The adducts CdCl2.xGly (x = 1, 2; Gly = glycine) were synthesized and chara
cterized by IR spectroscopy, thermogravimetry (TG) and differential scannin
g calorimetry (DSC). The bisadduct was prepared in a water medium and the m
onoadducts were isolated with water or water-ethanol mixtures as solvents.
IR, TG and DSC data obtained showed that metal-amino acid interactions can
be strongly influenced by the total amount of amino acid present. By using
TG data, the kinetic parameters, activation energy (E-a), frequency factor
(A) and order of reaction (n), were calculated. E-a values can provide very
important information about the influences of the stoichiometry and polari
ty of the medium on cation-amino acid interactions at pH values of about 7.
0. CdCl2 . 2Gly lost both ligands in a single step with an E-a value of 113
kJ mol(-1). CdCl2 . Gly prepared from water or a water-ethanol mixture los
t the single ligand in two steps, whose activation energy values are 193; 1
34 and 88; 156 kJ mol(-1), respectively. (C) 1999 Elsevier Science Inc. All
rights reserved.