ИСТИНА

The small silver clusters Agn (n=1-3, 13) and their complexes win Cholesterol (Ch) and Thiocholesterol (TCh) ligands are studied with DFT-B3LYP аnd second order Moeller-Plesset perturbation theory (MP2). Large complexes Agn- Ch and Agn-TCh (n=3,13) are calculated at DFT level of theory. The equilibrium structures and binding energies are calculated. The trends of the structures and energetics with the growth of cluster size are discussed. The metal part of the Ag13-Ch and Ag13-TCh complexes is the slightly distorted icosahedron with the Ag-Ag distances are about 2.8-3.0 A. The cholesterol ligand is coordinated to a face of the silver icosahedron whereas the thiocholesterol ligand - to the edge of polyhedron. In the case of thiocholesterol ligand the complex structure both Ag-S distances (2.537 and 2.547 A) are almost equal. Acknowledgements. The authors thank the Research Computing Center of MSU for providing computational resources. The work is financially supported by Russian Science Foundation RSF- 16-13-10365