scholarly journals The Supramolecular Organogel Formed by Self-Assembly of Ursolic Acid Appended with Aromatic Rings

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 614 ◽  
Author(s):  
Jinrong Lu ◽  
Jinshan Hu ◽  
Yinghua Liang ◽  
Wenquan Cui
Keyword(s):  
Ursolic Acid ◽  
Self Assembly ◽  
Driving Forces ◽  
Variable Temperature ◽  
Proton Nuclear Magnetic Resonance ◽  
Aromatic Rings ◽  
Pharmacological Activities ◽  
Aggregation Property ◽  
Π Stacking Interaction ◽  
Ft Ir

Ursolic acid (UA) as a natural ursane-triterpenoid has rich pharmacological activities. We have found that it possesses aggregation properties and could self-assemble into organogels. Based on the aggregation property of ursolic acid in suitable solvents, its derivative appended with aromatic rings by amide groups was synthesized. The property of self-assembly into organogel was studied in this paper. The results revealed that this derivative could form supramolecular gel in halogenated benzene and also gelate chloroform in the presence of toluene or p-xylene. By Fourier-transform infrared spectra (FT-IR) and variable temperature proton nuclear magnetic resonance (1H NMR), it was proved that intermolecular hydrogen bonding and π–π stacking interaction were the primary driving forces for the aggregation to form organogel.

Self-Assembly of Hydrogels From Elastin-Mimetic Block Copolymers

2002 ◽  
Vol 724 ◽  
Author(s):  
Elizabeth R. Wright ◽  
R. Andrew McMillan ◽  
Alan Cooper ◽  
Robert P. Apkarian ◽  
Vincent P. Conticello
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Triblock Copolymers ◽  
Variable Temperature ◽  
Inverse Temperature ◽  
Temperature Transition ◽  
Scanning Calorimetry ◽  
Design Synthesis ◽  
Inverse Temperature Transition ◽  
Functional Biomaterials

AbstractTriblock copolymers have traditionally been synthesized with conventional organic components. However, triblock copolymers could be synthesized by the incorporation of two incompatible protein-based polymers. The polypeptides would differ in their hydrophobicity and confer unique physiochemical properties to the resultant materials. One protein-based polymer, based on a sequence of native elastin, that has been utilized in the synthesis of biomaterials is poly (Valine-Proline-Glycine-ValineGlycine) or poly(VPGVG) [1]. This polypeptide has been shown to have an inverse temperature transition that can be adjusted by non-conservative amino acid substitutions in the fourth position [2]. By combining polypeptide blocks with different inverse temperature transition values due to hydrophobicity differences, we expect to produce amphiphilic polypeptides capable of self-assembly into hydrogels. Our research examines the design, synthesis and characterization of elastin-mimetic block copolymers as functional biomaterials. The methods that are used for the characterization include variable temperature 1D and 2D High-Resolution-NMR, cryo-High Resolutions Scanning Electron Microscopy and Differential Scanning Calorimetry.

Stochastic Computing via In Operando Modulation of Rectification in Molecular Tunneling Junctions

2020 ◽  
Author(s):  
Xinkai Qiu ◽  
Sylvia Rousseva ◽  
Gang Ye ◽  
Jan C. Hummelen ◽  
Ryan Chiechi
Keyword(s):  
Self Assembly ◽  
Variable Temperature ◽  
Self Assembled Monolayers ◽  
Microfluidic Channels ◽  
Proof Of Concept ◽  
Glycol Ethers ◽  
Stochastic Computing ◽  
Assembled Monolayers ◽  
In Operando ◽  
Tunneling Junctions

This paper describes the reconfiguration of molecular tunneling junctions during operation via the self-assembly of bilayers of glycol ethers. We use well-established functional groups to modulate the magnitude and direction of rectification in assembled tunneling junctions by exposing them to solutions containing different glycol ethers. Variable-temperature measurements establish that rectification occurs by a bias-dependent tunneling-hopping mechanism and that glycol ethers, beside being an unusually efficient tunneling medium, behave identically to alkanes. We fabricated memory bits from crossbar junctions prepared by injecting eutectic Ga-In into microfluidic channels. Two 8-bit registers were able to perform logical AND operations on bit strings encoded into chemical packets as microfluidic droplets that alter the composition of the crossbar junctions through self-assembly to effect memristor-like properties. This proof of concept work demonstrates the potential for fieldable molecular-electronic devices based on tunneling junctions of self-assembled monolayers and bilayers.

Synthesis of PMMA-b-PS Block Copolymer by Emulsion ATRP and its Self-Assembly Property

2013 ◽  
Vol 705 ◽  
pp. 115-119
Author(s):  
Bao Yong Tian ◽  
Er Jun Tang ◽  
Miao Yuan ◽  
Rui Xia Hao ◽  
Cun Man Li ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Block Copolymer ◽  
Self Assembly ◽  
Potential Application ◽  
Morphological Characteristic ◽  
Living Polymerization ◽  
The Self ◽  
Emulsion System ◽  
Copolymer Concentration ◽  
Ft Ir

The well-defined block copolymer PMMA-b-PS was prepared by two-step ATRP in emulsion system. GPC results indicate that Mn increased linearly with conversion and polydispersity remained relatively narrow. It presents the characteristics of living polymerization in emulsion system. FT-IR demonstrated that block copolymer PMMA-b-PS could be successfully synthesized by ATRP with macroinitiator PMMA-Cl in emulsion system. The morphological characteristic of the self-assembly depends on the block copolymer concentration and transforms between spheres and rodlike micelles. The property indicates a perfect potential application in drug delivery materials.

Estimating the shape and size of supramolecular assemblies by variable temperature diffusion ordered spectroscopy

2014 ◽  
Vol 12 (40) ◽  
pp. 7932-7936 ◽  
Author(s):  
Benjamin M. Schulze ◽  
Davita L. Watkins ◽  
Jing Zhang ◽  
Ion Ghiviriga ◽  
Ronald K. Castellano
Keyword(s):  
Self Assembly ◽  
Variable Temperature ◽  
Supramolecular Assemblies ◽  
The Self ◽  
Conjugated Oligomers ◽  
Photovoltaic Devices ◽  
Temperature Diffusion ◽  
Shape And Size

Reported is characterization of the self-assembly of π-conjugated oligomers, molecules studied recently in photovoltaic devices, using variable temperature diffusion ordered spectroscopy; the approach has allowed estimation of assembly size, shape, and molecularity.

Microwave-assisted solvent-free synthesis and spectral and structural characterization of cyclotriphosphazene hexakis(o-tolylamide)

2018 ◽  
Vol 73 (12) ◽  
pp. 999-1003 ◽  
Author(s):  
Mohammad Hakimi ◽  
Homeyra Rezaei ◽  
Keyvan Moeini ◽  
Heidar Raissi ◽  
Vaclav Eigner ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Microwave Irradiation ◽  
Stacking Interactions ◽  
X Ray Diffraction ◽  
Aromatic Rings ◽  
X Ray ◽  
Microwave Assisted ◽  
Ft Ir ◽  
Solvent Free Synthesis

AbstractA new cyclotriphosphazene, 2,2,4,4,6,6-hexakis (o-tolylamono)-1,3,5,2λ5,4λ5,6λ5-triazatriphosphinine (MPAP), was prepared using microwave irradiation and identified by elemental analysis, FT-IR, Raman, 31P NMR spectroscopy, and single-crystal X-ray diffraction. In the crystal, in addition to hydrogen bonds, the network is further stabilized by inter- and intramolecular π–π stacking interactions between aromatic rings.

Driving Forces for Layer-by-Layer Self-Assembly of Films of SiO2Nanoparticles and Heme Proteins

Langmuir ◽  
2004 ◽  
Vol 20 (3) ◽  
pp. 722-729 ◽  
Author(s):  
Pingli He ◽  
Naifei Hu ◽  
James F. Rusling
Keyword(s):  
Self Assembly ◽  
Heme Proteins ◽  
Driving Forces ◽  
Layer By Layer

scholarly journals ISOLATION OF 2-CHLOROBENZIMIDAZOLE FROM MELIA DUBIA LEAF EXTRACT AND ITS STRUCTURAL CHARACTERISATION

2017 ◽  
Vol 9 (10) ◽  
pp. 67 ◽  
Author(s):  
G. Dayana Jeyaleela ◽  
S. Irudaya Monisha ◽  
J. Rosaline Vimala ◽  
A. Anitha Immaculate
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr ◽  
Research Work ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Ft Ir ◽  
Uv Visible ◽  
Isolated Compound ◽  
Promising Source

Objective: Natural products from medicinal plants, either as isolated compounds or as standardized plant extracts exhibit promising source of medicinal activity against various diseases. The aim of the present work was to make an attempt of isolation of bioactive principle and characterization of the isolated compound, from the medicinal plant Melia dubaiMethods: The extraction was done by a cold percolation method and the compound was separated and isolated by chromatography technique such as a thin layer chromatography (TLC), column chromatography and high-performance liquid chromatography (HPLC). The isolated compound was crystallized and the structural characterization of the isolated compound was made using UV-Visible, FT-IR, 1H-NMR, GC-MS and MS techniques which confirmed the structure of the isolated compound.Results: The separated and isolated compound was characterized by both physical and spectral methods like Ultraviolet-Visible spectroscopy (UV-Visible), Fourier transform infrared spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), Gas chromatography-mass spectrometry (GC-MS), and Mass spectrometry(MS). Based on the studies, organizational characteristics of one bioactive principle were deciphered. The results revealed that the isolated species is 2-chlorobenzimidazole and it agreed well with the reported value and spectra for 2-chlorobenzimidazole.Conclusion: The above results obtained in this research work clearly indicated the promising occurrence of 2-chlorobenzimidazole in Media dubia plant leaves. The future scope of these studies may guide us to view the biological activity of the isolated compound.

scholarly journals SYNTHESIS OF AN AZIDE–THIOL LINKER FOR HETEROGENEOUS POLYMER FUNCTIONALIZATION VIA THE “CLICK” REACTION

2018 ◽  
Vol 55 (1B) ◽  
pp. 152
Author(s):  
Thuy Thu Truong
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Click Reaction ◽  
Proton Nuclear Magnetic Resonance ◽  
Reaction Yield ◽  
Reaction Conditions ◽  
Click Reactions ◽  
Heterogeneous Polymer ◽  
Ft Ir ◽  
First Time ◽  
Layer Chromatography

In this study, the synthesis of a telechelic linker bearing both azide and thiol functional groups was described. The reaction conditions were investigated to optimize the reaction yield. The product was analyzed using thin layer chromatography (TLC) and proton nuclear magnetic resonance (1H NMR). The employment of the obtained azide–thiol linker in heterogeneous polymer “click” functionalization was demonstrated for the first time, which was monitored by an online FT–IR method. The obtained telechelic azide–thiol linker is envisioned to be useful chemical tools to link macromolecular chains via orthogonal click reactions.

scholarly journals Synthesis, Characterization and Properties of Antibacterial Polyurethanes

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 213
Author(s):  
Jihua Duan ◽  
Guichang Jiang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Gray Mold ◽  
Proton Nuclear Magnetic Resonance ◽  
Step Method ◽  
Chemical Structures ◽  
Physically Crosslinked ◽  
Scanning Electron

Novel physically crosslinked polyurethane (PUII), based on isophorone diisocyanates, was prepared by a conventional two-step method. The chemical structures of the PUII were characterized by fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), scanning electron microscopy (SEM) and DSC. The PUII hydrogels were subjected to solvent-induced self-assembly in THF + water to construct a variety of morphologies. The self-assembly morphology of the PUII was observed by scanning electron microscopy (SEM). The PUII films with different amounts (0.2%, 0.4%, 0.6%, 0.8%, 1.0%) of 1,3,5-Tris(2-hydroxyethyl)hexahydro-1,3,5-triazine (TNO) were challenged with Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Gray mold. The results showed that when a small amount of antibacterial agent were added, the antibacterial effect of films on Botrytis cinerea was more obvious. The mechanical evaluation shows that the antimicrobial polyurethane films exhibit good mechanical properties.

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