A series of piano-stool Fe−NHC complexes have been prepared and characterized. The NHC ligands used herein possess a benzyl and a mesityl wingtip groups and have different electronic structures within the NHC rings. The catalytic activities of these Fe complexes have been examined for the homodimerization of terminal alkynes.

Thiolate-capped RhNPs in imidazolium-based ionic liquids were synthesized from [Rh(μ-SR)(COD)]2 dimmers under H2 pressure without external addition of ligand stabilizers, preserving thiolate integrity on the nanoparticle surface. This nanoparticulated systems showed a remarkable selectivity that led to their application in the one pot reductive N-alkylation to produce amines.

Mesoionic N-heterocyclic olefins (mNHOs) were first reported last year and their reactivity remains largely unexplored. Herein we report the reaction of unprotected mNHOs and organic azides as a novel synthetic...

Reaction of copper(II) methoxide with N-R-2-iminopyrroles (LH) and pyridylmethanol (R′OH) provided the dinuclear complexes {LCu(μ-OR′)} 2 (R = naphtyl, CHPh 2 , 2,6-xylyl, 2,6-diisopropylphenyl (diip), or p-bromobenzyl). All complexes crystallized as dinuclear compounds with a square-pyramidal coordination geometry around copper and either imine or pyridine (for R = diip) in the apical position. The naphthyl-substituted complex was inactive in rac-lactide polymerization at room temperature in benzene. All other complexes showed good activity with apparent rate constants of k obs = 0.16(1)−1.89(8) h −1 at 2 mM catalyst concentration. All complexes showed a preference for slight isotactic monomer enchainment with P m = 0.60−0.68. Stereoerror analysis indicate that the chain-end determines stereocontrol. A dependance of stereocontrol on the steric bulk of the ligand, on the initial monomer concentration and on the symmetry of the catalytic site support that the chiral information on the chain-end is mediated via the catalytic site (catalytic-site-mediated chain-end control).