supramolecular system
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2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Elisabeth Weyandt ◽  
Luigi Leanza ◽  
Riccardo Capelli ◽  
Giovanni M. Pavan ◽  
Ghislaine Vantomme ◽  
...  

AbstractMulti-component systems often display convoluted behavior, pathway complexity and coupled equilibria. In recent years, several ways to control complex systems by manipulating the subtle balances of interaction energies between the individual components have been explored and thereby shifting the equilibrium between different aggregate states. Here we show the enantioselective chain-capping and dilution-induced supramolecular polymerization with a Zn2+-porphyrin-based supramolecular system when going from long, highly cooperative supramolecular polymers to short, disordered aggregates by adding a monotopic Mn3+-porphyrin monomer. When mixing the zinc and manganese centered monomers, the Mn3+-porphyrins act as chain-cappers for Zn2+-porphyrin supramolecular polymers, effectively hindering growth of the copolymer and reducing the length. Upon dilution, the interaction between chain-capper and monomers weakens as the equilibria shift and long supramolecular polymers form again. This dynamic modulation of aggregate morphology and length is achieved through enantioselectivity in the aggregation pathways and concentration-sensitive equilibria. All-atom and coarse-grained molecular simulations provide further insights into the mixing of the species and their exchange dynamics. Our combined experimental and theoretical approach allows for precise control of molecular self-assembly and chiral discrimination in complex systems.


2022 ◽  
Author(s):  
Suma S. Thomas ◽  
Helia Hosseini-Nejad ◽  
Cornelia Bohne

The dynamics of naphthalene derivatives with different hydrophobicities bound to F127 polyethyleneoxide-polypropyleneoxide-polyethyleneoxide (PEO-PPO-PEO) micelles in the gel and sol phases were studied using a quenching methodology for the triplet excited states of the naphthalenes. Studies with triplet excited states probe a larger reaction volume than the volumes accessible when using fluorescent singlet excited states. The use of triplet excited states enables the determination of the dynamics between different compartments of a supramolecular system, which in the case of F127 micelles are the micellar core, the micellar corona and the aqueous phase. This report includes laser flash photolysis studies for the four naphthalene derivatives in the F127 gel and sol phases. The triplet excited states were quenched using the nitrite anion as the quenchers. The association and dissociation rate constants of the naphthalenes from the micelles and the quenching rate constants for the naphthalenes bound to the micelles were determines from the curved quenching plot (observed decay rate constant vs. nitrite concentration).


Soft Matter ◽  
2022 ◽  
Author(s):  
Yan Wang ◽  
Zhen Feng ◽  
Yawei Sun ◽  
Lijun Zhu ◽  
Daohong Xia

The newly developed porous liquids known as liquids with permanent microporosity, are of considerable application potential which still has many unknown areas. Herein, a supramolecular system composed of α-cyclodextrin porous...


2021 ◽  
pp. 72-87
Author(s):  
G.K. Mukusheva ◽  
◽  
A.R. Zhasymbekova ◽  
Z.B. Satpaeva ◽  
Е.V. Minayeva ◽  
...  

The alkaloid cytisine is of great importance for modern pharmacological studies. This alkaloid can be used as a component of the supramolecular system with cyclic oligosaccharides, namely β-cyclodextrins, which have a truncated cone-shaped molecule with internal protons Н3 and Н5 and external ones Н2 and Н4. The aim of the work is to obtain inclusion complexes of pharmaceutically active derivatives of the alkaloid cytisine. The inclusion complexes of cytisine alkaloid derivatives with β-CD and 2-HP-β-CD were obtained by the coprecipitation method. Thermogravimetric, differential thermal, and differential scanning calorimetric analyzes were performed. It was shown that inclusion complexes of substrate with cyclodextrin cavity of receptors were formed. The greatest change in the chemical shifts of protons during the formation of supra-molecular complexes occurs with the internal protons H-3 and H-5 of the cyclodextrin cavity. All calculated values are in good agreement with experimental data. The prepa-ration of supramolecular complexes has been proven using a variety of physicochemical methods of analysis. According to DSC data, the process of complexes destruction in the temperature range of 30-610°C was studied in comparison with the data of the initial cyclodextrin. The hemorheological effects of the investigated samples were studied in vitro. Among four samples studied, two samples showed the ability to reduce blood viscosity in vitro in the blood hyperviscosity model.


2021 ◽  
Author(s):  
Yingxian Ma ◽  
Liqiang Huang ◽  
Zhi Zhu ◽  
Yurou Du ◽  
Jie Lai ◽  
...  

Abstract Inspired by non-covalent enhancement mechanism, we introduced glycinamide-conjugated monomer (NAGA) with dual-amide in one side group to amplify the hydrogen bonding interactions. Via one-step free radical polymerization strategy, we prepared a type of supramolecular thickener based on binary polymer. With NMR, FT-IR and SEM results’ help, we determined that PNAGA-AM system had unique bis-amide structure of glycinamide-conjugated monomer. As a result, the synthesized polymer could generate a much denser structure based on the high-ordered multiple hydrogen bonding with lower molecular weight (Mn = 778,400 g/mol), increasing the strength and stability of the chains. PNAGA-AM system had good thickening and temperature-resistant properties. The thickener viscosity of PNAGA-AM(3.0wt%) had twice as much as that of corresponding PAM system. And the viscosity of the 1.5 wt% solution prepared by PNAGA-AM could maintain 74 mPa·s at 150 °C. Meanwhile, the supramolecular system showed excellent salt resistance and self-healing performance with the non-covalent/hydrogen bonding interactions and physical entanglements. The viscosity of the PNAGA-AM system did not drop but increase in high salinity (≤ 300,000 mg/L salinity), and the maximum viscosity could increase nearly 44 % compared with the initial situation. In addition, the self-healing efficiency was over 100 % at 120 °C. Overall, the fracturing fluid system based on PNAGA-AM system could maintain outstanding rheological properties under extreme conditions and showed brilliant recovery performance, to make up the disadvantages of currently used fracturing fluid. It is expected to mitigate potential fluid issues caused by low water quality, harsh downhole temperatures and high-speed shearing.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yun Hao ◽  
Feiyi Zhang ◽  
Shanshan Mo ◽  
Jinming Zhao ◽  
Xiangdong Wang ◽  
...  

Glucocorticoids are a class of steroid hormones secreted from the adrenal glands. The strong anti-inflammatory effects make it be one of the most popular and versatile drugs available to treat chronic inflammatory diseases. Additionally, supramolecular materials have been widely exploited in drug delivery, due to their biocompatibility, tunability, and predictability. Thus, steroid-based supramolecular materials and the release of steroids have been applied in the treatment of inflammatory diseases. This mini-review summarized recent advances in supramolecular materials loaded with glucocorticoid drugs in terms of hydrophobic interactions, electrostatic interactions, hydrogen bonding, and π-π stackings. We also discussed and prospected the application of the glucocorticoid drugs-based supramolecular system on chronic rhinosinusitis, multifactorial inflammatory disease of the nasal and paranasal sinuses mucosal membranes. Overall, supramolecular materials can provide an alternative to traditional materials as a novel delivery platform in clinical practice.


2021 ◽  
Author(s):  
D. V. Vishnevetskii ◽  
A. I. Ivanova ◽  
S. D. Khizhnyak ◽  
P. M. Pakhomov

Synlett ◽  
2021 ◽  
Author(s):  
Joaquim Crusats ◽  
Albert Moyano

In order to explain the origin of the single-handedness of the molecules of life (biological homochirality), the appearence of an initial enantiomeric imbalance by spontaneous mirror-symmetry breaking (SMSB) in prebiotic reactions is usually assumed, but examples of its experimental realization are very scarce. SMSB in the self-assembly of achiral molecules is much more common, and the chirality sign of the resulting supramolecular system can be controlled by the action of macroscopic chiral forces. We have proposed a new mechanism for the generation of net chirality in molecular systems, in which the SMSB takes place in the formation of chiral supramolecular dissipative structures from achiral monomers, leading to asymmetric imbalances in their composition that are subsequently transferred to a standard enantioselective catalytic reaction, dodging in this way the highly limiting requirement of finding suitable reactions in solution that show enantioselective autocatalysis. We propose the name “absolute asymmetric catalysis” for this approach, in which an achiral monomer is converted to a nonracemic chiral aggregate that is generated with SMSB and that is catalytically active. We present in this Account a step-by-step narrative of the development of this prebiotically plausible, alternative mechanism for the emergence of net chirality in molecular reactions.


2021 ◽  
Vol 9 ◽  
Author(s):  
Joanna Bojarska ◽  
Roger New ◽  
Paweł Borowiecki ◽  
Milan Remko ◽  
Martin Breza ◽  
...  

Targeting the polyamine biosynthetic pathway by inhibiting ornithine decarboxylase (ODC) is a powerful approach in the fight against diverse viruses, including SARS-CoV-2. Difluoromethylornithine (DFMO, eflornithine) is the best-known inhibitor of ODC and a broad-spectrum, unique therapeutical agent. Nevertheless, its pharmacokinetic profile is not perfect, especially when large doses are required in antiviral treatment. This article presents a holistic study focusing on the molecular and supramolecular structure of DFMO and the design of its analogues toward the development of safer and more effective formulations. In this context, we provide the first deep insight into the supramolecular system of DFMO supplemented by a comprehensive, qualitative and quantitative survey of non-covalent interactions via Hirshfeld surface, molecular electrostatic potential, enrichment ratio and energy frameworks analysis visualizing 3-D topology of interactions in order to understand the differences in the cooperativity of interactions involved in the formation of either basic or large synthons (Long-range Synthon Aufbau Modules, LSAM) at the subsequent levels of well-organized supramolecular self-assembly, in comparison with the ornithine structure. In the light of the drug discovery, supramolecular studies of amino acids, essential constituents of proteins, are of prime importance. In brief, the same amino-carboxy synthons are observed in the bio-system containing DFMO. DFT calculations revealed that the biological environment changes the molecular structure of DFMO only slightly. The ADMET profile of structural modifications of DFMO and optimization of its analogue as a new promising drug via molecular docking are discussed in detail.


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