Clusters in bis-tridentate tethered domains of an iron chelating drug

摘要

The tridentate metal binding domains of iron chelating agents have been tethered via a variable length methylene (CH_2)_n linker (n=1,2,4,6,8,10,14). The single-crystal X-ray structures of monomeric ([Fe(HL~8)].2.5H_2O n=8; H_4L~8 is 1,10-decanedioyl di(salicylaldehyde hydrazone)) and dimeric ([{Fe(H_2PL~4)}_2]Cl_2.2H_2O n=4; H_4PL~4 is 1,6-hexanedioyl di(pyridoxal hydrazone)) iron(III) complexes have been determined. The complexes exhibit oligomerism: with chain lengths of n>=6 monomers are prevalent whereas for shorter chains this is not possible and a series of clusters exist as shown by ESMS and molecular modelling.