Cu–NHC azide complex : synthesis and reactivity

The first example of a NHC-based copper azide complex is reported. Its reactivity was investigated with various reagents affording 8 new complexes

Synthesis, characterization and catalytic activity of stable [(NHC)H][ZnXY2] (NHC = N-Heterocyclic carbene, X, Y = Cl, Br) species

The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C) and the EPSRC (EP/J500549/1, EP/K00445X/1) for funding. S.P. N. acknowledges support from KSU.The synthesis and characterization of imidazol(in)ium-based zinc(II) halide salts are reported. These compounds present interesting structural features and exhibit high stability. Their catalytic activity was explored in the methylation of amines with CO2 and PhSiH3.PostprintPeer reviewe

Neutral dinuclear copper(I)-NHC complexes : synthesis and application in the hydrosilylation of ketones

The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C.) for funding.The synthesis of a class of highly stable neutral dinuclear Cu(I)-NHC complexes using 1,2,4-triazole as a bridging ligand is described. Various NHCs were used to generate a library of [Cu(μ-trz)(NHC)]2, complexes. Interestingly, [Cu(μ-trz)(IPr)]2 was found to be highly active in the hydrosilylation of ketones, without the need for an external base or any other additive. A wide range of aryl and alkyl ketones, as well as sterically hindered ketones, was successfully reduced to alcohols using the lowest catalyst loading reported to date.PostprintPeer reviewe

Generalization of the copper to late-transition-metal transmetallation to carbenes beyond N-heterocyclic carbenes

The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C.), the EPSRC (EP/J500549/1) and the DOE (DE-FG02-13ER16370) for financial support.Carbene transition-metal complexes have become a prevalent family of catalysts enabling numerous organic transformations. Their facile synthetic access is a matter of great importance. To this end, the CuI-NHC transfer methodology has emerged as a powerful alternative presenting attractive advantages over other methods. Herein, we report the remarkable ability of copper to transfer not only NHCs but also other types of carbenes such as abnormal NHCs (aNHCs), cyclic (alkyl)(amino)carbenes (CAACs), and mesoionic carbenes (MICs) to various transition metal precursors.PostprintPeer reviewe

Synthesis and reactivity of [Au(NHC)(Bpin)] complexes

The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C.), AstraZeneca (Studenship to C.M.Z) and VLAIO (CO2PERATE) for support of this work. We thank King Saud University (DSF Program) and KAUST (Award No.OSR-2015-CCF-1974-03) for support.A new class of [Au(NHC)(Bpin)] complexes has been synthesized and their unusual reactivity was investigated using computational and experimental methods. The gold-boryl complexes exhibit unexpected high stability and reactivity.PostprintPeer reviewe

Comparison of the reactivity of the low buried-volume carbene complexes (ITMe)2Pd(PhC≡CPh) and (ITMe)2Pd(PhN=NPh)

The novel Pd(0)-azobenzene complex (ITMe)2Pd(PhN=NPh) (5) (ITMe = 1,3,4,5-tetramethylimidazol 2-ylidene) has been isolated and characterized in the solid state and by cyclic voltammetry. Its reactivity towards E-E’ bonds (E, E’= Si, B, Ge) has been compared with that of the known palladium carbene complex (ITMe)2Pd(PhC≡CPh) (2). Whereas 2 reacts with all E-E’ bonds studied, 5 only reacted with B-B and B-Si moieties, echoing our previous catalytic studies on azobenzenes

Synthesis of gold(I)-trifluoromethyl complexes and their role in generating spectroscopic evidence for a gold(I)-difluorocarbene species

We thank the Ghent University (IoF), the Special Research Fund (BOF) starting (SPN, CSJC) and advanced (SPN, KVH) grants and Research Foundation Flanders (FWO) (fellowship to SVB and grant to CSJC and KVH) for funding.Readily-prepared and bench-stable [Au(CF3)(NHC)] compounds were synthesized using new methodologies, starting from [Au(OH)(NHC)], [Au(Cl)(NHC)] or [Au(L)(NHC)]HF2 precursors (NHC = N-heterocyclic carbene). The mechanism of formation of these species was investigated. Consequently, a new and straightforward strategy for the mild and selective cleavage of a single carbon-fluorine bond from [Au(CF3)(NHC)] complexes was attempted and found to be reversible in the presence of an additional nucleophilic fluoride source. This straightforward technique has led to the unprecedented spectroscopic observation of a gold(I)-NHC difluorocarbene species.PostprintPeer reviewe

Investigating the structure and reactivity of azolyl-based copper(I)-NHC complexes : the role of the anionic ligand

The authors gratefully acknowledge the Royal Society (University Research Fellowship to C.S.J.C.), the Spanish MINECO (CTQ2014-59832-JIN), and EU (FEDER fund UNGI08-4E-003) for funding.A family of copper(I)-NHC azolyl complexes was synthesized and deployed in the hydrosilylation of dicyclo-hexylketone to probe the role of the anionic ligand on catalytic performance. The azolyl ligand is shown to have a crucial role in catalytic activity without the need for additives, and this at very low catalyst loading.PostprintPeer reviewe