Abstract
The purpose of this work is to shed light on the reactivity of benzimidazol-2-ylidenes with respect to gold nanoparticles (AuNPs), using a combined experimental/computational approach. First, the grafting of benzimidazol-2-ylidenes bearing benzyl groups on the nitrogen atoms is described, and comparisons are made with structurally similar N-heterocyclic carbenes (NHCs) bearing other N-groups. Similar reactivity was observed for all NHCs, with (i) the erosion of the AuNPs under the effect of the NHC and (ii) the formation of bis(NHC) gold complexes. Density Functional Theory (DFT) calculations were performed to investigate the modes of grafting of such ligands, and to determine adsorption energies. Two types of computational models were developed, in order to describe the grafting onto large or small AuNPs, using either periodic or cluster-type DFT calculations. Calculations of NMR parameters were also performed on some these models, and discussed in light of the experimental data.