A novel 18-membered metallacrown containing a double-azathiacrown

A new type of 18-metallacrown-6, [Fe 6 (H 2 O) 6 L 6 ] (L = 1-(2-hydroxy-benzoyl)-thiosemicarbazide), has been prepared and characterized. The backbone of this metal-organic assembly is the double-azathiacrown, which is formed by six repeating units of the five-membered rings [Fe–S–C–N–N]. It is the first metal complex containing a double-azathiacrown. Due to the meridional coordination of the ligand to the Fe 3+ ion, the ligand enforces the stereochemistry of the Fe 3+ ions as a propeller configuration with alternating Λ/Δ forms. Antibacterial screening data showed that the metallacrown has strong antimicrobial activity against Escherichia coli and Staphylococcus aureus .