KR20160101495A - A method for preparing rose-like palladium-iron oxide hybrid nanocomposite-supported Au nanoparticles and carbon-carbon cross coupling reactions using them as a catalyst - Google Patents

Abstract

The present invention relates to a method for preparing a rose-shaped Au/Pd-Fe_3O_4 nanocomposite which is synthesized through fixing gold nanoparticles on a Pd-Fe_3O_4 support prepared from thermal decomposition of Fe(CO)_5 and reduction of Pd(OAc)_2, and a carbon-carbon cross coupling reaction using the same as a catalyst. The nanocomposite of the present invention, due to the rose petal-shaped Pd-Fe_3O_4 nanosheet structure, has a large specific surface area imparting a high catalytic activity to the Pd-Fe_3O_4 support. Also, due to the characteristic of a catalyst in which two metals are hybridized, the nanocomposite has superior catalytic activity and reusability compared to various conventionally used catalysts. Synthesized Au/Pd-Fe_3O_4 nanocomposites can be advantageously used for the carbon-carbon cross coupling reaction.

Description

[0001] The present invention relates to a process for preparing a rose-like palladium-iron oxide hybrid nanocomposite having gold nanoparticles and a carbon-carbon cross-coupling reaction using the same as a catalyst. cross coupling reactions using them as a catalyst}

The invention of a rose-shaped carrying gold nanoparticles palladium-iron oxide hybrid nanocomposite relates to a manufacturing method in more detail is prepared by reduction of the Fe (CO) ₅ pyrolysis and Pd (OAc) ₂ Pd- relates to a carbon cross-coupling reaction - Fe ₃ O ₄ bearing member manufacturing method of a rose-shaped Au / Pd-Fe ₃ O ₄ nanocomposite is synthesized easily by fixing the gold nanoparticles on carbon and using it as a catalyst.

In recent years, metal nanoparticles have been applied in a variety of fields, including medicine, materials, environment, and energy. Unlike conventional bulk metal materials, nanoparticles exhibit excellent reactivity in a variety of reactions due to their large surface area. As the economic and environmental friendliness of metal nanocatalysts becomes more important in chemistry, reusing expensive and toxic catalysts has become important in organic synthesis. To this end, metal nanoparticles are used as charcoal, acetylene black, , Alumina, and porous silica materials have been reported.

There have also been many studies to control the shape and size of nanoparticles through solution-growth fabrication to synthesize hybrid nanocomposites. These hybrid complexes show a tendency to increase physical and chemical properties compared to single nanoparticles and are applicable to various fields. It was such as Au-Pd, FePt, FePt- Au, FePd-Fe 3 O 4 reported as the hybrid nanocomposite These hydrogenation reactions, the oxygen reduction reaction, carbon-have been effectively used in a variety of reactions, such as carbon cross-linking reaction, the photo-catalytic reaction .

On the other hand, carbon-carbon cross-linking reactions that can efficiently and simply obtain products have been attracting attention as recent organic reaction researches have developed. Among these synthesis methods, a number of Sonogashira carbon-carbon cross-linking reactions, important in pharmaceutical and organic synthesis, have been reported. Also, a method of synthesizing an indole compound through a carbon-carbon pairing / ring addition reaction of 2-haloaniline and an alkyne has been reported. Since indole compounds are important precursors for synthesizing natural products and drugs, there is a growing need for studies on methods for easy and economical synthesis.

It is an object of the present invention to provide a method for producing Au / Pd-Fe ₃ O ₄ nanocomposite which can obtain high yield and selectivity and can be recovered and recycled.

Another object of the present invention is to provide a carbon-carbon cross-linking reaction using Au / Pd-Fe ₃ O ₄ nanocomposite prepared by the above method as a catalyst.

Another object of the present invention is to provide an economical Au / Pd-Fe ₃ O ₄ nanocomposite which is applicable to a carbon-carbon cross-linking reaction, obtains high yield and selectivity, and is recoverable and recyclable.

One aspect of the present invention to attain the above object is to provide a method for preparing a solution in which palladium (II) acetate is dissolved in oleylamine and 1-octadecene at room temperature Adding Fe (CO) ₅ to the solution, raising the temperature of the reaction solution to 160 DEG C, holding it for 30 minutes and cooling to room temperature, separating and purifying the product, dispersing the mixture in hexane Preparing a hybrid Pd-Fe ₃ O ₄ carrier solution; The Pd-Fe ₃ O ₄ injecting a carrier solution in the gold precursor solution and the step of then stirred at 80 ℃ 30 bungan to cool to room temperature; rose comprising centrifuged and the product was purified shaped Au / Pd-Fe ₃ < / RTI > ₄ nanocomposite.

Another aspect of the present invention relates to a catalyst for a carbon-carbon cross-linking reaction comprising an Au / Pd-Fe ₃ O ₄ nanocomposite in which gold nanoparticles are immobilized on a rose-like Pd-Fe ₃ O ₄ hybrid carrier.

Another aspect of the present invention relates to a process for preparing diphenylacetylene comprising reacting a Pd-Fe ₃ O ₄ nanocomposite, iodobenzene, and phenylacetylene in an organic solvent.

Another aspect of the present invention relates to a process for preparing a 2-aryl indole comprising reacting an Au / Pd-Fe ₃ O ₄ nanocomposite, 2-iodoaniline and aryl acetylene in an organic solvent will be.

According to the present invention, gold nanoparticles are immobilized on a Pd-Fe ₃ O ₄ carrier prepared by thermal decomposition of Fe (CO) ₅ and reduction of Pd (OAc) ₂ , whereby a rosin-like Pd-Fe ₃ O ₄ nanocomposite Can be easily synthesized. These nanocomposites have a wide specific surface area due to the rose petal-shaped Pd-Fe ₃ O ₄ nanosheet structure, and thus have high catalytic activity on the Pd-Fe ₃ O _{4 support} . In addition, since the two metals have hybrid catalytic properties, they exhibit superior catalytic activity and recyclability in comparison with various catalysts that have been used in the past. The synthesized Au / Pd-Fe ₃ O ₄ nanocomposite can be usefully used as a catalyst for carbon-carbon cross-linking reactions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a synthesis schematic diagram of a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite according to an embodiment of the present invention; FIG.
FIGS. 2A and 2B are scanning electron microscopy (SEM) photographs of the Pd-Fe ₃ O ₄ carrier synthesized according to Example 1. FIG.
3A and 3B are SEM micrographs of Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG.
4A and 4B are transmission electron microscopy (TEM) photographs of the Pd-Fe ₃ O ₄ carrier synthesized according to Example 1. FIG.
4C and 4D are transmission electron micrographs of the Au / Pd-Fe ₃ O ₄ nanocomposite synthesized by Example 1.
4E is a high-resolution TEM (HR-TEM) photograph of the Pd-Fe ₃ O ₄ carrier synthesized according to Example 1. FIG.
4f is a high-resolution TEM photograph of the Au / Pd-Fe ₃ O ₄ nanocomposite synthesized by Example 1. FIG.
Figs. 5A to 5F are graphs showing changes in the amount of Fe (CO) ₅ in Examples 1 to 3 TEM photograph of a Pd-Fe ₃ O ₄ carrier.
6A to 6F are TEM photographs of the Pd-Fe ₃ O ₄ carrier synthesized at different temperatures according to Example 1, Comparative Example 1 and Comparative Example 2. FIG.
FIG. 7 is an X-ray diffraction (XRD) photograph of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG.
FIG. 8 is a view showing a high-angle scattering electron microscope (SEM) of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1, HAADF-STEM).
9 is a superconducting quantum interference device (SQUID) data of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG.
10a to 10d are diagrams showing the elemental analysis of Au / Pd-Fe ₃ O ₄ by X-ray photoelectron spectroscopy (XPS) of Au / Pd-Fe ₃ O ₄ nanocomposite synthesized by Example 1 Fig.
FIG. 11 is an energy-dispersive X-ray spectroscopy (EDS) spectrum of an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG.
12 is a graph comparing the catalytic activities of the Au / Pd-Fe ₃ O ₄ nanocomposite catalyst prepared in Example 1 and the conventional heterogeneous catalyst.

The rose-like Au / Pd-Fe ₃ O ₄ nanocomposite according to the present invention is a solution-growing method, and the rose-like Pd-Fe ₃ O ₄ Synthesizing a carrier, and fixing gold nanoparticles to the carrier. Hereinafter, the present invention will be described in more detail with reference to the drawings and examples.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a synthesis schematic diagram of a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite according to an embodiment of the present invention; FIG. Referring to FIG. 1, the rose-like Pd-Fe ₃ O ₄ nanocomposite is prepared by pyrolysis of Fe (CO) ₅ in oleylamine (OAm) and 1-octadecene (ODE) OAc) _{2. &} Lt; / _RTI > To synthesize the hybrid Pd-Fe ₃ O ₄ carrier, Pd (OAc) ₂ , oleylamine and octadecane are mixed at room temperature and then heated to 120 ° C. A predetermined amount of Fe (CO) ₅ is added in an argon gas atmosphere. Subsequently, the solution was heated to 4 ° C / min, heated to 160 ° C, maintained at 160 ° C for 30 minutes, and then cooled to room temperature. During the course of the reaction, Pd (OAc) ₂ is reduced to Pd nanoparticles and Fe (CO) ₅ is synthesized as Fe ₃ O ₄ through pyrolysis.

The individual hybrid nanosheets comprising Pd and Fe ₃ O ₄ synthesized under the above synthesis conditions are self-assembled to form Pd-Fe ₃ O ₄ nanocomposites in the form of three-dimensional roses. The Fe / Pd ratio of the nanocomposites synthesized at 160 ° C can be adjusted from 64:36 to 80:20 by increasing the amount of Fe (CO) ₅ from 0.15 to 0.45 mL.

The synthesized Pd-Fe ₃ O ₄ nanocomposite is dispersed in hexane, injected into a gold precursor solution, and reacted at 80 ° C. for 30 minutes. Thereby, the gold nanoparticles in the gold precursor solution are fixed on the Pd-Fe ₃ O ₄ carrier. After the reaction was completed, the reaction mixture was centrifuged in ethanol to obtain a black precipitate, Au / Pd-Fe ₃ O ₄ nanocomposite.

The gold precursor may be at least one selected from the group consisting of HAuCl ₄ .H ₂ O, AuCl, AuCl _3, and AuBr ₃ , but is not necessarily limited thereto.

Since the Au / Pd-Fe ₃ O ₄ nanocomposite has a large specific surface area due to the support made of Pd-Fe ₃ O ₄ nanosheets, it is preferable to use 2-iodoaniline and aryl acetylene in an organic solvent And exhibits excellent catalytic activity in the synthesis of 2-arylindoles prepared by the reaction.

Aryl acetylenes which can be used in the present invention for the synthesis of 2-arylindoles include 2-methylphenylacetylene, 3-methylphenylacetylene, 4-fluoro phenylacetylene, 4-trifluorophenylacetylene, 4-nitrophenylacetylene, 4-trifluorophenylacetylene, 4-nitrophenylacetylene, and the like.

Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to specific examples. However, these examples are merely for a better understanding of the present invention, and are not intended to limit the scope of the present invention.

All the compounds used in the present invention were samples of Aldrich Chemical Co. and TCI Chemical Co. without purification. The solvent used was a solvent of DAEJUNG Co., Ltd. and SAMCHUN Co., Ltd. without purification.

The morphology of the product was measured by transmission electron microscopy (TEM) (FEI, Tecnai F30 Super-Twin, National Institute of Nanoscience), and a few drops of the corresponding colloidal solution were transferred to a carbon- (mesh, F / C coated, Ted Pella Inc., Redding, CA, USA). Magnetization data were measured using Superconducting Quantum Interference Device (SQUID) (MPMS-7, Quantum design). The atomic composition of the hybrid catalysts was obtained by energy-dispersive X-ray spectroscopy (EDS) (550i, IXRF Systems, Inc.), and X-ray diffraction, XRD) pattern was recorded by a Rigaku D / MAX-RB (12 kW) diffractometer.

X-ray photoelectron spectroscopy (XPS) (Theta Probe, Thermo) was used to measure the structural and chemical properties of nanocomposites. The amounts of Pd, Fe and Au in the samples were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES) (iCAP 6300). The surface area and pore-size variance of the samples were determined using the Brunauer-Emmett-Teller (BET) equation and the Barrett-Joyner-Halenda (BJH) Lt; / RTI > The catalyst-assisted tandem reaction product was analyzed by ¹ H nuclear magnetic resonance (NMR) spectroscopy (Varian Mercury Plus, 300 MHz). The chemical shift values were recorded in ppm with tetramethylsilane as the standard, and the coupling constants are given in Hz. The mass spectrum was measured by a mass spectrometer (Shimadzu GC / MS QP-2010 SE (EI), Pusan National University).

Example 1: Pd-Fe ₃ O ₄  Carrier and Au / Pd-Fe ₃ O ₄  Manufacture of Nanocomposites

0.114 g of Pd (OAc) ₂ was added while flowing argon (Ar) gas into a 50 ml three-neck flask containing 10 ml of oleylamine and 10 ml of 1-octadecane at room temperature. The three-necked flask was heated to 60 占 폚 and heated to 120 占 폚 at a heating rate of 6 占 폚 / min. 0.15 m Fe (CO) ₅ was added in an argon gas atmosphere. Then, the solution was heated to 4 ° C / min and heated to 160 ° C, and the reaction product was maintained at 160 ° C for 30 minutes. Then, the heat source was removed and the solution was cooled to room temperature. Excess ethanol and hexane were added to precipitate the product and then centrifuged. The dark-yellow supernatant was removed, and the product was dispersed in 5 ml of hexane. 45 ml of ethanol was added and centrifuged to obtain a black Pd-Fe ₃ O ₄ nanocomposite, Pd-Fe ₃ O ₄ carrier .

After dissolving 41 mg of HAuCl ₄ .H ₂ O as a gold precursor in 12 ml of oleylamine and 3 ml of hexane, the solution was heated to 80 ° C to prepare a gold precursor solution. A precursor solution in which 150 mg of Pd-Fe ₃ O ₄ carrier was dispersed in 10 ml of hexane was injected into the gold precursor solution and stirred at 80 ° C for 30 minutes. The reaction temperature was lowered to room temperature. The product was centrifuged in excess ethanol and hexane to obtain a black precipitate, Au / Pd-Fe ₃ O ₄ nanocomposite.

Example 2: Pd-Fe ₃ O ₄  Preparation of Carrier

A Pd-Fe ₃ O ₄ carrier was prepared in the same manner as in Example 1, except that 0.30 ml of Fe (CO) ₅ was added.

Example 3: Pd-Fe ₃ O ₄  Preparation of Carrier

A Pd-Fe ₃ O ₄ carrier was prepared in the same manner as in Example 1, except that 0.45 ml of Fe (CO) ₅ was added.

Comparative Example 1: Pd-Fe ₃ O ₄  Preparation of Carrier

Pd-Fe ₃ O ₄ carrying member for manufacturing the reaction to prepare a Pd-Fe ₃ O ₄ carrying member in the same manner as in Example 1 except that the holding at 140 ℃ 30 minutes.

Comparative Example 2: Pd-Fe ₃ O ₄  Preparation of Carrier

Pd-Fe ₃ O ₄ carrier the factory reaction was prepared in Example 1 in the same manner as Pd-Fe ₃ O ₄ except that the carrier held at 120 ℃ 30 minutes.

FIGS. 2A and 2B are scanning electron microscopy (SEM) photographs of the Pd-Fe ₃ O ₄ carrier synthesized according to Example 1. FIG. Referring to FIG. 2, it can be confirmed that a rosin-like Pd-Fe ₃ O ₄ nano-support having a well-dispersed average diameter of 213 nm was synthesized.

3A and 3B are SEM micrographs of Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG. The size of the bar included in FIG. 3 is 200 nm. Comparing FIGS. 2B and 3B, it is confirmed that the gold nanoparticles are uniformly fixed on the Pd-Fe ₃ O ₄ support.

4A and 4B are transmission electron microscopy (TEM) photographs of the Pd-Fe ₃ O ₄ carrier synthesized according to Example 1. FIG. In the Pd-Fe ₃ O ₄ carrying member according to Figure 4a and 4b, the whole Fe / Pd ratio is 64:36. 4C and 4D are transmission electron micrographs of the Au / Pd-Fe ₃ O ₄ nanocomposite synthesized by Example 1. 4C and 4D, it can be seen that the gold nanoparticles are well fixed on the Pd-Fe ₃ O ₄ support. The diameter of the fixed gold nanoparticles is 5.8 ± 0.7 nm, spherical and well dispersed. The size of the bar included in the inside of Figs. 4A and 4C is 20 nm.

4E is a high-resolution TEM (HR-TEM) image of the Pd-Fe ₃ O ₄ carrier and FIG. 4F is a high-resolution TEM image of the Au / Pd-Fe ₃ O ₄ nanocomposite. According to FIG. 4e, the Pd and Fe ₃ O ₄ structures have a uniformly spaced lattice fringe structure with a fringe distance of 0.22 nm measured at the Pd (111) plane and a 0.30 nm fringe distance measured at the Fe ₃ O ₄ (220) (Fcc) Pd and Fe ₃ O ₄ structures, respectively. According to FIG. 4F, the gold nanoparticles are uniformly spaced lattice fringes, the fringe distance is measured at 0.24 nm, and corresponds to the interplanar spacing 111 in the face-centered cubic structure.

Figs. 5A to 5F are graphs showing changes in the amount of Fe (CO) ₅ in Examples 1 to 3 TEM photograph of a Pd-Fe ₃ O ₄ carrier. 5a and 5d show the case where the amount of Fe (CO) ₅ used is 0.15 ml (Example 1), Figures 5b and 5e show the case where the amount of Fe (CO) ₅ used is 0.30 ml (Example 2) Figures 5c and 5f show the case where the amount of Fe (CO) ₅ used is 0.45 ml (Example 3). Referring to FIG. 5, it can be seen that as the amount of Fe (CO) ₅ used increases from 0.15 mL to 0.30 and 0.45 mL, the diameter of the Pd-Fe ₃ O ₄ structure gradually decreases. Further, it can be seen that not only the Fe / Pd ratio is controlled by the amount of Fe (CO) ₅ used, but also the morphology of the Pd-Fe ₃ O ₄ nanocomposite is determined.

The specific surface area of the Pd-Fe ₃ O ₄ nanocomposite prepared in Example 1 was measured by a Brunauer-Emmett-Teller equation to obtain a result of 23.79 m ² g ^-1 . This is much wider than the previously reported hollow Fe ₃ O ₄ microspheres having a surface area of 12.27 m ² g ^-1 and a solid spherical Fe ₃ O ₄ microspheres having a surface area of 5.43 m ² g ^-1 . It is believed that the reason why the specific surface area of the Pd-Fe ₃ O ₄ nanocomposite according to the present invention is wide is due to the self-assembled individual Pd-Fe ₃ O ₄ nanosheets having a rose flower petal shape. That is, the structure of the Pd-Fe ₃ O ₄ carrier is a three-dimensional rosette structure, and has a wide specific surface area, which is very advantageous to be applied to electronic devices such as lithium ion batteries and photocatalyst sensors.

6A to 6F are TEM photographs of the Pd-Fe ₃ O ₄ carrier synthesized at different temperatures according to Example 1, Comparative Example 1 and Comparative Example 2. FIG. FIGS. 6A and 6D show the case where the temperature is 160 DEG C (Example 1), FIGS. 6B and 6E show the case where the temperature is 140 DEG C (Comparative Example 1) 2). 6 shows that the thermal decomposition of Fe (CO) ₅ and the reduction of Pd (OAc) ₂ are not sufficiently performed at 120 ° C. and 140 ° C., and the diameter of the Pd-Fe ₃ O ₄ nanocomposite is shortened and aggregations Results are shown.

The Pd-Fe ₃ O ₄ nanocomposite and the Au / Pd-Fe ₃ O ₄ nanocomposite prepared according to Example 1 were analyzed by X-ray diffraction (XRD). FIG. 7 is an X-ray diffraction (XRD) photograph of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG. Referring to the XRD results shown in FIG. 7, the overall compositional ratio of the synthesized complex is 7: 77: 1 for Au: Fe: Pd, and 64:36 for Fe: Pd. The crystallinity of Pd and Fe ₃ O ₄ was confirmed by XRD. All the peaks of the XRD pattern in the Pd-Fe ₃ O ₄ structure were assigned to the lattice planes 111, 200 and 220 of the Pd crystal structure and the lattice planes of the Fe ₃ O ₄ cubic spinel structure 220, 311, 422, 511 and 440 (JPCDS 46-1043). In the case of Au / Pd-Fe ₃ O ₄ , fixed gold nanoparticles were assigned to (111), (200), (220) and (311) of the face-centered cubic Au crystal structure (JCPDS No. 04-0784). Wide peaks of gold nanoparticles mean that the size of the crystal domain is small.

FIG. 8 is a view showing a high-angle scattering electron microscope (SEM) of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1, HAADF-STEM), which is an elemental mapping of Fe and Pd. According to FIG. 8, it can be seen that Pd and Fe ₃ O ₄ are uniformly dispersed in the entire region of the nanocomposite and are a hybrid Pd-Fe ₃ O ₄ structure.

9 is a superconducting quantum interference device (SQUID) data of a Pd-Fe ₃ O ₄ nanocomposite and an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG. The SQUID data according to FIG. 9 shows a magnetic curve as a function in the applied region 300K, and the magnetism of the synthesized Au / Pd-Fe ₃ O ₄ nanocomposite can be measured. The measured saturation magnetization value of the Au / Pd-Fe ₃ O ₄ nanocomposite is 5.49 emu · g ^{-1, which} is similar to the saturation magnetization value of Pd-Fe ₃ O ₄ of 5.67 emu · g ^-1 . In addition, the remanence Mr and coercivity (Hc) of the nanocomposite are near zero and exhibit superparamagnetism.

10a to 10d are diagrams showing the elemental analysis of Au / Pd-Fe ₃ O ₄ by X-ray photoelectron spectroscopy (XPS) of Au / Pd-Fe ₃ O ₄ nanocomposite synthesized by Example 1 Fig. As shown in FIG. 10B, for Au ⁰ , The doublet bond energy of Au 4f _7/2 is 83.2 eV and the doublet bond energy of Au 4f _5/2 is 86.8 eV, indicating Au ⁰ characterization. Referring to Fig. 10C, the strongest peak of binding energy for Pd is 335.1 eV for 3d _5/2 and 340.3 eV for 3d _3/2 , indicating the metal Pd characteristics. On the other hand, FIG. 10D shows the XPS signals of the Fe 2p region, indicating that both Fe ²⁺ and Fe ³⁺ form Fe ₃ O ₄ . The additional satellite peak, 719 eV, represents a component between Fe 2p _1/2 (724.8 eV) and Fe 2p _3/2 (710.9 eV), and as a characteristic peak of Fe ³⁺ in γ-Fe ₂ O ₃ , Fe ₃ O ₄ nanoparticles are partially oxidized.

FIG. 11 is an energy-dispersive X-ray spectroscopy (EDS) spectrum of an Au / Pd-Fe ₃ O ₄ nanocomposite synthesized according to Example 1. FIG. The atomic composition of the Au / Pd-Fe ₃ O ₄ nanocomposite can be confirmed in FIG.

The Pd-Fe ₃ O ₄ nanocomposite prepared according to Example 1 was subjected to a Sonokashira carbon-carbon cross-linking reaction (Sonogashira, K. (2002), "Development of Pd-Cu catalyzed cross-coupling of terminal acetylenes with sp ² - carbon halides ", J. Organomet. Chem., 653: 46-49).

Examples 4 to 16: Sonogashira carbon-carbon cross-linking reaction

1 mmol of iodobenzene, 1.1 mmol of phenylacetylene, 2 mmol of piperidine, 5 ml of dimethyl sulfoxide (DMSO) and 1 g of Pd-Fe ₃ O ₄ nano Sonogashira carbon - carbon cross - linking reaction was carried out using the complex as a catalyst. The amounts of catalyst, reaction temperature, time, base and solvent were reacted differently as described in Examples 4 to 16 of Table 1 below. The conversion of the product Measurement by GC / MS mass spectrometry is shown in Table 1 below.

                  [Sonogashira carbon-carbon cross-linking reaction]

Catalyst (mol%) Temperature (℃) Time (h) base menstruum Conversion Rate (%) Example 4 One 120 18 Piperidine DMF 72 Example 5 One 120 18 Piperidine NMP 76 Example 6 One 120 18 Piperidine DMSO 99 Example 7 One 120 18 Cs ₂ CO ₃ DMSO 73 Example 8 One 120 18 NaOAc DMSO 98 Example 9 One 120 18 K ₂ CO ₃ DMSO 78 Example 10 One 100 18 Piperidine DMSO 99 Example 11 One 90 18 Piperidine DMSO 92 Example 12 0.25 100 18 Piperidine DMSO 99 Example 13 0.5 100 6 Piperidine DMSO 88 Example 14 0.5 120 3 Piperidine DMSO 99 Example 15 0.25 120 3 Piperidine DMSO 94 Example 16 0.5 120 One Piperidine DMSO 93

Referring to Table 1, when the reaction was carried out while changing the solvent, DMSO showed the highest catalytic activity (conversion rate: 99%). In addition, when the base was controlled, the best catalytic activity was observed when piperidine was used. According to Example 14, the catalytic reaction results were optimized at a catalyst amount of 0.5 mol%, a reaction time of 3 hours, and a temperature of 120 ° C.

In addition, a rose-like palladium-iron oxide hybrid nanocomposite carrying the gold nanoparticles prepared in Example 1 was used as a catalyst for a tandem synthesis continuous reaction of 2-phenylindole. Tandem synthesis was carried out to synthesize 2-phenylindole from 2-iodoaniline and aryl acetylene as follows.

[2-페닐인돌의 탠덤 합성]

[Tandem synthesis of 2-phenylindole]

Examples 17 to 21: Tandem synthesis of 2-phenylindole

Of 0.1mol% Pd-Fe ₃ O ₄ catalyst, 2-iodo-aniline (0. 11g, 0.5 mmol, 1.0 eq), phenylacetylene (0.061 ml, 0.55 mmol, 1.1 eq), base (1.0 mmol, 2.0 eq.) And the solvent (2.5 mL) were mixed in 10 mL vial glass. The mixture was stirred vigorously at 150 < 0 > C. When the reaction is complete, the catalyst is separated off with an external magnet and the reaction mixture is filtered with diethyl ether. Dry the filtered reaction mixture was dried MgSO _4, and evaporation of the solvent of the filtrate to give the reaction product. The temperatures, times, bases and solvents were reacted differently as described in Examples 17-21 in Table 2 below. Based on 2-iodoaniline The conversion of the product as determined by GC / MS mass spectrometry is shown in Table 2 below. ¹ H-NMR data of the resulting 2-phenylindole are as follows.

_{^{2-phenyl-indole: 1 H-NMR (CDCl 3}} , 300 MHz): δ = 7.53 (dd, J = 2.4 and 8.1Hz 2H), 7.38-7.39 (m, 1H), 7.35 (dd, J = 2.4 and 4.8 Hz, 3H) 7.15 (td, J = 1.5 and 7.8 Hz, IH) 6.74 (d, 7.5 Hz, 2H) 4.28 (br, IH). MS (EI) m / z: 193 (100), 165 (44), 89 (20), 28 (16).

Examples 22 to 25: Tandem synthesis of 2-phenylindole

Of 0.1mol% based on the content of gold Au / Pd-Fe ₃ O ₄ catalyst, 2-iodo-aniline (0.11g, 0.5 mmol, 1.0 eq), phenylacetylene (0.061 ml, 0.55 mmol, 1.1 eq), base ( 1.0 mmol, 2.0 eq.) And solvent (2.5 mL) were mixed in 10 mL vial glass. The mixture was stirred vigorously at 150 < 0 > C. When the reaction is complete, the catalyst is separated off with an external magnet and the reaction mixture is filtered with diethyl ether. Dry the filtered reaction mixture was dried MgSO _4, and evaporation of the solvent of the filtrate to give the reaction product. The temperatures, times, bases and solvents were reacted differently as described in Examples 22 to 25 of Table 2 below. Based on 2-iodoaniline The conversion of the product as determined by GC / MS mass spectrometry is shown in Table 2 below.

Example 26: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized by the same method as in Example 24 except that 0.05 mol% of Au / Pd-Fe ₃ O ₄ catalyst was used based on the gold content.

catalyst Temperature (℃) Time (h) base menstruum Conversion Rate (%) Example 17 Pd-Fe ₃ O ₄ 120 18 Piperidine DMF a very small amount Example 18 Pd-Fe ₃ O ₄ 120 18 Piperidine DMA 3 Example 19 Pd-Fe ₃ O ₄ 120 18 Piperidine DMSO 41 Example 20 Pd-Fe ₃ O ₄ 120 18 LiOAc DMSO 45 Example 21 Pd-Fe ₃ O ₄ 120 18 CsOAc DMSO 48 Example 22 Au / Pd-Fe ₃ O ₄ 120 18 CsOAc DMSO 57 Example 23 Au / Pd-Fe ₃ O ₄ 150 18 CsOAc DMSO 97 Example 24 Au / Pd-Fe ₃ O ₄ 150 9 CsOAc DMSO 97 Example 25 Au / Pd-Fe ₃ O ₄ 150 6 CsOAc DMSO 59 Example 26 Au / Pd-Fe ₃ O ₄ 150 9 CsOAc DMSO 38 ^a

^a 0.05 mol% of catalyst is used

The solvent effects were evaluated in Examples 17 to 19. According to Example 17, when the reaction was carried out in dimethylformamide (DMF) for 18 hours at a temperature of 120 ° C with 0.1 mol% of Pd-Fe ₃ O ₄ catalyst, the reaction hardly proceeded. According to Example 19, when the solvent was changed to DMSO, the reaction conversion rate was increased to 48%. As a result, it can be seen that the use of DMSO as a polar solvent increases the conversion ratio. This is believed to be due to the good solubility of the reactants and catalyst in the reaction medium.

Further, in Examples 19 to 21, the influence of bases such as piperidine, lithium acetate (LiOAc) and cesium acetate (CsOAc) was evaluated. According to Example 21, when the base was adjusted, CsOAc showed 48%, which is higher than that of using piperidine and LiOAc, and the highest conversion was obtained when CsOAc was used. According to the hard-soft acid and base theory, Cs ⁺ maximizes soft-soft interaction and is the best Pearson to remove iodide from palladium nanoparticles It is a pearson acid.

In comparison between Example 21 and Example 24, when the catalyst was changed to Au / Pd-Fe ₃ O ₄ , the catalyst activity was higher than that of Pd-Fe ₃ O ₄ . This is because the dual-catalyst system of gold and palladium exhibits better catalytic properties than a single catalyst system. The dual-catalyst system of gold and palladium prevents the transfer of electrons by crossing the interface and preventing the formation of stoichiometric metal exchange by-products during the cross-linking reaction. Thus, Au / Pd-Fe ₃ O ₄ catalysts exhibit better catalytic activity than single Pd-Fe ₃ O ₄ catalysts because gold nanoparticles are used to be more effective in activating phenylacetylene.

Comparing Example 22 with Example 23, 97% conversion was achieved at a high temperature of 150 ° C, indicating that the reaction effect was excellent at a high temperature. The effects of catalyst amount and time were also evaluated. According to Examples 24 to 26, it can be seen that the conversion rate is decreased as the reaction time is short and the amount of catalyst used is small.

In conclusion, according to Example 24, in the tandem synthesis of 2-phenylindole using the Au / Pd-Fe ₃ O ₄ nanocomposite according to the present invention as a catalyst The optimum reaction conditions are as follows.

Au / Pd-Fe ₃ O ₄ catalyst: 0.1 mol% based on Au

Solvent: DMSO (2.5 mL)

Reaction temperature: 150 ° C

Reaction time: 9 hours

The catalytic activities of the Au / Pd-Fe ₃ O ₄ catalyst according to the present invention and the previously reported heterogeneous catalysts were compared.

Example 27: Tandem synthesis of 2-phenylindole

Pd-Fe ₃ O ₄ catalyst, 2-iodoaniline (0.11 g, 0.5 mmol, 1.0 eq.), Phenylacetylene (0.061 ml, 0.55 mmol, 1.1 eq.), CsOAc 1.0 mmol, 2.0 eq.) And DMSO (2.5 mL) were mixed in 10 ml vial glass. The mixture was vigorously stirred at 150 < 0 > C for 4.5 hours. When the reaction is complete, the catalyst is separated off with an external magnet and the reaction mixture is filtered with diethyl ether. Dry the filtered reaction mixture was dried MgSO _4, and evaporation of the solvent of the filtrate to give the reaction product.

Comparative Example 3: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized in the same manner as in Example 27 except that Pd / CMK-3 (Pd / Mesostructured, KAIST) was used as the catalyst.

Comparative Example 4: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized in the same manner as in Example 27 except that Pd @ SiO ₂ having a core-shell structure was used as a catalyst.

Comparative Example 5: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized in the same manner as in Example 27 except that Pd / Fe ₃ O ₄ was used as a catalyst.

Comparative Example 6: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized in the same manner as in Example 27 except that Pd / Fe ₃ O ₄ / C was used as a catalyst.

Comparative Example 7: Tandem synthesis of 2-phenylindole

2-phenylindole was synthesized in the same manner as in Example 27 except that a core-shell structure Au / Fe ₃ O ₄ @polymer was used as a catalyst.

12 is a graph comparing the catalytic activities of the Au / Pd-Fe ₃ O ₄ nanocomposite catalyst prepared in Example 1 and the conventional heterogeneous catalyst. Referring to FIG. 12, it can be seen that Au / Pd-Fe ₃ O ₄ exhibits the highest turnover frequency (TOF) under the same conditions. It is believed that the Au / Pd-Fe ₃ O ₄ nanocomposite catalyst according to the present invention is a dual-catalyst system having a catalytic effect between a Pd-Fe ₃ O ₄ carrier and gold nanoparticles. In addition, the Pd-Fe ₃ O ₄ carrier exhibits excellent catalytic activity because the Pd-Fe ₃ O ₄ nanosheet has a large surface area Pd ⁰ site that can self-assemble as a catalytically active site. Without any additive or ligand, the Au / Pd-Fe ₃ O ₄ catalyst exhibited superior catalytic activity in conversion as compared to the preceding copper-gold complex or gold nanoparticles.

The Au / Pd-Fe ₃ O ₄ catalyst according to the present invention is completely separated by the external magnet after the tandem reaction because the Fe ₃ O ₄ particles exhibit superparamagnetic properties. The recovered particles can be reused as a catalyst for the next reaction. The Au / Pd-Fe ₃ O ₄ catalyst was reused three times and maintained initial high activity 99% or more without loss of catalyst during reuse.

Pd dissolution experiment and evaluation of catalyst stability

After the catalytic reaction, thermal filtration was carried out to check whether the catalyst eluted during the reaction. The leaching test of Pd and Au was performed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). For the dissolution experiments of Pd and Au, the filtered solution after the catalytic reaction was analyzed and a small amount of 79.8 ppm Pd and 80.9 ppm Au were measured in solution.

In order to determine the leaching degree of Pd, 150 equivalents of poly (4- (vinylpyridine)) (poly (4-vinylpyridine)) (PVPy) was used before the catalytic reaction was started. PVPy acts as a poison to capture homogeneous Pd through chelation in solution during the coupling reaction.

The stability of the catalyst was also evaluated by ultrasonic testing. First, the Au / Pd-Fe ₃ O ₄ catalyst prepared in Example 1 was placed in an aqueous solution (0.5 mg / mL) in an ultrasonic cleaner for two hours. After removing the catalyst, the mass of Au, Pd and Fe atoms separated from Au / Pd-Fe ₃ O ₄ was measured. ICP-AES measurement results using ICP-OES (Thermo Scientific iCAP 6300) are shown in Table 3 below.

Element wavelength (nm) Measurement concentration (/ / kg, ppb) Au / Pd-Fe ₃ O ₄ Au (242.7) 187 Fe (259.9) 448 Pd (324.2) 441

              Temperature: Measured at (23 ± 3) ℃, Relative humidity: (50 ± 10)%

According to Table 3, it can be seen that the measurement concentration of Au, Pd and Fe atoms separated from Au / Pd-Fe ₃ O ₄ is very low, which means high stability of the catalyst. Thus, it can be seen that the Au / Pd-Fe ₃ O ₄ catalyst maintains catalytic activity and stability, even though the particles elute slightly during the reaction.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as set forth in the appended claims. Modifications and variations are intended to be included within the scope of the present invention.

Claims (15)

Mixing a solution prepared by dissolving palladium (II) acetate in oleylamine and 1-octadecene at room temperature and raising the temperature to 120 ° C;
Adding Fe (CO) ₅ to the solution, raising the temperature of the reaction solution to 160 캜, holding the mixture for 30 minutes, and cooling to room temperature;
Separating and purifying the product, and dispersing the purified product in hexane to prepare a hybrid Pd-Fe ₃ O ₄ carrier solution;
Injecting the Pd-Fe ₃ O ₄ carrier solution into a gold precursor solution, stirring the mixture at 80 ° C for 30 minutes, and cooling to room temperature;
Pd-Fe ₃ O ₄ nanocomposite comprising centrifuging and purifying the product.
The method according to claim 1, wherein the Pd-Fe ₃ O ₄ carrier is composed of self-assembled Pd-Fe ₃ O ₄ nanosheets having a rose flower petal shape A method for producing a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite. The method according to claim 1, wherein the gold precursor solution is prepared by dissolving at least one gold precursor selected from the group consisting of HAuCl ₄ .H ₂ O, AuCl, AuCl ₃ and AuBr ₃ in oleic amine and hexane A method for producing a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite.
The method for producing a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite according to claim 1, wherein the heating rate for raising the temperature of the reaction solution is 4 ° C./min to 6 ° C./min.
The method of claim 1, wherein the Fe / Pd ratio in the Pd-Fe ₃ O _{4 support} is adjusted from 64:36 to 80:20 by increasing the amount of Fe (CO) ₅ to 0.15 to 0.45 mL A method for producing a rose-like Au / Pd-Fe ₃ O ₄ nanocomposite.
A catalyst for carbon-carbon cross-linking reaction composed of Au / Pd-Fe ₃ O ₄ nanocomposite with gold nanoparticles immobilized on rose-like Pd-Fe ₃ O ₄ hybrid carriers. The carbon-carbon cross-coupling reaction catalyst according to claim 6, wherein the Pd-Fe ₃ O ₄ hybrid carrier is composed of a self-assembled Pd-Fe ₃ O ₄ nanosheet having a petal shape of rose flower. .
7. The catalyst for carbon-carbon cross-linking reaction according to claim 6, wherein the diameter of the gold nanoparticles is 5.8 +/- 0.7 nm.
8. A process for producing a 2-aryl-2-aryl-4-methyl-2-pyrrolidone compound, which comprises the step of stirring a reaction solution obtained by dissolving a catalyst for a carbon-carbon crosslinking reaction according to any one of claims 6 to 8, 2-iodoaniline and aryl acetylene in a dimethylsulfoxide solvent ≪ / RTI >
10. The process according to claim 9, wherein the process is carried out at a catalytic amount of 0.1 mol% based on gold, a reaction time of 9 hours and a temperature of 150 < 0 > C.
10. The method according to claim 9, wherein the reaction solution further comprises cesium acetate (CsOAc) as a base.
The method of claim 9, wherein the aryl acetylene is selected from the group consisting of 2-methylphenylacetylene, 3-methylphenylacetylene, 4-fluorophenylacetylene, 4- (4-trifluorophenylacetylene), 4-nitrophenylacetylene (4-trifluorophenylacetylene), and the like.
A step of stirring a reaction solution in which a rose-like Pd-Fe ₃ O ₄ hybrid nanocomposite catalyst, iodobenzene and phenylacetylene are dissolved in a dimethyl sulfoxide solvent, Gt;
14. The process for producing diphenylacetylene according to claim 13, wherein the process is carried out at a catalyst content of 0.5 mol% based on gold, a reaction time of 3 hours and a temperature of 120 < 0 > C.
14. The process for producing diphenylacetylene according to claim 13, wherein the reaction solution further comprises piperidine as a base.

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