%I mi
%X Three new dihydroxamic acids (HO(CH3)NCO–(CH2)2–CO–NH–(CH2)x–CON(CH3)OH where the x values are 4; 3 and 2, and
the compounds are abbreviated as 2,4-DIHA, 2,3-DIHA and 2,2-DIHA), containing the peptide group in a certain position to one
of the two functional groups and in different distances to the other one, were synthesized and their complexation with Fe(III),
Mo(VI) and V(V) was studied by pH-potentiometric, spectrophotometric and in some cases by CV methods to evaluate the redox
behaviour of the Fe(III) complexes and assess their potential biological activity as siderophore models. All these compounds are
structural models for the natural siderophore, desferrioxamine B (DFB). The results were compared to those of the complexes of
2,5-DIHA having the same connecting chain structure and length as DFB has, and the effects of the length of the connecting chain
on the co-ordination mode and on the stability of the complexes formed were evaluated.
Very similar stability of the mono-chelated complexes formed with all these dihydroxamic acids was found. All the results
obtained suggest that one dihydroxamic acid (even the 2,2-DIHA) is able to complete the four coordination sites of a MoO 2Ăž 2 core
forming simple mononuclear complexes. Favoured monomeric structures of the bis-chelated complexes of these dihydroxamic acids
are also suggested with V(V) having the smallest ionic radius among the three metal ions studied. In the case of iron(III), however,
clear indication was obtained for the slightly different complexation behaviour of 2,2-DIHA. Namely, the formation of the
mononuclear bis-chelated complex with this shortest ligand seems to have sufficient strain to induce the formation of bimetallic
species such as [Fe(2,2-DIHA)2Fe)]2Ăž.
%R MTMT:1074892 10.1016/j.ica.2004.02.007
%D 2004
%N 9
%V 357
%A  Farkas Etelka
%A  BuglyĂł PĂŠter
%A  Enyedy Éva Anna
%A  Santos M. Amelia
%J INORGANICA CHIMICA ACTA
%L publicatio34358
%T Factors affecting the metal ion–hydroxamate interactions II: effect of the length of the connecting chain on the Fe(III), Mo(VI) and V(V) complexation of some new desferrioxamine B (DFB) model dihydroxamic acids
%P 2451-2461