A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II)

Abstract

This invention relates to a method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), belonging to the field of noble metal organometallic compound synthesis technology. The method involves de-airing a solvent and pentamethylcyclopentadiene to obtain a pretreated solvent and pretreated pentamethylcyclopentadiene, respectively. Under a protective atmosphere, ruthenium chloride is dissolved in the pretreated solvent to obtain a ruthenium solution. A reducing agent and pentamethylcyclopentadiene are added sequentially to the ruthenium solution, and the mixture is heated uniformly to 50-90°C and stirred for 4-10 hours. After cooling and crystallization, the solid and liquid are separated. The solid is washed sequentially with deionized water and methanol, and dried to obtain crude bis(pentamethylcyclopentadienyl)ruthenium(II). The crude bis(pentamethylcyclopentadienyl)ruthenium(II) is dissolved in hot anhydrous ethanol, filtered to remove impurities, and the filtrate is cooled and crystallized. After solid-liquid separation, the solid is dried to obtain high-purity bis(pentamethylcyclopentadienyl)ruthenium(II). This invention has a simple method, a product yield greater than 74%, and a purity of over 98%.

Description

Technical Field

[0001] This invention relates to a method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), belonging to the field of noble metal organometallic compound synthesis technology. Background Technology

[0002] Ruthenium thin films possess thermal stability, chemical stability, low resistivity, and a large work function, making them widely used in the manufacture of nanomaterials and semiconductor devices. Examples of such applications include transistor gate electrodes, DRAM or ferroelectric RAM capacitor electrode materials, resistive films, antimagnetic films for hard disk recording layers, and solid polymer fuel cell electrode catalyst materials.

[0003] Chemical vapor deposition (CVD) and atomic layer deposition (ALD) are the main methods for preparing ruthenium-containing thin films. CVD and ALD readily yield uniform films with excellent step-by-step coverage capabilities, meeting the requirements of precision and density in electronic device components, and are becoming important technologies for thin film manufacturing in the microelectronics industry. Bis(pentamethylcyclopentadiene)ruthenium(II) exhibits low-temperature volatility and is an important precursor for the preparation of ruthenium-containing thin films and materials by CVD and ALD. It can also be used as a catalyst in chemical reaction processes.

[0004] There are very few literatures on the synthesis of bis(pentamethylcyclopentadienyl)ruthenium(II). It is mainly prepared by reacting (1,5-cyclooctadienyl)ruthenium chloride polymer with tributyl(pentamethylcyclopentadienyl)tin in ethanol. (Chemistry of Cyclopentadienyl-Ruthenium and -Osmium Complexes. 3. New High-Yield Syntheses of Ruthenocenes and Osmocenes. The Crystal and Molecular Structures of Decamethylruthenocene [Ru(η 5 -C5Me5)2] and Decamethylosmocene [Os(η 5 -C5Me5)2],Organometallics 1986, 5(11), 2321-2327。(1,5-cyclooctadiene)ruthenium chloride polymer can be prepared from hydrated ruthenium trichloride, while tributyl(pentamethylcyclopentadiene)tin is sensitive to water and oxygen in the air. The chemical reaction process requires strict anhydrous and oxygen-free operation. The raw materials are expensive and the operating conditions are harsh, making it difficult to achieve mass production. Summary of the Invention

[0005] To address the difficulties and harsh reaction conditions in the synthesis of bis(pentamethylcyclopentadienyl)ruthenium(II) in existing technologies, this invention proposes a method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II). This method utilizes readily available ruthenium chloride as a raw material. Under a protective atmosphere and with the participation of a reducing agent, the ruthenium chloride reacts with pentamethylcyclopentadiene in a one-step reaction to obtain crude bis(pentamethylcyclopentadienyl)ruthenium(II). The crude product is then purified by recrystallization to obtain the high-purity target product, bis(pentamethylcyclopentadienyl)ruthenium(II), with a yield greater than 74% and a purity higher than 98%.

[0006] A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II) includes the following steps:

[0007] (1) The solvent and pentamethylcyclopentadiene are subjected to de-air treatment to obtain pretreated solvent and pretreated pentamethylcyclopentadiene; the de-air treatment is to pass a protective gas (nitrogen, argon or helium) into the solution to replace the air, each time the gas is passed for no less than 30 minutes, and after the protective gas is stopped, a vacuum (vacuum degree of 0.07 atmospheres) is drawn for more than 10 minutes, and the above operation is repeated several times to remove the air;

[0008] (2) Under a protective atmosphere, ruthenium chloride is stirred and dissolved in a pretreatment solvent to obtain a ruthenium solution. A reducing agent and pentamethylcyclopentadiene are added to the ruthenium solution in sequence. The temperature is raised to 50-90℃ and stirred at a constant temperature for 4-10 hours (to prevent the reactants from evaporating due to heat and causing loss, the reaction is preferably carried out by reflux). The mixture is cooled to room temperature, and the solid and liquid are separated. The solid is washed with deionized water and methanol in sequence and dried under vacuum to obtain crude bis(pentamethylcyclopentadienyl)ruthenium(II).

[0009] (3) Crude bis(pentamethylcyclopentadienyl)ruthenium(II) was dissolved in hot anhydrous ethanol, filtered to remove impurities, the filtrate was cooled to crystallize, the solid and liquid were separated, and the solid was dried under vacuum to obtain high-purity bis(pentamethylcyclopentadienyl)ruthenium(II).

[0010] The solvent in step (1) is one or two of methanol, ethanol, isopropanol, and water, preferably an ethanol-water mixed solvent, with a volume ratio of ethanol to water of 1 to 3:1.

[0011] The protective atmosphere in step (2) is a nitrogen atmosphere, an argon atmosphere, or a helium atmosphere, preferably a nitrogen atmosphere.

[0012] The ruthenium chloride in step (2) is potassium pentachlororuthenate hydrate, ruthenium trichloride hydrate, ruthenium trichloride, ammonium hexachlororuthenate, or potassium hexachlororuthenate.

[0013] In step (2), the solid-liquid ratio of ruthenium chloride to pretreatment solvent is 1:5~15 g:mL.

[0014] The reducing agent in step (2) is hydrazine hydrochloride, hydrazine hydrate, formic acid or formaldehyde, and the amount of reducing agent used is 1.0 to 1.3 times the stoichiometry of the reduction reaction.

[0015] In step (2), the amount of pentamethylcyclopentadiene used is 4 to 10 times the stoichiometric amount.

[0016] The temperature of the heated anhydrous ethanol in step (3) is 40~70℃.

[0017] The beneficial effects of this invention are:

[0018] (1) This invention uses readily available ruthenium chloride as raw material. Under a protective atmosphere and with the participation of a reducing agent, the ruthenium chloride reacts with pentamethylcyclopentadiene in one step to obtain crude bis(pentamethylcyclopentadiene)ruthenium(II). After recrystallization and purification, the crude product is purified to obtain high-purity target product bis(pentamethylcyclopentadiene)ruthenium(II). The product yield is greater than 74% and the purity is higher than 98%.

[0019] (2) The method of the present invention is simple, has a high yield, and is easy to industrialize; it can solve the technical problems that the existing chemical synthesis reaction of bis(pentamethylcyclopentadiene)ruthenium(II) requires strict anhydrous and oxygen-free operation, the raw materials are expensive, the operating conditions are harsh, and it is not easy to achieve mass production. Attached Figure Description

[0020] Figure 1 For example 1, bis(pentamethylcyclopentadiene)ruthenium(II) 1 HNMR spectrum. Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0022] Example 1: A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), the specific steps of which are as follows:

[0023] (1) The water-ethanol mixed solvent (water and ethanol volume ratio of 1:1) and pentamethylcyclopentadiene were subjected to de-air treatment to obtain pretreated water-ethanol mixed solvent and pretreated pentamethylcyclopentadiene; specifically, nitrogen gas was introduced into the water-ethanol mixed solvent and pentamethylcyclopentadiene to replace the air, and the gas was introduced for 30 min each time. After stopping the nitrogen gas, the vacuum was drawn (vacuum degree of 0.07 atmospheres) and the air was exhausted for 30 min. The above operation was repeated 3 times to exhaust the air.

[0024] (2) Under a nitrogen atmosphere, 9.7 g of ruthenium trichloride hydrate (37 mmol) was stirred and dissolved in 100 mL of pretreated water-ethanol mixed solvent to obtain a ruthenium solution. A reducing agent (0.68 g (11 mmol) of hydrazine hydrate solution with a mass content of 80%) and 58 mL (370 mmol) of pentamethylcyclopentadiene were added to the ruthenium solution in sequence. The temperature was raised to 80 °C at a constant rate and stirred under reflux for 6 h. The mixture was cooled to room temperature and then transferred to an ice-water bath for 1 h to allow crystallization. The solid and liquid were separated, and the solid was washed with deionized water and methanol in sequence. The solid was dried under vacuum at 60 °C to obtain 12.0 g of grayish-white crude bis(pentamethylcyclopentadienyl)ruthenium(II).

[0025] (3) The crude bis(pentamethylcyclopentadienyl)ruthenium(II) was dissolved in hot anhydrous ethanol at 50°C, filtered at a constant temperature to remove impurities, the filtrate was cooled to crystallize, the solid and liquid were separated, and the solid was dried under vacuum at 60°C to obtain 11.2g of high-purity white bis(pentamethylcyclopentadienyl)ruthenium(II);

[0026] This embodiment uses bis(pentamethylcyclopentadiene)ruthenium(II). 1 HNMR spectrum Figure 1 The elemental analysis results showed Ru 27.30%, H 8.25%, C 64.53%, while the theoretical values ​​were Ru 27.20%, H 8.14%, C 64.66%, which matched the structure of the target product bis(pentamethylcyclopentadienyl)ruthenium(II). The synthesis yield was 81.5%.

[0027] Example 2: A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), the specific steps of which are as follows:

[0028] (1) The water-methanol mixed solvent (water and methanol volume ratio of 1:1) and pentamethylcyclopentadiene were de-aired to obtain pretreated water-methanol mixed solvent and pretreated pentamethylcyclopentadiene; specifically, He gas was introduced into the water-methanol mixed solvent and pentamethylcyclopentadiene to replace the air, and the gas was introduced for 40 min each time. After stopping the nitrogen gas, the vacuum was drawn (vacuum degree of 0.07 atmospheres) and the gas was exhausted for 40 min. The above operation was repeated 4 times to exhaust the air.

[0029] (2) Under a He atmosphere, 14.3 g of ammonium hexachlororuthenate hydrate (37 mmol) was stirred and dissolved in 200 mL of pretreated water-methanol mixed solvent to obtain a ruthenium solution. A reducing agent (1.7 g (24 mmol) of hydrazine hydrochloride) and 81 mL (518 mmol) of pentamethylcyclopentadiene were added to the ruthenium solution in sequence. The temperature was raised to 50 °C at a constant rate and stirred under reflux for 8 h. The solution was cooled to room temperature and then transferred to an ice-water bath for 1.5 h to allow crystallization. The solid and liquid were separated, and the solid was washed with deionized water and methanol in sequence. The solid was dried under vacuum at 80 °C to obtain 11.5 g of grayish-white crude bis(pentamethylcyclopentadienyl)ruthenium(II).

[0030] (3) The crude bis(pentamethylcyclopentadienyl)ruthenium(II) was dissolved in hot anhydrous ethanol at 60°C, filtered at constant temperature to remove impurities, the filtrate was cooled to crystallize, the solid and liquid were separated, and the solid was dried under vacuum at 80°C to obtain 10.9g of high-purity white bis(pentamethylcyclopentadienyl)ruthenium(II);

[0031] The elemental analysis results of bis(pentamethylcyclopentadienyl)ruthenium(II) in this embodiment are Ru 27.15%, H 8.15%, C 64.73%, which are consistent with the structure of the target product bis(pentamethylcyclopentadienyl)ruthenium(II), and the synthesis yield is 79.3%.

[0032] Example 3: A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), the specific steps of which are as follows:

[0033] (1) Methanol and pentamethylcyclopentadiene were subjected to de-air treatment to obtain pretreated methanol and pretreated pentamethylcyclopentadiene; specifically, Ar gas was introduced into methanol and pentamethylcyclopentadiene to replace the air, and the gas was introduced for 30 min each time. After stopping the nitrogen gas, the vacuum was drawn (the vacuum degree was 0.07 atmospheres) and the gas was exhausted for 30 min. The above operation was repeated 4 times to exhaust the air.

[0034] (2) Under an Ar atmosphere, 13.9 g of potassium pentachlororuthenate hydrate (37 mmol) was stirred and dissolved in 150 mL of pretreated methanol to obtain a ruthenium solution. A reducing agent (2.0 g of formic acid (44 mmol)) and 58 mL of pentamethylcyclopentadiene (370 mmol) were added to the ruthenium solution in sequence. The temperature was raised to 60 °C at a constant rate and stirred under reflux for 10 h. The solution was cooled to room temperature and then transferred to an ice-water bath for 2 h to allow crystallization. The solid and liquid were separated, and the solid was washed with deionized water and methanol in sequence. The solid was dried under vacuum at 70 °C to obtain 11.0 g of grayish-white crude bis(pentamethylcyclopentadienyl)ruthenium(II).

[0035] (3) The crude bis(pentamethylcyclopentadienyl)ruthenium(II) was dissolved in hot anhydrous ethanol at 60°C, filtered at a constant temperature to remove impurities, the filtrate was cooled to crystallize, the solid and liquid were separated, and the solid was dried under vacuum at 70°C to obtain 10.2g of high-purity white bis(pentamethylcyclopentadienyl)ruthenium(II);

[0036] The elemental analysis results of bis(pentamethylcyclopentadienyl)ruthenium(II) in this embodiment are Ru 27.26%, H 8.27%, C 64.61%, which are consistent with the structure of the target product bis(pentamethylcyclopentadienyl)ruthenium(II), and the synthesis yield is 74.2%.

[0037] Example 4: A method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II), the specific steps of which are as follows:

[0038] (1) The water-isopropanol mixed solvent (water and isopropanol volume ratio of 1:3) and pentamethylcyclopentadiene were subjected to de-air treatment to obtain pretreated water-isopropanol mixed solvent and pretreated pentamethylcyclopentadiene; specifically, Ar gas was introduced into the water-isopropanol mixed solvent and pentamethylcyclopentadiene to replace the air, and the gas was introduced for 35 min each time. After stopping the nitrogen gas, the vacuum was drawn (vacuum degree of 0.07 atmospheres) and the air was exhausted for 35 min. The above operation was repeated 3 times to exhaust the air.

[0039] (2) Under an Ar atmosphere, 14.5 g of potassium hexachlororuthenate (37 mmol) was stirred and dissolved in 80 mL of pretreated water-isopropanol mixed solvent to obtain a ruthenium solution. A reducing agent (formaldehyde 0.7 g (24 mmol)) and 93 mL (592 mmol) of pentamethylcyclopentadiene were added to the ruthenium solution in sequence. The temperature was raised to 70 °C at a constant rate and stirred under reflux for 7 h. The solution was cooled to room temperature and then transferred to an ice-water bath for 1 h to allow crystallization. The solid and liquid were separated, and the solid was washed with deionized water and methanol in sequence. The solid was dried under vacuum at 80 °C to obtain 11.1 g of grayish-white bis(pentamethylcyclopentadienyl)ruthenium(II) crude product.

[0040] (3) The crude bis(pentamethylcyclopentadienyl)ruthenium(II) was dissolved in hot anhydrous ethanol at 70°C, filtered at a constant temperature to remove impurities, the filtrate was cooled to crystallize, the solid and liquid were separated, and the solid was dried under vacuum at 80°C to obtain 10.3g of high-purity white bis(pentamethylcyclopentadienyl)ruthenium(II);

[0041] The elemental analysis results of bis(pentamethylcyclopentadienyl)ruthenium(II) in this embodiment are Ru 27.10%, H 8.25%, C 64.51%, which are consistent with the structure of the target product bis(pentamethylcyclopentadienyl)ruthenium(II), and the synthesis yield is 74.9%.

[0042] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A process for the preparation of bis(pentamethylcyclopentadienyl)ruthenium(II) characterized by, The specific steps are as follows: (1) the solvent and pentamethylcyclopentadiene are respectively subjected to deaeration treatment to obtain pretreated solvent and pretreated pentamethylcyclopentadiene; (2) under a protective atmosphere, the ruthenium-containing chloride is stirred and dissolved into the pretreated solvent to obtain a ruthenium solution, a reducing agent and pentamethylcyclopentadiene are sequentially added into the ruthenium solution, the temperature is uniformly increased to 50-90℃ and constant temperature stirring is performed for 4-10h, cooling and crystallization are performed, solid-liquid separation is performed, the solid is sequentially washed by deionized water and methanol, and drying is performed to obtain a crude bis(pentamethylcyclopentadienyl)ruthenium(II); the reducing agent is hydrazine hydrochloride, hydrazine hydrate, formic acid or formaldehyde, and the amount of the reducing agent is 1.0-1.3 times of the stoichiometric amount of the reducing reaction; (3) the crude bis(pentamethylcyclopentadienyl)ruthenium(II) is dissolved in hot anhydrous ethanol, impurities are removed by filtration, the filtrate is cooled and crystallized, solid-liquid separation is performed, and the solid is dried to obtain high-purity bis(pentamethylcyclopentadienyl)ruthenium(II).

2. The process according to claim 1 for the preparation of bis(pentamethylcyclopentadienyl)ruthenium(II) characterized by: The solvent in step (1) is one or two of methanol, ethanol, isopropanol and water.

3. The process according to claim 1 for the preparation of bis(pentamethylcyclopentadienyl)ruthenium(II) characterized by the fact that: The deaeration treatment of the solvent and pentamethylcyclopentadiene in step (1) is to replace air in the solution by passing a protective gas, and after stopping the passage of the protective gas, vacuum is applied to exhaust the air.

4. The process according to claim 1 for the preparation of bis(pentamethylcyclopentadienyl)ruthenium(II) characterized by the fact that: The protective atmosphere in step (2) is a nitrogen atmosphere, an argon atmosphere or a helium atmosphere.

5. The method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II) according to claim 1, characterized in that: The ruthenium-containing chloride in step (2) is hydrated potassium pentachlororuthenate, hydrated ruthenium trichloride, ruthenium trichloride, ammonium hexachlororuthenate or potassium hexachlororuthenate.

6. The method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II) according to claim 1, characterized in that: The solid-liquid ratio g:mL of the ruthenium-containing chloride to the pretreated solvent in step (2) is 1:5-15.

7. The method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II) according to claim 1, characterized in that: The amount of pentamethylcyclopentadiene in step (2) is 4-10 times of the stoichiometric amount.

8. The method for preparing bis(pentamethylcyclopentadienyl)ruthenium(II) according to claim 1, characterized in that: The temperature of the hot anhydrous ethanol in step (3) is 40-70℃.

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