Sugar complexes with metal(2+) ions: thermodynamic parameters of associations of Ca2+, Mg2+ and Zn2+ with galactaric acid

Citation
M. Saladini et al., Sugar complexes with metal(2+) ions: thermodynamic parameters of associations of Ca2+, Mg2+ and Zn2+ with galactaric acid, CARBOHY RES, 336(1), 2001, pp. 55-61
Citations number
36
Categorie Soggetti
Agricultural Chemistry","Chemistry & Analysis","Organic Chemistry/Polymer Science
Journal title
CARBOHYDRATE RESEARCH
ISSN journal
00086215 → ACNP
Volume
336
Issue
1
Year of publication
2001
Pages
55 - 61
Database
ISI
SICI code
0008-6215(20011101)336:1<55:SCWMIT>2.0.ZU;2-A
Abstract
A solution study on the complex ability of galactaric acid (GalaH(2)) for c omplexation with Ca2+, Mg2+ and Zn2+ ions is reported. The stability consta nts of the complex species are determined by means of potentiometric measur ements. From the dependence of stability constants on temperature, the Delt aH degrees and DeltaS degrees values are also determined. The formation of the complex species is an endothermic process and DeltaH degrees and DeltaS degrees values suggest a chelate coordination mode of galactaric acid invo lving carboxylic oxygen and a-hydroxylic group. The prevailing species at a cidic or neutral pH is [MGala] (M = Ca2+, Mg2+, Zn2+) which is also isolate d in the solid state and characterised by means of IR spectroscopy. On incr easing pH, the [MGalaH -(1)](-) species is also formed, where the coordinat ed OH group undergoes deprotonation. (C) 2001 Elsevier Science Ltd. All rig hts reserved.