Lariat ether carboxylic acids as ionizable hosts in the second coordination sphere of the siderophore ferrioxamine B in chloroform

A secondary sphere complex is formed with the association of the cyclic cavity of a lariat ether with a protonated amine side chain of ferrioxamine B, a trivalent iron siderophore. A binary assembly is formed at pH conditions more basic than the dissociation constant of the carboxylic acid side chain from the lariat ether. The length of the side arm chain of the lariat ether influences the stability of the assembly.