New water soluble bis-imidazolium salts with a saldach scaffold: Synthesis, characterization and in vitro cytotoxicity/bactericidal studies

• Novel water-soluble saldach scaffold with two dangling imidazolium terminals were developed.
• Their Mn(III) and Fe(III) complexes with the [M(N2O2)Cl] core have been synthesized and characterized.
• Optimization of X = BF4− (IC50 = 22.17 μM) may offer a candidate for breast cancer chemotherapy.
• X = BF4− ((MIC/MBC)S. aureus = 1.33/4.99 mM) may be a S. aureus antibiotic candidate.
• X = PF6− ((MIC/MBC)E. coli = 1.39/2.58 mM) could serve as E. coli infection fighter.

A series of water-soluble bis-imidazolium salts of the type H2(iPr)2saldach(1,2-Me2Im+-X−)2 (4) and their mononuclear complexes [M(III)Cl{(iPr)2saldach(1,2-Me2Im+-X−)2}] (M = Mn, 5; Fe, 6), (X = Cl, a; PF6, b; BF4, c), where saldach = N,N′-bis(salicylidene)-(±)-trans-1,2-diaminocyclohexane, have been synthesized and characterized using elemental analysis, electronic, spectral, magnetic as well as conductometric methods and MALDI-TOF-, ESI-MS. All complexes possess a distorted square pyramidal coordination geometry with MN2O2Cl chromophore, as revealed by the elemental, spectral and literature data. These salts have been evaluated for in vitro cytotoxicity against HepG-2 and MCF-7 cell lines. Among them, 4c (IC50 = 22.17 μM) exhibited potency against MCF-7. The bactericidal efficacy of 4a–c was screened against a panel of common pathogenic bacteria. Compound 4a was found to be the most potent antibacterial agent and could inhibit all the bacterial strains more effectively than standard antibiotics.

A new family of water-soluble bis-imidazolium salts, H2(iPr)2saldach(1,2-Me2Im+-X−)2 (4a–c) and their mononuclear Mn(III)/Fe(III) complexes has been successfully isolated and evaluated for their cytotoxic/bactericidal effects.Figure optionsDownload as PowerPoint slide