Dimeric and trimeric homo- and heteroleptic hydroxamic acid macrocycles formed using mixed-ligand Fe(III)-based metal-templated synthesis

Reaction between 1 equivalent of Fe(III) and 2 equivalents of endo-hydroxamic acid monomers containing amine and carboxylic acid terminal groups promoted the assembly of 1:2 Fe(III):ligand pre-complexes with in situ peptide coupling furnishing dimeric Fe(III)-hydroxamic acid macrocycles. Mixed-ligand systems gave a mixture of Fe(III)-putrebactin, -avaroferrin and -bisucaberin. Demetallation furnished apo-macrocycles.94