Synthesis, structure, electrochemical and antimicrobial properties of N,N′-bis(ferrocenylmethyl)imidazolinium salts

• New N,N′-bis(ferrocenylmethyl)imidazolinium salts were synthesized and characterized.
• The synthesized imidazolinium salts showed good antibacterial and antifungal activity.
• Studied salts would be interesting as antimicrobial drug candidates.

The N,N′-bis(ferrocenylmethyl)imidazolinium chloride (3) and bromide (4) were prepared by reaction of N,N’-bis(ferrocenylmethyl)ethylenediamine (2) with NH4X (X = Cl, Br). The N,N′-bis(ferrocenylmethyl)imidazolinium tetrafluoroborate (6) was obtained in two steps from compound (2). The first step involves the synthesis of N,N′-bis(ferrocenylmethyl)imidazolidine (5) by condensation of (2) with aqueous formaldehyde. Compound (5) was successfully converted to the N,N′-bis(ferrocenylmethyl)imidazolinium tetrafluoroborate (6) by treatment with tritylium tetrafluoroborate. The new compounds were characterized by 1H and 13C NMR, IR and elemental analysis techniques which support the proposed structures. The X-ray crystal structure of the N,N′-bis(ferrocenylmethyl)imidazolidine (5) shows two ferrocenyl moieties bridged by an imidazolidine ring. The electrochemical properties were determined by cyclic voltammetry for all compounds. The compounds were screened for their in vitro antimicrobial activities against the Gram-positive, Gram-negative bacteria and antifungal activity against a Candida albicans. (3), (4), (6) show significant antimicrobial activity and theirs MIC values ranged from 169 to 520 μg/mL.

New saturated N,N′-bis(ferrocenylmethyl)imidazolinium salts ((3),(4),(6)) and N,N′-bis(ferrocenylmethyl)imidazolidine (5) were synthesized and characterized. The salts were screened for their in vitro antimicrobial activities against the Gram-positive, Gram-negative bacteria and antifungal activity against a Candida albicans. Compound (4) showed very strong activity against Staphylococcusepidermidis with the best MIC (169 μg/mL).Figure optionsDownload as PowerPoint slide