Trifluoromethylpyridine-Substituted N-Heterocyclic Carbenes Related to Natural Products: Synthesis, Structure, and Potential Antitumor Activity of some Corresponding Gold(I), Rhodium(I), and Iridium(I) Complexes

This work presents the synthesis, characterization, and application of several new metal(I) complexes with trifluoromethylpyridine-containing N-heterocyclic carbene (NHC) ligands. The metal of choice was gold(I) for compounds 7-10, rhodium(I) for 11-12, and iridium(I) for 13-14, respectively. The trifluoromethylpyridine moiety was incorporated, along with other biologically active moieties, with the intention of modifying the lipophilicity of the complexes, so that the transport of the active units (M-NHC) through the cell wall barrier is facilitated. The biological activity of the complexes was investigated. In vitro assessment of antitumor activity in a panel of 12 human tumor cell lines by a monolayer assay revealed good potency (mean IC50 12.6m) and tumor selectivity for one compound. The solid-state structures of two solvates of compound 7, one with MeOH and one with THF, were determined by X-ray diffraction analysis.