Catalytic activities in the direct C5 arylation of novel palladium N-heterocyclic carbene complexes containing benzimidazol-2-ylidene nucleus

N-Heterocyclic Carbene Complexes in C-H Activation Reactions

In this contribution, we provide a comprehensive overview of C-H activation methods promoted by NHC-transition metal complexes, covering the literature since 2002 (the year of the first report on metal-NHC-catalyzed C-H activation) through June 2019, focusing on both NHC ligands and C-H activation methods. This review covers C-H activation reactions catalyzed by group 8 to 11 NHC-metal complexes. Through discussing the role of NHC ligands in promoting challenging C-H activation methods, the reader is provided with an overview of this important area and its crucial role in forging carbon-carbon and carbon-heteroatom bonds by directly engaging ubiquitous C-H bonds.

C–C couplings in water by micellar catalysis at low loadings from a recyclable polymer-supported Pd(ii)–NHC nanocatalyst

A robust and recyclable polymer-supported Pd(ii)–NHC₂ nanocatalyst enables highly efficient micellar catalysis of the Suzuki–Miyaura reaction at low loadings with a broad substrate scope.

Pd(ii)–NHC coordination-driven formation of water-soluble catalytically active single chain nanoparticles

Intramolecular coordination of a linear copolymer precursor yields single chain nanoparticles (SCNP's) consisting of Pd(ii)-NHC₂ crosslinks and showing a beneficial SCNP effect when used for the Suzuki coupling in water.

N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd-NHC complexes: synthesis, characterization and catalytic activity in carbon-carbon bond-forming reactions

A series of novel benzimidazolium salts (1–4) and their pyridine enhanced precatalyst preparation stabilization and initiation (PEPPSI) themed palladium N-heterocyclic carbene complexes [PdCl₂(NHC)(Py)] (5–8), where NHC = 1-(N-methylphthalimide)-3-alkylbenzimidazolin-2-ylidene and Py = 3-chloropyridine, were synthesized and characterized by means of ¹H and ¹³C{¹H} NMR, UV–vis (for 5–8), ESI-FTICR-MS (for 2, 4, 6–8) and FTIR spectroscopic methods and elemental analysis. The synthesized compounds were tested in Suzuki–Miyaura cross-coupling (for 1–8) and arylation (for 5–8) reactions. As catalysts, they demonstrated a highly efficient route for the formation of asymmetric biaryl compounds even though they were used in very low loading. For example, all compounds displayed good catalytic activity for the C–C bond formation of 4-tert-butylphenylboronic acid with 4-chlorotoluene.

Crystal structure of 1,3-bis-(4-methyl-benz-yl)-1H-1,3-benzimidazol-3-ium bromide monohydrate

In the title hydrated symetrically substituted 1,3-bis­(4-methyl­benz­yl)benzimidazolium salt, C₂₃H₂₃N₂⁺·Br⁻·H₂O, the dihedral angles between the benzimidazole ring system (r.m.s. deviation = 0.003 Å) and the pendant benzene rings are 73.18 (16) and 77.52 (16)°. Both benzene rings lie to the same side of the benzimidazole ring system, giving the cation an overall U-shape. In the crystal, the cation is linked to the water mol­ecule by a short C—H⋯O hydrogen bond and the water mol­ecule forms O—H⋯Br hydrogen bonds. Together, these inter­actions lead to [010] chains. The packing is consolidated by C—H⋯Br hydrogen bonds and aromatic π–π stacking inter­actions [centroid–centroid distances = 3.5401 (17) and 3.8815 (18) Å], generating a three-dimensional network.