Sulfonate improves water solubility and cell selective toxicity and alters the lysozyme binding activity of half sandwich Rh(iii) complexes

Introduction of the propyl-sulfonic acid group at N1 of the coordinated 2-(2-pyridyl)benzimidazole ligand (L) in [RhCl(η⁵-C₅Me₅)L](CF₃SO₃) gives rise to a water-soluble complex, which can bind to the model protein lysozymevianon-covalent interactions. The complex shows selective moderate toxicity againstCryptococcus neoformans(MIC = 21.6-43.3 μM) and exhibits no cytotoxicity to healthy HEK293 cells.