Organizing co mmittee

ON THE SYNTHESIS OF CHITOSAN METAL COMPLEXES 
BOMBYX MORI WITH MANGANESE IONS (II) 
 
K. Ergashev, N. Vokhidova, S. Rashidova 
Institute of Chemistry and Physics of Polymers Academy of Scientific of Uzbekistan, 
Tashkent 100128, Uzbekistan
, e-mail: [e-mail]

Undoubtedly, the versatility of chitosan (CS) makes it possible to use it as a 
polymeric ligand in complexation with d-metal ions. Manganese belongs to the family 
of d-elements and in most cases the Mn
2+
coordination number is 6, it has an octahedral 
and tetrahedral system. Manganese plays an important role in living organisms, 
affecting the growth of living organisms, hematopoiesis, and the function of the gonads 
[1]. In this regard, taking into account the biocompatibility, biodegradability, and 
bioactive properties of chitosan, the synthesis of its metal complexes with metal ions 
leads to the production of metal complexes with special properties. 
The purpose of the research is to obtain metal complexes (MC) based on 
Bombyx 
mori
chitosan with Mn
2+
ions, as well as to study their physicochemical properties. For 
the synthesis of MC, 0.1 M solutions of CS (MM=196×10
3
, DD=82%) and 
MnCl
2
×4H
2
O were used. Firstly, at 30±2⁰С, the pH of CS solutions was adjusted to 
pH=5 with 1 M NaOH and titrated with a solution 0.1 M MnCl
2
×4H
2
O.
The reaction mixture was vigorously stirred for one hour. The resulting MC was 
precipitated with acetone and dried in a lyophilizer to constant weight.
In the UV spectrum of chitosan, there are absorption bands at λ max 220 nm and 300 
nm for acetamide and amino groups, respectively. In the spectrum of CS:Mn
2+
metal 
complexes, the absorption bands of manganese ions at λmax=270-320 nm overlap with 
the absorption band of chitosan functional groups, which leads to an increase in 
intensity in this zones. In the spectrum of CS:Mn
2+
complexes, with a decrease in the 
CS content, one can observe a shift in the absorption region towards low absorption 
bands of Mn
2+
(λ=211→205 nm). The UV spectra show absorption bands at λmax=270-
320 nm, which are characteristic of n-p-electronic transitions associated with the 
formation of the Mn-N covalent bond. 
By Ostromyslensky-Djob method established, that under the chosen synthesis 
conditions, the chitosan macromolecule interacts with manganese ions (II) in 6:4 and 
9:1 molar ratio, respectively. The results obtained are of interest for the creation of 
medical preparations.