Neutral, C2-symmetric S/C/S ligands based on N-heterocyclic carbenes and thioether functionalities were incorporated into transition metal complexes characterised by two direct metal-stereogenic sulfur bonds. This new ligand design was applied to 1,3-dipolar cycloadditions as the first example of the use silver of carbenes in asymmetric catalysis.

An asymmetric Ni-catalyzed reductive cross-coupling of (hetero)aryl iodides and benzylic chlorides has been developed to prepare enantioenriched 1,1-diarylalkanes. As part of these studies, a new chiral bioxazoline ligand, 4-heptyl-BiOX (L1), was developed in order to obtain products in synthetically useful yield and enantioselectivity. The reaction tolerates a variety of heterocyclic coupling ...

The synthesis and characterisation of a thallium(I) triscarbene complex of the chelating, tripodal carbene ligand 1,3,5-[tris(3-tert-butylimidazol-2-ylideno)methyl]-2,4,6-trimethylbenzene is reported, in which the thallium ion is coordinated by three N-heterocyclic carbene donors in a distorted trigonal planar environment.

Synthesis of coordinatively unsaturated Cp*Co(IPr) (2), is accomplished by addition of free N-heterocyclic carbene IPr to [(Cp*Co)2-μ-(η(4):η(4)-toluene)] (1). Stoichiometric reactivity is consistent with a 16 electron species, as 2 undergoes ligand addition/NHC displacement and reversible reaction with dihydrogen. Cp*Co(IPr) represents an elusive example of a stable Cp*CoL fragment.

The unique Hg(II) ion in the title centrosymmetric dinuclear complex, [Hg(2)Cl(4)(C(12)H(9)BrN(2))(2)], is in a distorted trigonal-bipyramidal coordination environment formed by the bis-chelating N-heterocyclic ligand, two bridging Cl atoms and one terminal Cl atom. One of the bridging Hg-Cl bonds is significantly longer than the other.

The coordination geometry about the Pd centre in the title compound, [Pd(C(40)H(42)N(5))Cl], is approximately square-planar. The CNC pincer-type N-heterocyclic carbene ligand binds to the Pd atom in a tridentate fashion by the amido N atom and the two carbene atoms and generates two six-membered chelate rings, completing the coordination.

Ruthenium-based metathesis catalysts with a N-heterocyclic carbene ligand bearing 2,3,4,5-tetraphenylphenyl moieties (1-TPPh and 1-TPPh*) are developed. The highly active catalyst system has been realized in THF by the combination of 1-TPPh* and CuCl as a phosphine scavenger.

A ruthenium benzylidene complex with a neutral bidentate N-heterocyclic carbene was prepared and evaluated in ring-closing metathesis of diallyl substrates. Reaction with AgPF6 to generate a four-coordinate complex produced an unexpected dicationic ruthenium benzyl degradation product through nucleophilic attack of the NHC ligand on the benzylidene carbon.

A novel pentacoordinate mono iron dicarbonyl complex bearing a nitrogen heterocyclic carbene ligand was reported as a model of a [Fe]-hydrogenase active site, which exhibits interesting proton coupled CO binding reactivity, electro-catalytic proton reduction and catalytic transfer hydrogenation reactivity.

The synthesis of a ruthenium complex that catalyzes Z-selective (up to 98% Z) asymmetric ring-opening/cross-metathesis with high enantioselectivity (up to 95% ee) is reported. The synthesis of the catalyst features the resolution of a chelating N-heterocyclic carbene complex by ligand substitution with a chiral carboxylate.