Numerous structural defects, such as vacancies, dislocations, admixtures, grain boundaries and edges in the 2 D-MoS₂ particles change their optical, mechanical, and electrical properties that influences their application. Here we investigate the heat annealing of MoS₂ particles at 700 °C in an argon atmosphere, and demonstrate the appearance of sulfur vacancies in them using FTIR spectroscopy. The new IR absorption bands belonging to deformation and stretching vibrations of $S{O}_4^{2-}$ anions centered at 614 cm⁻¹ and 1115 cm⁻¹, respectively, were registered after annealing. In both MoS₂ samples, those before and after the heat annealing, the Mo-O_x vibrations were registered by FTIR and Raman spectroscopy. Negligible changes observed in the Raman spectra of the title compound are discussed.

Experimental results, which confirm the nonlinear dynamic behavior of bacterial photosynthetic reaction centers under light-activated conditions, are presented. Different light-adapted conformational states of the reaction centers can be obtained by varying the exposition time. It is shown that the fast and slow equilibration kinetics of the reaction centers reflect the mechanisms of electron transfer processes. The reaction centers possessing light-induced structural changes, which have not relaxed completely before a flash, produce the pronounced slow relaxation component. This slow component splits into two separate components with increase in the exposition time. The amplitudes of the resulting components depend on the light adaptation time.

Nanostructured MoS ₂ was catalytically active in hydrogenation of bromoquinolines, allowing to obtain respective bromo-containing tetrahydroquinolines.

Objectives: The purpose of the work was to study the effect of carbon nanotubes on the formation of fibril structures in lysozyme at room temperature under different pH values. Materials and methods: For the preparation of the samples, hen egg-white lysozyme protein (HEWL, Fluka), as well as single-walled (SWCNT, Sigma-Aldrich) and multi-walled (MWCNT, OOO TM “Spetsmash”, Kyiv, Ukraine) carbon nanotubes were used. Used techniques: IR-Fourier Absorption Spectroscopy; confocal microscopy. Results: In this paper, the study of molecular mechanisms of interaction of lysozyme with carbon nanotubes by vibrational spectroscopy was carried out and a conformational analysis of the formed complexes was performed. It is shown that carbon nanotubes can affect the structure of lysozyme even at room temperature and normal pH values, as evidenced by conformational changes in lysozyme due to interaction with carbon nanotubes. Complexes which are formed as a result of such interaction, have characteristic features of amyloid fibrillar structures. It reveals one of possible mechanisms of carbon nanotubes cytotoxicity. On the other hand, such a technique can be introduced to obtain model amyloid fibrils for further study. Conclusion: The method of vibtarional spectroscopy has shown that carbon nanotubes can influence the structure of lysozyme, as it is shown by the conformational analysis of the absorption band Amide I. After the interaction of lysozyme with CNT, an increase in the contribution of antiparallel β-conformation in the structure of lysozyme is observed, and the contribution of the α-helix conformation is reduced, which are characteristic features in the formation of fibrillar structures. The possibility of amyloid fibril formation without the use of high temperatures at different pH values with the interaction of lysozyme and carbon nanotubes, which can be applied as a method for obtaining the model amyloid fibrils, is shown.

The transient processes in the electric conduction of fine disperse 2D-MoS₂ powder samples, occurring at changing voltages applied to the sample under the conditions of uniaxial compression, have been studied. The long-term transient changes in conduction occurring both after switching on and off the applied voltage were observed. The current–voltage characteristics have a hysteresis of branches corresponding to increasing and decreasing voltages. The observed results are explained within the frame of the migration (interlayer) polarization model.