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Synthesis and coordinating ability of chitosan dithiocarbamate and analogs towards Cu(II) ions
Author(s) -
Humeres Eduardo,
Pinheiro de Souza Eduardo,
Debacher Nito Angelo,
Aliev Abil E.
Publication year - 2002
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.559
Subject(s) - chemistry , dithiocarbamate , chitosan , chelation , stability constants of complexes , metal ions in aqueous solution , chitin , equilibrium constant , amino acid , medicinal chemistry , nuclear chemistry , metal , ion , inorganic chemistry , polymer chemistry , stereochemistry , organic chemistry , biochemistry
Potassium chitosan dithiocarbamate (ChitDTC) was synthesized and characterized by elemental analysis and solid‐state 13 C NMR spectroscopy. The degree of substitution (DS) (number of substituents per 100 2‐amino‐2‐deoxyglucopyranoside units) and molalities of the groups were calculated for acetylamino, amino and dithiocarbamate substituents in chitin, chitosan and ChitDTC. A comparative study of the retention and exchange of Cu(II) was performed with chitin, chitosan and ChitDTC at 30 °C, pH 6.0 (0.1 M succinate). The stability constants, K X , for the heterogenous equilibrium$\hbox{ChitX} + \hbox{Cu(II)}\ {\buildrel K_{\rm X} \over \rightleftharpoons}\ \hbox{ChitXCu(II)}$were calculated assuming that complexing of Cu(II) ions was largely in a 1:1 ratio with respect to each group. The values of K X for each group were NHAc 45.1, DTC 3.14 × 10 3 , and NH 2 1.12 × 10 4 . It is proposed that in the presence of succinate, the main species of aqua Cu(II) ion present in solution must be the uncharged Cu(II)–succinate complex that prevents the acetylamino, amino and DTC groups from forming complexes higher than 1:1. Also, this may explain the fact that the stability constant for DTC was lower than for the amino group. The method allows the characterization of the chelating ability of each group in ChitDTC with respect to metal ions. Copyright © 2002 John Wiley & Sons, Ltd.