A method for synthesizing Group VIB metal precursors

Abstract

This invention belongs to the field of transition metal organometallic synthesis technology, specifically disclosing a method for synthesizing a Group VIB metal precursor. The method includes: using the metal raw material MO2X2 and [R...] 1 The reaction of compounds with the N=C] structure to prepare intermediates (R) 1 The step of N)2MX2; making the intermediate and alkaline substance M 0 (NR 2 R 3 ) y The reaction yields a Group VIB metal precursor (R) 1 N)2M(NR 2 R 3 Step 2; where M is Mo or W, X is a halogen, and R 1 Selected from C1-C10 alkyl groups, R 2 R 3 At least one alkyl group independently selected from H and C1-C10, M 0 It is an alkali metal or an alkaline earth metal, and y is M. 0 The valence of the compounds. The synthesis method of this invention has a simple and efficient overall reaction route, short reaction time, high and stable reaction yield, and is suitable for industrial production. The obtained product is easier to purify, and the purity of the purified product can reach ≥6N.

Description

Technical Field

[0001] This invention relates to the field of transition metal organometallic synthesis technology, specifically to a method for synthesizing Group VIB metal precursors. Background Technology

[0002] Group VIB metals play a crucial role in semiconductor device manufacturing due to their unique physicochemical properties (such as high melting point, low resistivity, excellent thermal stability, and controllable band structure). For example, W (WN) or W / TiN stacks, as copper interconnect barrier layers, can suppress copper atom diffusion into the dielectric layer, improving interconnect reliability; as filler metals in vertical interconnect structures, they connect transistors to the underlying metal (contact holes) or metal layers (vias); they can also be used as capacitor electrodes in dynamic random access memory (DRAM) and as word line filling and hard mask barrier layers in three-dimensional non-volatile memory (3D NAND). For example, Mo (Mo), with its even lower resistivity, is an emerging alternative to W for high-density interconnect wiring and word line metallization in 3D NAND, reducing resistance and increasing I / O (input / output) bandwidth.

[0003] A series of Group VIB metal precursors have been developed, such as tungsten halides, molybdenum halides, molybdenum halide halides, carbonyl tungsten, carbonyl molybdenum, and organotungsten / molybdenum precursors. However, tungsten halides or molybdenum halides can generate halides during thin film preparation, leading to halogen residues in semiconductor devices. Furthermore, they can generate corrosive acids upon contact with water, corroding equipment and polluting the environment. Carbonyl tungsten is highly toxic and has poor stability, severely limiting its applications. In recent years, halogen-free organotungsten / molybdenum precursors with better thermal stability, such as (… t BuN)2W(NMe2)2 [bis(tert-butylimino)bis(dimethylamino)tungsten, i.e. BTBMW], ( t BuN)2Mo(NMe2)2 [bis(tert-butylimino)bis(dimethylamino)molybdenum, i.e. BTBMM], ( t BuN)2W(NEtMe)2

bis(tert-butylimino)bis(methylethylamino)tungsten

[0004] Taking BTBMW as an example, the following synthesis methods have been reported so far:

[0005] The first method was first developed by Roy G. Gordon et al. at Harvard University (Chem. Mater. 2003, 15(15), 2969–2976), and its synthetic route is as follows:

[0006]

[0007] The method requires four steps to synthesize BTBMW, each of which requires separation and purification. The operation is complex, time-consuming, and has a low yield (39%), which cannot meet the requirements for large-scale production.

[0008] The second method is a synthetic route (WO2020120150A1) developed by Umicore AG and its joint venture in Germany, and its synthetic route is as follows:

[0009]

[0010] This method first obtains the intermediate W( t BuN)2( t BuNH)2, this intermediate, after sublimation or purification, reacts with dimethylamine. During the reaction, liquid nitrogen is required to remove the dimethylamine and intermediate W( t BuN)2( t After BuNH2 solidifies, it is slowly heated to a liquid state and maintained at -15°C for the reaction, with an overall yield of 66%. This method requires very precise temperature control and involves the post-processing of a large amount of dimethylamine, making it difficult to scale up.

[0011] The third method is the one developed by MECARO Corporation of South Korea (KR102231296B1), and its synthetic route is as follows:

[0012]

[0013] This synthesis method requires extremely low temperatures (< -50 °C) and slow dropping rates, and the yield is only 32%.

[0014] The fourth method is the synthesis of BTBMW using sodium tungstate as a starting material, developed by Anhui Dunmao New Material Technology Co., Ltd. (CN112125931B). The synthesis route is as follows:

[0015]

[0016] Because the raw material sodium tungstate has a high Mo content, the synthesized BTBMW product also has a high Mo content that is difficult to remove, and the resulting product is difficult to meet the requirements of semiconductor thin film deposition.

[0017] The fifth method is the preparation of BTBMW from the reaction of WCl6 with tert-butylamine to synthesize an intermediate (CN115584487B), developed by Hefei Andekeming Semiconductor Technology Co., Ltd. The reaction route is as follows:

[0018]

[0019] The crude product obtained by this method contains impurities that are difficult to separate, and multiple purification processes are required to obtain a product with a metal purity of ≥6N, which seriously reduces the production efficiency of the product.

[0020] To address the problems existing in the prior art, this application develops a method for synthesizing BTBMW. This method is simple to operate, does not involve filtering intermediates, and yields a product with high purity that is easy to purify. Summary of the Invention

[0021] The purpose of this invention is to provide a method for synthesizing Group VIB metal precursors, so as to overcome the defects in the prior art, improve the production efficiency and yield of the Group VIB metal precursor synthesis process (especially the yield of industrial production), and obtain high-purity products.

[0022] First, this application provides a method for synthesizing a Group VIB metal precursor, comprising: A1, using the metal raw material MO2X2 and [R]... 1 The reaction of compounds with the N=C] structure to prepare intermediates (R) 1 Step N)2MX2; A2, making the intermediate and alkaline substance M 0 (NR 2 R 3 ) y The reaction yields a Group VIB metal precursor (R) 1 N)2M(NR 2 R 3 Step 2;

[0023] Where M is Mo or W, X is a halogen, and R is a halogen. 1 Selected from C1-C10 alkyl groups, R 2 R 3 At least one selected independently from H, C1-C10 alkyl groups, M 0 It is an alkali metal or an alkaline earth metal, and y is M. 0 The valence of the compound.

[0024] Furthermore, X is selected from any one of Cl, Br, and I, preferably Br or Cl.

[0025] In one embodiment, the [R]-containing 1 Compounds with the N=C] structure are R 1 NCO.

[0026] In one embodiment, the [R]-containing 1 Compounds with the N=C] structure are R 1 NCR'R", wherein R' and R" are independently selected from C1-C5 alkyl groups, such as, but not limited to, any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, etc.

[0027] Furthermore, the R 1 The alkyl group is selected from C1-C6, including, but not limited to, any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, etc. In one embodiment, the R... 2 R 3 Independently selected from at least one of H and C1-C8 alkyl groups, exemplified but not limited to at least one of H, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, neopentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1-ethylbutyl, 2,2-dimethylbutyl, n-heptane, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 3-ethylpentyl, 2,2-dimethylpentyl, n-octyl, 1-methylheptyl, 2-ethylhexyl, 2,2,4-trimethylpentyl, etc.

[0028] Furthermore, M 0 Selected from any one of Li, Na, K, Mg, Ca, Sr, and Ba; in one embodiment, M 0 It is an alkali metal, selected from any one of Li, Na, and K.

[0029] Furthermore, the MO2X2 and containing [R] 1The equivalence ratio of compounds with the N=C structure is 1:2-6, and the selectable equivalence ratios include, but are not limited to, any one of 1:2, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.7, 1:2.8, 1:3, 1:3.3, 1:3.5, 1:3.8, 1:4, 1:4.1, 1:4.3, 1:4.5, 1:4.8, 1:5.0, 1:5.2, 1:5.4, 1:5.6, 1:5.8, and 1:6. In one embodiment, the reaction temperature of Al is 60-120°C, and selectable temperatures include, but are not limited to, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, and 120°C. In one embodiment, the reaction time of A1 is 2-24 hours, preferably 4-12 hours, and more preferably 6-10 hours.

[0030] Preferably, the MO2X2 and the [R] 1 The equivalence ratio of compounds with the N=C] structure is 1:2-4; the reaction temperature of Al is 70-100℃.

[0031] Furthermore, the (R) 1 N)2MX2 and M 0 (NR 2 R 3 ) y The equivalence ratio is 1:2-5, and selectable equivalence ratios include, but are not limited to, any one of 1:2.1, 1:2.3, 1:2.5, 1:2.7, 1:2.9, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:4, 1:4.2, 1:4.4, 1:4.5, 1:4.7, 1:4.9, and 1:5; in one embodiment, the reaction temperature of A2 is 10-100°C, such as, but not limited to, 15-90°C, 20-100°C, 20-90°C, 20-80°C, and 20-70°C. The temperature range is selected from any one of the following: 20-60℃, 20-50℃, 20-45℃, 20-40℃, 20-35℃, 10-15℃, 10-20℃, 10-25℃, 10-30℃, 10-35℃, 10-40℃, 10-45℃, 10-50℃, 15-20℃, 15-25℃, 15-30℃, 15-40℃, 15-50℃, 15-60℃, 25-30℃, 25-35℃, 25-40℃, 25-50℃, 25-60℃, 25-70℃, 25-80℃. In one embodiment, the reaction time of A2 is 2-24 hours, preferably 3-12 hours, and more preferably 4-10 hours.

[0032] Preferably, the (R) 1 N)2MX2 and M 0 (NR2 R 3 ) y The equivalence ratio is 1:2-4; the reaction temperature of A2 is 15-50℃.

[0033] Furthermore, M 0 (NR 2 R 3 ) y It can be a commercially available chemical, or it can be produced by R. 4 M 0 and HNR 2 R 3 It can be prepared by reaction, or by metal M. 0 and HNR 2 R 3 The reaction yielded M, according to the present invention. 0 (NR 2 R 3 ) y The source or preparation method of the substance is not subject to mandatory restrictions.

[0034] Furthermore, the synthesis method includes the following steps: S1, mixing the metal raw material MO2X2 with [R... 1 The N=C] structure compound reacts with the first solvent to give a compound containing an intermediate (R). 1 N)2MX2 system one; S2, make R 4 M 0 and HNR 2 R 3 The reaction in the second solvent yields a substance M containing an alkaline base. 0 (NR 2 R 3 ) y System 2; S3, mix System 1 and System 2 and react to obtain the Group VIB metal precursor (R 1 N)2M(NR 2 R 3 2. Crude product; separation and purification of the crude product are sufficient;

[0035] Where R 4 It is selected from any one of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, 1-methylbutyl, 2-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, and 2,2-dimethylpropyl.

[0036] Further, the first solvent includes at least one of ether solvents, aromatic hydrocarbon solvents, nitrile solvents, halogenated hydrocarbon solvents, ester solvents, and nitrogen-cyclic solvents; in one embodiment, the ether solvent includes at least one of methyl ether, diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, methyl tert-butyl ether, petroleum ether, tetrahydrofuran, 2-methyltetrahydrofuran, and 2-ethyltetrahydrofuran; in one embodiment, the aromatic hydrocarbon solvent includes at least one of benzene, toluene, and ethylbenzene; in one embodiment, the nitrile solvent includes at least one of acetonitrile, butyronitrile, and benzonitrile; in one embodiment, the halogenated hydrocarbon solvent includes at least one of dichloromethane and chloroform; the ester solvent includes at least one of ethyl acetate, methyl acetate, and butyl acetate; in one embodiment, the nitrogen-cyclic solvent includes at least one of pyridine, methylpyridine, and ethylpyridine.

[0037] In one embodiment, the first solvent includes at least one of ether solvents, aromatic hydrocarbon solvents, and nitrile solvents.

[0038] Further, the second solvent includes at least one of ether solvents, aromatic hydrocarbon solvents, nitrile solvents, halogenated hydrocarbon solvents, ester solvents, nitrogen-cyclic solvents, and alkane solvents; in one embodiment, the alkane solvent includes at least one of propane, cyclopropane, n-butane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, and n-dodecane.

[0039] In one embodiment, the second solvent includes at least one of ether solvents, aromatic hydrocarbon solvents, nitrile solvents, and alkane solvents.

[0040] The group VIB metal precursors include ( t BuN)2Mo(NHMe)2、( t BuN)2Mo(NMe2)2、( t BuN)2Mo(NHEt)2、( t BuN)2Mo(NEt2)2、( t BuN)2Mo(NMeEt)2、( t BuN)2Mo(N i Pr2)2、( t BuN)2Mo(NMe i Pr)2、( t BuN)2Mo(NEt i Pr)2、( t BuN)2Mo(N n Pr2)2、( t BuN)2Mo(NEt n Pr)2、( t BuN)2Mo(NMen Pr)2、( t BuN)2Mo(N i Pr n Pr)2、( t BuN)2Mo(N n Pr n Bu)2、( t BuN)2Mo(N n Pr t Bu)2、 ( t BuN)2Mo(N t Bu2)2、( t BuN)2Mo(NEt t Bu)2、( t BuN)2Mo(NMe t Bu)2、( t BuN)2Mo(N i Pr t Bu)2、( t BuN)2Mo(N n Pr t Bu)2、( t BuN)2Mo(N n Bu2)2、( t BuN)2Mo(NMe n Bu)2、( t BuN)2Mo(NEt n Bu)2、( t BuN)2Mo(N i Pr n Bu)2、( t BuN)2Mo(N n Pr n Bu)2、( n BuN)2Mo(NHMe)2、( n BuN)2Mo(NMe2)2、( n BuN)2Mo(NHEt)2、( n BuN)2Mo(NEt2)2、( n BuN)2Mo(NMeEt)2、( n BuN)2Mo(N i Pr2)2、( n BuN)2Mo(NMe i Pr)2、( n BuN)2Mo(NEt i Pr)2、( n BuN)2Mo(N n Pr2)2、( nBuN)2Mo(NEt n Pr)2、( n BuN)2Mo(NMe n Pr)2、( n BuN)2Mo(N i Pr n Pr)2、( n BuN)2Mo(N n Pr n Bu)2、( n BuN)2Mo(N n Pr t Bu)2、 ( n BuN)2Mo(N t Bu2)2、( n BuN)2Mo(NEt t Bu)2、( n BuN)2Mo(NMe t Bu)2、( n BuN)2Mo(N i Pr t Bu)2、( n BuN)2Mo(N n Pr t Bu)2、( n BuN)2Mo(N n Bu2)2、( n BuN)2Mo(NEt n Bu)2、( n BuN)2Mo(NMe n Bu)2、( n BuN)2Mo(N i Pr n Bu)2、( n BuN)2Mo(N n Pr n Bu)2、 (MeN)2Mo(NHMe)2、(MeN)2Mo(NMe2)2、(MeN)2Mo(NHEt)2、(MeN)2Mo(NEt2)2、(MeN)2Mo(NMeEt)2、(MeN)2Mo(N i Pr2)2、(MeN)2Mo(NMe i Pr)2、(MeN)2Mo(NEt i Pr)2、(MeN)2Mo(N n Pr2)2、(MeN)2Mo(NEt n Pr)2、(MeN)2Mo(NMe n Pr)2、(MeN)2Mo(Ni Pr n Pr)2、(MeN)2Mo(N n Pr n Bu)2、(MeN)2Mo(N n Pr t Bu)2、 (MeN)2Mo(N t Bu2)2、(MeN)2Mo(NEt t Bu)2、(MeN)2Mo(NMe t Bu)2、(MeN)2Mo(N i Pr t Bu)2、(MeN)2Mo(N n Pr t Bu)2、(MeN)2Mo(N n Bu2)2、(MeN)2Mo(NEt n Bu)2、(MeN)2Mo(NMe n Bu)2、(MeN)2Mo(N i Pr n Bu)2、(MeN)2Mo(N n Pr n Bu)2、(EtN)2Mo(NHMe)2、(EtN)2Mo(NMe2)2、(EtN)2Mo(NHEt)2、(EtN)2Mo(NEt2)2、(EtN)2Mo(NMeEt)2、(EtN)2Mo(N i Pr2)2、 (EtN)2Mo(NMe i Pr)2、(EtN)2Mo(NEt i Pr)2、(EtN)2Mo(N n Pr2)2、(EtN)2Mo(NEt n Pr)2、(EtN)2Mo(NMe n Pr)2、(EtN)2Mo(N i Pr n Pr)2、(EtN)2Mo(N n Pr n Bu)2、(EtN)2Mo(N n Pr t Bu)2、 (EtN)2Mo(N t Bu2)2、(EtN)2Mo(NEt t Bu)2、(EtN)2Mo(NMe t Bu)2、(EtN)2Mo(N i Pr t Bu)2、(EtN)2Mo(Nn Pr t Bu)2、(EtN)2Mo(N n Bu2)2、(EtN)2Mo(NEt n Bu)2、(EtN)2Mo(NMe n Bu)2、(EtN)2Mo(N i Pr n Bu)2、 (EtN)2Mo(N n Pr n Bu)2、( i PrN)2Mo(NHMe)2、( i PrN)2Mo(NMe2)2、( i PrN)2Mo(NHEt)2、( i PrN)2Mo(NEt2)2、( i PrN)2Mo(NMeEt)2、( i PrN)2Mo(N i Pr2)2、( i PrN)2Mo(NMe i Pr)2、( i PrN)2Mo(NEt i Pr)2、( i PrN)2Mo(N n Pr2)2、( i PrN)2Mo(NEt n Pr)2、( i PrN)2Mo(NMe n Pr)2、( i PrN)2Mo(N i Pr n Pr)2、( i PrN)2Mo(N n Pr n Bu)2、( i PrN)2Mo(N n Pr t Bu)2、( i PrN)2Mo(N n Bu2)2、( i PrN)2Mo(NEt n Bu)2、( i PrN)2Mo(NMe n Bu)2、( i PrN)2Mo(N i Pr n Bu)2、( i PrN)2Mo(N i Prn Bu)2、( n PrN)2Mo(NMe2)2、( n PrN)2Mo(NEt2)2、( n PrN)2Mo(NMeEt)2、( n PrN)2Mo(N i Pr2)2、( n PrN)2Mo(NMe i Pr)2、( n PrN)2Mo(NEt i Pr)2、( n PrN)2Mo(N n Bu2)2、( n PrN)2Mo(N n Pr2)2、( n PrN)2Mo(NEt n Bu)2、( n PrN)2Mo(NMe n Bu)2、( n PrN)2Mo(N i Pr n Bu)2、( n PrN)2Mo(N i Pr n Bu)2、( t BuN)2W(NHMe)2、( t BuN)2W(NMe2)2、( t BuN)2W(NHEt)2、( t BuN)2W(NEt2)2、( t BuN)2W(NMeEt)2、( t BuN)2W(N i Pr2)2、( t BuN)2W(NMe i Pr)2、( t BuN)2W(NEt i Pr)2、( t BuN)2W(N n Pr2)2、( t BuN)2W(NEt n Pr)2、( t BuN)2W(NMe n Pr)2、( t BuN)2W(N i Pr n Pr)2、( t BuN)2W(N n Prn Bu)2、( t BuN)2W(N n Pr t Bu)2、 ( t BuN)2W(N t Bu2)2、( t BuN)2W(NEt t Bu)2、( t BuN)2W(NMe t Bu)2、( t BuN)2W(N i Pr t Bu)2、( t BuN)2W(N n Pr t Bu)2、( t BuN)2W(N n Bu2)2、( t BuN)2W(NMe n Bu)2、( t BuN)2W(NEt n Bu)2、( t BuN)2W(N i Pr n Bu)2、( t BuN)2W(N n Pr n Bu)2、( n BuN)2W(NHMe)2、( n BuN)2W(NMe2)2、( n BuN)2W(NHEt)2、( n BuN)2W(NEt2)2、( n BuN)2W(NMeEt)2、( n BuN)2W(N i Pr2)2、( n BuN)2W(NMe i Pr)2、( n BuN)2W(NEt i Pr)2、( n BuN)2W(N n Pr2)2、( n BuN)2W(NEt n Pr)2、( n BuN)2W(NMe n Pr)2、( n BuN)2W(N i Pr n Pr)2、( nBuN)2W(N n Pr n Bu)2、( n BuN)2W(N n Pr t Bu)2、 ( n BuN)2W(N t Bu2)2、( n BuN)2W(NEt t Bu)2、( n BuN)2W(NMe t Bu)2、( n BuN)2W(N i Pr t Bu)2、( n BuN)2W(N n Pr t Bu)2、( n BuN)2W(N n Bu2)2、( n BuN)2W(NEt n Bu)2、( n BuN)2W(NMe n Bu)2、( n BuN)2W(N i Pr n Bu)2、( n BuN)2W(N n Pr n Bu)2、 (MeN)2W(NMe2)2、(MeN)2W(NEt2)2、(MeN)2W(NMeEt)2、(MeN)2W(N i Pr2)2、(MeN)2W(NMe i Pr)2、(MeN)2W(NEt i Pr)2、(MeN)2W(N n Pr2)2、(MeN)2W(NEt n Pr)2、(MeN)2W(NMe n Pr)2、(MeN)2W(N i Pr n Pr)2、(MeN)2W(N n Pr n Bu)2、(MeN)2W(N n Pr t Bu)2、 (MeN)2W(N t Bu2)2、(MeN)2W(NEt t Bu)2、(MeN)2W(NMe tBu)2、(MeN)2W(N i Pr t Bu)2、(MeN)2W(N n Pr t Bu)2、(MeN)2W(N n Bu2)2、(MeN)2W(NEt n Bu)2、(MeN)2W(NMe n Bu)2、(MeN)2W(N i Pr n Bu)2、(MeN)2W(N n Pr n Bu)2、(EtN)2W(NMe2)2、(EtN)2W(NEt2)2、(EtN)2W(NMeEt)2、(EtN)2W(N i Pr2)2、 (EtN)2W(NMe i Pr)2、(EtN)2W(NEt i Pr)2、(EtN)2W(N n Pr2)2、(EtN)2W(NEt n Pr)2、(EtN)2W(NMe n Pr)2、(EtN)2W(N i Pr n Pr)2、(EtN)2W(N n Pr n Bu)2、(EtN)2W(N n Pr t Bu)2、 (EtN)2W(N t Bu2)2、(EtN)2W(NEt t Bu)2、(EtN)2W(NMe t Bu)2、(EtN)2W(N i Pr t Bu)2、(EtN)2W(N n Pr t Bu)2、(EtN)2W(N n Bu2)2、(EtN)2W(NEt n Bu)2、(EtN)2W(NMe n Bu)2、(EtN)2W(N i Pr n Bu)2、 (EtN)2W(N n Pr n Bu)2、( i PrN)2W(NMe2)2、( iPrN)2W(NEt2)2、( i PrN)2W(NMeEt)2、( i PrN)2W(N i Pr2)2、( i PrN)2W(NMe i Pr)2、( i PrN)2W(NEt i Pr)2、( i PrN)2W(N n Pr2)2、( i PrN)2W(NEt n Pr)2、( i PrN)2W(NMe n Pr)2、( i PrN)2W(N i Pr n Pr)2、( i PrN)2W(N n Pr n Bu)2、( i PrN)2W(N n Pr t Bu)2、( i PrN)2W(N n Bu2)2、( i PrN)2W(NEt n Bu)2、( i PrN)2W(NMe n Bu)2、( i PrN)2W(N i Pr n Bu)2、( i PrN)2W(N i Pr n Bu)2、( n PrN)2W(NMe2)2、( n PrN)2W(NEt2)2、( n PrN)2W(NMeEt)2、( n PrN)2W(N i Pr2)2、( n PrN)2W(NMe i Pr)2、( n PrN)2W(NEt i Pr)2、( n PrN)2W(N n Bu2)2、( n PrN)2W(N n Pr2)2、( nPrN)2W(NEt n Bu)2、( n PrN)2W(NMe n Bu)2、( n PrN)2W(N i Pr n Bu)2、( n PrN)2W(N i Pr n Any one of Bu)2. Wherein, Me is methyl, Et is ethyl, n Pr is n-propyl i Pr is isopropyl. n Bu is an butyl group. t Bu is tert-butyl.

[0041] Furthermore, the purified Group VIB metal precursor has a purity of 5N or higher, preferably 6N or higher (tested using ICP-MS), and the optional purification methods include, but are not limited to, at least one of filtration, distillation, slurry distillation, adsorption, recrystallization, etc.

[0042] Furthermore, this application also provides the application of the group VIB metal precursor in the deposition of group VIB metal thin films.

[0043] Furthermore, using the aforementioned Group VIB metal precursor, Mo-containing or W-containing films are deposited on planar or non-planar substrates via methods such as ALD (atomic layer deposition), CVD (chemical vapor deposition), PVD (physical vapor deposition), PEALD (plasma-enhanced atomic layer deposition), and PECVD (plasma-enhanced chemical vapor deposition).

[0044] Furthermore, the Mo- or W-containing film is exemplarily any one of a single metal film, a metal alloy film, an oxide film, a nitride film, a nitrogen oxide film, a carbide film, a carbonitride film, a carbonitride film, a carbonitride film, a sulfide film, a selenide film, a boride film, etc.; the Mo- or W-containing film is also exemplarily a thin film doped with Mo or W; the present invention does not strictly define the type of Mo- or W-containing film.

[0045] The beneficial effects of this invention are:

[0046] (1) The synthesis method of the present invention does not involve purification operations such as filtration, distillation or recrystallization of intermediates. The overall reaction route is simple, efficient and time-saving, and suitable for industrial production.

[0047] (2) This invention utilizes the metallic raw material MO2X2 and [R] 1 The reaction of compounds with the N=C] structure to prepare intermediates (R) 1 N)2MX2, then the intermediate and alkaline substance M0 (NR 2 R 3 ) y The reaction yields a Group VI B metal precursor (R) 1 N)2M(NR 2 R 3 )2. Compared with the prior art, the reaction raw materials of this application do not involve high content of other metal impurities and chlorine, and the resulting product is easier to purify. The purity of the purified product can reach the level of ≥6N.

[0048] (3) The reaction of the present invention is easier to occur, and the reaction yield is high and stable, which significantly improves the group VIB metal precursor (R 1 N)2M(NR 2 R 3 )2 Industrial production efficiency. Attached Figure Description

[0049] Figure 1 The (N) prepared in this invention t Bu)2W(NMe2)2 1 HNMR image.

[0050] Figure 2 The (N) prepared in this invention t TGA curve of Bu)2W(NMe2)2.

[0051] Figure 3 The (N) prepared in this invention t Bu)2Mo(NMe2)2 1 HNMR image.

[0052] Figure 4 The (N) prepared in this invention t Bu)2W(NH t Bu)2 1 HNMR image. Detailed Implementation

[0053] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0054] Example 1

[0055] This embodiment provides a Group VIB metal precursor—(N t The synthesis method of Bu)2W(NMe2)2 includes the following steps:

[0056] S1. Under nitrogen protection, WO2Cl2 (500g) and toluene (1000mL) are added. t BuNCO (380.5g) was mixed and refluxed at 95℃ for 8 hours. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0057] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0058] S3. At 0℃, System 1 is added to System 2 and reacted at 25℃ for 6 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N t Crude product Bu)2W(NMe2)2 (629.3g), yield 87.3%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0059] (N t The 1H NMR spectrum of Bu)2W(NMe2)2 is attached. Figure 1 The corresponding data is: 1 HNMR (400MHz, C6D6): δ 3.50 (s, 12H), 1.40 (s, 18H).

[0060] (N t The thermogravimetric characterization diagram of Bu)2W(NMe2)2 is attached. Figure 2 As can be seen from the figure: (N) t Bu)2W(NMe2)2 begins to lose weight at 133.48℃, and when the temperature is raised to 170.59℃, the residual mass of the compound is only 0.02%, indicating that the product has a low sublimation temperature, which is convenient for depositing W-containing films and can obtain better film quality.

[0061] Example 2

[0062] This embodiment provides a Group VIB metal precursor—(N t The synthesis method of Bu)2W(NMe2)2 includes the following steps:

[0063] S1. Under nitrogen protection, WO2Cl2 (500g) and acetonitrile (500mL) are added. t BuNCO (518.5g) was mixed and refluxed at 85℃ for 10h. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0064] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0065] S3. At 0℃, System 1 is added to System 2 and reacted at 30℃ for 5 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N) t Crude product Bu)2W(NMe2)2 (650.8g), yield 90.2%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0066] Example 3

[0067] This embodiment provides a Group VIB metal precursor—(N t The synthesis method of Bu)2W(NMe2)2 includes the following steps:

[0068] S1. Under nitrogen protection, WO2Cl2 (500g) and ethylene glycol dimethyl ether (600mL) are added. t BuNCO (431.2 g) was mixed and refluxed at 70 °C for 12 h. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0069] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0070] S3. At 0℃, System 1 is added to System 2 and reacted at 18℃ for 12 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N) t Crude product Bu)2W(NMe2)2 (642.0 g), yield 80.1%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0071] Example 4

[0072] This embodiment provides a Group VIB metal precursor—(N t The method for synthesizing Bu)2Mo(NMe2)2 includes the following steps:

[0073] S1. Under nitrogen protection, MoO2Cl2 (300g), toluene (1000mL), t BuNCO (380.5g) was mixed and refluxed at 120℃ for 8 hours. After the reaction was complete, a product containing ( tSystem 1 of BuN)2MoCl2.

[0074] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0075] S3. At 0℃, System 1 is added to System 2 and reacted at 23℃ for 6 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N t Crude Bu)2Mo(NMe2)2 (693.0 g), yield 86.5%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0076] (N t The 1H NMR spectrum of Bu)2Mo(NMe2)2 is attached. Figure 3 The corresponding data is: 1 HNMR (400MHz, C6D6): δ 3.39 (s, 12H), 1.29 (s, 18H).

[0077] Example 5

[0078] This embodiment provides a Group VIB metal precursor—( t BuN)2W(NH t The method for synthesizing Bu)2 includes the following steps:

[0079] S1. Under nitrogen protection, WO2Cl2 (500g) and toluene (1000mL) are added. t BuNCO (380.5g) was mixed and refluxed at 95℃ for 8 hours. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0080] S2, At room temperature (23℃), n-hexane (1000 mL) and LiNH t After mixing Bu (344g), system two is obtained.

[0081] S3. At 0℃, System 1 is added to System 2 and reacted at 25℃ for 6 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N t Bu)2W(NH t Crude product Bu2 (624.2g), yield 86.9%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0082] (N t Bu)2W(NH tThe 1H NMR spectrum of Bu)2 is attached. Figure 4 The corresponding data is: 1 HNMR (400MHz, C6D6): δ 1.45 (s, 18H), 1.28 (s, 18H).

[0083] Example 6

[0084] This embodiment provides a Group VIB metal precursor—(N t The synthesis method of Bu)2W(NMe2)2 includes the following steps:

[0085] S1. Under nitrogen protection, WO2Cl2 (500g) and toluene (1000mL) are added. t BuNCO (346.0 g) was mixed and refluxed at 90 °C for 8 h. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0086] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0087] S3. At 0℃, System 1 is added to System 2 and reacted at 22℃ for 6 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N) t Crude product of Bu)2W(NMe2)2 (591.7g), yield 82.0%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0088] Example 7

[0089] This embodiment provides a Group VIB metal precursor—(N t The synthesis method of Bu)2W(NMe2)2 includes the following steps:

[0090] S1. Under nitrogen protection, WO2Cl2 (500g) and n-hexane (1000mL) are added. t BuNCO (380.5g) was mixed and refluxed at 95℃ for 8 hours. After the reaction was complete, a product containing ( t The system of BuN)2WCl2.

[0091] S2, at -20℃, add n-hexane (1000mL) to another reaction vessel. n The reaction of BuLi (1460 mL) and HNMe2 (164.6 g) yielded system II containing LiNMe2.

[0092] S3. At 0℃, System 1 is added to System 2 and reacted at 25℃ for 6 hours to obtain a reaction solution; the reaction solution is filtered to obtain a filtrate, and the filtrate is distilled under reduced pressure to obtain (N t Crude product of Bu)2W(NMe2)2 (520.39g), yield 72.2%. The crude product can be purified by distillation to obtain a product with a purity of 6N.

[0093] Results Analysis: The synthetic route provided in this application is simple, time-saving and efficient, and does not require additional intermediate processing (such as distillation purification, sublimation purification, etc.). It can also obtain higher yields and better product purity. Therefore, the above method can be used as an industrial synthetic route for Group VI B metal precursors.

[0094] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0095] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing a Group VIB metal precursor, characterized in that, Includes the following steps: S1, making the metallic raw material MO2X2, containing [R] 1 The N=C] structure compound reacts with the first solvent to give a compound containing an intermediate (R). 1 N)2MX2 system one; S2, make R 4 M 0 and HNR 2 R 3 The reaction in the second solvent yields a substance M containing an alkaline base. 0 (NR 2 R 3 ) y System Two; S3. Mix and react systems 1 and 2 to obtain the Group VIB metal precursor (R). 1 N)2M(NR 2 R 3 )2. Crude product; separation and purification of the crude product are sufficient; Where M is Mo or W, X is a halogen, and R is a halogen. 1 Selected from C1-C10 alkyl groups, R 2 R 3 Independently selected from at least one of H and C1-C10 alkyl groups, R 4 Selected from any one of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, 1-methylbutyl, 2-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, and 2,2-dimethylpropyl, M 0 It is an alkali metal or an alkaline earth metal, and y is M. 0 valence; The [R] 1 Compounds with the N=C] structure are R 1 NCO; The first solvent is at least one of ether solvents, aromatic hydrocarbon solvents, and nitrile solvents; the second solvent is at least one of alkane solvents. The ether solvent is at least one of ethylene glycol dimethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran; the aromatic hydrocarbon solvent is at least one of toluene and ethylbenzene; the nitrile solvent is acetonitrile; and the alkane solvent is at least one of n-pentane, n-hexane, n-heptane, and n-octane.

2. The synthesis method according to claim 1, characterized in that, X is Br or Cl; and / or, M is Br or Cl; and / or M is Br or Cl. 0 It is an alkali metal, selected from Li, Na, and K; and / or, the R 1 Alkyl groups selected from C1-C6; and / or, R 2 R 3 Alkyl groups independently selected from H and C1-C8.

3. The synthesis method according to claim 1, characterized in that, MO2X2 and containing [R] 1 The equivalence ratio of compounds with the N=C] structure is 1:2-6; and / or, the reaction temperature of S1 is 60-120℃; and / or, (R 1 N)2MX2 and M 0 (NR 2 R 3 ) y The equivalence ratio is 1:2-5; and / or, the reaction temperature of S3 is 10-100℃.

4. The synthesis method according to claim 1, characterized in that, MO2X2 and containing [R] 1 The equivalence ratio of compounds with the N=C] structure is 1:2-4; and / or, the reaction temperature of S1 is 70-100℃; and / or, (R 1 N)2MX2 and M 0 (NR 2 R 3 ) y The equivalence ratio is 1:2-4; and / or, the reaction temperature of S3 is 15-50℃.

5. The synthesis method according to claim 1, characterized in that, Including the Group VIB metal precursors mentioned above ( t BuN)2Mo(NHMe)2, ( t BuN)2Mo(NMe2)2, ( t BuN)2Mo(NHEt)2, ( t BuN)2Mo(NEt2)2, ( t BuN)2Mo(NMeEt)2, ( t BuN)2Mo(N i Pr2)2, ( t BuN)Mo(NMe i Pr)2, ( t BuN)2Mo(NEt i Pr)2, ( t BuN)2Mo(N n Pr2)2, ( t BuN)2Mo(NEt n Pr)2, ( t BuN)Mo(NMe n Pr)2, ( t BuN)2Mo(N i Pr n Pr)2, ( t BuN)2Mo(N n Pr n Bu)2, ( t BuN)2Mo(N n Pr t Bu)2, ( t BuN)2Mo(N t Bu2)2, ( t BuN)2Mo(NEt t Bu)2, ( t BuN)Mo(NMe t Bu)2, ( t BuN)2Mo(N i Pr t Bu)2, ( t BuN)2Mo(N n Pr t Bu)2, ( t BuN)2Mo(N n Bu2)2, ( t BuN)Mo(NMe n Bu)2, ( t BuN)2Mo(NEt n Bu)2, ( t BuN)2Mo(N i Pr n Bu)2、( t BuN)2Mo(N n Pr n Bu)2、( n BuN)2Mo(NHMe)2、( n BuN)2Mo(NMe2)2、( n BuN)2Mo(NHEt)2、( n BuN)2Mo(NEt2)2、( n BuN)2Mo(NMeEt)2、( n BuN)2Mo(N i Pr2)2、( n BuN)2Mo(NMe i Pr)2、( n BuN)2Mo(NEt i Pr)2、( n BuN)2Mo(N n Pr2)2、( n BuN)2Mo(NEt n Pr)2、( n BuN)2Mo(NMe n Pr)2、( n BuN)2Mo(N i Pr n Pr)2、( n BuN)2Mo(N n Pr n Bu)2、( n BuN)2Mo(N n Pr t Bu)2、 ( n BuN)2Mo(N t Bu2)2、( n BuN)2Mo(NEt t Bu)2、( n BuN)2Mo(NMe t Bu)2、( n BuN)2Mo(N i Pr t Bu)2、( n BuN)2Mo(N n Pr t Bu)2、( n BuN)2Mo(N n Bu2)2、( n BuN)2Mo(NEt n Bu)2、( n BuN)2Mo(NMe n Bu)2、( n BuN)2Mo(N i Pr n Bu)2、( n BuN)2Mo(N n Pr n Bu)2、 (MeN)2Mo(NHMe)2、(MeN)2Mo(NMe2)2、(MeN)2Mo(NHEt)2、(MeN)2Mo(NEt2)2、(MeN)2Mo(NMeEt)2、(MeN)2Mo(N i Pr2)2、(MeN)2Mo(NMe i Pr)2、(MeN)2Mo(NEt i Pr)2、(MeN)2Mo(N n Pr2)2、(MeN)2Mo(NEt n Pr)2、(MeN)2Mo(NMe n Pr)2、(MeN)2Mo(N i Pr n Pr)2、(MeN)2Mo(N n Pr n Bu)2、(MeN)2Mo(N n Pr t Bu)2、 (MeN)2Mo(N t Bu2)2、(MeN)2Mo(NEt t Bu)2、(MeN)2Mo(NMe t Bu)2、(MeN)2Mo(N i Pr t Bu)2、(MeN)2Mo(N n Pr t Bu)2、(MeN)2Mo(N n Bu2)2、(MeN)2Mo(NEt n Bu)2、(MeN)2Mo(NMe n Bu)2、(MeN)2Mo(N i Pr n Bu)2、(MeN)2Mo(N n Pr n Bu)2、(EtN)2Mo(NHMe)2、(EtN)2Mo(NMe2)2、(EtN)2Mo(NHEt)2、(EtN)2Mo(NEt2)2、(EtN)2Mo(NMeEt)2、(EtN)2Mo(N i Pr2)2、 (EtN)2Mo(NMe i Pr)2、(EtN)2Mo(NEt i Pr)2、(EtN)2Mo(N n Pr2)2、(EtN)2Mo(NEt n Pr)2、(EtN)2Mo(NMe n Pr)2、(EtN)2Mo(N i Pr n Pr)2、(EtN)2Mo(N n Pr n Bu)2、(EtN)2Mo(N n Pr t Bu)2、 (EtN)2Mo(N t Bu2)2、(EtN)2Mo(NEt t Bu)2、(EtN)2Mo(NMe t Bu)2、(EtN)2Mo(N i Pr t Bu)2、(EtN)2Mo(N n Pr t Bu)2、(EtN)2Mo(N n Bu2)2、(EtN)2Mo(NEt n Bu)2、(EtN)2Mo(NMe n Bu)2、(EtN)2Mo(N i Pr n Bu)2、 (EtN)2Mo(N n Pr n Bu)2、( i PrN)2Mo(NHMe)2、( i PrN)2Mo(NMe2)2、( i PrN)2Mo(NHEt)2、( i PrN)2Mo(NEt2)2、( i PrN)2Mo(NMeEt)2、( i PrN)2Mo(N i Pr2)2、( i PrN)2Mo(NMe i Pr)2、( i PrN)2Mo(NEt i Pr)2、( i PrN)2Mo(N n Pr2)2、( i PrN)2Mo(NEt n Pr)2、( i PrN)2Mo(NMe n Pr)2、( i PrN)2Mo(N i Pr n Pr)2、( i PrN)2Mo(N n Pr n Bu)2、( i PrN)2Mo(N n Pr t Bu)2、( i PrN)2Mo(N n Bu2)2、( i PrN)2Mo(NEt n Bu)2、( i PrN)2Mo(NMe n Bu)2、( i PrN)2Mo(N i Pr n Bu)2、( i PrN)2Mo(N i Pr n Bu)2、( n PrN)2Mo(NMe2)2、( n PrN)2Mo(NEt2)2、( n PrN)2Mo(NMeEt)2、( n PrN)2Mo(N i Pr2)2、( n PrN)2Mo(NMe i Pr)2、( n PrN)2Mo(NEt i Pr)2、( n PrN)2Mo(N n Bu2)2、( n PrN)2Mo(N n Pr2)2、( n PrN)2Mo(NEt n Bu)2、( n PrN)2Mo(NMe n Bu)2、( n PrN)2Mo(N i Pr n Bu)2、( n PrN)2Mo(N i Pr n Bu)2、( t BuN)2W(NHMe)2、( t BuN)2W(NMe2)2、( t BuN)2W(NHEt)2、( t BuN)2W(NEt2)2、( t BuN)2W(NMeEt)2、( t BuN)2W(N i Pr2)2、( t BuN)2W(NMe i Pr)2、( t BuN)2W(NEt i Pr)2、( t BuN)2W(N n Pr2)2、( t BuN)2W(NEt n Pr)2、( t BuN)2W(NMe n Pr)2、( t BuN)2W(N i Pr n Pr)2、( t BuN)2W(N n Pr n Bu)2、( t BuN)2W(N n Pr t Bu)2、 ( t BuN)2W(N t Bu2)2、( t BuN)2W(NEt t Bu)2、( t BuN)2W(NMe t Bu)2、( t BuN)2W(N i Pr t Bu)2、( t BuN)2W(N n Pr t Bu)2、( t BuN)2W(N n Bu2)2、( t BuN)2W(NMe n Bu)2、( t BuN)2W(NEt n Bu)2、( t BuN)2W(N i Pr n Bu)2、( t BuN)2W(N n Pr n Bu)2、( n BuN)2W(NHMe)2、( n BuN)2W(NMe2)2、( n BuN)2W(NHEt)2、( n BuN)2W(NEt2)2、( n BuN)2W(NMeEt)2、( n BuN)2W(N i Pr2)2、( n BuN)2W(NMe i Pr)2、( n BuN)2W(NEt i Pr)2、( n BuN)2W(N n Pr2)2、( n BuN)2W(NEt n Pr)2、( n BuN)2W(NMe n Pr)2、( n BuN)2W(N i Pr n Pr)2、( n BuN)2W(N n Pr n Bu)2、( n BuN)2W(N n Pr t Bu)2、 ( n BuN)2W(N t Bu2)2、( n BuN)2W(NEt t Bu)2、( n BuN)2W(NMe t Bu)2、( n BuN)2W(N i Pr t Bu)2、( n BuN)2W(N n Pr t Bu)2、( n BuN)2W(N n Bu2)2、( n BuN)2W(NEt n Bu)2、( n BuN)2W(NMe n Bu)2、( n BuN)2W(N i Pr n Bu)2、( n BuN)2W(N n Pr n Bu)2、(MeN)2W(NMe2)2、(MeN)2W(NEt2)2、(MeN)2W(NMeEt)2、(MeN)2W(N i Pr2)2、(MeN)2W(NMe i Pr)2、(MeN)2W(NEt i Pr)2、(MeN)2W(N n Pr2)2、(MeN)2W(NEt n Pr)2、(MeN)2W(NMe n Pr)2、(MeN)2W(N i Pr n Pr)2、(MeN)2W(N n Pr n Bu)2、(MeN)2W(N n Pr t Bu)2、 (MeN)2W(N t Bu2)2、(MeN)2W(NEt t Bu)2、(MeN)2W(NMe t Bu)2、(MeN)2W(N i Pr t Bu)2、(MeN)2W(N n Pr t Bu)2、(MeN)2W(N n Bu2)2、(MeN)2W(NEt n Bu)2、(MeN)2W(NMe n Bu)2、(MeN)2W(N i Pr n Bu)2、(MeN)2W(N n Pr n Bu)2、(EtN)2W(NMe2)2、(EtN)2W(NEt2)2、(EtN)2W(NMeEt)2、(EtN)2W(N i Pr2)2、 (EtN)2W(NMe i Pr)2、(EtN)2W(NEt i Pr)2、(EtN)2W(N n Pr2)2、(EtN)2W(NEt n Pr)2、(EtN)2W(NMe n Pr)2、(EtN)2W(N i Pr n Pr)2、(EtN)2W(N n Pr n Bu)2、(EtN)2W(N n Pr t Bu)2、 (EtN)2W(N t Bu2)2、(EtN)2W(NEt t Bu)2、(EtN)2W(NMe t Bu)2、(EtN)2W(N i Pr t Bu)2、(EtN)2W(N n Pr t Bu)2、(EtN)2W(N n Bu2)2、(EtN)2W(NEt n Bu)2、(EtN)2W(NMe n Bu)2、(EtN)2W(N i Pr n Bu)2、 (EtN)2W(N n Pr n Bu)2、( i PrN)2W(NMe2)2、( i PrN)2W(NEt2)2、( i PrN)2W(NMeEt)2、( i PrN)2W(N i Pr2)2、( i PrN)2W(NMe i Pr)2、( i PrN)2W(NEt i Pr)2、( i PrN)2W(N n Pr2)2、( i PrN)2W(NEt n Pr)2、( i PrN)2W(NMe n Pr)2、( i PrN)2W(N i Pr n Pr)2、( i PrN)2W(N n Pr n Bu)2、( i PrN)2W(N n Pr t Bu)2、( i PrN)2W(N n Bu2)2、( i PrN)2W(NEt n Bu)2、( i PrN)2W(NMe n Bu)2,( i PrN)2W(N i Pr n Bu)2,( i PrN)2W(N i Pr n Bu)2,( n PrN)2W(NMe2)2,( n PrN)2W(NEt2)2,( n PrN)2W(NMeEt)2,( n PrN)2W(N i Pr2)2,( n PrN)2W(NMe i Pr)2,( n PrN)2W(NEt i Pr)2,( n PrN)2W(N n Bu2)2,( n PrN)2W(N n Pr2)2,( n PrN)2W(NEt n Bu)2,( n PrN)2W(NMe n Bu)2,( n PrN)2W(N i Pr n Bu)2,( n PrN)2W(N i Pr n Any one of Bu)2.

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