Details

Autor(en) / Beteiligte

• Sun, Biyun
• Southam, Hannah M
• Butler, Jonathan A
• Poole, Robert K
• Burgun, Alexandre
• Tarzia, Andrew
• Keene, F. Richard
• Collins, J. Grant

Titel

Synthesis, isomerisation and biological properties of mononuclear ruthenium complexes containing the bis[4(4′-methyl-2,2′-bipyridyl)]-1,7-heptane ligandElectronic supplementary information (ESI) available. CCDC 1559396 and 1558934. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7dt04595f

Erscheinungsjahr

2018-02

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A series of mononuclear ruthenium( ii ) complexes containing the tetradentate ligand bis[4(4′-methyl-2,2′-bipyridyl)]-1,7-heptane have been synthesised and their biological properties examined. In the synthesis of the [Ru(phen′)(bb 7 )] 2+ complexes (where phen′ = 1,10-phenanthroline and its 5-nitro-, 4,7-dimethyl- and 3,4,7,8-tetramethyl- derivatives), both the symmetric cis -α and non-symmetric cis -β isomers were formed. However, upon standing for a number of days (or more quickly under harsh conditions) the cis -β isomer converted to the more thermodynamically stable cis -α isomer. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) of the ruthenium( ii ) complexes were determined against six strains of bacteria: Gram-positive Staphylococcus aureus ( S. aureus ) and methicillin-resistant S. aureus (MRSA); and the Gram-negative Escherichia coli ( E. coli ) strains MG1655, APEC, UPEC and Pseudomonas aeruginosa ( P. aeruginosa ). The results showed that the [Ru(5-NO 2 phen)(bb 7 )] 2+ complex had little or no activity against any of the bacterial strains. By contrast, for the other cis -α-[Ru(phen′)(bb 7 )] 2+ complexes, the antimicrobial activity increased with the degree of methylation. In particular, the cis -α-[Ru(Me 4 phen)(bb 7 )] 2+ complex showed excellent and uniform MIC activity against all bacteria. By contrast, the MBC values for the cis -α-[Ru(Me 4 phen)(bb 7 )] 2+ complex varied considerably across the bacteria and even within S. aureus and E. coli strains. In order to gain an understanding of the relative antimicrobial activities, the DNA-binding affinity, cellular accumulation and water-octanol partition coefficients (log  P ) of the ruthenium complexes were determined. Interestingly, all the [Ru(phen′)(bb 7 )] 2+ complexes exhibited stronger DNA binding affinity ( K a 1 × 10 7 M −1 ) than the well-known DNA-intercalating complex [Ru(phen) 2 (dppz)] 2+ (where dppz = dipyrido[3,2- a :2′,3′- c ]phenazine). The strained complexes cis -β-[Ru(phen′)(bb 7 )] 2+ isomerise to the corresponding cis -α isomers, with cis -α-[Ru(Me 4 phen)(bb 7 )] 2+ showing good antibacterial activity.