Timur Anvarovich Mukhametzyanov

Polytetrahydrofuran (PTHF) was employed for analysis of the effect of heating rate q on the peak temperature of cold crystallization Tp and enthalpy of cold crystallization Δhcc to follow crystal nucleation. The isothermal increase of the number of nuclei in the highly supercooled melt can be analyzed by heating at experimentally realizable rates between qmin and qmax, with slower and faster heating yielding maximum and zero cold-crystallization enthalpy, respectively. At intermediate fast heating, with q close to qmin, the cold-crystallization enthalpy first increases with the number of nuclei, reaches a plateau, and then decreases since crystals grow already at the nucleation temperature. The observation of a plateau is caused by completion of crystallization during slow heating if the number of nuclei exceeds a specific value. This limits the detection of a further increase of the number of nuclei, which, however, still causes a decrease of Tp, being a more sensitive measure of the number of nuclei than Δhcc, with the effect of the number of nuclei and q on Tp summarized with a continuous heating transformation (CHT) diagram. In contrast, fast heating, with q close to qmax, is unable to detect the initial stage of the nucleation process, caused by the limited time for growth to yield measurable crystallinity and the initial formation of nuclei of only sub-critical size at Tp. Besides the progress in understanding the interplay between nucleation and non-isothermal cold crystallization, the study also provides quantitative information about the kinetics of hot crystallization of PTHF as well as nucleation-pathway-dependent morphological features, requiring sophisticated experimentation to assess crystallization and melting below ambient temperature. Finally, a previously developed theoretical model of the effects of the heating rate and crystal nucleus density on Tp (Polymer 2026, 358, 130181) has successfully been tested, revealing agreement between morphological analyses of the time dependence of nucleation and theory: Homogeneous crystal nucleation of PTHF close to the glass transition temperature yields submicrometer-distant nuclei after sufficiently long annealing.

The application of supramolecular chemistry approaches involving multivalent macrocyclic derivatives offers a potential strategy to prevent adverse drug–macroelement interactions under conditions of electrolyte abnormalities. In this work, a peptidomimetic concept was employed to synthesize water-soluble, nontoxic pillar[5]arene derivatives bearing L–phenylalanine fragments. The macrocycles demonstrated affinity for the known immunosuppressant Cyclosporine A (CsA), resulting in the formation of assemblies with varying size and morphology, as evidenced by dynamic light scattering and transmission electron microscopy. UV–vis, fluorescence, and circular dichroism spectroscopies were employed for both the qualitative and quantitative assessment of the interaction between the pillar[5]arenes and CsA (lg Ka values for the two systems were determined to be 5.16 and 5.03), and to confirm that conformational changes in the CsA structure were prevented upon association. Molecular docking predicted the binding mode of the synthesized pillar[5]arenes with CsA, indicating the likely formation of rotaxane-type structures, which remained stable over a 70–100 ns simulation range. Furthermore, the water-soluble macrocycle in a binary pillar[5]arene+CsA system demonstrated a protective function, suppressing the undesirable interaction of the immunosuppressant with calcium ions, despite the drug’s high intrinsic affinity for this macroelement. The results highlight the promise of these peptidomimetic macrocycles as supramolecular shields for mitigating uncontrolled drug-ion interactions in disrupted homeostasis.

The paper presents new symmetric and asymmetric cationic imidazole-triazole amines. Their aggregation behavior in water using spectrofluorimetry (with pyrene and eosin Y probes), UV spectroscopy, and dynamic light scattering was studied. It was demonstrated that all of the compounds form positively charged nanoassociates. For the asymmetric amphiphilic derivatives, an increase in the length of the alkyl tail was found to result in a decrease in the critical micelle concentration, as well as the formation of a more hydrophobic core of aggregates. The interaction of compounds with DNA was studied using competitive displacement of ethidium bromide, fluorescence lifetime analysis, UV spectroscopy, circular dichroism spectroscopy, nanoparticle tracking analysis and zeta potential measurements. A mixed binding mechanism involving electrostatic and hydrophobic interactions was established. Compounds with a symmetrical imidazole-triazole structure and a tetradecyl tail were the most effective inverting its charge. These results demonstrate the potential of controlled structure design in creating effective non-viral nucleic acid delivery vectors.

The zeotype material Co _1.28 (NH ₄ ) _0.44 (BP ₂ O ₈ )(H ₂ O) _2.41 (Z-CoBP) was synthesized and its polarity and enantioselectivity were studied. The chirality of Z-CoBP was due to Viedma ripening.

New chiral square-like sulfonylcalix[4]arene-supported {Co ^II ₁₆ }-coordination cages with edge-centred chirality induction showed selective (+)-/(−)-α-pinene adsorption.