Jump to main content
Jump to site search


Antimicrobial properties of half-sandwich Ir(iii) cyclopentadienyl complexes with pyridylbenzimidazole ligands

Author affiliations

Abstract

Reaction between 2-(2′-pyridyl)benzimidazole derivatives and [{IrCl(η5-C5Me5)}2(μ-Cl)2] afforded mono- and binuclear “piano-stool” Ir(III) compounds of type [IrnCln5-C5Me5)n(L)]Cln (n = 1, L = LET (1) and LSO3H (2); n = 2, L = LBN (3)), which were fully characterized, including the X-ray crystallographic analysis of 1. While the free ligands and compound 3 exhibited no toxicity to the tested microbes, compound 1 was highly potent against bacteria (MIC = 12.9–25.8 nM) and fungi (MIC < 0.40 nM). However, complex 1 induced damage to non-malignant cell lines (human embryonic kidney (HEK293), CC50 = 0.995 μg mL−1) and human RBCs (HC10 = 10.9 μg mL−1 and HC50 > 32 μg mL−1). Interestingly, complex 2, bearing the benzimidazole ligand with an alkylated sulfonate side chain (LSO3H), was selectively potent against C. neoformans with MIC value of 11.2 nM and was non-toxic to HEK293. According to DNA binding studies, compounds 1–3 could be considered as moderate metallo intercalators with a binding constant of 5.0 × 104–1.0 × 105 M−1. Alternatively, evidence was obtained, from ESI-MS measurements, for the non-covalent mode of binding of 2 to hen egg white lysozyme, while compounds 1 and 3 decomposed during the interaction with that protein. This may be attributed to the electrostatic and H-bonding interactions between the polar sulfonate group and charged protein side-chains.

Graphical abstract: Antimicrobial properties of half-sandwich Ir(iii) cyclopentadienyl complexes with pyridylbenzimidazole ligands

Back to tab navigation

Supplementary files

Article information


Submitted
06 Feb 2020
Accepted
06 Mar 2020
First published
19 Mar 2020

Dalton Trans., 2020, Advance Article
Article type
Paper

Antimicrobial properties of half-sandwich Ir(III) cyclopentadienyl complexes with pyridylbenzimidazole ligands

A. M. Mansour and K. Radacki, Dalton Trans., 2020, Advance Article , DOI: 10.1039/D0DT00451K

Social activity

Search articles by author

Spotlight

Advertisements