Organizing co mmittee

 
 

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Poster presentation 
212 
DFT INVESTIGATION CHITOSAN-STABILIZED Cu/Ag 
NANOPARTICLES 
 
I.N. Nurgaliev, N.J. Burkhanova, S.Sh. Rashidova. 
 
Institute of Polymer Chemistry and Physics of the Academy of Sciences of the Republic 
of Uzbekistan, Tashkent, Uzbekistan 
e-mail: ilnarvodnik@gmail.сom 
 
Clusters are atomic or molecular agglomerated constituted by few or many identical 
or different atoms. The possibility of modulating the properties of bimetallic clusters, in 
particular polymer metal complexes (PMCs), for example, bionanocomposites based on 
polysaccharides and metal nanoparticles (BNCs), has been studied from a theoretical 
and experimental point of view in order to achieve the goals. It has been established that 
the antibacterial effect is a size-dependent property of nanoparticles (NPs). BNCs based 
on chitosan (ChS) are widely used in many cases and biological applications, for 
example, wound healing, biosensors, and treatment of burns and cancer [1]. 
The aim of this work was quantum-chemical calculations of the interaction of the 
monomeric form of ChS with metal nanoclusters, as well as the stability of Cu/Ag 
bimetallic structures. 
We calculated gas-phase optimized geometries of ChS, ChS–Ag and ChS–Ag– 
(H
2
O)
3
. From calculation results it is clear that ChS unit is stabilized by different types 
of intramolecular H-bonds viz. O-H---O-H, O-H--Oring, and N-H–O-H. Bond length of 
H-bonds ranges from 2.30 Å to 2.50 Å with one exceptionally elongated N-H—O-H 
bond (2.60 Å). Zero imaginary frequency ensures minimum energy state for the 
molecule. To identify the most probable site on glucosamine for Ag adsorption, 
different site-dependent complexations were studied. Theoretical investigalions shows 
the most stable gas-phase complex of ChS and Ag. The amino and hydroxyl groups are 
responsible for stabilization and complexation of Ag nanoparticles with ChS.
The next calculations are the bimetallic clusters of Cu
3
Ag
m 
composition (3≤m≤20) 
tend to present the segregated subcluster pattern. As the amount of Ag atoms increases, 
the clusters have a tendency to present similar structures to a core-shell with some 
copper atoms exposed, which can be noted in the oscillations obtained in the mixing 
energy analysis. The geometries of larger clusters tend to be the result of the fusion of 
simpler cluster structures. In particular, the Cu
3
Ag
10
cluster has an icosahedral structure, 
while the Cu
3
Ag
15
and Cu
3
Ag
20
clusters have structures that resemble a fusion of two 
icosahedrons, which partially explains why these structures are also stable, because 
icosahedral structures are naturally stable. The Density Functional Theory calculations 
of the most stable clusters Cu
3
Ag
10
, Cu
3
Ag
15
and Cu
3
Ag
20
reveal that these have an 
electronic behavior similar to their pure Ag analogues. 
References 
1. Rashidova S.Sh., Vokhidova N.R., Alekseeva O.V., Shibaeva V.D., Evdokimova 
A.V., Agafonov A.V. Biologically Active Cu/Ag Core–Shell Nanoparticles: Synthesis 
and Physicochemical Properties // Russ. J. Inorg. Chem. 2022. V67(12). -P. 2062–2068. 
DOI: 10.1134/S0036023622601490.