Synthesis, characterization, computational and antimicrobial activities of a novel iridium thiourea complexCCDC 1515629. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c7nj02019h

• Main Authors: Kumar, S, Purcell, W, Conradie, J, Bragg, R. R, Langner, E. H. G
• Format: Journal Article
• Language: English
• Published: 25.09.2017
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c7nj02019h

A new iridium( iii ) complex, [Ir(cod)(dmtu) 2 ]Cl (1,5-cyclooctadiene)-bis( N,N ′-dimethylthiourea)-iridium( iii ), was successfully synthesized and characterized using IR, NMR and mass spectroscopy. The electrochemical properties of the iridium complex have been studied using cyclic voltammetry, showing chemically irreversible nature. The molecular structure of the complex was also determined using single-crystal X-ray crystallography, which indicates a distorted octahedral coordination geometry around the iridium centre surrounded by two π bonds of the cod ligand and the other four coordination sites being occupied by the N,S atoms of two dmtu groups. The molecular geometry of the complex was optimized using the density functional theory with a hybrid functional B3LYP. The fully optimized structure results obtained for the [Ir(cod)(dmtu) 2 ] + complex are in good agreement with the X-ray diffraction results. These results indicate that the HOMO level is a mixture of the iridium d xy and the nitrogen p of the thiourea ligand orbitals, while the iridium d z 2 LUMO show antibonding character to the p sulphur orbitals. The antimicrobial activity of the new complex was evaluated using the agar diffusion method. The complex was tested against a panel of antimicrobial-susceptible and resistant Gram-negative and Gram-positive bacteria. Good antimicrobial activity was observed against the Gram-positive bacteria Staphylococcus aureus , while no antimicrobial activity was observed against the Gram-negative Escherichia coli . A zone of inhibition was seen against the Gram-negative Pseudomonas aeruginosa . A novel octahedral iridium( iii )thiourea complex with potential medical applications.