62827-82-1Relevant academic research and scientific papers
Multidentate N-Heterocyclic Carbene Complexes of Nickel and Palladium: Structural Analysis and Catalytic Application in Mizoroki–Heck Coupling Reaction
Liu, Li-Cheng,Tzeng, Yan-Hsiang,Hung, Cheng-Hau,Lee, Hon Man
, p. 3601 - 3611 (2020/09/01)
Two series of electron-rich metal (Ni and Pd) complexes, namely a pyridine-coordinated tridentate NHC/amidate/phenoxy metal complex and a tetradentate complex bearing an extra pyridyl group, were synthesized. Two carbene moieties, imidazole-based and benzimidazole-based NHCs, were also incorporated into the ligand backbones. Seven of the new complexes were structurally characterized and comparative structural analysis revealed that the tetradentate complex with a flanking pyridyl side-arm was less distorted, leading to chelation-assisted stronger NHC coordination and hence a shorter metal–carbene bond. The catalytic activities of the two sets of palladium complexes for the Mizoroki–Heck coupling reaction were investigated. The comparative data showed that despite the higher thermal stability and the presence of the flanking hemilabile pyridyl side-arm which provided unsaturation to the metal center, the catalytic performance was slightly inferior to that of the tridentate palladium complex with a “throw-away” pyridine ligand. The tridentate palladium complex with the benzimidazole-based NHC moiety was the most effective catalyst, allowing the utilization of a range of aryl chlorides including deactivated substrates with a low 0.2 mol-% Pd loading in molten n-tetrabutylammonium bromide.
Synthesis and characterization of a new zwitterionic palladium complex as an environmentally friendly catalyst for the Heck-Mizoroki coupling reaction in GVL
Bagherzadeh, Mojtaba,Mahmoudi, Hamed,Ataie, Saeed,Bahjati, Mohammad,Kia, Reza,Raithby, Paul R.,Vaccaro, Luigi
, (2019/06/05)
A new zwitterionic Palladium (II) complex has been synthesized by the one-pot mixing of Pd(OAc)2, 2-aminophenol and (3-formyl-4-hydroxy-5-methylbenzyl) triphenylphosphonium chloride, in refluxing ethanol. The metal complex formed was characterized by 1H NMR, 13C NMR, 31P NMR and X-ray crystallographic technique and its efficiency tested as a homogeneous pre-catalyst in Heck-Mizoroki cross coupling reaction using γ-Valerolactone (GVL) as a biomass-derived green medium. All the products were obtained in good to excellent yields.
Postmodification Approach to Charge-Tagged 1,2,4-Triazole-Derived NHC Palladium(II) Complexes and Their Applications
Nguyen, Van Ha,Ibrahim, Mansur B.,Mansour, Waseem W.,El Ali, Bassam M.,Huynh, Han Vinh
, p. 2345 - 2353 (2017/06/30)
Charge-tagged bis(1,2,4-triazolin-5-ylidene)palladium(II) complexes have been successfully synthesized via a postmodification strategy. Reacting PdBr2 with bromo-functionalized 1,2,4-triazolium salts A·HBr and B·HBr in the presence of silver oxide afforded the bis(carbene)palladium(II) complexes trans-[PdBr2(A)2] (1a) and trans-[PdBr2(B)2] (1b), which contain tethered bromoalkyl chains. Subsequent postcoordinative nucleophilic substitution converted the bromo into ammonium groups, producing the water-soluble complexes trans-[PdBr2(C)2]Br2 (2a) and trans-[PdBr2(D)2]Br2 (2b), while attempts to prepare ammonium-functionalized triazolium salts for direct metalation were futile. All four complexes were fully characterized by means of multinuclear NMR spectroscopy, ESI mass spectrometry, elemental analysis, and X-ray diffraction analysis. The presence of trans-anti and trans-syn rotameric complexes in solution was elucidated by 1H and 13C NMR spectroscopy and theoretical calculations. Additionally, the two charge-tagged complexes, 2a,b, were found to be highly active precatalysts for the Suzuki-Miyaura and Mizoroki-Heck reactions in iPrOH/H2O and molten TBAB as an ionic liquid.
Iminophosphine palladium(II) complexes: Synthesis, characterization, and application in Heck cross-coupling reaction of aryl bromides
Yilmaz, Mustafa Kemal,Guezel, Bilgehan
, p. 529 - 536 (2014/07/07)
Palladium(II) complexes containing phosphorus and nitrogen donor atoms (iminophosphine), dichlorido{N-[2-(diphenylphosphino)benzylidene]-2- trifluoromethylaniline}palladium(II) 1, dichlorido{N-[2-(diphenylphosphino) benzylidene]-3-trifluoromethylaniline}palladium(II) 2, dichlorido{N-[2- (diphenylphosphino)benzylidene]-2-methylaniline}palladium(II) 3, dichlorido{N-[2-(diphenylphosphino)benzylidene]-3-methylaniline}palladium(II) 4 have been successfully synthesized and fully characterized by FT-IR and NMR (1H, 31P, 19F, and 13C) spectroscopy techniques. These complexes were first step tested in the reaction of bromobenzene and styrene to determine the optimal coupling reaction conditions and then successfully applied as catalysts for Heck cross-coupling reactions of activated and deactivated aryl bromides with styrene derivatives and several acrylates. Copyright
