Author: Konstantin
Last saved by: Marina

Specialization: 010700 Physics
Program: Theoretical and applied spectroscopy of molecular systems
Program manager: Prof. Dr. K.G. Tokhadze
Department of Molecular Spectroscopy
Scientific adviser: A.V. Shurukhina
Reviewer: Prof. Dr. G.S. Denisov

The study of hydrogen bond cooperativity in complexes that simulates proton transfer in serine protease fragment by IR and UV spectroscopy 
Klykov Alexander Nikolaevich

This work is part of the research conducted by the Department of Molecular Spectroscopy, St. Petersburg State University with the laboratory of Professor H.-kh. Limbakh at the Institute of Chemistry and Biochemistry at the Free Uni-versity of Berlin on the spectroscopic study of the structure and properties of complexes with hydrogen bonds and proton transfer processes.
The task of this study was to identify by IR and UV spectroscopy of the cooperativity of hydrogen bonds in a row of model complexes  that imitate catalytic triad of the active center of serine proteases. The objects of study were selected  intermolecular complexes formed by o-hydroxyphenyl benzimidazole (HBPI) with organic bases of different proton acceptor ability: 2,4,6-trimetylpyridine, tetrahydropyrrole, hexahydropyridine and 4-dimethylaminopyridine in a CH2Cl2 solution. Also for comparison were investigated complexes phenylbenzimidazole (PBI) with the same bases, which does not contain an intramolecular hydrogen bond. As well as IR spectra were obtained HBPI and PBI in the solid phase.
To estimate the value geometric cooperativity of hydrogen bonds in the complexes HPBI and PBI with various organic bases, quantum mechanical calculations were carried out at the Hartree-Fock-(HF) and MP2 levels, using different types of basis sets. 
The presence of cooperative interaction between two hydrogen bonds in the complexes with the bases HPBI demonstrated in the form of correlations between  the centres of gravity of NH and OH bonds of stretching vibrations. Strengthening intermolecular hydrogen bond in complexes HPBI with stronger proton acceptors leads to a low-frequency shift of the NH and OH bond, which indicates a strengthening of intramolecular OHN connection. 
The list of the publications 
1.	A. Klykov. The study of hydrogen bond cooperativity in complexes that simulate proton transfer in serine protease fragment by infrared and ultraviolet spectroscopy. International Student Conference "Science and Progress". 14 - 18 November 2011. St.Petersburg. Russia. Book of Abstracts 154.
2.	E.Y. Tupikina, S.N. Smornov, A.V. Shurukhina, А.N. Klykov, N.S. Golubev, G.S. Denisov, P.M. Tolstoy. hydroxyphenylbenzimidazole as a active center model of serine protease. 8th Winter Youth School-Conference "Magnetic resonance and its applications" Spinus 2011. 27 November - 03 December 2011. Saint-Petersburg. Russia. Book of Abstracts 205.