Guanidine-equipped thiacalix[4]arenes: Synthesis, interaction with DNA and aggregation properties

New tetrakis-guanidinium-containing p-tert-butylthiacalix[4]arene forms monodisperse nanoparticles with diameter 44 nm in the concentration range of 40-100 μm. Its association constant with model DNA was evaluated as pK a = 3.96 by fluorescent intercalator displacement assay. © 2014 Mendeleev Communications. All rights reserved

Guanidine-equipped thiacalix[4]arenes: Synthesis, interaction with DNA and aggregation properties

New tetrakis-guanidinium-containing p-tert-butylthiacalix[4]arene forms monodisperse nanoparticles with diameter 44 nm in the concentration range of 40-100 μm. Its association constant with model DNA was evaluated as pK a = 3.96 by fluorescent intercalator displacement assay. © 2014 Mendeleev Communications. All rights reserved

Effect of catalytic aquathermolysis on high-molecular-weight components of heavy oil in the ashal'cha field

© 2015 Springer Science+Business Media New York. We have studied the effect of catalytic aquathermolysis on the high-molecular-weight components of crude oil in the Ashal'cha field (Republic of Tatarstan). We used an iron(III) tris(acetylacetonate) complex as the catalyst. The change in the structure and composition of the resins and asphaltenes in aquathermolysis was studied by PMR and IR spectroscopy

P-tert-Butylthiacalix[4]arenes equipped with guanidinium fragments: Aggregation, cytotoxicity, and DNA binding abilities

© The Royal Society of Chemistry 2016.Mono-, di- and tetracationic thiacalix[4]arenes in a 1,3-alternate conformation functionalized with guanidinium groups showed a strong dependence of the aggregation properties with the ratio of guanidinium/n-decyl fragments attached to phenolic groups. Increasing the amount of guanidinium fragments improved the macrocycles solubility in water as well as the sorption capacity towards polynucleotide molecules. The synthesized thiacalixarenes showed relatively high toxicity comparable with that for similar receptors based on the classical calixarene

Investigation of DNA binding abilities of solid lipid nanoparticles based on p-tert-butylthiacalix[4]arene platform

© The Royal Society of Chemistry 2015. An amphiphilic thiacalix[4]arene derivative functionalized with guanidinium groups forms stable solid lipid nanoparticles (SLNs) with high ζ-potential in water. Applying gel electrophoresis and fluorescent spectroscopy methods shows that the SLNs have high binding affinity to double-stranded DNA, but despite this fact, we have not observed any significant transfection activity toward three different mammalian cell lines. A UV-spectroscopic study reveals that interaction between the SLNs and the polynucleotide leads to partial denaturation of the DNA located on the surface of the nanoparticles that can hinder transfection

Thermal decomposition of Tatarstan Ashal'cha heavy crude oil and its SARA fractions

© 2016 Elsevier LtdIn this research, heavy crude oil from Ashal'cha field, Republic of Tatarstan, and its SARA (saturate, aromatic, resin and asphaltene) fractions were analyzed by differential scanning calorimetry (DSC) and thermogravimetry (TGA) methods. The experiments were performed at three different heating rates (10, 20, 30 °C/min) for DSC and at single heating rate for TGA analysis, all under the air atmosphere. In DSC experiments, two main reaction regions were detected at each heating rate known as low and high temperature oxidation reactions. On the other hand, in TGA experiments, one main region was observed. For all the SARA fractions studied, highest heat of reaction was observed in lowest heating rate. The kinetic analysis of the crude oils and their fractions was also performed using ASTM E-698 and Arrhenius methods, respectively. Activation energy values of the crude oil sample and the fractions varied between 69.2 and 201.8 kJ/mol in LTO region and 82.9–182.1 kJ/mol in HTO regions, respectively. In Arrhenius method, the activation energy values were in the range of 33.1–108.9 kJ/mol

Pyrolysis of Kerogen of Bazhenov Shale: Kinetics and Influence of Inherent Pyrite

© 2017 American Chemical Society. In the present study, we investigated in detail the influence of the depyritization procedure on the structure and morphology of the organic matter of Bazhenov shale. We monitored both structural and morphological properties of the organic matter of shale during chemical treatment by a complex of physical methods, including different types of spectroscopies, scanning electron microscopy, and physisorption analysis. We also applied non-istothermal kinetic analysis to study the effect of inherent pyrite on the pyrolysis of kerogen in a wide temperature range and showed that the presence of inherent pyrite has no impact on the pyrolysis process

Synthesis and complexation properties of 1,3-alternate stereoisomers of p-tert-butylthiacalix[4]arenes tetrasubstituted at the lower rim by the phthalimide group

Thiacalix[4]arenes containing the phthalimide group were synthesized and their extraction ability toward monocharged cations (alkali metals and Ag+) was investigated. © 2009

Phenylurea-equipped p-tert-butylthiacalix[4]arenes as the synthetic receptors for monocharged anions

New p-tert-butylthiacalix[4]arenes linked with phenylurea fragments can serve as synthetic receptors for fluoride, acetate or dihydrogen phosphate anions depending on the conformation of the macrocycle (cone, 1,3-alternate) and the number of substituents. © 2013 Mendeleev Communications. All rights reserved

Pentakis-thiacalix[4]arenes with nitrile fragments: Receptor properties toward cations of some s-and d-metals and self-assembly of nanoscale aggregates

Pentakis-thiacalix[4]arenes containing thiacalix[4]arene fragments in cone, partial cone and 1,3-alternate conformations as their central core have been obtained. Their interaction with cations of s- and d-metals gives supramolecular assemblies whose composition depends on the conformation of pentakis-thiacalix[4]arenes and the nature of the 'guests'. © 2013 Mendeleev Communications. All rights reserved