Hydroxamic acid polymers. II. Design of a polymeric chelating agent for iron

Abstract

SynopsisThe iron chelating ability of hydroxamic acid polymers was studied as a function of the atomic chain spacing separating neighboring hydroxamic acid units. Two polymers were prepared, one having the hydroxamic acid group separated by 11 atoms and the other by three atoms. The iron binding of these polymers was compared with the model compound desferrioxamine B (DFO) and with a previously prepared polymer having a nine-atom spacing. Mole ratio plots indicated the following order of stability: DFO = 11 atom > 9 atom > 3 atom. These results are in accordance with the picture derived from molecular models which shows that with a spacing of 11 atoms, three neighboring hydroxamic acids can fit the octahedral arrangement of the iron(II1) complex without appreciable strain. Some strain is introduced when the spacing becomes only nine atoms, and with three atoms, complex formation between three neighboring groups becomes virtually impossible.

Beyond Biological Chelation: Coordination of f‐Block Elements by Polyhydroxamate Ligands

“…The larger spacing allowed for similar chelating efficiency as DFOB. A smaller, more crowded polymer, HAP‐III (Figure ), showed a much lower affinity for Fe III consistent with the lack of the 8–9 atom spacers . These results further confirm the importance of spacing between hydroxamic acid groups for metal chelation that was previously reported by Evers et al.…”

“…As maller,m ore crowded polymer,H AP-III (Figure 4), showed am uch lower affinity for Fe III consistent with the lack of the 8-9 atom spacers. [98] These results further confirm the importance of spacing between hydroxamic acid groups for metal chelation that was previously reportedb y Evers et al. [70] The polymerization of an acrylonitrile-divinylbenzene copolymer,f ollowed by hydrolysis and subsequent reactiono ft he polyamide with hydroxylamine, led to ap romisingp olyhydroxamica cid ion-exchange resin which was investigatedf or removal of uranium from seawater.T he authors were able to remove Fe III and U VI from seawater with 97-99 %e fficiency.…”

“… Structures of DFOB‐inspired polyhydroxamic acid resins with varying spacing between hydroxamic acid units …”

The Status of New Iron Chelators*

“…Studies are now in progress both to further evaluate the efficacy of CHA in humans and to determine the extent to which the drug can be reutilized via intraluminal exchange of iron with nonabsorbable hydroxamic acid polymers. 35 Another chelator that showed promise as an orally effective drug is ethylene-…”

Synthesis, spectral and thermal properties of poly(2-hydroxy-4-methacryloyloxybenzaldehyde)-metal complexes

“…Selective chelations of specific metal ions from a metal ion mixture by using a number of tetradentate ligands attached to polystyrenedivinylbenzene have reported.12 A polymer containing hydroxamic acid has been studied as a polymeric chelating agent for iron. 13 Polymeric Schiff s base chelates based on bissalicylaldehyde and o-phenylenediamine have been investigated. [14][15][16] In continuation of our research in polymer-metal c o m p l e~e s , l~-~~ the present work deals with the synthesis, spectral and thermal properties of a new poly(2-hydroxy-4-methacryloyloxybenzaldehyde) and their metal complexes.…”