Bioactive and luminescent indole and isatin based gold(I) derivatives, Fernández-Moreira, V.; Val-Campillo, C.; Ospino, I.; Herrera, R. P.; Marzo, I.; Laguna, A.; Gimeno, M. C. Dalton Trans. 2019. DOI: 10.1039/C8DT00298C

Abstract. A series of luminescent monometallic [AuL(PPh3)] (1-3) and bimetallic [Au2(µ-dppe)L2] (4, 6, 8) and [Au2(µ-dppp)L2] (5, 7, 9) complexes, where L is either 4-cyano-indole, isatin, or 5,7-dimethyl-isatin, and dppe and dppp are 1,2-bis(diphenylphosphino)ethane and 1,3-bis(diphenylphosphino)propane, respectively, have been synthesised. X-ray diffraction confirmed the tendency to establish aurophillic interations for those complexes containing dppe. Luminescent studies and theoretical calculations revealed a different origin for both families, i.e. indole and isatin species. Thus, indole derivatives presented a ligand-to-ligand-charge-transfer transition (LLCT) from the indole to the PPh3 fragment, whereas for the isatin derivatives an intraligand–charge-transfer transition (ILCT) within the isatin fragment is proposed. In both cases the gold centre slightly implicated as a ligand-to-metal-charge transfer transition (LMCT) (from the indole/isatin to Au(I)). Cell antiproliferative assays in lung cancer cells (A549), leukemia Jurkat-pLVTHM and Jurkat-shBak cells (cisplatin sensitive and resistant respectively) showed excellent cytotoxic values (10.11 – 0.28 μM), resulting the leukemia cells the most sensitive and the bimetallic species the most active agents. Preliminary studies associated the cytotoxicity to a combination of diferent factors, being the metallic fragment the main responsible. Remarkably, these complexes are able to inhibit the cellular growth of cisplatin resistant Jurkat-shBak cells highlighting their promising future as an alternative anticancer agent.