Synthesis of pH-responding palladium N-heterocyclic carbene chelate and catalytic application thereof

A heterocyclic carbene and chelate technology, which is applied in the synthesis and catalytic application of pH-responsive palladium N-heterocyclic carbene chelates, and can solve the problem of less research on catalytic reaction systems

Inactive Publication Date: 2013-02-20
FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although palladium nitrogen heterocyclic carbene compounds have excellent water and air stability, the coupling reaction catalyzed in organic solvents has been widely studied, but the catalytic reaction system in aqueous media has been less reported.

Method used

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  • Synthesis of pH-responding palladium N-heterocyclic carbene chelate and catalytic application thereof
  • Synthesis of pH-responding palladium N-heterocyclic carbene chelate and catalytic application thereof
  • Synthesis of pH-responding palladium N-heterocyclic carbene chelate and catalytic application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017]

[0018] At room temperature, under the protection of nitrogen, the ligand L1 (0.3g, 0.5mmol) and palladium acetate (0.1g, 0.5mmol) were added to 5.0mL dimethylsulfoxide. Stir, heat to 60 degrees centigrade and react for 12 hours, then heat up to 130 degrees centigrade and continue to react for 2 hours. After cooling down, it was concentrated to dryness in vacuum at 90 degrees Celsius, washed 3 times with tetrahydrofuran and dried in vacuum to obtain the N-heterocyclic carbene chelate of palladium with a yield of 86%. 1 H NMR (400 MHz, d 6-DMSO): δ 8.3-7.8 (m, 12H), 6.7-6.5 (m, 2H), 4.39 (q, J = 6.8 Hz,4H), 1.39 (t, J = 7.2 Hz, 4H); 13 C NMR (100 MHz, d 6-DMSO): δ 165.8, 159.9, 143.4, 130.5, 129.8, 125.9, 123.2, 61.5, 14.7.

Embodiment 2

[0020]

[0021] at room temperature, the 1 (0.3g, 0.4mmol) and lithium hydroxide (0.05g, 1.3 mmol) were added to a mixed solvent of 3 mL methanol and 3 mL water, stirred and reacted for 2 hours, concentrated to remove methanol, in an ice-water bath, dilute hydrogen bromide Acidify the acid until the pH value reaches 4, and a white solid is precipitated. The white solid is washed twice with 5 mL of water and 5 mL of tetrahydrofuran respectively, and dried in vacuum to obtain a white pH-responsive palladium N-heterocyclic carbene chelate 2 , the yield is 80 %; 1 H NMR (400 MHz, d 6-DMSO): δ 8.30-8.15 (m, 4H), 8.00-7.80 (m, 8H), 6.60-6.45 (m, 2H); 13 C NMR (100 MHz, d 6-DMSO): δ 167.3, 159.9, 143.1, 130.9, 130.6, 125.7, 123.1. Elemental analysis theoretical value: C 21 h 16 Br 2 N 4 o 4 Pd·H 2 O (672.6): C 37.50, H 2.70, N 8.33, measured by elemental analysis: C 37.48, H 2.89, N 8.21 %.

Embodiment 3

[0023]

[0024] at room temperature, the 1 (0.3g, 0.4mmol) and lithium hydroxide (0.05g, 1.3 mmol) were added to a mixed solvent of 3 mL methanol and 3 mL water, stirred and reacted for 2 hours, concentrated to remove methanol, acidified with dilute hydrochloric acid in an ice-water bath When the pH value reached 4, a white solid was precipitated, and the white solid was washed twice with 5 mL of water and 5 mL of tetrahydrofuran respectively, and dried in vacuum to obtain a white pH-responsive palladium N-heterocyclic carbene chelate 3 , yield 73 %; 1 H NMR (400 MHz, d 6-DMSO): δ 8.30-8.15 (m, 4H), 8.10-7.80 (m, 8H), 6.60-6.45 (m, 2H); 13 C NMR (100 MHz, d 6-DMSO): δ 167.3, 158.6, 143.0, 130.8, 130.6, 125.5, 125.5, 123.2, 123.0. Elemental analysis theoretical value: C 21 h 16 BrClN 4 o 4 Pd 0.5H 2 O (619.2): C 40.74, H 2.77, N 9.05, measured by elemental analysis: C 40.76, H 2.97, N 8.95 %.

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Abstract

The invention provides synthesis of a pH-responding palladium N-heterocyclic carbene chelate and catalytic application thereof. The synthesis process consists of: taking dimethyl sulfoxide as a solvent, adding palladium acetate and a benzoate-containing dibromodiimidazole ionic salt, leaving them to react for 12h at 60DEG C, then raising the temperature to 130DEG C to make them further react for 2h, conducting concentration, carrying out washing with tetrahydrofuran, and performing vacuum drying to obtain a water insoluble N-heterocyclic carbene chelate of palladium; and hydrolyzing the ester group in the chelate by lithium hydroxide, then conducting acidification with hydrochloric acid or hydrobromic acid, thus obtaining the pH-responding palladium N-heterocyclic carbene chelate. The palladium N-heterocyclic carbene chelate synthesized in the invention contains a carboxyl group and has a pH-responding function. The palladium N-heterocyclic carbene chelate has high catalytic activity to the coupling reaction of aryl halides in water, and a catalyst can be separated by adjusting the pH of the reaction system and can be recycled repeatedly. The catalytic system is environment-friendly, thus providing a new path for development of organometallic chemistry and application of N-heterocyclic carbine compounds.

Description

technical field [0001] The present invention relates to the synthesis and catalytic application of pH-responsive palladium N-heterocyclic carbene chelates. Background technique [0002] The transition metal-catalyzed cross-coupling reaction of aryl halides and metal organic reagents is an effective means to realize carbon-carbon bond and carbon-nitrogen bond coupling. It is used in dyes, medicines, pesticides, daily chemicals and polymers It plays an extremely important role in the industrial synthesis production and is widely used in the synthesis of natural products, pharmaceutical intermediates and functional materials. Current research focuses on non-phosphine ligands and environmentally friendly reaction media, especially for scoring coupling reactions in water. Water has unique advantages such as cheap, non-toxic, non-flammable, easy to recycle, and does not pollute the environment. In addition to replacing organic solvents and reducing pollution, water also provides...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F15/00B01J31/22C07B37/04C07C49/784C07C45/68C07C25/18C07C17/263C07C43/205C07C41/30C07C15/14C07C1/32C07D333/08B22F9/20
Inventor 王瑞虎李留义周春山
Owner FUJIAN INST OF RES ON THE STRUCTURE OF MATTER CHINESE ACAD OF SCI
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