Abstract
A macrocyclic hexanuclear iron(III) 18-metallacrown-6 complex, [Fe6(C9H6BrN2O3)6(CH3OH)4(H2O)2] · 7CH3OH · 4H2O, has been prepared using a trianionic pentadentate ligand N-acetyl-5-bromosalicylhydrazidate, abshz3–, and characterized by X-ray diffraction. The crystal structure contains a neutral 18-membered metallacrown ring consisting of six Fe(III) and six abshz3– ligands. The 18-membered metallacrown ring is formed by combination of six structural moieties, [Fe(III)–N–N]. Due to meridional coordination of ligand to Fe3+, the ligand enforces the stereochemistry of the Fe3+ ions as a propeller configuration with alternating Δ/Λ forms. Methanol and water are linked with Fe1, Fe1A, Fe,3 and Fe3A. The ratios of methanol to water are 0.76 : 0.24 for Fe1 and Fe1A, and 0.30 : 0.70 for Fe3 and Fe3A, which results in four component crystals of metallacrown rings with ratio of 0.168 : 0.072 : 0.532 : 0.228. Antibacterial screening data showed that the iron metallacrown has moderate antimicrobial activity against Bacillus subtilis.
Acknowledgements
This work was supported by the Key Project of Natural Science Foundation of Hubei Province, China (2008CDA067).