China 
Africa 
Explore chapters and articles related to this topic
Organometallic Compounds as Heterogeneous Catalysts
Published in Varun Rawat, Anirban Das, Chandra Mohan Srivastava, Heterogeneous Catalysis in Organic Transformations, 2022
Garima Sachdeva, Monu Verma, Varun Rawat, Ved Prakash Verma, Manish Srivastava, Sudesh Kumar, Singh Vanshika
Pd-Catalyzed Suzuki–Miyaura cross-coupling reactions have become essential tools for the construction of carbon–carbon and carbon–heteroatom bonds. In the last few decades, countless efforts have been made in the discovery and development with Suzuki–Miyaura cross-coupling chemistry and its application in pharmaceuticals and agrochemicals. The reaction occurs between aryl halide and organoborane derivatives [64]. Many organoselenium–palladium compounds have tremendous use as catalyst for this coupling reaction. Among the many catalysts known, catalyst 1 showed the best catalytic activity even with catalyst loading of only 0.04 mol% (Figure 4.30) [65].
Pd(0) immobilized on Fe3O4@AHBA: an efficient magnetically separable heterogeneous nanocatalyst for C–C coupling reactions
Published in Journal of Coordination Chemistry, 2019
Tonmoy Chakraborty, Abani Sarkar, Tanmay Chattopadhyay
Palladium compounds are used as homogeneous catalysts [1, 2] in many coupling reactions. Electronegativity [3, 4] of palladium leads to relatively strong Pd–H and Pd–C bonds and also develops a polarized Pd–X bond; it allows easy access of Pd(0) to Pd(II) oxidation states, essential for oxidative addition, transmetalation, and reductive elimination [5–8]. These homogeneous catalysts have some major drawbacks such as catalyst separation from the reaction mixture, recycling, and product contamination. Heterogenization of metal catalysts can avoid these problems [9–13]. There are two major drawbacks preparing nanoparticles; they tend to aggregate and their recovery is difficult. To prevent aggregation of nanoparticles electrostatic–steric stabilizers like polymers, surfactants and organic ligands are used [14, 15]. Magnetic nanoparticles (MNPs) have been extensively used in immobilization of metal nanoparticles as these catalysts show high activity due to the large surface area and have simple and efficient recycling from the reaction mixtures by applying an external magnetic field, simultaneously with simple decantation of the product from the reaction mixture [16–24]. Although synthesis and applicability of various magnetically separable Pd(0)-nanocatalysts have been reported, including Fe3O4/DAG/Pd [25], Pd/WO3 [26], Pd/Fe3O4@C(MFC) [27], Fe3O4@SiO2-EDTA-Pd NPs [28], Pd@ZPGly [29], Pd/TiO2 [30] and Fe3O4@OA-Pd [31] for the Heck reaction. In most cases, the synthetic procedure for nanocatalysts requires complicated steps. Furthermore, the use of toxic organic solvent, high temperature, and long reaction time for catalytic reaction (C–C coupling reactions) are other disadvantages for Pd(0)-nanocatalysts. Therefore, the development of an alternative general and mild procedure employing a stable and inexpensive Pd(0)-nanocatalyst is in demand.