The non-toxic inorganic antimicrobial agents iodine (I2) and copper (Cu) are interesting alterna-tives for biocidal applications. Iodine is broad-spectrum antimicrobial agent but its use is over-shadowed by compound instability, uncontrolled iodine release and short-term effectiveness. These disadvantages can be reduced by forming complex-stabilized, polymeric polyiodides. In a facile, in-vitro synthesis we prepared the copper-pentaiodide complex [Cu(H2O)6(12-crown-4)5]I6 2I2, investigated its structure and antimicrobial properties. The chemical structure of the com-pound has been verified. We used agar well and disc-diffusion method assays against nine mi-crobial reference strains in comparison to common antibiotics. The stable complex revealed ex-cellent inhibition zones against C. albicans WDCM 00054, and strong antibacterial activities against several pathogens. [Cu(H2O)6(12-crown-4)5]I6 2I2 is a strong antimicrobial agent with an inter-esting crystal structure consisting of complexes located on an inversion center and surrounded by six 12-crown-4 molecules forming a cationic substructure. The six 12-crown-4 molecules form hydrogen bonds with the central Cu(H2O)6 . The anionic substructure is a halogen bonded pol-ymer which is formed by formal I5− repetition units. The topology of this chain-type polyiodide is unique. The I5− repetition units can be understood as a triodide anion connected to two iodine molecules.
The non-toxic inorganic antimicrobial agents iodine (I2) and copper (Cu) are interesting alterna-tives for biocidal applications. Iodine is broad-spectrum antimicrobial agent but its use is over-shadowed by compound instability, uncontrolled iodine release and short-term effectiveness. These disadvantages can be reduced by forming complex-stabilized, polymeric polyiodides. In a facile, in-vitro synthesis we prepared the copper-pentaiodide complex [Cu(H2O)6(12-crown-4)5]I6 2I2, investigated its structure and antimicrobial properties. The chemical structure of the com-pound has been verified. We used agar well and disc-diffusion method assays against nine mi-crobial reference strains in comparison to common antibiotics. The stable complex revealed ex-cellent inhibition zones against C. albicans WDCM 00054, and strong antibacterial activities against several pathogens. [Cu(H2O)6(12-crown-4)5]I6 2I2 is a strong antimicrobial agent with an inter-esting crystal structure consisting of complexes located on an inversion center and surrounded by six 12-crown-4 molecules forming a cationic substructure. The six 12-crown-4 molecules form hydrogen bonds with the central Cu(H2O)6 . The anionic substructure is a halogen bonded pol-ymer which is formed by formal I5− repetition units. The topology of this chain-type polyiodide is unique. The I5− repetition units can be understood as a triodide anion connected to two iodine molecules.