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Speciation 98: Abstracts
Attila Szorcsik1, Jorunn Sletten2 and László Nagy3
1 Biocoordination Chemistry Research Group
of Hungarian Academy of Sciences, H-6701, Szeged, PO. Box 440,
Hungary;
2 Department of Chemistry, University of
Bergen, Allegt. 41. N-5007, Bergen, Norway;
3 Department of Inorganic and Analytical
Chemistry, A. József University, H-9701, Szeged, P.O. Box
440, Hungary
Recently a number of the papers on the preparation and characterization of carbohydrates and their derivatives complexes formed with metal ions have been published. For examples, Rao et al. [1] have introduced a new well reproducable and very convenient preparation procedure for water-soluble monomeric or dimeric iron(III)-D-fructose and -D-glucose, zinc(II)-, manganese(II)- or vanadyl(IV)-monosaccharides complexes, and for the dimeric chromium(III)-carbohydrate adducts [2], while Tonkovic et al. [3] have reported the first isolation and characterization of aluminum(III) sugar complexes.
Complexes of D-lactobionic acid (4-O-b-D-Galactopyranosyl-D-gluconic
acid with cesium(I), iron(III) and aluminum(III) ions in different
L:M ratio have been prepared in the solid state. The composition
of the complexes was determined by standard analytical methods.
The bonding sites of the ligands studied have been verified by
means of FTIR and Raman spectroscopic measurements. It was shown
that in the complexes formed under acidic and neutral conditions
the ligands bond to the metal via deprotonated carboxylate
groups. In alkaline solutions the deprotonated carboxylate, the
a-alcoholic hydroxyl and in some cases other hydroxyl group
(b) are also involved in co-ordination. According to the ESR measurements
the iron(III complexes have at least dimeric structure. The Cs-lactobionate
complex was obtained in single crystal form (the space group is
P21). The X-ray crystallographic results on the Cs-lactobionate
show that each cesium ion is bonded to four different lactobionate
ions forming a quite complex 3D-network. The asymmetric unit consists
of one cesium, one lactobionate ion and one water molecule.
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