Palladium Nanoparticles Immobilized on Chemically Modified Silica Gel: Efficient Heterogeneous Catalyst for Suzuki, Stille and Sonogashira Cross-Coupling Reactions

Greener Biogenic Approach for the Synthesis of Palladium Nanoparticles Using Papaya Peel: An Eco-Friendly Catalyst for C-C Coupling Reaction

The development of a green and sustainable synthetic methodology still remains a challenge across the globe. Encouraging the prevailing challenge, herein, we have synthesized Pd nanoparticles (Pd NPs) in a green and environmentally viable route, using the extract of waste papaya peel without the assistance of any reducing agents, high-temperature calcination, and reduction procedures. The biomolecules present in the waste papaya peel extract reduced Pd(II) to nanosize Pd(0) in a one-pot green and sustainable process. As a catalyst, the new Pd NPs offer a simple and efficient methodology in direct Suzuki-Miyaura and Sonogashira coupling with excellent yields under mild reaction conditions.

A Highly Efficient and Reusable Palladium(II)/Cationic 2,2'-Bipyridyl-Catalyzed Stille Coupling in Water

A water-soluble PdCl₂(NH₃)₂/cationic 2,2'-bipyridyl system was found to be a highly efficient catalyst for Stille coupling of aryl iodides and bromides with organostannanes. The coupling reaction was conducted at 110 °C in water, under aerobic conditions, in the presence of NaHCO₃ as a base to afford corresponding Stille coupling products in good to high yields. When aryltributylstannanes were employed, the reactions proceeded smoothly under a very low catalyst loading (as little as 0.0001 mol %). After simple extraction, the residual aqueous phase could be reused in subsequent runs, making this Stille coupling economical. In the case of tetramethylstannane, however, a greater catalyst loading (1 mol %) and the use of tetraethylammonium iodide as a phase-transfer agent were required in order to obtain satisfactory yields.

Palladium nanoparticles in the catalysis of coupling reactions

Palladium catalyzed coupling reactions have emerged as a versatile, convenient, selective and mild protocol that can usually be adapted in any synthetic scheme for important target molecules with various degrees of structural complexity.

Can microwave assisted in situ reduction of supported Pt nanoparticles challenge the chemical method in controlling the dispersion profile-catalytic performance relationship?

In this comparative study of dispersion profile-catalytic performance relationships, Pt (of 0.3, 0.6 and 0.9 wt%) was supported on mesoporous silica surface via microwave assisted solution method or rotary chemical evaporation method in the in situ reduction step.

Phosphine-stabilized Pd nanoparticles supported on silica as a highly active catalyst for the Suzuki–Miyaura cross-coupling reaction

Highly dispersed silica-supported Pd nanoparticles were synthesizedviaa simple strategy. The material showed excellent catalytic activity for Suzuki–Miyaura reactions and could be reused several times.