Complexation models of N-(2-carboxyethyl)chitosans with copper(II) ions

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Skorik, YA (Author) Other; Gomes, CAR (Author) FCUP; Podberezskaya, NV (Author) Other; Romanenko, GV (Author) Other; Pinto, LF (Author) Other; Yatluk, YG (Author) Other

Journal

Title: Biomacromolecules

Vol. 6

Pages: 189-195

ISSN: 1525-7797

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 38 Citations

Scopus - 39 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-592

DOI: 10.1021/bm049597r

Abstract (EN): The copper(II) complex formation equilibria of N-(2-carboxyethyl)chitosans with three different degrees of substitution (DS = 0.42, 0.92, and 1.61) were studied in aqueous solution by pH-potentiometric and UV-spectrophotometric techniques. It was demonstrated that the complexation model of CE-chitosans depends on DS: the [Cu(Glc-NR2)(2)] complexes are predominant for two lower substituted samples ("bridge model", log beta(12) = 10.06 and 11.6, respectively), whereas the increase of DS leads to formation mainly of the [Cu(Glc-NR2)] complexes ("pendant model", log beta(11) = 6.41). As a model for copper complexation with a disubstituted residue of CE-chitosan, the complex of N-methyliminodipropionate [CuMidp(H2O)].(H2O) was synthesized and structurally characterized by XRD. The unit cell consists of two crystallographically nonequivalent Cu atoms having slightly distorted square pyramidal coordination; Midp constitutes the basal plane of the pyramid and acts as a tetradentate NO3 chelate-bridging ligand by the formation of two six-membered chelate rings (average Cu-O 1.99 Angstrom, Cu-N 2.04 Angstrom) and a bridge via carbonyl O atom (average Cu-O 1.99 Angstrom), an apical position is occupied by a water molecule (average Cu-Ow 2.30 Angstrom).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7