scholarly journals Tetrameric Aryl Palladium Bromide Intermediates Leading to Facile Transmetalation in Suzuki–Miyaura Cross-Couplings with Pd@MIL-101-NH2(Cr)

2021 ◽  
Author(s):  
Alejandro Valiente ◽  
Cheuk-Wai Tai ◽  
Mårten Ahlquist ◽  
Belén Martín-Matute
Keyword(s):  
Inductively Coupled Plasma ◽  
Density Functional ◽  
Nuclear Magnetic Reso ◽  
Coupling Reaction ◽  
Optical Emission ◽  
Ionization Mass ◽  
Activation Free Energy ◽  
Inductively Coupled ◽  
Cross Coupling Reaction ◽  
Scanning Transmission

The composition and structure of catalytic intermediates in the context of the Suzuki–Miyaura cross-coupling reaction cata-lyzed by Pd@MIL-101-NH2(Cr) has been investigated. Trimeric and tetrameric palladium species with formula [Br-Pd-Ar]nBr- (n = 3–4) have been identified by electrospray ionization mass spectrometry (ESI-MS) and density-functional theory (DFT) calculations, and their role in the transmetalation step has been studied. The weak nature of the bonds between Pd and the bridging halides in these species enables a very easy transmetalation step, with an estimated activation free energy of only 10 kcal/mol. Further experimental support for Pd speciation was obtained using scanning transmission electron micros-copy (STEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and fluorine-19 nuclear magnetic reso-nance spectroscopy (19F NMR).

scholarly journals Copper Immobilization on Fe3o4@Agar: An Efficient Superparamagnetic Nanocatalyst for Green Buchwald-Hartwig Cross-coupling Reaction of Primary and Secondary Amines With Aryl Iodide Derivatives

2021 ◽  
Author(s):  
Kimia Hoseinzade ◽  
Seyed Ali Mousavi-Mashhadi ◽  
Ali Shiri
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanoparticles ◽  
Inductively Coupled Plasma ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Secondary Amines ◽  
Aryl Iodide ◽  
X Ray ◽  
Inductively Coupled ◽  
Cross Coupling Reaction

Abstract Immobility of copper on magnetic nanoparticles was performed using surface rectification of Fe3O4 with Agar. The magnetic Fe3O4@Agar-Cu nanocatalyst was prepared and entirely characterized by different analyses such as Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), energy dispersive X-ray (EDX), thermogravimetric (TGA), and inductively coupled plasma (ICP). The nanocatalyst was applied in C-N bond formation through the cross-coupling reaction of aryl halides with primary or secondary amines in water as a green medium known as the Buchwald-Hartwig reaction. The results of the Buchwald-Hartwig reaction by Fe3O4@Agar-Cu magnetic nanoparticles as catalyst demonstrate excellent activity and stability in water. Moreover, this catalyst can be recycled several times without considerable loss in its activity.

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