Nataliya Pavlovna Belskaya

The effect of the chlorine atom in the sixth position and methyl group in the third position of the uracil ring on the structural parameters, NBO charge distribution, and molecular properties of the 6-chloro-3-methyluracil (M6CU) biomolecule was analyzed in the isolated state, solid-state arrangement and within a double-stranded RNA microhelix. This effect, which was also compared to those with uracil and several uracil derivatives, leads to higher reactivity and the special properties of this pharmaceutical compound. Several correlations were established using MP2 and several DFT methods. The structural characterization of M6CU and a detailed analysis of the experimental FT-IR and FT-Raman spectra in the solid state was another aim studied in detail. For an accurate assignment, a simple approximation to a crystalline unit cell was optimized using a trimer form and the wavenumbers were subsequently corrected using several scaling procedures. The modified nucleobase M6CU forms base pairs with the complementary adenine and, therefore, it could replace uracil in the helix; based on our calculations, it leads to a noticeable helix deformation. This computational finding suggests its possible potential effect by binding to cancer-related or viral RNA helices. Molecular docking also revealed that M6CU could act as an active ligand within the 1JPW active site of the target β-catenin/Tcf4 protein complex.

We developed highly fluorescent photocages based on a 2-aryl-1,2,3-thiazol-4-yl-1,2,3-thiazole core. Extensive experimental and theoretical studies demonstrated their excellent properties compared to published light-based masking systems.

Functional nitrile and isocyanide groups form noncovalent bonds with different donor centers in the cocrystals of functionalized 1,2,3-triazole with selenodiazole.

The experimental IR and Raman vibrational spectra of a hydrated La(III) complex with a 1,2,3-triazole ligand were characterized by using four different Density Functional Theory (DFT) levels and two accurate scaling procedures. In the theoretical calculations, the hydration water in the experimental sample was considered under the Discrete Model (DM) with different numbers of explicit water molecules and different positions around the La(III) ion and the carboxylate groups. The predicted IR spectra at the M06-2X/Lanl2dz level appear to be the closest to the experimental ones. Based on the optimized structures, molecular properties and global chemical descriptors were also calculated, and the findings obtained are discussed in detail herein. Additionally, several photophysical properties were determined in both the free ligand and in several lanthanide complexes, and with the sample in the solid state and in DMSO solution. A blue shift in the fluorescence of the complexes was observed compared to the free ligand, as well as in the solid-state sample compared to the solution.

Metal-free reactions of thioacetamide derivatives with N-sulfonyliminoiodinane, affording isothiazoles under mild conditions, are described. 2-Substituted thioacetamides modified with an enamine moiety undergo reactions with iminoiodinane to form 4,5-disubstituted isothiazoles in 72-93% yields. Reactions of (het)arylidene-substituted 2-thioacetamides and iminoiodinane with subsequent one-pot oxidation of the formed sulfonylisothiazolines afford 3,4,5-trisubstituted isothiazoles in 44-96% yields. A scale-up synthesis of the developed methods was performed. The photophysical properties of the new isothiazoles were investigated, and UV- or blue-light-shifted fluorescence has been detected (QY up to 11%).

Novel biocompatible photocleavable protective groups for photocaging of amino acids and peptides have been synthesised. The mechanism of effective release of biomolecules has been studied in detail.

The effect of La, Ce, Pr and Nd ions on four Ln(ligand)₃ complexes and at three DFT levels of calculation was analyzed. Four ligands were chosen, three of which were based on the 1,2,3-triazole ring. The DFT methods used were B3LYP, CAM-B3LYP and M06-2X. The relationships established were between the geometric parameters, atomic charges, HOMO-LUMO energies and other molecular properties. These comparisons and trends will facilitate the synthesis of new complexes by selecting the ligand and lanthanide ion best suited to the desired property of the complex. The experimental IR and Raman spectra of Ln(2b′)₃ complexes where Ln = La, Ce, Pr, Nd, Sm, Gd, Dy, Ho and Er ions have been recorded and compared to know the effect of the lanthanide ion on the complex. The hydration in these complexes was also analyzed. Additionally, the effect of the type of coordination center on the ability of an Ln(ligand)₃ complex to participate in electron exchange and hydrogen transfer was investigated using two in vitro model systems—DPPH and ABTS.