Sofia Slavova

Bulgarian Academy of Sciences | BAS · Institute of General and Inorganic Chemistry

Theoretical design of several proton cranes, based on 7-hydroxyquinoline and 3-hydroxypyridine as proton-transfer frames, has been attempted using ground and excited-state density functional theory (DFT) calculations in various environments. Imidazo[1,2-a]pyridine, pyrazolo[1,5-a]pyridine and benzimidazole were considered as proton crane units. The...

Herein, the detailed mechanism of intramolecular proton transfer in molecular switches, constructed from 7-hydroxy quinoline substituted in the eight-position C–C single axle, connected to three different proton cranes (morpholine, piperidine, and 1,3,5-dioxazine), was investigated by means of theoretical chemistry. The theoretical interpretation o...

The tautomeric properties of favipiravir were investigated experimentally for the first time by using molecular spectroscopy (UV-Vis absorption, fluorescence and NMR), as well as DFT quantum-chemical calculations. According to the obtained results, the enol tautomer is substantially more stable in most of the organic solvents. In the presence of wa...

In this work we show, using the example of a series of [Cu(Xantphos)(N^N)]+ complexes (N^N being substituted 5-phenyl-bipyridine) with different peripheral N^N ligands, that substituents distant from the main action zone can have a significant effect on the physicochemical properties of the system. By using the C≡C bond on the periphery of the coor...

Abiotic synthesis of nucleobases and amino acids is of critical importance as it sheds light on potential prebiotic chemical reactions. During thermal decomposition of formamide in vacuum conditions, purine, cytosine, adenine, hypoxanthine, uracil, pterin, urea, urocanic acid, glycine, alanine and norvaline were detected. The compounds were obtaine...

Reaction pathway of prebiotic reactions for formation of the pteridines: pterin, xanthopterine, isoxanthopterine and leucopterine, as well as the purine nucleobase guanine from pure formamide are presented. In these reactions, formamide or its tautomer, formimidic acid, play the role of proton-carrying catalyst. All required raw materials, such as...

Mechanisms of reactions for formylation of urea, leading to N,N 0-diformylurea, and for the dehydration of glycinamide and N,N 0-diformylurea, yielding hypoxanthine, are suggested. It is shown that these reactions are self-catalyzed. The first is catalyzed by formic acid, while the second is catalyzed by N,N 0-diformylurea. The suggested reaction m...

Mechanisms of reactions for formylation of urea leading to N,N'-diformylurea and for the dehydration of glycinamide and N,N'-diformylurea yielding hypoxanthine are suggested. It is shown that these reactions are self-catalyzed. The first is catalyzed by formic acid while the second one is N,N'-diformylurea-catalyzed. The suggested reaction mechanis...

Molecular dynamics simulations were carried out for a finite sample of NaA zeolite in contact with bulk carbon dioxide in a wide range of temperatures and CO2 contents. Density and diffusion profiles were obtained to estimate the depth at which the external surfaces of the zeolite affect CO2 diffusion in porous space. The approximate depth of surfa...

Complete reaction pathway of prebiotic reactions for formation of the purine nucleobases adenine, hypoxanthine, guanine, isoguanine, 2,6‐diaminopurine, and xanthine from pure formamide are presented. All reactants (hydrogen cyanide, ammonia, water, formic acid, urea) and catalysts (formamide and formimidic acid) needed in the self‐catalyzed reactio...

Phosphine ligands, containing chromophore substituents –π-spacer–NPh2 (π-spacer = biphenyl, L1; naphthalene-ethynylphenyl, L2; and ethynyl-(phenylethynyl)anthracene, L3), were used to generate the corresponding gold(I) alkynyl complexes Au1–Au3 (alkynyl = ethynylphenyl-2,2′-bipyridine, epbpy). These compounds demonstrate intense fluorescence, which...

A substituted pyridazine was used to construct a family of mononuclear heteroleptic complexes [Ln(tta)3(pybpy)], Ln = Pr−Lu; Htta = thenoyltrifluoroacetone; pybpy = 3,6-di(2-pyridyl)pyridazine. All complexes obtained were characterized by CHN elemental analysis, NMR spectroscopy, ESI mass-spectrometry, FTIR spectroscopy and single crystal X-Ray ana...