The coordination of a fully deacetylated chitosan with zinc ion was studied in the homogeneous reaction condition．The composition and structure of chitosan-Zn (Ⅱ) complex were investigated by elemental analysis．infrared and UV-visible spectrometry solid state 13C—NMR

thermogrativimetric analysis and X-ray diffraction The results of elemental analysis show that the ratio of glucosamine repeat unit to Zn(Ⅱ) was 2：1 with the complex formation in a pH=7 solution．The absorption at 3420cm-1 due to O—H and N—H stretching shifted to 3391cm-1; the absorptions at 1597cm-1 due to N—H stretching and at 1093cm-1 due to secondary alcohol—OH stretching shifted to 1620cm-1 and 1062cm-1

respectively．But the absorption at 1038cm-1 due to primary alcohol—OH did not shift supporting that both the amino and secondary hyrdroxyl groups of chitosan molecules are coordinated to Zn (Ⅱ)．Comparing the 13C-NMR spectra of chitosan and chitosan-Zn(Ⅱ) complex

the shifts of the key bands showed that Zn (Ⅱ) is coordinated to the—NH

and secondary alcohol—OH of chitosan molecules．Marked difference of the characteristic peaks of both chitosan and chitosan—Zn(Ⅱ) complex was not observed in the x-ray diffraction pattern．indicating that the extended 2-fold helical conformation of the chitosan molecule is retained even after the complexation．Final decomposed product of the complex is sulfate zinc

and the residue percentage is 28．8％and is correspond to the calculated value of 29．0％

accordign to the composition of elemental analvsis of chitosan-Zn(Ⅱ) complex．The structure of the complex seems to correspond to Zn(chitosan)2SO4·4H2O at pH=7．Thecomplexisinsolubleinwater

acetone and ethanol

partly solublein dilute fclrmic acid solution

DMF and DMSO

completely soluble in dilute hydrochloric acid solution.