Preparation method of tris (methylcyclopentadienyl) yttrium

Abstract

The invention relates to a preparation method of tris (methyl cyclopentadienyl) yttrium, which comprises the following steps: under a protective atmosphere, S1, carrying out first heating reaction on yttrium chloride and methyl cyclopentadienyl sodium in the presence of a first organic solvent, and adding an organic ligand to carry out second heating reaction after full reaction to obtain an intermediate product; the organic ligand is lithium bis (trimethylsilyl) amide and / or potassium bis (trimethylsilyl) amide; and S2, carrying out a stirring reaction on the intermediate product and methyl cyclopentadiene in the presence of a second organic solvent, filtering, collecting filtrate, and removing the solvent to obtain the tri (methyl cyclopentadienyl) yttrium. According to the preparation method, chlorine which is not substituted by methyl cyclopentadienyl in N (TMS) 2-substituted yttrium chloride is introduced and then substituted by methyl cyclopentadiene to prepare tris (methyl cyclopentadienyl) yttrium, so that the substitution efficiency of chlorine in the raw material yttrium chloride can be effectively improved, the yield of a target product is greatly improved and can reach 86%, and the purity can reach 5N.

Description

Technical Field

[0001] This invention relates to the fields of organic chemistry and microelectronic materials technology, specifically to a method for preparing tris(methylcyclopentadienyl)yttrium. Background Technology

[0002] Tris(methylcyclopentadienyl)yttrium(III) (hereinafter referred to as (MeCp)3Y) is an important class of organoraven-earth metal complexes with broad application prospects in olefin polymerization catalysts, organic synthesis reagents, and precursors for new materials. For example, it is used as a precursor source material for the deposition preparation of yttrium oxide. In the microelectronics field, yttrium oxide is mainly used as a high-performance dielectric material, diffusion barrier layer, and encapsulation material, and is widely used in advanced integrated circuits, MEMS, optoelectronic devices, and other high-end technologies. These applications demonstrate the diversity and importance of yttrium oxide in modern science and industry, and with the development of materials science and nanotechnology, the potential application areas of yttrium oxide are constantly expanding.

[0003] Currently, the conventional methods for synthesizing (MeCp)3Y in this field mainly draw upon the synthetic routes of other rare earth metallocenes, namely, employing metathesis reactions. This traditional method typically uses anhydrous yttrium trichloride (YCl3) and sodium methylcyclopentadienyl (MeCpNa) as raw materials, reacting them in an inert organic solvent (such as toluene, tetrahydrofuran, etc.). A typical chemical reaction equation is shown below: YCl3+ 3 MeCpNa → (MeCp)3Y + 3 NaCl Although this route is feasible in principle and is a standard method for preparing rare-earth metal cyclopentadiene compounds in the laboratory, it has significant and urgent drawbacks in its practical application to the preparation of (MeCp)3Y. The most prominent problem is the generally low yield. This is due to the inherent low reaction efficiency, unavoidable side reactions, and large post-processing losses in the above-mentioned synthetic method, which results in the yield of (MeCp)3Y remaining at a low level (usually below 60%) for a long time. This greatly limits the large-scale preparation and practical application of this compound and also increases its cost.

[0004] Therefore, there is an urgent need for a preparation method that can obtain high yield and high purity (MeCp)3Y, in order to reduce the preparation cost of this compound and promote its wider application in different fields. Summary of the Invention

[0005] To address the low yield issue in traditional synthetic methods for (MeCp)3Y, this invention provides a method for preparing tris(methylcyclopentadienyl)yttrium. After the chlorine atom in yttrium chloride is partially substituted with a methylcyclopentadienyl group, a specific organic ligand is introduced to replace the unsubstituted chlorine atoms in the yttrium chloride to obtain an intermediate product. This intermediate product is then substituted with methylcyclopentadiene to prepare tris(methylcyclopentadienyl)yttrium. By introducing this intermediate product, the substitution efficiency of chlorine in the raw material yttrium chloride can be effectively improved, thereby significantly increasing the yield of the target product, which can reach up to 86%, and the purity can reach 5N.

[0006] Specifically, the following technical solutions are provided: The first aspect of this invention provides a method for preparing tris(methylcyclopentadienyl)yttrium, comprising the following steps: under a protective atmosphere, S1. Yttrium chloride and sodium methylcyclopentadienyl chloride are subjected to a first heating reaction in the presence of a first organic solvent. After the reaction is complete, an organic ligand is added and a second heating reaction is carried out to obtain an intermediate product. The organic ligand is lithium di(trimethylsilyl)amino (LiN(TMS)2) and / or potassium di(trimethylsilyl)amino (KN(TMS)2). S2. The intermediate product is directly reacted with methylcyclopentadiene by stirring, or reacted by stirring in the presence of a second organic solvent. After the reaction is complete, the filtrate is collected by filtration and the solvent is removed to obtain the tris(methylcyclopentadienyl)yttrium.

[0007] This invention was discovered accidentally by the inventors during the optimization of the synthesis method of tris(methylcyclopentadienyl)yttrium. By replacing the chlorine atom in yttrium chloride with a methylcyclopentadienyl group, and then introducing specific organic ligands bis(trimethylsilyl)aminolithium and / or bis(trimethylsilyl)aminopotassium to replace the unsubstituted chlorine atoms in yttrium chloride, followed by the addition of methylcyclopentadiene to replace the bis(trimethylsilyl)amino group to prepare tris(methylcyclopentadienyl)yttrium, the yield of the target product can be effectively improved. However, changing the order of adding methylcyclopentadienyl sodium and the organic ligand, or directly using sufficient amounts of the aforementioned organic ligand to fully react with yttrium chloride before reacting with methylcyclopentadiene to prepare the target product, significantly reduces the yield of the target product. Furthermore, replacing the aforementioned specific organic ligand with other organic ligands such as dimethylaminolithium and diethylaminolithium fails to yield the target product.

[0008] Furthermore, the protective atmosphere includes, but is not limited to, nitrogen.

[0009] Further, in step S1, the preferred molar ratio of yttrium chloride to sodium methylcyclopentadienyl and organic ligand is 1:(2-2.4):1, such as 1:2:1, 1:2.1:1, 1:2.2:1, 1:2.3:1, 1:2.4:1, etc., including but not limited to the molar ratios listed above.

[0010] In this invention, the molar ratio of yttrium chloride to sodium methylcyclopentadienyl chloride affects the product yield. If the molar ratio is less than 2, insufficient ligands will bind to yttrium chloride, reducing the product yield. Furthermore, experiments have shown that within the preferred range, decreasing the amount of sodium methylcyclopentadienyl chloride and increasing the amount of organic ligands significantly reduces the yield. Excessive sodium methylcyclopentadienyl chloride, for example, a ratio greater than 2.4, negatively impacts product purification and reduces the yield. Simultaneously, when the molar ratio of yttrium chloride to sodium methylcyclopentadienyl chloride is 1:(2-2.4), the amount of organic ligand added should also be limited, as excessive addition will generate byproducts, hindering product purification.

[0011] Under the above-mentioned molar ratio conditions, the chemical reaction equations involved in the preparation method are as follows: YCl3+2 MeCpNa→YCl(MeCp)2+2 NaCl; YCl(MeCp)2+KN(TMS)2→Y(MeCp)2[N(TMS)2]+KCl; Y(MeCp)2[N(TMS)2]+MeCpH→Y(MeCp)3+HN(TMS)2.

[0012] Further, in step S1, the first organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane, more preferably toluene.

[0013] Furthermore, in step S1, the temperature of the first heating reaction is 60-100 ℃, such as 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, etc., and the reaction time is not less than 4 h, such as 6 h, etc.

[0014] Furthermore, in step S1, the temperature of the second heating reaction is 60-100 ℃, such as 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, etc., and the reaction time is not less than 1 h, such as 1 h, 2 h, etc.

[0015] Furthermore, after the second heating reaction in step S1, methylcyclopentadiene can be directly added to the mixed solution containing the intermediate product and stirred for reaction, or the filtrate can be filtered to separate the intermediate product, and after desolventizing to obtain the intermediate product, the intermediate product and methylcyclopentadiene can be stirred for reaction in the presence of a second organic solvent.

[0016] Furthermore, the preferred molar ratio of the organic ligand to the methylcyclopentadiene is 1:(1-2) to fully replace N(TMS)2 in the intermediate product. - Adding a functional group can improve the yield of the target product; however, if too much is added, methylcyclopentadiene is prone to dimerization and may undergo some side reactions with the product, which may lead to a decrease in yield.

[0017] Further, in step S2, the second organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane.

[0018] Furthermore, in step S2, the temperature of the stirring reaction is preferably -20~80 ℃, and the reaction time is not less than 1 hour, for example, reacting at 80 ℃ for 1 hour.

[0019] Furthermore, the preparation method further includes a step of sublimating the tris(methylcyclopentadienyl)yttrium obtained by removing the solvent in step S2 to obtain tris(methylcyclopentadienyl)yttrium with a purity of 5 N.

[0020] Furthermore, the sublimation was carried out at 155-185 °C for 1 Torr.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for preparing tris(methylcyclopentadienyl)yttrium. The method involves replacing the chlorine atom in yttrium chloride with a methylcyclopentadienyl group, then introducing specific organic ligands lithium di(trimethylsilyl)amino and / or potassium di(trimethylsilyl)amino to replace the unsubstituted chlorine atoms in yttrium chloride to prepare an intermediate product. Finally, methylcyclopentadiene is added to replace the di(trimethylsilyl)amino group to prepare tris(methylcyclopentadienyl)yttrium. This method effectively increases the yield of the target product (not less than 70%), and can even reach up to 86%, with a product purity of up to 5N, meeting the purity requirements of precursor materials for yttrium oxide in the microelectronics field. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of tris(methylcyclopentadienyl)yttrium; Figure 2 The 1H NMR spectrum of tris(methylcyclopentadienyl)yttrium prepared in Example 1. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms “comprising” or “including” used in this invention may also be replaced with the closed form “is” or “consisting of”.

[0025] Example 1: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium, the specific operation of which is as follows: Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and sodium methylcyclopentadienyl (0.4 mol, 40.8 g) were transferred into a reaction flask. 500 mL of toluene was added at room temperature, and the mixture was heated to 80 °C for 6 hours. Then, a toluene solution of KN(TMS)2 (0.2 mol, 40.0 g) was added, and the mixture was stirred at this temperature for another hour. Freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added, and the mixture was stirred at this temperature for another hour. The mixture was filtered, the solvent was removed from the filtrate, and the solution was sublimated at 180 °C under 1 Torr vacuum to obtain the product: a pale yellow solid (0.164 mol, 53.5 g), with a yield of 82%. The 1H NMR spectrum is shown below. Figure 2 As shown. The ICP test result shows the product purity is 5N.

[0026] Example 2: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium, the specific operation of which is as follows: Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and sodium methylcyclopentadienyl (0.4 mol, 40.8 g) were transferred into a reaction flask. Toluene (500 mL) was added at room temperature, and the mixture was heated at 80 °C for 6 hours. Then, a toluene solution of LiN(TMS)2 (0.2 mol, 33.5 g) was added, and the mixture was stirred at this temperature for another hour. Freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added, and the mixture was stirred at this temperature for another hour. The mixture was filtered, the solvent was removed from the filtrate, and the product was sublimated at 180 °C under a vacuum of 1 Torr to obtain a pale yellow solid (0.158 mol, 51.5 g), with a yield of 79%. NMR confirmed it to be the target product, tris(methylcyclopentadienyl)yttrium. ICP testing showed the product purity to be 5N.

[0027] Example 3: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium, the specific operation of which is as follows: (1) Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and sodium methylcyclopentadienyl (0.4 mol, 40.8 g) were transferred into the reaction flask. 500 mL of toluene was added at room temperature. After heating at 80 °C for 6 hours, a toluene solution of KN(TMS)2 (0.2 mol, 40.0 g) was added. The reaction was continued at this temperature for 1 hour with stirring. The mixture was then filtered, and the solvent was removed from the filtrate to obtain the intermediate product.

[0028] (2) The intermediate product was dissolved in toluene at room temperature, and freshly depolymerized methylcyclopentadiene (0.2 mol, 16.1 g) was added. The mixture was stirred at 80 °C for 1 hour. The product was then sublimated at 180 °C under a vacuum of 1 Torr to obtain a pale yellow solid (0.172 mol, 56.1 g), with a yield of 86%. The product was confirmed by NMR to be the target product tris(methylcyclopentadienyl)yttrium. The purity of the product was determined by ICP testing to be 5N.

[0029] Example 4: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The only difference from Example 3 is that in step (2), the intermediate product is dissolved in a large amount of freshly depolymerized methylcyclopentadiene (0.8 mol, 64.1 g) at room temperature, and the reaction is continued to be stirred at room temperature for 1 hour.

[0030] All other procedures were performed identically, yielding a pale yellow solid (0.162 mol, 52.9 g) with a yield of 81%, which was confirmed by NMR to be the target product, tris(methylcyclopentadienyl)yttrium. ICP analysis showed the product purity to be 5N.

[0031] Example 5: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The only difference from Example 3 is that in step (2), an equal volume of tetrahydrofuran is used to replace toluene.

[0032] All other procedures were performed identically, yielding a pale yellow solid (0.142 mol, 46.3 g) with a yield of 71%, which was confirmed by NMR to be the target product, tris(methylcyclopentadienyl)yttrium. ICP analysis showed the product purity to be 5N.

[0033] Example 6: This example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The only difference from Example 3 is that in step (1), the amount of sodium methylcyclopentadienyl added is 0.48 mol.

[0034] All other procedures were performed identically, yielding a pale yellow solid (0.162 mol, 52.9 g) with a yield of 81%, which was confirmed by NMR to be the target product, tris(methylcyclopentadienyl)yttrium. ICP analysis showed the product purity to be 5N.

[0035] Comparative Example 1: This comparative example relates to a method for preparing tris(methylcyclopentadienyl)yttrium, the specific operation of which is as follows: Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and sodium methylcyclopentadienyl (0.6 mol, 61.2 g) were transferred into a reaction flask. 500 mL of toluene was added at room temperature, and the mixture was heated at 80 °C for 8 hours. After filtration, the filtrate was desolventized and sublimed at 180 °C under a vacuum of 1 Torr to obtain the product, a pale yellow solid (0.118 mol, 38.5 g), with a yield of 59%. NMR confirmed it to be the target product, tris(methylcyclopentadienyl)yttrium. ICP testing showed the product purity to be 5N.

[0036] Comparative Example 2: This comparative example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The difference from Example 1 is that YCl3 and three equivalents of KN(TMS)2 are reacted completely first, and then methylcyclopentadiene is added for further reaction. The specific operation is as follows: Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and 500 mL of toluene were transferred into a reaction flask. A toluene solution of KN(TMS)2 (0.6 mol, 120.0 g) was added, and the mixture was heated at 80 °C for 6 hours. Then, freshly depolymerized methylcyclopentadiene (0.6 mol, 48.3 g) was added, and the mixture was stirred at this temperature for another hour. The mixture was filtered, the solvent was removed from the filtrate, and the solution was sublimated at 180 °C under 1 Torr vacuum to obtain the product: a pale yellow solid (0.042 mol, 13.7 g), with a yield of 21%. NMR confirmed it to be the target product, tris(methylcyclopentadienyl)yttrium. ICP testing showed the product purity to be 5N.

[0037] Compared to Example 3, the yield of the target product in this comparative example was significantly reduced. It is speculated that this is because the ligand is too sterically hindered and too basic, making it difficult to form the intermediate Y[N(TMS)2]3. The unreacted KN(TMS)2 reacts with methylcyclopentadiene to form methylcyclopentadienyl potassium, which reacts with the remaining chlorine on yttrium chloride, resulting in very low substitution efficiency.

[0038] Comparative Example 3: This comparative example relates to a method for preparing tris(methylcyclopentadienyl)yttrium, which differs from Example 1 in that the order of addition of sodium methylcyclopentadienyl and KN(TMS)2 is changed. The specific operation is as follows: Under nitrogen protection, freshly prepared YCl3 (0.2 mol, 39.1 g) and 500 mL of toluene were transferred into a reaction flask. A toluene solution of KN(TMS)2 (0.2 mol, 40.0 g) was added, and the mixture was heated at 80 °C for 1 hour. Then, sodium methylcyclopentadienyl (0.4 mol, 40.8 g) was added, and the mixture was heated at 80 °C for 6 hours. Freshly depolymerized methylcyclopentadiene (0.4 mol, 32.1 g) was added, and the mixture was stirred at this temperature for another hour. The mixture was filtered, the solvent was removed from the filtrate, and the product was sublimated at 180 °C under a vacuum of 1 Torr to obtain a pale yellow solid (0.064 mol, 20.9 g), with a yield of 32%. NMR confirmed it to be the target product, tris(methylcyclopentadienyl)yttrium. ICP testing showed the product purity to be 5N.

[0039] Comparative Example 4: This comparative example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The difference from Example 1 is that an equimolar amount of dimethylaminolithium was used to replace KN(TMS)2. All other operations were the same, and the target product was not obtained.

[0040] Comparative Example 5: This comparative example relates to a method for preparing tris(methylcyclopentadienyl)yttrium. The difference from Example 1 is that an equimolar amount of lithium diethylaminodimethylamine is used to replace KN(TMS)2. All other operations are the same, and the target product was not obtained.

[0041] The embodiments described above are merely preferred examples to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A process for the preparation of tris(methylcyclopentadienyl) yttrium, characterized in that, The method comprises the following steps: under a protective atmosphere, S1, the yttrium chloride and sodium methylcyclopentadienyl are subjected to a first heating reaction in the presence of a first organic solvent, and after sufficient reaction, an organic ligand is added for a second heating reaction to obtain an intermediate product; the organic ligand is lithium bis(trimethylsilyl)amide and / or potassium bis(trimethylsilyl)amide; S2, the intermediate product is subjected to a stirring reaction with methylcyclopentadiene directly or in the presence of a second organic solvent, and after sufficient reaction, the filtrate is collected by filtration and the solvent is removed to obtain the tris(methylcyclopentadienyl) yttrium.

2. The production method according to claim 1, characterized by, In step S1, the molar ratio of the yttrium chloride, sodium methylcyclopentadienyl, and organic ligand is 1: (2-2.4):

1.

3. The preparation method according to claim 1, characterized in that, In step S1, the first organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane.

4. The method of claim 1, wherein, In step S1, the temperature of the first heating reaction is 60-100 ℃, and the reaction time is not less than 4 h.

5. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the second heating reaction is 60-100 ℃, and the reaction time is not less than 1 h.

6. The method of claim 1, wherein, The molar ratio of the organic ligand to the methylcyclopentadiene is 1: (1-2).

7. The preparation method according to claim 1, characterized in that, In step S2, the second organic solvent is selected from one or more of toluene, tetrahydrofuran, and n-hexane.

8. The method of claim 1, wherein, In step S2, the temperature of the stirring reaction is -20-80 ℃, and the reaction time is not less than 1 h.

9. The method of claim 1, wherein, The preparation method further comprises a step of sublimating the tris(methylcyclopentadienyl) yttrium obtained by removing the solvent in step S2 to obtain tris(methylcyclopentadienyl) yttrium with a purity of 5 N.

10. The method of claim 9, wherein, The sublimation is carried out at 155-185 ℃ and 1 Torr.

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