Recyclable ligand-free mesoporous heterogeneous Pd catalysts for Heck coupling

Dendrimeric Structures in the Synthesis of Fine Chemicals

Dendrimers are highly branched structures with a defined shape, dimension, and molecular weight. They consist of three major components: the central core, branches, and terminal groups. In recent years, dendrimers have received great attention in medicinal chemistry, diagnostic field, science of materials, electrochemistry, and catalysis. In addition, they are largely applied for the functionalization of biocompatible semiconductors, in gene transfection processes, as well as in the preparation of nano-devices, including heterogeneous catalysts. Here, we describe recent advances in the design and application of dendrimers in catalytic organic and inorganic processes, sustainable and low environmental impact, photosensitive materials, nano-delivery systems, and antiviral agents' dendrimers.

New insights into catalysis for Heck reactions with fine supported Pd particles

The catalytic activity over supported Pd particles is dependent on the concentration of soluble active Pd species. The correlation that the smaller the size of supported Pd particles, the higher the catalytic activity is confirmed.

An immobilized symmetrical bis-(NHC) palladium complex as a highly efficient and recyclable Suzuki–Miyaura catalyst in aerobic aqueous media

A novel palladium-silica complex was prepared and characterized. This complex is a highly efficient and easily recyclable catalyst for Suzuki–Miyaura cross-coupling reaction under mild aqueous conditions, and can be reused efficiently up to 6 consecutive runs.

Palladium chloride catalyzed photochemical Heck reaction

PdCl2 catalyzed carbon–carbon bond formation (Heck reaction) between substituted aryl halides and olefins was carried out without a ligand, under irradiation with UV–visible light. The results demonstrated that UV–visible light accelerated the rate of the reaction, leading to an excellent yield of corresponding products. The recovered palladium nanoparticles could be thermally recycled several times. PdCl2 gave excellent conversion up to the fifth addition of substrate.