N-hydroxy amides. Part 8. Synthesis and iron(III)-holding properties of di- and tri-hydroxamic acids extending from benzene-di- and -tri-carbonyl units through oligo(ethyleneoxy) arms

Abstract

Benzene-ring centred di- and tri-hydroxamic acids (9a–c and 10a–c) having oligo(ethyleneoxy) chains are prepared by reaction of benzene-di- and -tri-carbonyl chlorides with amino [oligo(ethyleneoxy]ethyl hydroxylamine derivatives (6a–c). Trihydroxamic acids (10a–c) form more stable iron(III) complexes than dihydroxamic acids (9a–c) in several respects. In iron(III) transport experiments using a H₂O–CHCl₃/CCl₄ system, however, compounds (9a–c) show greater rates than compounds (10a–c). The number of ethyleneoxy units in the arm apparently influences these iron(III) holding properties and the iron-transport rates.