Steric and electronic effects in gold N-heterocyclic carbene complexes revealed by computational analysis
CITATION: De Kock, S., Dillen, J. & Esterhuysen, C. 2019. Steric and electronic effects in gold N-heterocyclic carbene complexes revealed by computational analysis. ChemistryOpen, 8(4):539-550, doi:10.1002/open.201900076.
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A computational analysis of a series of cationic and neutral gold imidazolylidene and benzimidizolylidene complexes is reported. The Bond Dissociation Energies of the various ligands in the complexes calculated at the PBE0-D3/def2-TZVP level of theory increase with increasing ligand volume, except for those of complexes containing t-butyl-substituted ligands, which are anomalously low particularly for the benzimidazolylidene species. Atoms in Molecules studies show the presence of a variety of weak intramolecular interactions, characterised by the presence of bond critical points with a range of different properties. Energy Decomposition Analysis and calculation of Electrostatic Surface Potentials indicate that some interactions are weakly attractive dispersion-type interactions, while others are repulsive. The octanol/water partition coefficients (log P values) were calculated as a measure of the lipophilicities of the complexes and were found to increase with increasing volume.