Cavitand-based anion receptors and self-assembled (hemi)capsules in polar competitive media

This thesis is focused on a study of two basic supramolecular phenomena, viz. recognition and self-assembly in polar competitive media using appropriately functionalized cavitands

Increase of resistance against wear of a cranked shaft with babbitt bearings by nanodiamond saturation of friction surfaces

Oshovsky, V. Increase of resistance against wear of a cranked shaft with babbitt bearings by nanodiamond saturation of friction surfaces = Двищення стійкості проти зносу колінчастого валу з бабітовими підшипниками наноалмазним насиченням поверхонь тертя / V. Oshovsky, S. Dotsenko, A. Kairov // Innovative Approaches to Ensuring the Quality of Education, Scientific Research and Technological Processes : monograph / M. Ekkert, M. Gawron-Łapuszek, T. Nestorenko, A. Ostenda, Y. Suchikova, M. Wierzbik-Strońska. – Katowice : Publishing House of University of Technology, 2021. – 4.10. – P. 1071–1196.Defects of crankshaft friction surface treatment,which reduce their wear resistance, are analyzed.The technology of processing of friction surfaces of a shaft and babbitt sliding bearings which increases their geometrical accuracy and wear resistance and reduces coefficient of friction is developed and investigated. The essence of the main technology in the grinding and penetration of diamond grains based on disulfide-molybdenum oil in the surface during their friction and compression. The absence of surface wear for a long time of operation of the crankshaft has been experimentally confirmed

Aqueous Self-Sorting in Extended Supramolecular Aggregates

Self-organization and self-sorting processes are responsible for the regulation and control of the vast majority of biological processes that eventually sustain life on our planet. Attempts to unveil the complexity of these systems have been devoted to the investigation of the binding processes between artificial molecules, complexes or aggregates within multicomponent mixtures, which has facilitated the emergence of the field of self-sorting in the last decade. Since, artificial systems involving discrete supramolecular structures, extended supramolecular aggregates or gel-phase materials in organic solvents or—to a lesser extent—in water have been investigated. In this review, we have collected diverse strategies employed in recent years to construct extended supramolecular aggregates in water upon self-sorting of small synthetic molecules. We have made particular emphasis on co-assembly processes in binary mixtures leading to supramolecular structures of remarkable complexity and the influence of different external variables such as solvent and concentration to direct recognition or discrimination processes between these species. The comprehension of such recognition phenomena will be crucial for the organization and evolution of complex matter

Protein-Mimetic, Molecularly Imprinted Nanoparticles for Selective Binding of Bile Salt Derivatives in Water

A tripropargylammonium surfactant with a methacrylate-terminated hydrophobic tail was combined with a bile salt derivative, divinyl benzene (DVB), and a photo-cross-linker above its critical micelle concentration (CMC). Surface-cross-linking with a diazide, surface-functionalization with an azido sugar derivative, and free-radical-core-cross-linking under UV irradiation yielded molecularly imprinted nanoparticles (MINPs) with template-specific binding pockets. The MINPs resemble protein receptors in size, complete water-solubility, and tailored binding sites in their hydrophobic cores. Strong and selective binding of bile salt derivatives was obtained, depending on the cross-linking density of the system

Supramolecular Assemblies Constructed by Cucurbituril-Catalyzed Click Reaction

Cataloged from PDF version of article.Cucurbituril homologues are multi-functional macrocycles that can find applications in many areas and have numerous interesting features setting them apart from the other macrocycles. Among them, the ability of one of the cucurbituril homologues, cucurbit[6]uril (CB6), to catalyze 1,3-dipolar cycloaddition in a regiospecific fashion is truly exceptional. Using this feature, small molecules can be clicked together to form complex structures in a very efficient way. Accordingly, in this article we review recent research involving the use of CB6-catalyzed 1,3-dipolar cycloaddition or the click reaction of CB6 in the construction of supramolecular assemblies including rotaxanes, pseudorotaxanes, polyrotaxanes, polypseudorotaxanes, molecular switches, machines, and nanovalves

Supramolecular Encapsulation of Neutral Diazoacetate Esters and Catalyzed 1,3-Dipolar Cycloaddition Reaction by a Self-Assembled Hexameric Capsule

Diazoacetate esters proved to be suitable neutral guests for the self-assembled resorcin[4]arene hexameric capsule. The hydrogen- bonded supramolecular host catalyzed the 1,3-dipolar cycloaddition reaction between diazoacetate esters and electron- poor alkenes such as acrolein, acrylonitrile, crotonaldehyde, trans-2-hexenal, methyl, and butyl acrylate, which led to the corresponding 4,5-dihydro-1H-pyrazole derivatives. The cycloaddition reaction occurred within the cavity of the capsule. In fact, substantial inhibition of the catalytic activity was observed by employing tetraethylammonium tetrafluoroborate characterized by greater affinity for the hexameric capsule as a competitive guest; its presence inhibited access of the substrates. The 1,3-dipolar cycloaddition reaction between diazoacetate esters and acrylate esters of different lengths showed a significant degree of substrate selectivity owing to the encapsulation of the reagents before the cycloaddition reaction.Diazoacetate esters proved to be suitable neutral guests for the self-assembled resorcin[4]arene hexameric capsule. The hydrogen-bonded supramolecular host catalyzed the 1,3-dipolar cycloaddition reaction between diazoacetate esters and electron-poor alkenes such as acrolein, acrylonitrile, predominantly trans-crotonaldehyde, trans-2-hexenal, methyl, and butyl acrylate, which led to the corresponding 4,5-dihydro-1H-pyrazole derivatives. The cycloaddition reaction occurred within the cavity of the capsule. In fact, substantial inhibition of the catalytic activity was observed by employing tetraethylammonium tetrafluoroborate characterized by greater affinity for the hexameric capsule as a competitive guest; its presence inhibited access of the substrates. The 1,3-dipolar cycloaddition reaction between diazoacetate esters and acrylate esters of different lengths showed a significant degree of substrate selectivity owing to the encapsulation of the reagents before the cycloaddition reaction

Aerogen Bonds Formed Between AeOF2 (Ae = Kr, Xe) and Diaziness: Comparisons Between σ-Hole and π-Hole Complexes

The interaction between KrOF2 or XeOF2 and the 1,2, 1,3, and 1,4 diazines is characterized chiefly by a Kr/Xe···N aerogen bond, as deduced from ab initio calculations. The most stable dimers take advantage of the σ-hole on the aerogen atom, wherein the two molecules lie in the same plane. The interaction is quite strong, as much as 18 kcal mol-1. A second class of dimer geometry utilizes the π-hole above the aerogen atom in an approximate perpendicular arrangement of the two monomers; these structures are not as strongly bound: 6-8 kcal mol-1. Both sorts of dimers contain auxiliary CH···F H-bonds which contribute to their stability, but even with their removal, the aerogen bond energy remains as high as 14 kcal mol-1. The nature and strength of each specific interaction is confirmed and quantified by AIM, NCI, NBO, and electron density shift patterns. There is not a great deal of sensitivity to the identity of either the aerogen atom or the position of the two N atoms in the diazine

Two-pronged attack: dual inhibition of Plasmodium falciparum M1 and M17 metalloaminopeptidases by a novel series of hydroxamic acid-based inhibitors

Plasmodium parasites, the causative agents of malaria, have developed resistance to most of our current antimalarial therapies, including artemisinin combination therapies which are widely described as our last line of defense. Antimalarial agents with a novel mode of action are urgently required. Two Plasmodium falciparum aminopeptidases, PfA-M1 and PfA-M17, play crucial roles in the erythrocytic stage of infection and have been validated as potential antimalarial targets. Using compound-bound crystal structures of both enzymes, we have used a structure-guided approach to develop a novel series of inhibitors capable of potent inhibition of both PfA-M1 and PfA-M17 activity and parasite growth in culture. Herein we describe the design, synthesis, and evaluation of a series of hydroxamic acid-based inhibitors and demonstrate the compounds to be exciting new leads for the development of novel antimalarial therapeutics