Efficient heck reactions catalyzed by palladium(0) and -(II) complexes bearing n-heterocyclic carbene and amide functionalities

Jhen Yi Lee, Pi Yun Cheng, Yi Hua Tsai, Guan Ru Lin, Shih Pu Liu, Ming Han Sie, Hon Man Lee

Research output: Contribution to journalArticle

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Abstract

A palladium(0) NHC complex Pd0(LH1)2(MA) (MA = maleic anhydride) was prepared from the amide-imidazolium salt [LH 1H2]Cl (H1 = NH proton; H2 NCHN proton). The X-ray diffraction studies confirmed that a η2-MA ligand and two monodentate NHC ligands with the H1 protons remaining intact are coordinated. These NH protons are involved in intra- or intermolecular hydrogen bonds stabilizing the solid-state structure. Degradation of Pd(LH1)2(MA) in air leads to the formation of the chelate complex trans-PdIIL2 and other unidentified products. Negative-ion electrospray mass spectrometry revealed some intriguing Pd(0) species, including a 14-electron [Pd0L]- species that bears only a bidentate NHC/amido ligand. The anionic amido group imparts a high electron density on a palladium center, as shown by X-ray photoelectron study. The palladium(0) precatalyst is highly efficient in catalyzing Heck reactions with activated aryl chlorides in ionic liquid. For deactivating aryl chlorides and bulky aryl bromides, cis-PdIIL2 is more effective. A range of Heck-coupled products can be prepared by Pd 0(LH1)2(MA) and cis-PdIIL 2. The latter complex also successfully mediates one-pot sequential Heck/Heck and Suzuki/Heck coupling reactions with 4-bromochlorobenzene as substrate.

Original languageEnglish
Pages (from-to)3901-3911
Number of pages11
JournalOrganometallics
Volume29
Issue number17
DOIs
Publication statusPublished - 2010 Sep 13

Fingerprint

Bearings (structural)
Palladium
carbenes
Amides
amides
Protons
palladium
protons
Ligands
ligands
Chlorides
chlorides
Maleic Anhydrides
Ionic Liquids
anhydrides
products
Photoelectrons
bears
Bromides
chelates

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Cite this

Lee, Jhen Yi ; Cheng, Pi Yun ; Tsai, Yi Hua ; Lin, Guan Ru ; Liu, Shih Pu ; Sie, Ming Han ; Lee, Hon Man. / Efficient heck reactions catalyzed by palladium(0) and -(II) complexes bearing n-heterocyclic carbene and amide functionalities. In: Organometallics. 2010 ; Vol. 29, No. 17. pp. 3901-3911.
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abstract = "A palladium(0) NHC complex Pd0(LH1)2(MA) (MA = maleic anhydride) was prepared from the amide-imidazolium salt [LH 1H2]Cl (H1 = NH proton; H2 NCHN proton). The X-ray diffraction studies confirmed that a η2-MA ligand and two monodentate NHC ligands with the H1 protons remaining intact are coordinated. These NH protons are involved in intra- or intermolecular hydrogen bonds stabilizing the solid-state structure. Degradation of Pd(LH1)2(MA) in air leads to the formation of the chelate complex trans-PdIIL2 and other unidentified products. Negative-ion electrospray mass spectrometry revealed some intriguing Pd(0) species, including a 14-electron [Pd0L]- species that bears only a bidentate NHC/amido ligand. The anionic amido group imparts a high electron density on a palladium center, as shown by X-ray photoelectron study. The palladium(0) precatalyst is highly efficient in catalyzing Heck reactions with activated aryl chlorides in ionic liquid. For deactivating aryl chlorides and bulky aryl bromides, cis-PdIIL2 is more effective. A range of Heck-coupled products can be prepared by Pd 0(LH1)2(MA) and cis-PdIIL 2. The latter complex also successfully mediates one-pot sequential Heck/Heck and Suzuki/Heck coupling reactions with 4-bromochlorobenzene as substrate.",
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Efficient heck reactions catalyzed by palladium(0) and -(II) complexes bearing n-heterocyclic carbene and amide functionalities. / Lee, Jhen Yi; Cheng, Pi Yun; Tsai, Yi Hua; Lin, Guan Ru; Liu, Shih Pu; Sie, Ming Han; Lee, Hon Man.

In: Organometallics, Vol. 29, No. 17, 13.09.2010, p. 3901-3911.

Research output: Contribution to journalArticle

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T1 - Efficient heck reactions catalyzed by palladium(0) and -(II) complexes bearing n-heterocyclic carbene and amide functionalities

AU - Lee, Jhen Yi

AU - Cheng, Pi Yun

AU - Tsai, Yi Hua

AU - Lin, Guan Ru

AU - Liu, Shih Pu

AU - Sie, Ming Han

AU - Lee, Hon Man

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N2 - A palladium(0) NHC complex Pd0(LH1)2(MA) (MA = maleic anhydride) was prepared from the amide-imidazolium salt [LH 1H2]Cl (H1 = NH proton; H2 NCHN proton). The X-ray diffraction studies confirmed that a η2-MA ligand and two monodentate NHC ligands with the H1 protons remaining intact are coordinated. These NH protons are involved in intra- or intermolecular hydrogen bonds stabilizing the solid-state structure. Degradation of Pd(LH1)2(MA) in air leads to the formation of the chelate complex trans-PdIIL2 and other unidentified products. Negative-ion electrospray mass spectrometry revealed some intriguing Pd(0) species, including a 14-electron [Pd0L]- species that bears only a bidentate NHC/amido ligand. The anionic amido group imparts a high electron density on a palladium center, as shown by X-ray photoelectron study. The palladium(0) precatalyst is highly efficient in catalyzing Heck reactions with activated aryl chlorides in ionic liquid. For deactivating aryl chlorides and bulky aryl bromides, cis-PdIIL2 is more effective. A range of Heck-coupled products can be prepared by Pd 0(LH1)2(MA) and cis-PdIIL 2. The latter complex also successfully mediates one-pot sequential Heck/Heck and Suzuki/Heck coupling reactions with 4-bromochlorobenzene as substrate.

AB - A palladium(0) NHC complex Pd0(LH1)2(MA) (MA = maleic anhydride) was prepared from the amide-imidazolium salt [LH 1H2]Cl (H1 = NH proton; H2 NCHN proton). The X-ray diffraction studies confirmed that a η2-MA ligand and two monodentate NHC ligands with the H1 protons remaining intact are coordinated. These NH protons are involved in intra- or intermolecular hydrogen bonds stabilizing the solid-state structure. Degradation of Pd(LH1)2(MA) in air leads to the formation of the chelate complex trans-PdIIL2 and other unidentified products. Negative-ion electrospray mass spectrometry revealed some intriguing Pd(0) species, including a 14-electron [Pd0L]- species that bears only a bidentate NHC/amido ligand. The anionic amido group imparts a high electron density on a palladium center, as shown by X-ray photoelectron study. The palladium(0) precatalyst is highly efficient in catalyzing Heck reactions with activated aryl chlorides in ionic liquid. For deactivating aryl chlorides and bulky aryl bromides, cis-PdIIL2 is more effective. A range of Heck-coupled products can be prepared by Pd 0(LH1)2(MA) and cis-PdIIL 2. The latter complex also successfully mediates one-pot sequential Heck/Heck and Suzuki/Heck coupling reactions with 4-bromochlorobenzene as substrate.

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