Influence of wing-tip substituents and reaction conditions on the structure, properties and cytotoxicity of Ag(i)- and Au(i)-bis(NHC) complexesElectronic supplementary information (ESI) available: NMR and UV-vis spectra for all compounds, further details of crystallographic characterization, cytotoxicity studies and DFT calculations (PDF), and CIF files (CIF). CCDC 1511526-1511533. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6dt04559f

• Main Authors: Rieb, Julia, Dominelli, Bruno, Mayer, David, Jandl, Christian, Drechsel, Jonas, Heydenreuter, Wolfgang, Sieber, Stephan A, Kühn, Fritz E
• Format: Journal Article
• Language: English
• Published: 21.02.2017
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c6dt04559f

The formation of different conformers of dinuclear silver( i ) and gold( i ) 1,1′-(2-hydroxyethane-1,1-diyl) bridge-functionalized bis(NHC) complexes with various wing-tip substituents (R = methyl, isopropyl and mesityl) has been investigated using multinuclear NMR spectroscopy and SC-XRD as well as DFT calculations. The ratio of anti / syn isomers strongly depends both on wing-tip substituents and the metal. Moreover, the reaction temperature plays a significant role during the transmetallation process for the ratio of gold( i ) conformers, which is further affected by purification procedures. All obtained Au( i )-bis(NHC) complexes have been applied in a standard MTT assay performed for screening the antiproliferative activity against human lung and liver cancer cells. Strong evidence for a significant influence of both wing-tip substituents and conformation on the cytotoxic properties of the applied complexes has been found. Sterically demanding N -substituents favour the syn conformation leading to increase in cytotoxicity.