A simple procedure for the polymer-supported N-heterocyclic carbene-rhodium complex via click chemistry: a recyclable catalyst for the addition of arylboronic acids to aldehydes

From agricultural waste residue to wealth support: A magnetically N-heterocyclic carbene functionalized corn cob cellulose as a new stabilizer for Pd catalyst in Suzuki reaction

Because of eco-friendliness, biodegradability and ease of modification, cellulose is deemed as alternative to unrenewable petroleum resources. Nonetheless, it is more indispensable to exploit corn cob cellulose produced from agricultural waste residue as supportive materials in green catalysis. In this study, a new magnetically benzimidazole functionalized cellulose/Fe3O4 derived from corn cob cellulose as a stabilizer agent (Fe3O4@CL-NHC) was prepared, and palladium was immobilized on this stabilizer (Fe3O4@CL-NHC-Pd). The catalyst was fully characterized by different techniques including TEM, SEM, and XPS analyses, etc. The abundant hydroxyl groups of cellulose provided uniform dispersion and high stability of palladium, while Fe3O4 as a support offered simple magnetic separation. High efficiency (up to 99 %) was demonstrated by this biocatalyst under green conditions in relatively short reaction times towards Suzuki reactions. Due to collaborative interactions of N-heterocyclic carbene and hydroxyl groups with palladium, the synthesized complex prevented metal leaching effectively (<1 %). Moreover, the magnetic property of this catalyst (43.0 emu g-1) provides facile recovery of this composite from the reaction mixture with great ease for several times, which overcomes issues of complicated work-up separation. This work offers a promising avenue to enriching the application of biopolymer from agricultural residue in the potential organic transformations.

Click-derived multifunctional metal complexes for diverse applications

The Click reaction that involves Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) serves as the most potent and highly dependable tool for the development of many complex architectures. It has paved the way for the synthesis of numerous drug molecules with enhanced synthetic flexibility, reliability, specificity and modularity. It is all about bringing two different molecular entities together to achieve the required molecular properties. The utilization of Click chemistry has been well demonstrated in organic synthesis, particularly in reactions that involve biocompatible precursors. In pharmaceutical research, Click chemistry is extensively utilized for drug delivery applications. The exhibited bio-compatibility and dormancy towards other biological components under cellular environments makes Click chemistry an identified boon in bio-medical research. In this review, various click-derived transition metal complexes are discussed in terms of their applications and uniqueness. The scope of this chemistry towards other streams of applied sciences is also discussed.

Arylation of aldehydes catalyzed by fluorinated NHC-Rh(I) complexes

The synthesis and characterization of twelve Rh(I) complexes with fluorinated NHC ligands is described. Seven molecular structures of these complexes were unequivocally elucidated by single crystal X-ray diffraction techniques. In...

Efficient Approach to Carbinol Derivatives through Palladium-Catalyzed Base-Free Addition of Aryltriolborates to Aldehydes

Palladium-catalyzed base-free addition of aryltriolborates to aldehydes has been developed, leading to a wide range of carbinol derivatives in good to excellent yields. The efficiency of this transformation was demonstrated by compatibility with a wide range of functional groups. The present synthetic route to carbinol derivatives could be readily scaled up to gram quantity without difficulty. Thus, this method represents a simple and practical procedure to access carbinol derivatives.

A click strategy for the immobilization of palladium nanoparticles onto silica: efficient and recyclable catalysts for carbon–carbon bond formation under mild reaction conditions

The synthesis of silica-grafted palladium catalyst through “click” reaction of azide-functionalized silica with methylpropargylimidazolium bromide, for Heck and Suzuki–Miyaura coupling reactions.

Palladium N-Heterocyclic Carbene Precatalyst Site Isolated in the Core of a Star Polymer

An approach for supporting a Pd-NHC complex on a soluble star polymer with nanoscale dimensions is described. The resulting star polymer catalyst exhibits excellent activity in cross-coupling reactions, is stable in air and moisture, and is easily recoverable and recyclable. These properties are distinct and unattainable with the small-molecule version of the same catalyst.

‘Auto-click’ functionalization for diversified copper(i) and gold(i) NHCs

A self-clicking precursor for diversified coinage metal NHCs.

Cross-linked reverse micelles with embedded water pools: a novel catalytic system based on amphiphilic block copolymers

The shell cross-linked reverse micelles were used as a more reactive and recoverable catalytic system.