A bisphosphine compound based on a phospholene structure unit and a method for preparing the same

Abstract

The application provides an organic phosphorus compound based on a diphosphole structural unit and a preparation method thereof; the organic phosphorus compound is a diphosphine compound containing a diphosphole structural unit shown in formula (III), the process method avoids the use of chloric gas which is extremely polluting and the subsequent emission problems in traditional phosphorus chemical production, and is a more environmentally friendly production method. In addition, the method disclosed by the application has the advantages of mild reaction conditions, short reaction time, simple post-treatment and high yield.

Description

Technical Field

[0001] This invention relates to the field of organophosphorus chemistry and chemical engineering, and more specifically, to a bisphosphonate compound based on a bisphosphonium fluorene structural unit and its preparation method. Background Technology

[0002] Phosphafluorenes are a class of compounds in which the carbon atom at position 9 of a fluorene compound is replaced by a phosphorus atom; they are also known as dibenzophospholes. Because of the introduction of the heteroatom—phosphorus—into phosphafluorenes, they can be used as ligands in organometallic chemistry to synthesize rare-earth metal complexes or transition-metal complexes (see Non-Patent Literature 1 and 2). Furthermore, phosphafluorenes possess a tricyclic large π-conjugated structure with a rigid conjugated plane, thus maintaining the excellent photoelectric properties of fluorene compounds. In addition, the phosphorus atom can alter the electronic structure of the material through the interaction between the d-orbital and the π-conjugated system, and can be modified through oxidation reactions, thereby effectively regulating the photoelectric properties of the material. They are widely used in the fabrication of optoelectronic devices (see Non-Patent Literature 3 and 4).

[0003] Organic bisphosphine ligands containing bisphosphonium structural units are commonly used in organic synthesis methodologies and organometallic chemistry. For example, Pt complexes synthesized with such ligands can catalyze the aldehyde functionalization of alkenes (see Non-Patent Literature 5); Rh complexes synthesized with such ligands can catalyze the hydrogenation of alkenes (see Non-Patent Literature 6). In the prior art, the preparation of such organic bisphosphine ligands containing bisphosphonium structural units requires first reacting 9-phenyl-9-phosphonium with an alkali metal to obtain lithium phosphonium salts, followed by further reaction with an electrophilic reagent to synthesize the bisphosphine ligands (see Non-Patent Literatures 2 and 7).

[0004] As can be seen from the various preparation schemes in the aforementioned literature, the reaction substrate 9-phenyl-9-phosphazene used in them needs to be synthesized from the basic phosphorus chemical product arylphosphine dichloride (ArPCl2). Currently, the basic raw material for such compounds is prepared from white phosphorus (P4) in the phosphorus chemical industry, which requires the use of chlorine, a toxic gas that is harmful to both the environment and human health. Furthermore, the reaction process generates a large amount of waste gas and waste acid. Therefore, the entire production process is not only energy-intensive but also extremely polluting to the environment (see Non-Patent Literature 8).

[0005] Therefore, there is an urgent need to find a method that does not use chlorine gas and can easily synthesize organophosphine ligands containing diphosphine fluorene structural units to replace traditional synthesis methods.

[0006] Existing technical documents

[0007] Non-patent literature

[0008] Non-patent literature 1: N. and R.Louis,J.Organomet.Chem.1994,464,149-154;

[0009] Non-patent literature 2: S. Wolfdieter, S. Michael and H. Michael, J. Organomet. Chem. 1998, 560, 257-263;

[0010] Non-patent literature 3: R.-F. Chen, R. Zhu, Q.-L. Fan, and W. Huang, Org. Lett. 2008, 10, 2913-2916;

[0011] Non-patent literature 4: P. Hibner-Kulicka, J. Joule, J. Skalika and P. RSCAdv.2017,7,9194-9236;

[0012] Non-patent literature 5: JKStille, H.Su, P.Brechot, G.Parrinello, and L.S.Hegedus, Organometallics 1991, 10, 4, 1183-1189;

[0013] Non-patent literature 6: H. Teruyuki, T. Masato, I. Yoshikazu, O. Ikuei, Bull. Chem. Soc. Jpn. 1979, 52, 2605-2608;

[0014] Non-patent literature 7: T.Dang, J.-C.Poulin, H.B.Kagan, J.Organomet.Chem.1975, 91, 105-115;

[0015] Non-patent literature 8: Synthesis of Carbon-Phosphorus Bonds, 2nd edition, CRC Press, Boca Raton 2004. Summary of the Invention

[0016] The technical problem that the invention aims to solve

[0017] The present invention was made in view of the above-mentioned problems, and its object is to provide a method for synthesizing organobisphosphonic compounds based on bisphosphonium fluorene structural units that is not only efficient, but also environmentally friendly, low-cost and easy to synthesize.

[0018] Solution for solving the problem

[0019] The technical solution of the present invention is as follows:

[0020] One aspect of the present invention is a bisphosphine compound, which is a compound containing a bisphosphine fluorene structural unit as shown in formula (III), characterized in that:

[0021]

[0022] In equation (III): R 1 R 2 R 3 R 4 They can be the same or different, and can be hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl, C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridinyl, thiophene; Q represents alkylene (C1-C6), phenylene, pyridinyl, thiophene.

[0023] In formula (III): R 1 R 2 R 3 R 4 Preferably, each of the following is hydrogen, halogen, methyl, methoxy, tert-butyl, trifluoromethyl, or trifluoromethoxy; Q is a C1-C4 alkylene, phenylene, or pyridylene group.

[0024] Another aspect of the present invention relates to a method for preparing a bisphosphine compound, which is a method for preparing a bisphosphine compound containing a diphosphonium fluorene structural unit as shown in formula (III).

[0025]

[0026] In equation (IV): R 1 R 2 R 3 R 4 They can be the same or different, and can be hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl, C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridinyl, thiophene; Q represents alkylene (C1-C6), phenylene, pyridinyl, thiophene.

[0027] The preparation method includes the following steps:

[0028] Step 1-1: Prepare compound (V) by reacting compound (IV) with an organometallic reagent at low temperature.

[0029]

[0030] In compound (IV), X 1 It can be chlorine, bromine, or iodine, with bromine and iodine being preferred.

[0031] The organometallic reagent used in step 1-1 can be an organolithium reagent, Grignard reagent, sodium reagent, potassium reagent, or calcium reagent, with organolithium reagent being preferred.

[0032] The preferred organolithium reagents are n-butyllithium and tert-butyllithium.

[0033] M can be lithium, sodium, potassium, calcium, or magnesium, with lithium being the preferred choice.

[0034] In reaction step 1-1, the low temperature is in the range of -120℃ to -60℃, preferably -90℃ to -70℃; the reaction time is 0.5 to 3 hours at the aforementioned low temperature, and then the reaction continues at room temperature for 2 to 6 hours, preferably 3 to 4 hours.

[0035] There are no particular limitations on the solvent used in the above reactions; any organic solvent that can dissolve the reactants and does not react with the organometallic reagent is acceptable. Examples include tetrahydrofuran (THF), diethyl ether (Et₂O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA).

[0036] For the ratio of the compound of formula (IV) to the organometallic reagent, the ratio of the organometallic reagent to the compound of formula (IV) is 2 to 3 molar equivalents, preferably 2.2 to 2.5 molar equivalents.

[0037] Steps 1-2: Prepare compound (I) by reacting compound (V) with white phosphorus at room temperature or above.

[0038]

[0039] In reaction steps 1-2, the reaction temperature is in the range of room temperature to 50°C, preferably 25°C to 40°C; the reaction time is 6 to 24 hours, preferably 10 to 20 hours.

[0040] As the solvent used in the above reaction, an organic solvent is required that can dissolve the reactants without reacting with them; the solvent is the coordination solvent (sol) of metal M in the compound of formula (I), and the coordination solvent (sol) can be tetrahydrofuran (THF), diethyl ether (Et2O), dimethyl ethylene glycol (DME) or tetramethylethylenediamine (TMEDA), preferably tetrahydrofuran (THF) or diethyl ether (Et2O), and more preferably tetrahydrofuran (THF).

[0041] n represents the number of coordinating solvents, which is a positive integer or half-integer greater than 0 and less than 3.

[0042] For the ratio of compound (V) to white phosphorus (P4), the ratio of white phosphorus (P4) to compound (V) is 1 to 1.5 molar equivalents, preferably 1.1 to 1.45 molar equivalents.

[0043] Steps 1-3: Prepare compound (IV) by reacting compound (I) with compound (II).

[0044]

[0045] Among them, X in compound (II) 2 It consists of chlorine, bromine, and iodine.

[0046] For this reaction, the reaction temperature is in the range of room temperature to 50°C, preferably in the range of room temperature to 45°C, and the reaction time is 6 to 24 hours, preferably 10 to 20 hours.

[0047] There are no particular limitations on the solvent used in the above reaction; any organic solvent that can dissolve the reactants without reacting with the compound of formula (I) is acceptable. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA).

[0048] For the ratio of compound (I) to compound (II), the amount of compound (II) used relative to compound (I) is 0.2 to 1 molar equivalent, preferably 0.4 to 0.9 molar equivalent.

[0049] The solvents used in steps 1-1, 1-2, and 1-3 above can be the same or different. For ease of operation and post-processing, it is preferred that the solvents in each step be the same; however, for optimal yield and effect, it is also preferred that the solvents in each step be different.

[0050] In addition, the bisphosphine compounds containing phosphonium fluorene structural units described in this invention can be used as organophosphine ligands in organometallic chemistry or organic synthesis methodologies.

[0051] The effects of the invention

[0052] According to the present invention, a bisphosphine compound based on the diphosphonium fluorene structural unit and its preparation method are provided. Since the starting compound (I) used in the reaction, namely the phosphonium fluorene metal salt compound, is directly synthesized from white phosphorus, there is no need to use aryl phosphorus dichloride (ArPCl2) or diaryl phosphorus dichloride (Ar2PCl), thus avoiding the use of highly polluting chlorine gas and emission problems in traditional phosphorus chemical production, which is a more environmentally friendly production method.

[0053] The bisphosphine compounds containing bisphosphonium fluorene structural units described in this invention can be used as organophosphine ligands for the synthesis of novel metal complexes. They have excellent application prospects in the structural characterization and reaction chemistry research of novel metal complexes in the field of organometallic chemistry. In the field of organic synthesis methodology, novel metal complexes have also made good progress in the research of novel catalytic reactions as catalysts.

[0054] Furthermore, the method disclosed in this invention has mild reaction conditions, short reaction time, simple post-processing, and can achieve a high yield. Detailed Implementation

[0055] The following specific embodiments further illustrate the above-described contents of the present invention in detail, but should not be construed as limiting the scope of protection of the present invention in any way. All technical solutions implemented based on the above-described contents of the present invention fall within the scope of the present invention. The present invention provides a general and / or specific description of the materials and test methods used in the experiments. Those skilled in the art will understand that, unless otherwise specified, the room temperature mentioned in the following text has a technically known meaning in the art, generally referring to 20–25°C; all chemicals mentioned are commercially available.

[0056] One bisphosphine compound of the present invention is a bisphosphine compound containing a diphosphonium fluorene structural unit as shown in formula (III).

[0057]

[0058] In equation (IV): R 1 R 2 R 3 R 4 They can be the same or different, and can be hydrogen, halogen, nitro, cyano, trifluoromethyl, trifluoromethoxy, C1-C6 alkyl (including straight-chain alkyl, branched alkyl and cycloalkyl), C1-C6 alkoxy, substituted or unsubstituted phenyl, pyridinyl, thiophene; Q represents alkylene (C1-C6), phenylene, pyridinyl, thiophene.

[0059] R 1 R2 R 3 R 4 Preferred components include hydrogen, halogen, trifluoromethyl, trifluoromethoxy, methyl, methoxy, substituted or unsubstituted phenyl, and pyridyl.

[0060] Alkyl groups are preferably methyl or ethyl, tert-butyl, and alkoxy groups are preferably methoxy or ethoxy.

[0061] Q is preferably propylidene, butylidene, pentylene, hexylidene, 1,2-methylenephenyl, 1,3-methylenephenyl, 1,4-methylenephenyl, or 2,6-methylenepyridyl. More preferably, it is butylidene, pentylene, hexylidene, 1,3-methylenephenyl, 1,4-methylenephenyl, or 2,6-methylenepyridyl.

[0062] Preparation of compounds

[0063] The method for preparing a bisphosphine compound according to the present invention is a method for preparing a bisphosphine compound containing a diphosphine fluorene structural unit as shown in formula (III).

[0064] It includes the following steps:

[0065] Step 1-1: Prepare compound (V) by reacting compound (IV) with an organometallic reagent at low temperature.

[0066]

[0067] In compound (IV), X 1 It can be chlorine, bromine, or iodine, with bromine and iodine being preferred.

[0068] The organometallic reagent used in step 1-1 can be an organolithium reagent, Grignard reagent, sodium reagent, potassium reagent, or calcium reagent, with organolithium reagent being preferred.

[0069] The preferred organolithium reagents are n-butyllithium and tert-butyllithium.

[0070] M can be lithium, sodium, potassium, calcium, or magnesium, with lithium being the preferred choice.

[0071] In reaction step 1-1, the low temperature is in the range of -120℃ to -60℃, preferably -90℃ to -70℃; the reaction time is 0.5 to 3 hours at the low temperature, and then the reaction continues at room temperature for 2 to 6 hours, preferably 3 to 4 hours.

[0072] There are no particular limitations on the solvent used in the above reactions; any organic solvent that can dissolve the reactants and does not react with the organometallic reagent is acceptable. Examples include tetrahydrofuran (THF), diethyl ether (Et₂O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA).

[0073] For the ratio of the compound of formula (IV) to the organometallic reagent, the ratio of the organometallic reagent to the compound of formula (IV) is 2 to 3 molar equivalents, preferably 2.2 to 2.5 molar equivalents.

[0074] Steps 1-2: Prepare compound (I) by reacting compound (V) with white phosphorus at room temperature or above.

[0075]

[0076] In reaction steps 1-2, the reaction temperature is in the range of room temperature to 50°C, preferably 25°C to 40°C; the reaction time is 6 to 24 hours, preferably 10 to 20 hours.

[0077] As the solvent used in the above reaction, an organic solvent is required that can dissolve the reactants without reacting with them; the solvent is the coordination solvent (sol) of metal M in the compound of formula (I), and the coordination solvent (sol) can be tetrahydrofuran (THF), diethyl ether (Et2O), dimethyl ethylene glycol (DME) or tetramethylethylenediamine (TMEDA), preferably tetrahydrofuran (THF) or diethyl ether (Et2O), and more preferably tetrahydrofuran (THF).

[0078] n represents the number of coordinating solvents, which is a positive integer or half-integer greater than 0 and less than 3.

[0079] For the ratio of compound (V) to white phosphorus (P4), the ratio of white phosphorus (P4) to compound (V) is 1 to 1.5 molar equivalents, preferably 1.1 to 1.45 molar equivalents.

[0080] Steps 1-3: Prepare compound (III) by reacting compound (I) with compound (II).

[0081]

[0082] Among them, X in compound (II) 2 The components are chlorine, bromine, and iodine. Bromine and iodine are preferred.

[0083] In steps 1-3 of the reaction, the reaction temperature is in the range of room temperature to 50°C, preferably in the range of room temperature to 45°C, and the reaction time is 6 to 24 hours, preferably 10 to 20 hours.

[0084] There are no particular limitations on the solvent used in the above reaction; any organic solvent that can dissolve the reactants without reacting with the compound of formula (I) is acceptable. Examples include tetrahydrofuran (THF), diethyl ether (Et2O), benzene, toluene, 1,4-dioxane, dimethyl ethylene glycol ether (DME), or tetramethylethylenediamine (TMEDA).

[0085] For the ratio of compound (I) to compound (II), the amount of compound (II) used relative to compound (I) is 0.2 to 1 molar equivalent, preferably 0.4 to 0.9 molar equivalent.

[0086] The solvents used in steps 1-1, 1-2, and 1-3 above can be the same or different. For ease of operation and post-processing, it is preferred that the solvents in each step be the same; however, for optimal yield and effect, it is also preferred that the solvents in each step be different.

[0087] As can be seen from the above preparation method, the preparation method disclosed in this invention has very mild reaction conditions and a short reaction time. In addition, as can be seen from the reaction operation of the embodiments described later, the post-processing operation is also simple, and a high yield can be obtained.

[0088] The preparation method of the above compounds is described in detail below through examples.

[0089] Step 1-1 Synthesis of Compound (V)

[0090] Example 1: Synthesis of 2,2'-dilithium-1,1'-biphenyl

[0091]

[0092] At room temperature, 2.0 mmol of 2,2'-dibromo-1,1'-biphenyl was added to a 50 mL reaction flask and dissolved in 20 mL of diethyl ether. Then, 2.8 mL of n-butyllithium (4.4 mmol, 1.6 M) was added at -78 °C. After reacting at this low temperature for 1 hour, the reaction system became a pale yellow solution. After returning to room temperature and continuing the reaction for another 3 hours, the reaction was confirmed to be complete by GC-MS. The ether solvent was removed under reduced pressure to obtain 2,2'-dilithium-1,1'-biphenyl (white solid).

[0093] Key NMR data: 1 H NMR (400MHz, THF-d8): 6.87 (t, J = 6.9 Hz, 2H, CH), 7.12 (t, J = 7.8 Hz, 2H, CH), 7.96 (dd, J = 6.5, 1.8 Hz, 4H, CH).

[0094] Example 2: Synthesis of 4,4'-di-tert-butyl-2,2'-dilithium-1,1'-biphenyl

[0095]

[0096] At room temperature, 2.0 mmol of 4,4'-di-tert-butyl-2,2'-dibromo-1,1'-biphenyl was added to a 50 mL reaction flask and dissolved in 20 mL of diethyl ether. Then, 2.8 mL of n-butyllithium (4.4 mmol, 1.6 M) was added at -78 °C. After reacting at this low temperature for 1 hour, the reaction system became a pale yellow solution. After returning to room temperature and continuing the reaction for another 3 hours, the reaction was confirmed to be complete by GC-MS. The reaction solvent, diethyl ether, was removed under reduced pressure to obtain 4,4'-di-tert-butyl-2,2'-dilithium-1,1'-biphenyl (white solid).

[0097] Key NMR data: 1 H NMR(400MHz,THF-d8):1.27(s,18H, t Bu), 7.16 (dd, J=8.4, 2.5Hz, 2H, CH), 7.91 (d, J=8.4Hz, 2H, CH), 8.09 (d, J=2.4Hz, 2H, CH).

[0098] Example 3: Synthesis of 4-trifluoromethoxy-2,2'-dilithium-1,1'-biphenyl

[0099]

[0100] At room temperature, 2.0 mmol of 4-trifluoromethoxy-2,2'-dibromo-1,1'-biphenyl was added to a 50 mL reaction flask and dissolved in 20 mL of diethyl ether. Then, 2.8 mL of n-butyllithium (4.4 mmol, 1.6 M) was added at -78 °C. After reacting at this low temperature for 1 hour, the reaction system became a pale yellow solution. After returning to room temperature and continuing the reaction for another 3 hours, the reaction was confirmed to be complete by GC-MS. The reaction solvent, diethyl ether, was removed under reduced pressure to obtain 4-trifluoromethoxy-2,2'-dilithium-1,1'-biphenyl (white solid).

[0101] Key NMR data: 1 H NMR (400MHz, THF-d8): 6.88 (m, 3H, CH), 7.09 (m, 1H, CH), 7.82 (s, 1H, CH), 7.96 (d, J = 6.7Hz, 2H).

[0102] Synthesis of compound (I) in steps 1-2

[0103] Example 4: Synthesis of 9-phosphafluorene lithium salt

[0104]

[0105] At room temperature, 1.0 mmol of 2,2'-dilithium-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, and then 1.1 mmol of white phosphorus was added. After reacting at room temperature for 12 hours, the reaction system became a dark brown solution. The tetrahydrofuran solvent was removed under reduced pressure, and the remaining solid was extracted multiple times with diethyl ether to obtain an orange solution. The diethyl ether solvent was removed again under reduced pressure to obtain 366 mg of 9-phosphaphene lithium salt (orange-yellow solid), with a separation yield of 99%.

[0106] Key NMR data: 1 H NMR(400MHz,THF-d8): δ1.76-1.79(m,8H,β-CH2,THF),3.60-3.63(m,8H,α-CH2,THF),6.79(t ,J=6.9Hz,2H,CH),6.86(t,J=7.1Hz,2H,CH),7.75-7.85(m,2H,CH),8.00(d,J=7.8Hz,2H,CH); 13 C NMR(126MHz,THF-d8): δ26.5(s,β-CH2,THF),68.4(s,α-CH2,THF),115.9(s,CH),120.5(s,C H),120.8(d,J=10.4Hz;CH),127.3(d,J=25.2Hz;quat.C),136.1(s,CH),158.3(m,quat.C); 31 P{ 1 H}NMR(202MHz,THF-d8): δ9.63(s).

[0107] Example 5: Synthesis of 2,7-di-tert-butyl-9-phosphafluorene lithium salt

[0108]

[0109] At room temperature, 1.0 mmol of 2,2'-dilithium-4,4'-di-tert-butyl-1,1'-biphenyl was added to a 25 mL reaction flask, dissolved in 10 mL of tetrahydrofuran, followed by the addition of 1.1 mmol of white phosphorus. After reacting at room temperature for 12 hours, the reaction system became a dark brown solution. The tetrahydrofuran solvent was removed under reduced pressure, and the remaining solid was extracted multiple times with diethyl ether to obtain a red solution. The diethyl ether solvent was removed again under reduced pressure to obtain 405 mg of 2,7-di-tert-butyl-9-phosphafluorene lithium salt (red solid), with a separation yield of 90%.

[0110] Key NMR data: 1 H NMR(400MHz,THF-d8)δ1.37(s,18H, tBu),1.76-1.79(m,4H,β-CH2,THF),3.60-3.63(m,4H,α-CH2,THF),6.89(dd,J= 8.3,2.0Hz,2H,CH),7.82(dd,J=5.0,1.9Hz,1H,CH),7.89(d,J=8.2Hz,1H,CH), 13 C NMR(101MHz,THF-d8)δ26.5(s,β-CH2,THF),32.7(s,CH3, t Bu), 35.3(s,quat.C, t Bu),68.4(s,α-CH2,THF),114.7(s,CH),120.0(s,CH),122.8(d,J=25.6Hz,CH),134 .4(d,J=2.0Hz,quat.C),142.3(d,J=10.5Hz,quat.C),158.1(d,J=35.2Hz,quat.C); 31 P{ 1 H}NMR(202MHz,THF-d8):δ0.87(s).

[0111] Synthesis of compound (III) in steps 1-3

[0112] Example 7: Synthesis of 1,4-bis(9-phosphafluorenyl)methylbenzene

[0113]

[0114] At room temperature, 0.4 mmol of lithium 9-phosphafluorene salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of p-dibromobenzyl was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was a pale yellow solution. The reaction solvent, tetrahydrofuran, was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The solvent, toluene, was removed again under reduced pressure to give 91 mg of 1,4-bis(9-phosphafluorene)methylbenzene (white solid), with a separation yield of 97%.

[0115] Key NMR data: 1 H NMR (400MHz, THF-d8): δ3.01 (s, 4H, CH2), 6.74 (s, 4H, CH), 7.29 (td, J = 7.4, 1.4Hz, 4H, CH), 7.42(td,J=7.6,1.0Hz,4H,CH),7.48(dd,J=7.2,3.9Hz,4H,CH),7.93(d,J=7.7Hz,4H,CH); 13C NMR (100MHz, THF-d8): δ37.6 (d, J = 23.3Hz), 122.3, 127.8-127.9 (m), 129.4, 129. 6-129.7(m),131.3(d,J=21.6Hz),135.6(t,J=2.5Hz),143.7(d,J=8.1Hz),145.0; 31 P{ 1 H}NMR(202MHz,THF-d8):δ-11.26(s).

[0116] Example 8: Synthesis of 1,3-bis(9-phosphafluorenyl)methylbenzene

[0117]

[0118] At room temperature, 0.4 mmol of lithium 9-phosphafluorene salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of m-dibromobenzyl was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was an orange-red solution. The reaction solvent, tetrahydrofuran, was removed under reduced pressure, and the remaining solid was extracted with toluene to give a pale red solution. The solvent, toluene, was removed again under reduced pressure to give 94 mg of 1,3-bis(9-phosphafluorene)methylbenzene (pale red solid), with a separation yield of 99%.

[0119] Key NMR data: 1 H NMR (400MHz, THF-d8): δ2.97(s,4H,CH2),6.72-6.74(m,3H,CH),6.97(t,J=7.5Hz,1H,CH),7.25(td,J=7 .3,2.2Hz,4H,CH),7.39(t,J=7.5Hz,4H,CH),7.44(dd,J=7.2,4.3Hz,4H,CH),7.92(d,J=7.7Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ38.0 (d, J = 23.1Hz), 122.3, 127.9 (d, J = 7.4Hz), 128.6, 129.4, 131.0(t,J=5.4Hz),131.3(d,J=21.2Hz),138.0-138.0(m),143.7(d,J=8.4Hz),145.0; 31 P{ 1 H}NMR(202MHz,THF-d8):δ-11.86(s).

[0120] Example 9: Synthesis of 2,6-bis(9-phosphafluorenyl)methylpyridine

[0121]

[0122] At room temperature, 0.4 mmol of 9-phosphafluorene lithium salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, followed by 0.2 mmol of 2,6-dibromomethylpyridine. The reaction mixture was reacted at room temperature for 12 hours, resulting in a pale yellow solution. The tetrahydrofuran solvent was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The toluene solvent was then removed again under reduced pressure to give 93 mg of 2,6-bis(9-phosphafluorene)methylpyridine (pale yellow solid), with a separation yield of 98%.

[0123] Key NMR data: 1 H NMR (400MHz, THF-d8): δ3.23(s,4H,CH2),6.62(d,2H,CH),7.23-7.27(m,5H,CH),7.39 (td,J=7.7,1.0Hz,4H,CH),7.66(dd,J=7.4,4.3Hz,4H,CH),7.93(d,J=7.7Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ40.3(d,J=23.7Hz),121.4-121.4(m),122.2,127.9(d,J =7.1Hz), 129.3, 131.7 (d, J = 21.3Hz), 136.7, 144.3 (d, J = 8.5Hz), 144.9, 158.3; 31 P{ 1 H}NMR(202MHz,THF-d8): δ-13.91(s).

[0124] Example 10: Synthesis of 1,2-bis(9-phosphafluorenyl)methylbenzene

[0125]

[0126] At room temperature, 0.4 mmol of lithium 9-phosphafluorene salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of m-dibromobenzyl was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was an orange-red solution. The reaction solvent, tetrahydrofuran, was removed under reduced pressure, and the remaining solid was extracted with toluene to give a pale red solution. The solvent, toluene, was removed again under reduced pressure to give 93 mg of 1,2-bis(9-phosphafluorene)methylbenzene (pale red solid), with a separation yield of 99%.

[0127] Key NMR data: 1H NMR (400MHz, THF-d8): δ3.09(s,4H,CH2),6.89-6.91(m,2H,CH),6.89-6.91(m,2H,CH),7.08-7.11(m,4H,CH),7.23( td,J=7.4,1.5Hz,4H,CH),7.35(dd,J=7.3,3.7Hz,4H,CH),7.42(td,J=7.7,1.1Hz,4H,CH),7.97(d,J=7.8Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ36.4 (dd, J=23.4, 6.2Hz), 122.4, 127.2, 127.9-128.0 (m) ,129.5,131.2,131.7-131.8(m),136.7(t,J=2.9Hz),143.8(d,J=8.0Hz),144.9; 31 P{ 1 H}NMR(202MHz,THF-d8):δ-16.31(s).

[0128] Example 11: Synthesis of 1,6-bis(9-phosphafluorenyl)methylhexane

[0129]

[0130] At room temperature, 0.4 mmol of lithium 9-phosphafluorene salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of 1,6-dibromohexane was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was a pale yellow solution. The tetrahydrofuran solvent was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The toluene solvent was removed again under reduced pressure to give 89 mg of 1,6-bis(9-phosphafluorene)methylhexane (pale yellow solid), with a separation yield of 99%.

[0131] Key NMR data: 1 H NMR (400MHz, THF-d8): δ1.23-1.29(m,8H,CH2),1.66-1.70(m,4H,CH2),7.30(dd,J=7.3,1.9Hz ,4H,CH),7.41(t,J=7.5Hz,4H,CH),7.68(dd,J=7.1,4.8Hz,4H,CH),7.96(d,J=7.7Hz,4H,CH); 13C NMR (100MHz, THF-d8): δ26.7(d,J=8.1Hz), 30.4(d,J=19.3Hz), 31.5(d,J=9.8Hz), 122.3, 128.0 (d, J = 7.4Hz), 129.1, 130.7 (d, J = 21.5Hz), 144.5 (d, J = 6.5Hz), 144.9 (d, J = 1.5Hz); 31 P{ 1 H}NMR(202MHz,THF-d8):δ-14.43(s).

[0132] Example 12: Synthesis of 1,5-bis(9-phosphafluorenyl)methylpentane

[0133]

[0134] At room temperature, 0.4 mmol of 9-phosphafluorene lithium salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of 1,5-dibromopentane was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was a pale yellow solution. The reaction solvent, tetrahydrofuran, was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The solvent, toluene, was removed again under reduced pressure to give 78 mg of 1,5-bis(9-phosphafluorene)methylpentane (pale yellow solid), with a separation yield of 99%.

[0135] Key NMR data: 1 H NMR (400MHz, THF-d8): δ1.24-1.34(m,6H,CH2),1.62-1.69(m,4H,CH2),7.29(td,J=7.3,2.2Hz ,4H,CH),7.41(t,J=7.1Hz,4H,CH),7.66(dd,J=7.2,4.8Hz,4H,CH),7.96(d,J=7.7Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ26.2(d,J=8.0Hz), 30.2(d,J=19.4Hz), 33.3(t,J=9.7Hz), 122.3, 128.0(d,J=7.5Hz), 129.1, 130.7(d,J=21.5Hz), 144.5(d,J=6.5Hz), 144.9(d,J=1.6Hz); 31 P{ 1 H}NMR(202MHz,THF-d8):δ-14.38(s).

[0136] Example 13: Synthesis of 1,4-bis(9-phosphafluorenyl)methylbutane

[0137]

[0138] At room temperature, 0.4 mmol of 9-phosphafluorene lithium salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of 1,4-dibromobutane was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was a pale yellow solution. The reaction solvent, tetrahydrofuran, was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The solvent, toluene, was removed again under reduced pressure to give 79 mg of 1,4-bis(9-phosphafluorene)methylbutane (pale yellow solid), with a separation yield of 93%.

[0139] Key NMR data: 1 H NMR (400MHz, THF-d8): δ1.27-1.33(m,4H,CH2),1.64-1.67(m,4H,CH2),7.24-7.32(m,4H,CH ),7.39(td,J=7.7,1.1Hz,4H,CH),7.64(dd,J=7.3,4.7Hz,4H,CH),7.94(d,J=7.8Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ28.2 (dd, J = 9.8, 8.1Hz), 30.0 (d, J = 19.7Hz), 122.3, 128.0 (d, J = 7.5Hz), 129.1, 130.8 (d, J = 21.5Hz), 144.3 (d, J = 6.5Hz), 144.9; 31 P{ 1 H}NMR(202MHz,THF-d8):δ-14.45(s).

[0140] Example 14: Synthesis of 1,3-bis(9-phosphafluorenyl)methylpropane

[0141]

[0142] At room temperature, 0.4 mmol of lithium 9-phosphafluorene salt was added to a 25 mL reaction flask, dissolved in 8 mL of tetrahydrofuran, and then 0.2 mmol of 1,3-dibromopropane was added. The reaction mixture was reacted at room temperature for 12 hours. The reaction system was a pale yellow solution. The tetrahydrofuran solvent was removed under reduced pressure, and the remaining solid was extracted with toluene to obtain a pale yellow solution. The toluene solvent was removed again under reduced pressure to give 74 mg of 1,3-bis(9-phosphafluorene)methylpropane (pale yellow solid), with a separation yield of 91%.

[0143] Key NMR data: 1H NMR (400MHz, C6D6): δ1.32-1.37(m,2H,CH2),1.51-1.55(m,4H,CH2),7.08-7.12(m,4H,CH) ,7.21(td,J=7.6,1.1Hz,4H,CH),7.45(dd,J=7.2,4.7Hz,4H,CH),7.68(d,J=7.7Hz,4H,CH); 13 C NMR (100MHz, THF-d8): δ

[0144] 23.0 (t, J = 8.0Hz), 31.5 (dd, J = 20.4, 9.1Hz), 122.3, 128.0 (d, J = 7.5Hz), 129.2, 130.8 (d, J = 21.5Hz), 144.1 (d, J = 6.5Hz), 145.0 (d, J = 1.4Hz); 31 P{ 1 H}NMR(202MHz,THF-d8):δ-15.84(s).

[0145] Industry availability

[0146] The organobisphosphine compounds based on the phosphonium fluorene structural unit of the present invention have broad application prospects as organophosphine ligands in organometallic chemistry or organic synthesis methodology.

Claims

1. A method for preparing a bisphosphine compound, which is a method for preparing a bisphosphine compound containing a diphosphine fluorene structural unit as shown in formula (III), characterized in that: In equation (III): R 1 R 2 R 3 R 4 They may be the same or different, and each can be hydrogen, trifluoromethoxy, or a C1-C6 alkyl group; Q represents alkylene (C1-C6), phenylene, or pyridylene. The preparation method includes the following steps: Step 1-1: Prepare compound (V) by reacting compound (IV) with an organometallic reagent at low temperature; In compounds of formula (IV) and (V), R 1 R 2 Similar to equation (III) above, X 1 It is chlorine or bromine; The organometallic reagent used in step 1-1 is an organolithium reagent, which is n-butyllithium or tert-butyllithium; The low temperature range is -120°C to -60°C; The organometallic reagent used is in a ratio of 2 to 3 molar equivalents to the compound of formula (IV); Steps 1-2: Compound (I) is prepared by reacting compound (V) with white phosphorus at room temperature or above. The white phosphorus used is in a ratio of 1 to 1.5 molar equivalents relative to the compound of formula (V); Sol represents the coordinating solvent, which is tetrahydrofuran or diethyl ether; n represents the number of coordinating solvents, where n is a positive integer or half-integer greater than 0 and less than 3. The above-room temperature refers to room temperature to 50°C; Steps 1-3: Prepare compound (III) by reacting compound (I) with compound (II); Among them, compound (II) is a dihalogenated compound, X 2 It is chlorine or bromine, and Q is the same as in formula (III) above; For the ratio of compound (I) to compound (II), the compound (II) used is 0.2 to 1 molar equivalent relative to compound (I).

2. The method for preparing the bisphosphine compound according to claim 1, characterized in that, In step 1-1, the reaction is carried out at low temperature for 0.5 to 3 hours, and then the reaction continues at room temperature for 2 to 6 hours. In steps 1-2, the reaction time is 6–24 hours. In steps 1-3, the reaction temperature is between room temperature and 50°C, and the reaction time is 6 to 24 hours.

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