Cyclam-based iron(iii) and copper(ii) complexes: synthesis, characterization and application as antifungal agents

Abstract

New cyclam-based complexes of formulae [{H₂(^4-CF3PhCH₂)₂Cyclam}FeCl₂]Cl and [{H₂(^4-CF3PhCH₂)₂Cyclam}Cu](CH₃COO)₂·2H₂O were synthesized, in very high yields, by the reaction of H₂(^4-CF3PhCH₂)₂Cyclam with the corresponding metal salts in methanol. [{H₂(^4-CF3PhCH₂)₂Cyclam}FeCl₂]Cl was also prepared, quantitatively, in the solid state by mechanochemistry. The Mössbauer spectra of [{H₂(^4-CF3PhCH₂)₂Cyclam}FeCl₂]Cl show that the high-spin cis complex is the major product of both reactions. The EPR data of [{H₂(^4-CF3PhCH₂)₂Cyclam}Cu](CH₃COO)₂·2H₂O are consistent with two distinct Cu²⁺ species, whose solid state molecular structures were determined by single crystal X-ray diffraction and correspond to complexes displaying octahedral and square–pyramidal geometries. The screening of the antifungal activity of both metal complexes revealed the higher activity of [{H₂(^4-CF3PhCH₂)₂Cyclam}FeCl₂]Cl to inhibit the growth of unicellular and multicellular fungal species with described pathogenic potential.