Mono- and Biligand Silver Clusters with Cholesterol and Thiocholesterol: theDFT study.
Gromova, Y.A.1*; Shabatina, T.I.12; Ermilov, A.Yu1.

*Corresponding author: chemyaninka@mail.ru
1
Lomonosov Moscow State University, Department of Chemistry, 119991, Leninskie Gori 1/3,
Moscow, Russian Federation.
2
Faculty of Fundamental Sciences, N.E. Bauman Moscow Technical University, Moscow 105005,
Russian Federation.
Hybrid nanosystems based on stabilised silver nanoparticles attract the attention of researchers dueto their unique physicochemical properties and a wide range of practical applications including
biomedicine. Atoms and small clusters obtained as a beam using thermal evaporation of bulk metal
under high vacuum conditions and followed by condensation on cooled support surfaces of different
preparative cryostats possess a high chemical reactivity as compared to that of bulk metals. Silver
nanoparticles with size of 2-3 nm can interact with cholesteric molecules forming hybrid linear
aggregates (10 μ) which possess plasmonic collective absorbtion in the visible range of wavelengths[1]. In recent years stabilised silver nanoparticles have been actively used as drug carriers for transportdelivery. Cholesterol and it’s derivatives are natural biocompatible biomolecules with good cell
penetration. So the practical interest to these systems stimulates the need for theoretical modelingdeveloping primarily with modern quantum-chemical calculations.
This work is devoted to experimental studies and DFT calculations of the silver cluster (Ag13) andit’s complexes with O-containing cholesterol ligand (Ch) and S-containing thiocholesterol (TCh)ligand. TEM experimental data for Ag-Ch and Ag-TCh systems showed the formation of silvernanoclusters with sizes of (5.5±0.5)nm and (2.7±0.5)nm [1]. Supramolecular organisation of thesystems due to donor-acceptor or electrostatic interactions with cholesteric ligands led to theformation of elongated helix aggregates with plasmonic absorbtion in visible and near-IR spectral
regions (450 nm and 470 nm accordingly). Using the DFT/B3LYP5 method the structures of biligand
complexes of Ag13 silver cluster with cholesteric ligands were modeled and compared with thestructure of monoligand complexes. Thus the energies of the model reactions of monoligand complexformation were -19.9 kcal/mol (Ag13-TCh) and -3.5 kcal/mol (Ag13-Ch) [2]. The formation energiesof the bigand complexes were -21.1 kcal/mol (Ag13-(TCh)2) and -6.9 kcal/mol (Ag13-(Ch)2) [3]. Oand S-containing ligands were coordinated by vertices on different sides of the Ag13 icosahedron. Soa tendency of the Ag13 metal cluster to attach more ligands was found out. It can be assumed that thesystem retains the tendency of further aggregation with the attaching of the additional ligand
molecules [3].
Funding: The work was supported by the Program of the MSU Development, MSU Interdisciplinary
Grants for Scientific Schools NSH-2023-05-0026.
__________________________[1] Ya.A. Gromova, B.A. Sarvin, T.I. Shabatina. Adsorption Properties of Hybrid Metal-Mesogenic
Silver-Cholesterol and Silver-Thiocholesterol Nanosystems // Russ. J. Phys. Chem. A. 2019. V. 93.
2. P. 342-347.
[2] A.Yu. Ermilov, E.S. Lukyanova, Ya.A. Gromova, T.I. Shabatina. Interaction of Silver Clusters
with Cholesterol Ligands // Moscow. Univers. Chem. Bull. 2018. V. 73. 5. P. 251-256.
[3] Ermilov A.Yu, Shabatina T.I., Gromova Y.A. Biligand Complexes of Cholesterol andThiocholesterol with Silver Nanoparticles: Experimental Data and DFT-modeling // Moscow.
Univers. Chem. Bull. 2022. V. 77. 1. P. 65-71.