermore, the reaction includes a post-processing step: after cooling the reaction solution, solid-liquid separation is performed, the solid phase is washed with methanol, and vacuum dried to obtain the dibenzotetrathiofulvalene derivative.

[0027] Further, dibenzotetrathiofulvalene was prepared by dimerization of benzo-1,2-thiophenol; the molecular formula of the dibenzotetrathiofulvalene is C2. 14 H8S4, monoclinic crystal system P Space group 21 / c, with cell parameters a=12.0777Å, b=3.9553Å, c=14.5550Å, α=γ=90°, β=114.369°.

[0028] Furthermore, R1, R2, and R4 are H, and R3 is any one of methyl, ethyl, isopropyl, or tert-butyl.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] This invention provides a highly efficient and simple method for synthesizing dibenzotetrathiofulvalene derivatives. Benzo-1,2-thiophenol or its derivatives can be efficiently and environmentally prepared in a solvent containing acetic acid under solvothermal conditions, with acid promotion. No toxic byproducts are generated in the reaction, and the product requires no purification, yielding a high-purity crystalline compound. The reaction process is simple to operate, environmentally friendly, improves product efficiency, and ensures selectivity. Attached Figure Description

[0031] Figure 1The mass spectrum of TTF-Ph prepared in Example 1;

[0032] Figure 2 The 1H NMR spectrum of TTF-Ph prepared in Example 1;

[0033] Figure 3 The carbon NMR spectrum of TTF-Ph prepared in Example 1;

[0034] Figure 4 The 1H NMR spectrum of TTF-Ph prepared for Comparative Example 1;

[0035] Figure 5 The carbon NMR spectrum of TTF-Ph prepared for Comparative Example 1;

[0036] Figure 6 The mass spectrum of TTF-Ph prepared in Comparative Example 1 is shown.

[0037] Figure 7 X-ray powder diffraction pattern of TTF-Ph prepared in Example 1;

[0038] Figure 8 The crystal structure diagram of TTF-Ph prepared in Example 1;

[0039] Figure 9 The infrared spectrum of TTF-Ph prepared in Example 1. Detailed Implementation

[0040] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] This application addresses the numerous problems encountered in the synthesis of tetrathiofulvalene derivatives by providing an efficient and simple method for synthesizing dibenzotetrathiofulvalene derivatives.

[0042] An efficient and simple method for synthesizing a dibenzotetrathiofulvalene derivative is disclosed, wherein benzene-1,2-thiophenol or its derivative undergoes dimerization in a solvent containing acetic acid under solvothermal reaction conditions to obtain the dibenzotetrathiofulvalene or its derivative.

[0043] The preparation method of this application avoids the complex operation of existing technologies, eliminates metal catalysts and highly toxic reagents, and achieves "one-step synthesis"; using benzene-1,2-thiophenol or its derivatives as a single precursor, the DBTTF framework is directly constructed through intramolecular dimerization, which has significantly higher atom economy than multi-component coupling circuits; with "zero heavy metal catalysts, zero highly toxic emissions, and low energy consumption purification" as the core, it provides a sustainable solution for the large-scale production of DBTTF semiconductor materials.

[0044] As one embodiment, benzene-1,2-thiophenol and its derivatives, and dibenzotetrathiofulvalene derivatives are shown in Formula I and Formula II:

[0045] ;

[0046] R1, R2, R3, and R4 are independently selected from H and C1-C5 alkyl groups.

[0047] As one embodiment, dibenzotetrathiofulvalene is prepared by dimerization of benzo-1,2-thiophenol;

[0048] ;

[0049] The molecular formula of the dibenzotetrathiofulvalene is C 14 H8S4, monoclinic crystal system P Space group 21 / c, with cell parameters a=12.0777Å, b=3.9553Å, c=14.5550Å, α=γ=90°, β=114.369°.

[0050] In one embodiment, R1, R2 and R4 are H, and R3 is any one of methyl, ethyl, isopropyl or tert-butyl.

[0051] .

[0052] In one embodiment, the solvent containing acetic acid is a mixed solution of acetonitrile, water, and acetic acid.

[0053] As one embodiment, the volume ratio of acetonitrile, water and acetic acid is (1-5):1:(0.5-1.2).

[0054] In one embodiment, the volume ratio of acetonitrile, water and acetic acid is (1.5-3):1:(0.7-1).

[0055] In one embodiment, the mass-to-volume ratio of benzene-1,2-thiophenol and its derivatives to solvent is 2.5 mg: (0.5-1) ml. Benzene-1,2-thiophenol or its derivatives dimerize into rings, resulting in no atom waste and high atom economy.

[0056] In one embodiment, the solvothermal reaction conditions are: a reaction temperature of 110-120°C and a reaction time of 18-72 h. The preparation method of this application eliminates the need for ultra-low / high temperatures: the reaction can proceed at 110-120°C under normal pressure; the high-temperature solvent system suppresses side reactions, avoids SS coupling, and improves product selectivity.

[0057] The reaction does not require anhydrous conditions, only an inert gas atmosphere, and can be completed in one step, shortening the synthesis pathway. As one embodiment, the reaction is carried out under an inert gas atmosphere; the inert gas atmosphere is a nitrogen atmosphere.

[0058] As one implementation method, the reaction also includes a post-processing step: after cooling the reaction solution, solid-liquid separation is performed, the solid phase is washed with methanol, and vacuum dried to obtain the dibenzotetrathiofulvalene derivative. The reaction directly precipitates single-crystal-level products, and single crystals are obtained by filtration / washing, eliminating the need for purification steps; moreover, the purity is high (>99%), overcoming the bottleneck of "high temperature and energy consumption for sublimation purification and difficulty in separating impurities" in existing technologies.

[0059] The following provides a further explanation using specific implementation methods. Example 1

[0060]

[0061] 2.5 mg of 1,2-benzenedithiol was weighed and added to a reaction flask, followed by the addition of 160 μL of CH3COOH, 400 μL of acetonitrile, and 200 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 120 °C for 24 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered, washed with methanol, and then vacuum-sealed at room temperature to obtain dibenzotetrathiofulvalene crystals, named TTF-Ph, with a yield of 53.2%. Mass spectrometry, such as Figure 1 As shown; the mass spectrometry molecular weight is 304.85, which is the same as the theoretical molecular weight; 1H NMR spectrum as follows Figure 2 As shown, 1 H NMR (500MHz, CDCl3): δ=7.26 (m,4 H), 7.11 (m,4 H); Carbon NMR spectrum, such as Figure 3 As shown, 13 C NMR (500MHz, CDCl3): δ=136.72,126.02, 121.98,110.69. Example 2

[0062]

[0063] 2.5 mg of 4-methyl-1,2-dimercaptobenzene was weighed and added to a reaction flask, followed by the addition of 89 μL of CH3COOH, 383 μL of acetonitrile, and 128 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 110 °C for 72 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered out, washed with methanol, and then vacuumed at room temperature to obtain dibenzotetrathiofulvalene crystals with methyl substituents, with a yield of 61.4%. Example 3

[0064]

[0065] 2.5 mg of 4-ethyl-1,2-dimercaptobenzene was weighed and added to a reaction flask, followed by the addition of 100 μL of CH3COOH, 200 μL of acetonitrile, and 200 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 130 °C for 18 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered out, washed with methanol, and then vacuumed at room temperature to obtain dibenzotetrathiofulvalene crystals with ethyl substituents, with a yield of 59%. Example 4

[0066]

[0067] 2.5 mg of 4-isopropyl-1,2-dimercaptobenzene was weighed and added to a reaction flask, followed by the addition of 257 μL of CH3COOH, 385 μL of acetonitrile, and 257 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 115 °C for 36 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered out, washed with methanol, and then vacuumed at room temperature to obtain dibenzotetrathiofulvalene crystals with isopropyl substituents, with a yield of 61%. Example 5

[0068]

[0069] 2.5 mg of 4-tert-butyl-1,2-dimercaptobenzene was weighed and added to a reaction flask, followed by the addition of 167 μL of CH3COOH, 694 μL of acetonitrile, and 139 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 125 °C for 48 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered out, washed with methanol, and then vacuumed at room temperature to obtain dibenzotetrathiofulvalene crystals with tert-butyl substituents, with a yield of 60%.

[0070] Comparative Example 1

[0071] 2.5 mg of 1,2-benzenedithiol was weighed and added to a reaction flask, followed by 160 μL of oxalic acid, 400 μL of acetonitrile, and 200 μL of H2O. Nitrogen gas was introduced into the reaction flask, and the mixture was heated at 120 °C for 24 h under nitrogen protection. The mixture was then allowed to cool naturally to room temperature to obtain blocky crystals. The crystals were filtered out, washed with methanol, and the product was obtained under vacuum at room temperature with a yield of 49.1%.

[0072] 1H NMR spectrum as follows Figure 4 As shown, 1 H NMR (500MHz, CDCl3): δ=7.26 (m,4 H), 7.12 (m,4 H);

[0073] Carbon NMR spectrum, such as Figure 5 As shown, 13 C NMR (500MHz, CDCl3): δ=136.72,126.02, 121.98,110.68;

[0074] Mass spectrometry, such as Figure 6 As shown, the molecular weight measured by mass spectrometry is the same as the theoretical molecular weight.

[0075] Compound characterization and verification

[0076] (1) X-ray powder diffraction test was performed on the TTF-Ph prepared in Example 1. The X-ray powder diffraction pattern is shown below. Figure 7 As shown in the figure; the crystallographic parameters of TTF-Ph are shown in Table 1.

[0077] The X-ray powder diffraction results show that the peak positions of the synthesized TTF-Ph diffraction pattern are highly consistent with those of the simulated diffraction pattern, indicating that the synthesized TTF-Ph has good phase purity. The diffraction pattern also shows that the TTF-Ph diffraction peaks have very narrow full width at half maximum (FWHM), indicating that the synthesized TTF-Ph has excellent crystallinity.

[0078] Table 1

[0079]

[0080]

[0081] The crystal structure of TTF-Ph is as follows: Figure 8 The molecular formula is C 28 H 16 S8, monoclinic crystal system P Space group 21 / c, with cell parameters a=12.0777Å, b=3.9553Å, c=14.5550Å, α=γ=90°, β=114.369°.

[0082] (2) The TTF-Ph prepared in Example 1 was subjected to infrared spectroscopy testing. The infrared spectrum is shown below. Figure 9 As shown.

[0083] like Figure 9 As shown, at 2539cm -1 The thiol peak of the raw material can be seen at 671 cm⁻¹, and after dimerization, the disappearance of the thiol peak is clearly visible. -1 The peak can be attributed to the SCS bond, reflecting the coupling vibration of the sulfur atom and the carbon skeleton, indicating that the two thiol groups form a ring with the carbon.

[0084] (3) As can be seen from the NMR and mass spectrometry data of the compounds in the Examples and the compounds prepared in Comparative Example 1, dibenzotetrathiofulvar can be obtained under both acetic acid and oxalic acid promoting conditions, and the yield of the product obtained by using acetic acid in this application is 3 percentage points higher than that of oxalic acid. In addition, acetic acid has a lower cost and a higher atom utilization rate as a monocarboxylic acid, thus resulting in higher economic benefits.

[0085] In summary, this application provides an efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives. Benzene-1,2-thiophenol or its derivatives undergo dimerization under solvothermal conditions in a solvent containing acetic acid to obtain the dibenzotetrathiofulvalene or its derivatives. The reaction process is simple to operate, environmentally friendly, improves product efficiency, and ensures selectivity.

[0086] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A highly efficient and simple method for synthesizing dibenzotetrathiofulvalene derivatives, characterized in that, Benzene-1,2-thiophenol or its derivatives undergo dimerization in a solvent containing acetic acid under solvothermal reaction conditions to obtain the dibenzotetrathiofulvalene or its derivatives.

2. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, Benzene-1,2-thiophenol and its derivatives, and dibenzotetrathiofulvalene derivatives are shown in Formula I and Formula II: ； R1, R2, R3, and R4 are independently selected from H and C1-C5 alkyl groups.

3. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, The solvent containing acetic acid is a mixed solution of acetonitrile, water, and acetic acid; The volume ratio of acetonitrile, water and acetic acid is (1-5):1:(0.5-1.2).

4. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 4, characterized in that, The volume ratio of acetonitrile, water and acetic acid is (1.5-3):1:(0.7-1).

5. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, The mass-to-volume ratio of benzene-1,2-thiophenol and its derivatives to solvent is 2.5 mg: (0.5-1) ml.

6. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, The conditions for the solvothermal reaction are: reaction temperature of 110-120℃ and reaction time of 18-72h.

7. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, The reaction is carried out in an inert gas atmosphere, which is a nitrogen atmosphere.

8. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, The reaction also includes a post-processing step: after cooling the reaction solution, solid-liquid separation is performed, the solid phase is washed with methanol, and vacuum dried to obtain the dibenzotetrathiofulvalene derivative.

9. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 1, characterized in that, Dibenzotetrathiofulvalene was prepared by dimerization of benzene-1,2-thiophenol. The molecular formula of the dibenzotetrathiofulvalene is C 14 H8S4, monoclinic crystal system P Space group 21 / c, with cell parameters a=12.0777Å, b=3.9553Å, c=14.5550Å, α=γ=90°, β=114.369°.

10. The efficient and simple synthetic method for dibenzotetrathiofulvalene derivatives according to claim 2, characterized in that, R1, R2, and R4 are H, and R3 is any one of methyl, ethyl, isopropyl, or tert-butyl.

Images