3397-16-8Relevant academic research and scientific papers
Compressive Strain Modulation of Single Iron Sites on Helical Carbon Support Boosts Electrocatalytic Oxygen Reduction
Chen, Cai,Du, Junyi,Gu, Lin,Huang, Chun-Xiang,Wang, Lingxiao,Wang, Zhiyuan,Wu, Yuen,Yang, Jia,Yang, Li-Ming,Zhang, Qinghua,Zhang, Yida,Zhang, Ying,Zheng, Xusheng,Zhou, Huang,Zhou, Xiao
, p. 22722 - 22728 (2021)
Designing and modulating the local structure of metal sites is the key to gain the unique selectivity and high activity of single metal site catalysts. Herein, we report strain engineering of curved single atomic iron-nitrogen sites to boost electrocatalytic activity. First, a helical carbon structure with abundant high-curvature surface is realized by carbonization of helical polypyrrole that is templated from self-assembled chiral surfactants. The high-curvature surface introduces compressive strain on the supported Fe?N4 sites. Consequently, the curved Fe?N4 sites with 1.5 % compressed Fe?N bonds exhibit downshifted d-band center than the planar sites. Such a change can weaken the bonding strength between the oxygenated intermediates and metal sites, resulting a much smaller energy barrier for oxygen reduction. Catalytic tests further demonstrate that a kinetic current density of 7.922 mA cm?2 at 0.9 V vs. RHE is obtained in alkaline media for curved Fe?N4 sites, which is 31 times higher than that for planar ones. Our findings shed light on modulating the local three-dimensional structure of single metal sites and boosting the catalytic activity via strain engineering.
Amide-triazole isosteric substitution for tuning self-assembly and incorporating new functions into soft supramolecular materials
Bachl, Jürgen,Mayr, Judith,Sayago, Francisco J.,Cativiela, Carlos,Díaz Díaz, David
, p. 5294 - 5297 (2015)
The proof-of-concept for the modular synthesis of new functional soft gel materials based on amide-triazole isosteric replacement has been demonstrated. A coassembly approach of isosteric amino acid-based hydrogelators was fruitfully applied for fine-tuning the release of entrapped drugs. This journal is
Incorporation of graphene into photopolymerizable hydrogels of N-acyl glutanamides: Rheological and swelling behavior study of soft nanocomposite materials
Delbecq, Frederic,Endo, Hiroshi,Kono, Fumihiko,Kikuchi, Aoi,Kawai, Takeshi
, p. 1064 - 1071 (2013)
Two different respectively N-stearoyl and diacetylenic fatty acyl glutanamide were prepared and employed as both potent low molecular weight hydrogelators (LMWGs). These compounds were able to gelate water at 1.0 wt% of concentration independently of the pH. Due to the presence of two free amino groups on the extremities of the gelator, an aqueous colloidal dispersion of graphene oxide (GO) could be stabilized into the hydrogel matrix simply by ionic bonds. The inclusion of a slightly amount of GO inside the gel networks increased its natural rigidity, confirmed by rheology study. An in-situ reduction of GO afforded after treatment, a semi-transparent hydrogel containing reduced graphene (rGO) that could be easily manipulated without apparent syneresis phenomenon. When the diacetylenic type hydrogel containing GO was irradiated upon UV light, a deep blue coloration change was observed; evidence of an effective photopolymerization. In case of thermal stimulation of the resulted blue polydiacetylene (PDA) hydrogel, the material turned in a red solution precursor of a robust red (PDA) hydrogel at room temperature. This red hydrogel never displayed reversible color change and its swelling behavior was studied at different temperatures. All hydrogels were characterized by different methods such as Field-Emission Scanning Electron Microscopy (FE-SEM) for determining the homogeneity of the gel networks, but also by (FT-IR) Fourier Transform-Infrared spectroscopy and UV-visible measurement.
Inter- and intra-molecular H-bonds induced different nanostructures from a multi-H-bonding (MHB) amphiphile: Nanofibers and nanodisks
Gao, Peng,Zhan, Chuanlang,Liu, Lizhu,Zhou, Yanbiao,Liu, Minghua
, p. 1174 - 1175 (2004)
An MHB amphiphile, N-stearoyl-L-glutamic acid (C18-Glu), forms disk- and fiber-like nanostructures respectively in hydrophilic and hydrophobic environments due to the inter- and intra-molecular H-bonds.
Circularly polarized luminescent systems fabricated by Tr?ger's base derivatives through two different strategies
Qian, Cheng,Chen, Yuan,Zhao, Qian,Cheng, Ming,Lin, Chen,Jiang, Juli,Wang, Leyong
supporting information, p. 52 - 57 (2021/02/01)
The Tr?ger's base derivative rac-TBPP was synthesized and separated into two enantiomers R2N-TBPP and S2N-TBPP by chiral column chromatography. These compounds show a strong circularly polarized luminescence with glum values of +0.0021, and -0.0025, respectively. The second way to fabricate the rac-TBPP-based CPL-active material is to co-gel the fluorescent rac-TBPP with a chiral D-glutamic acid gelator DGG by co-assembly strategy. At the molar ratio of rac-TBPP/DGG = 1:80, the glum value of the co-gel was about three times higher than the glum values of R2N-TBPP and S2N-TBPP enantiomers. Interestingly, the CPL handedness of the rac-TBPP/DGG co-gel could be adjusted effectively by changing their stoichiometric ratios.
Preparation method and application of amido carboxylic acid compound
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Paragraph 0073-0076, (2019/06/05)
The invention discloses a preparation method and application of an amido carboxylic acid compound. The preparation method comprises the step of subjecting organic carboxylic acid with a structure represented by a formula (I) shown in the description and an amino acid compound with a structure represented by a formula (II) shown in the description to a grinding reaction in the presence of a coupling reagent, thereby preparing the amido carboxylic acid compound with a structure represented by a formula (III) shown in the description. The product prepared by the method is high in yield, is energy-saving and environmentally friendly and does not need aftertreatment. According to the application, the amido carboxylic acid compound is applied to mineral flotation separation as a collector, and the collector has relatively high collection capability and relatively good selectivity and is particularly applicable to the flotation separation of minerals such as wolframite, scheelite, rare earthminerals, cassiterite, ilmenite, bauxite, manganese oxide ores, phosphorite and fluorite.
Regulation of the chiral twist and supramolecular chirality in co-assemblies of amphiphilic L-glutamic acid with bipyridines
Zhu, Xuefeng,Duan, Pengfei,Zhang, Li,Liu, Minghua
supporting information; experimental part, p. 3429 - 3437 (2011/05/02)
A series of amphiphilic L-glutamic acid derivatives with various saturated alkyl chains has been designed and their co-assembly with 4,4′-bipyridine in aqueous media has been investigated. While the individual amphiphiles formed hydrogels with water and self-assembled into fine fiber networks, the addition of 4,4′-bipyridine caused significant changes in the co-assembled nanostructures such that twisted chiral ribbons were formed. In these supramolecular systems, either fine structural changes or adjustment of the stoichiometric ratio of the two components had crucial effects on the formation of the chiral twists. Based on detailed investigations by SEM and XRD analyses, FTIR, CD, and UV/Vis spectroscopies, and molecular simulation, it is considered that a delicate synergistic balance between π-π stacking, hydrophobic, and chiral interactions is responsible for the formation of the chiral twists. An interesting sandwich structure, in which an excess of 4,4′-bipyridine is inserted into the space of primary cages constructed from the amphiphile and 4,4′-bipyridine, is proposed. Remarkably, the handedness of these chiral twists is related not only to the chiral center of the glutamic unit, but also the chain length of the alkyl tails. This work provides a deeper understanding of the formation mechanism of chiral twists, and exemplifies a feasible shortcut to the rational design of chiral structures from basic molecular structures to supramolecular systems. Twisted nanostructures: A chiral twist has been obtained through the co-assembly of single-chain L-glutamic acids with bipyridines (see picture). The sandwiching of additional 4,4′-bipyridine within the cage formed by the amphiphile and the bipyridine caused the chiral twist. The dimensions and chirality of the twist could be regulated by adjusting the alkyl chain length of the amphiphile. Copyright
Preparation, characterization, and surface and biological properties of N-stearoyl amino acids
Sivasamy,Krishnaveni,Rao
, p. 897 - 902 (2007/10/03)
Several lipoamino acids were synthesized, in which n-octadecanoic acid (stearic acid) was coupled with the α-amino group of an amino acid. The products were characterized and their identities confirmed by advanced analytical techniques like Fourier transform infrared, 1H nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. Their surface properties, such as critical micelle concentration (CMC) and foaming properties, biodegradability, and antimicrobial activity were also evaluated. The N-stearoyl amino acids (NSA) had low CMC values, and some of them showed good foaming properties. They were screened for antimicrobial activity against the gram-positive bacteria Staphylococcus aureus, Micrococcus luteus, and Bacillus cerceus, the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and the yeast Candida albicans. All the compounds inhibited at least one of these organisms. N-Stearoyl proline was the most effective, the order of antimicrobial activity being aromatic NSA > acidic NSA > basic NSA. However, the effective inhibition by all the compounds indicates the desirability of more thorough investigation and suggests that some of these compounds may have potential utility as biostatic additives in commercial products. All NSA are highly biodegradable and can readily be removed under conditions of normal secondary sewage treatment.
