18910-24-2Relevant articles and documents
Synthesis, crystal structure, and catalytic activity of bridged-bis(N-heterocyclic carbene) palladium(II) complexes in selective Mizoroki-Heck cross-coupling reactions
El Ali, Bassam,Fettouhi, Mohammed,Iali, Wissam,Mansour, Waseem,Suleiman, Rami
, (2021/08/09)
A series of three 1,3-propanediyl bridged bis(N-heterocyclic carbene)palladium(II) complexes (Pd-BNH1, Pd-BNH2, and Pd-BNH3), with + I effect order of the N-substituents of the ligand (isopropyl > benzyl > methoxyphenyl), was the subject of a spectroscopic, structural, computational and catalytic investigation. The bis(NHC)PdBr2 complexes were evaluated in Mizoroki-Heck coupling reactions of aryl bromides with styrene or acrylate derivatives and showed high catalytic efficiency to produce diarylethenes and cinnamic acid derivatives. The X-ray structure of the most active palladium complex Pd-BNH3 shows that the Pd(II) center is bonded to the two carbon atoms of the bis(N-heterocyclic carbene) and two bromide ligands in cis position, resulting in a distorted square planar geometry. The NMR data of Pd-BNH3 are consistent with a single chair-boat rigid conformer in solution with no dynamic behavior of the 8-membered ring palladacycle in the temperature range 25–120 °C. The catalytic activities of three Pd-bridged bis(NHC) complexes in the Mizoroki-Heck cross-coupling reactions were not found to have a direct correlation with +I effect order of the N-substituents of the ligand. However, a direct correlation was found between the DFT calculated absolute softness of the three complexes with their respective catalytic activity. The highest calculated softness, in the case of Pd-BNH3, is expected to favor the coordination steps of both the soft aryl bromides and alkenes in the Heck catalytic cycle.
One-pot synthesis of l-dopa-functionalized water-dispersible magnetite nano-palladium catalyst and its application in the Suzuki and Heck reactions in water: A novel and highly active catalyst
Niu, Jianrui,Wang, Fushan,Zhu, Xiaohang,Zhao, Jiahui,Ma, Jiantai
, p. 37761 - 37766 (2014/11/07)
A palladium catalyst supported on water-dispersible magnetite nanoparticles end-functionalized with amino and carboxyl groups was successfully prepared by a facile one-pot template-free method combined with a metal adsorption-reduction procedure. It was characterized by TEM, XRD, XPS, FT-IR and VSM. This catalyst exhibits excellent catalytic activity for Suzuki and Heck reactions in water. Furthermore, the newly developed catalyst is easy to be recovered and recycled by magnetic separation from aqueous phase reactions. More importantly, the catalyst revealed high efficiency and high stability under the reaction conditions and during recycling stages. This catalyst can be used consecutively six times without significant loss in catalytic activity. the Partner Organisations 2014.
Linear polystyrene-stabilized PdO nanoparticle-catalyzed mizoroki-heck reactions in water
Ohtaka, Atsushi,Yamaguchi, Tomohiro,Teratani, Takuto,Shimomura, Osamu,Nomura, Ryoki
experimental part, p. 9067 - 9076 (2012/01/03)
Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs) were prepared by thermal decomposition of Pd(OAc)2 in the presence of polystyrene. X-ray diffraction (XRD) and transmission electron microscopy (TEM) indicated the production of PdO nanoparticles. The loading of palladium was determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). PS-PdONPs exhibited high catalytic activity for Mizoroki-Heck reactions under air in water and could be recycled without loss of activity.
