N-heterocyclic carbene adducts of cyclopalladated ferrocenylpyridine containing chloride or iodide anions: synthesis, crystal structures and application in the coupling of terminal alkynes with arylboronic acids

A Second-Generation Palladacycle Architecture Bearing a N-Heterocyclic Carbene and Its Catalytic Behavior in Buchwald–Hartwig Amination Catalysis

Palladacyclic architectures have been shown as versatile motifs in cross-coupling reactions. NHC-ligated palladacycles possessing unique electronic and steric properties have helped to stabilize the catalytically active species and provide additional control over reaction selectivity. Here, we report on a synthetic protocol leading to palladacycle complexes using a mild base and an environmentally desirable solvent, with a focus on complexes bearing backbone-substituted N-heterocyclic carbene ligands. The readily accessible complexes exhibit high catalytic activity in the Buchwald–Hartwig amination. This is achieved using low catalyst loading and mild reaction conditions in a green solvent.

A four-coordinate Cu(I)–N-heterocyclic carbene complex: Synthesis, structure, properties, and application in amination for the synthesis of 1-(2-N-heteroaryl)-1H-pyrazoles

A new luminescent, cationic, heteroleptic, four-coordinate Cu(I)– N-heterocyclic carbene complex [Cu(Br-Pyim)(POP)](PF6) is successfully prepared and characterized, where Br-Pyim and POP are 1-(6-bromopyridin-2-yl)imidazole-3-benzyl-2-ylidene and bis[2-(diphenylphosphino)phenyl]ether, respectively. Its detailed structure is determined by single-crystal X-ray analysis. It exists as a crystalline powder at room temperature and exhibits bright yellow-green emission. The use of the Cu(I)– N-heterocyclic carbene complex as a catalyst for amination reactions is also investigated and is found to be very efficient for the amination of 2- N-heteroaryl chlorides with pyrazoles, giving the desired substituted 1-(2- N-heteroaryl)-1 H-pyrazoles in good yields.

Nickel-catalyzed oxidative coupling of alkynes and arylboronic acids using the metal–organic framework Ni2(BDC)2(DABCO) as an efficient heterogeneous catalyst

The first Ni-catalyzed oxidative coupling of alkynes and arylboronic acids.