Ruthenium(ii) and osmium(ii) 1,2,3-triazolylidene organometallics: a preliminary investigation into the biological activity of 'click' carbene complexesElectronic supplementary information (ESI) available: Synthetic procedures and characterisation data, selected NMR spectra, mass spectra. CCDC 960089. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3dt52584h

Taking advantage of the facile and versatile synthetic properties of 'click' 1,2,3-triazolylidene N-heterocyclic carbenes (tzNHC's), a range of new organometallic Ru( ii ) and Os( ii ) arene complexes containing functionalised tzNHC ligands, [M(η 6 - p -cymene)(tzNHC)Cl 2 ] [M = Ru( ii ), Os( ii )], have been synthesised and fully characterised, including the X-ray crystal structure of one of the Os( ii ) complexes. The tzNHC ligands remain coordinated to the metal centres under relevant physiological conditions, and following binding to the model protein, ubiquitin. The in vitro cytotoxicity of the compounds towards human ovarian cancer cells is dependent on the substituent on the tzNHC ligand but is generally