Pyrrole thioamide complexes of organo-rhodium(III), -iridium(III) and -ruthenium(II)

Abstract

Reactions of the pentamethylcyclopentadienyl complexes [(η5-Cp*)MCl2]2 (M = Rh, Ir) and the ruthenium arene complex [(η6-C6Me6)RuCl2]2 with pyrrole-2-thioamide ligands (containing various substituents on the pyrrole ring) and triethylamine base were investigated. A set of new dinuclear complexes were obtained in which the pyrrole thioamide ligand bonds as a dianion, through the deprotonated pyrrole, and the sulfur atom bridging the two metal centres, as confirmed by a X-ray structure determination on an iridium derivative. When triphenylphosphine was included in the reaction mixture, mononuclear complexes were obtained, with the pyrrole thioamide dianion ligand coordinating through sulfur and the pyrrole nitrogen, forming a five-membered chelate ring. The complexes were characterised by NMR and IR spectroscopies, and ESI mass spectrometry. A preliminary investigation of the activity of a selection of compounds towards A549 (adenocarcinomic human alveolar basal epithelial) cells was also carried out.