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This study focuses on the molecular design and synthesis of salt spiropyrans with near-IR fluorescence. The structure of the obtained compounds was confirmed by NMR, IR and mass spectroscopy. In the course of studying the spectral and photoluminescent characteristics, it was possible to reveal the effect of some substituents in various positions on the properties of spiropyran dyes. Due to the structural similarity of one of the isomers to cyanine dyes, the obtained compounds are of interest as potential fluorescent probes for bioimagimg, in particular, for DNA studies. To reveal their ability of binding to DNA molecules molecular docking was carried out. Toxic effects of compounds demonstrating NIR fluorescence were studied on biofilms, as well as using bacterial lux-biosensors. [ABSTRACT FROM AUTHOR]

A hexacoordinated Co(II) complex of [CoL(NCS)2]·2DMSO (1) composition, where L is tetradentate bis-quinolyl hydrazone 2,2′-(2,2′-(butane-2,3-diylidene)bis(hydrazin-1-yl-2-ylidene))diquinoline, has been synthesised and characterized by IR, SCXRD, and AC and DC magnetic measurements. Due to helix-like distortion of the complex, the Co(II) coordination polyhedron is distorted towards trigonal prismatic symmetry. Complex 1 demonstrates slow relaxation of magnetization in an applied DC magnetic field of 1000 Oe, which is well described by the Raman mechanism. The performed CASSCF+NEVPT2 calculations provide clear insight into the origin of the magnetic anisotropy in 1. [ABSTRACT FROM AUTHOR]

In this work, a new binuclear nitrosyl complex with 3.4-dichlorothiophenolyl ligands [Fe2(SC6H3Cl2)2(NO)4] has been synthesized. Nitrosyl iron complexes (NICs) are systems for the storage and delivery of NO in the body. There is a dynamic equilibrium between dinitrosyl iron units bound to low molecular weight ligands and high molecular weight (protein) ligands in vivo. From this point of view, the transformation of the studied complex in DMSO and buffer, as well as in biological systems, has been analyzed. In DMSO, it decomposes into mononuclear NICs, which quickly decay in buffer solutions with NO release. The high molecular weight product is formed as a result of the binding of the complex to bovine serum albumin (the Stern–Volmer constant is 2.1 × 105 M−1). In this case, the complex becomes a prolonged NO-donor. Such a long-term effect has been observed for the first time. Similarly, in a system with oxyhemoglobin, NO generation is slower; the UV-vis spectra show a gradual formation of methemoglobin. On the other hand, reduced glutathione has little effect on the NO-donor properties of the complex despite the fact that ligand substitution is observed in the system and a binuclear product is formed. Mucin binds the complex, and the decomposition mechanism is different from that for buffer solutions. Thus, these proteins and glutathione are able to participate in the transformation of the complex and modulate its properties as a potential drug. [ABSTRACT FROM AUTHOR]

For the first time the neutron diffraction study of HZSM-5 zeolites with the general composition of (H1+x)[Al3+xSi4+12-xO24] × wH2O in the orthorhombic approximation (sp. gr. Pnma, z = 8) and initial silicate modules Si/Al = 12, 25, 40 was carried out. As a result, the composition was refined, the distribution of Al3+ ions over the tetrahedral sites (T sites) of the structure was found, and their content in each of them was estimated. It was found that T sites occupation in HZSM-5 structure differ depending on Si/Al, while samples with the same silicate module (Si/Al = 40) obtained under different synthesis conditions differ in the distribution of Al3+ ions over T sites of the structure. It was shown that the calculation of HZSM-5 zeolites crystal structure with substitutions in T sites performed using the VASP 5.2 program with different optimizations (atomic coordinates and unit cell parameters) can only reveal the most thermodynamically energetically favorable sites for Si4+ atoms substitution with other atoms (aluminum and titanium) without predicting their content in each site and regardless zeolite synthesis conditions and type of substituent atom. The relationship between HZSM-5 zeolites catalytic properties and silicate module (Si/Al, Si/Ti) was found and it cannot be ruled out that HZSM-5 catalytic activity is related to Ti4+ ions distribution over the tetrahedral sites of the structure. [ABSTRACT FROM AUTHOR]

Dihydroquercetin (DHQ) is a promising antioxidant for medical applications. The poor water solubility of this flavanonol at ambient conditions inhibits its implementation in clinical practice as an injectable dosage form. Thus, increasing water solubility is a critical step toward solving this problem. Herein we attempted to deal with this problem via DHQ phase modification while at the same time adhering to the principles of green chemistry as much as possible. Lyophilization is an appropriate method to achieve phase modification in an environment-friendly way. This method was employed to generate new phase modifications of DHQ that were then characterized. Mixtures of water with ethanol or acetonitrile were used as solvents for the preparation of the lyophilizates, DHQE, and DHQA, respectively. The results of dissolution testing of the obtained DHQE and DHQA demonstrated that the lyophilization increased water solubility at least 30-fold times. These new DHQ modifications were studied by scanning electron microscopy, mass-spectrometry, nuclear magnetic resonance spectroscopy, infrared spectroscopy, X-ray powder diffraction, and thermal analysis. Their solid-state phases were confirmed to differ from the initial DHQ substance without any changes in the molecular structure. Both DHQE and DHQA showed as high antioxidant activity as the initial DHQ. These data demonstrate the potential of DHQE and DHQA as active pharmaceutical ingredients for injectable dosage forms. [ABSTRACT FROM AUTHOR]

In this work a new donor of nitric oxide (NO) with antibacterial properties, namely nitrosyl iron complex of [Fe(C6H5C-SNH2)2(NO)2][Fe(C6H5C-SNH2)(S2O3)(NO)2] composition (complex I), has been synthesized and studied. Complex I was produced by the reduction of the aqueous solution of [Fe2(S2O3)2(NO)2]2− dianion by the thiosulfate, with the further treatment of the mixture by the acidified alcohol solution of thiobenzamide. Based on the structural study of I (X-ray analysis, quantum chemical calculations by NBO and QTAIM methods in the frame of DFT), the data were obtained on the presence of the NO...NO interactions, which stabilize the DNIC dimer in the solid phase. The conformation properties, electronic structure and free energies of complex I hydration were studied using B3LYP functional and the set of 6–31 + G(d,p) basis functions. The effect of an aquatic surrounding was taken into account in the frame of a polarized continuous model (PCM). The NO-donating activity of complex I was studied by the amperometry method using an "amiNO-700" sensor electrode of the "inNO Nitric Oxide Measuring System". The antibacterial activity of I was studied on gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. Cytotoxicity was studied using Vero cells. Complex I was found to exhibit antibacterial activity comparable to that of antibiotics, and moderate toxicity to Vero cells. [ABSTRACT FROM AUTHOR]

Three novel bis- and trinitroso compounds derived from 1,3,5- trihydrohybenzene (phloroglucinol), 2,4,6–trihydroxy benzoic acid, and 2,4,6-trihydroxyacetophenone were isolated, their spectral characteristics, ionization constants and thermodynamic parameters of dissociation process were calculated. The comparison of the stability of nitroso and hydroxylimino tautomeric forms was performed by DFT calculations. Nine complexes of the ligands with Cu(II), Cd(II), and Fe(III), were isolated and studied by elemental analyses, X Ray analysis and spectroscopic methods. According to the crystal structure determination, the Cd complex with the phloroglucinol based ligand exists in the form of a binuclear compound. The QTAIM Bader topological analysis indicated that the binuclearity of the Cd complex is due to strong interatomic interactions between Cd atoms with bifurcate carbonyl groups of the ligands and strong H-interactions involving coordinated and lattice water molecules. The equilibria of reactions of complex formation of the organic species with Cu2+, Cd2+, and Fe3+ was studied by spectrophotometric titration, and the composition of the complexes in solutions and their stability constants were calculated. The ability of the isolated organics to remove metal cations from the aqueous solutions was studied in the pH interval 3–6 and the rate of Cu2+ removal from aqueous solutions was found close to 100%. [ABSTRACT FROM AUTHOR]

The crystal and molecular structure of (4E,5Z)‐4,5‐dibenzylidene‐1,2,3,6,7,8‐hexahydroacridine as a biologically active substance with potential antioxidant, anti‐inflammatory and anti‐microbial activity is reported. The title compound is found to be non‐planar. The rings are twisted around the central fragment of the molecule by 54.0 and 32.5°. The dihedral angle between the two phenyl rings is 23°. In crystal, the molecules are packed in head‐to‐head stacks along the b‐axis with no intermolecular H‐bonds. DFT B3LYP theoretical modeling with the LANL2DZ basis is performed and a topological analysis of the electron density distribution is carried out in the framework of the Bader QTAIM theory for both isolated molecules and dimeric associates forming stacks in the crystal. It is found that some intermolecular and intramolecular non‐valent interactions are to some extent related to the formation of weak covalent interactions in the intermolecular and intramolecular space. [ABSTRACT FROM AUTHOR]

Two polymorph modifications of 5,7‐dinitro‐8‐(N‐phenylamino) quinoline (DNPAQ) are isolated in the form of single crystals and studied by experimental and theoretical methods. According to the X‐Ray analysis on single crystals, the two modifications differ by the twist angle between the nitro‐group and the quinoline fragment and the type of molecular packing in the crystals. The theoretical modeling of both polymorphs is performed. The DNPAQ molecular structures of the dimers of neighboring molecules in the polymorphs did not indicate the existence of a significant charge transfer. [ABSTRACT FROM AUTHOR]