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https://www.readbyqxmd.com/read/29346728/design-and-assembly-of-chiral-coordination-cages-for-asymmetric-sequential-reactions
#1
Jingjing Jiao, Chunxia Tan, Zijian Li, Yan Liu, Xing Han, Yong Cui
Supramolecular nanoreactors featuring multiple catalytically active sites are of great importance, especially for asymmetric catalysis, are yet challenging to construct. Here we report the design and assembly of five chiral single- and mixed-linker tetrahedral coordination cages using six dicarboxylate ligands derived-from enantiopure Mn(salen), Cr(salen) and/or Fe(salen) as linear linkers and four Cp3Zr3 clusters as three-connected vertices. The formation of these cages was confirmed by a variety of techniques including single-crystal and powder X-ray diffraction, inductively coupled plasma optical emission spectrometer, quadrupole-time of flight mass spectrometry and energy dispersive X-ray spectrometry...
January 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29345923/capped-polyoxometalate-pillars-between-metal-organic-layers-for-transferring-a-supramolecular-structure-into-a-covalent-3d-framework
#2
Yu-Jie Wang, Yang-Yang Zhou, Hong-Guo Hao, Man Song, Na Zhang, Shuang Yao, Jing-Hui Yan, Zhi-Ming Zhang, Tong-Bu Lu
Two robust metal-organic frameworks (MOFs), {H4[Ni(π-H2O)2]2[Ni(rt-H2O)2]8Ni4(Tri)24}[VIVW12O40]2·24H2O (1) and {H[Ni(π-O)2]2[Ni(rt-H2O)2]8Ni4(Tri)24}[VIVW10VV2O40V2][VIVW9VV3O40VIV2]·24H2O (2) (Tri = 1,2,4-triazole), composed of polyoxometalates (POMs) and metal-organic units, were designed and synthesized by a hydrothermal method. Structure analysis indicates that there is a metal-organic crown [{Ni3(Tri)6(H2O)4}4] ({Ni12}) in these two compounds. In 1, the {Ni12} crown embraces four pendant Tri ligands that could capture a cationic [Ni(H2O)2]2+ group, resulting in the Ni13-Tri building unit [Ni(H2O)2{Ni3(Tri)6(H2O)4}4] ({Ni13})...
January 18, 2018: Inorganic Chemistry
https://www.readbyqxmd.com/read/29345265/hierarchical-formation-of-fe-9eg-supramolecular-networks-via-flexible-coordination-bonds
#3
Chi Zhang, Lei Xie, Yuanqi Ding, Chunxue Yuan, Wei Xu
From the interplay between high-resolution scanning tunneling microscopy imaging/manipulations and density functional theory calculations, we display the hierarchical formation of supramolecular networks by codeposition of 9eG molecules and Fe atoms on Au(111) based on the flexible coordination bonds (the adaptability and versatility in the coordination modes). In the first step, homochiral islands composed of homochiral G4Fe2 motifs are formed; and then in the second step, thermal treatment results in the transformation into the porous networks composed of heterochiral G4Fe2 motifs with the ratio of the components being constant...
January 18, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29345067/supramolecular-gels-derived-from-the-salts-of-variously-substituted-phenylacetic-acid-and-dicyclohexyl-amine-design-synthesis-structures-and-dye-adsorption
#4
Parthasarathi Dastidar, Rajdip Roy, Tapas Kumar Adalder
A well-studied supramolecular synthon namely secondary ammonium monocarboxylate (SAM) was exploited to generate a new series of organic salts derived from variously substituted phenylacetic acid (PA) and dicyclohexyl amine (DCA) as potential low molecular weight gelators (LMWGs). As much as 25% of the SAM salts under study were gelators. The gels were characterized by rheology and the morphology of the gel networks was studied by high resolution electron microscopy. Single crystal and powder X-ray diffraction data were employed to study structure-property (gelation) correlation...
January 18, 2018: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/29343452/a-cell-penetrating-peptide-conjugated-carboxymethyl-%C3%AE-cyclodextrin-to-improve-intestinal-absorption-of-insulin
#5
Liuqing Yang, Manman Li, Yusheng Sun, Liefeng Zhang
In this study, a cell-penetrating peptide conjugate, R8-carboxymethyl-β-cyclodextrin (R8-CM-β-CD), was synthesized, and then we prepared the supramolecular complex (insulin/R8-CM-β-CD). The physicochemical properties of the complex were characterized. The supramolecular complex could facilitate the uptake of insulin, meanwhile, induce a significantly higher internalization of insulin. Interestingly, the transportation efficiency of insulin/R8-CM-β-CD across the Caco-2 cell monolayer was about 3 times greater than that of insulin/CM-β-CD...
January 14, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29341377/halogen-bonding-in-solution-from-anion-recognition-through-templated-self-assembly-to-organo-catalysis
#6
Ulrich S Schubert, Ronny Tepper
The halogen bond is a supramolecular interaction between a Lewis-acidic region of a covalently bound halogen and a Lewis base. It has been studied widely in silico and experimentally in the solid state; however, solution phase applications have attracted enormous interest in the last years. This Minireview highlights selected recent developments of halogen bond interactions in solution with focus on the use of halogen bond receptors in anion recognition and sensing, anion templated self-assembly as well as in organo-catalysis...
January 17, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29341288/lipid-and-nucleic-acid-chemistries-combining-the-best-of-both-worlds-to-construct-advanced-biomaterials
#7
REVIEW
Julie Baillet, Valérie Desvergnes, Aladin Hamoud, Laurent Latxague, Philippe Barthélémy
Hybrid synthetic amphiphilic biomolecules are emerging as promising supramolecular materials for biomedical and technological applications. Herein, recent progress in the field of nucleic acid based lipids is highlighted with an emphasis on their molecular design, synthesis, supramolecular properties, physicochemical behaviors, and applications in the field of health science and technology. In the first section, the design and the study of nucleolipids are in focus and then the glyconucleolipid family is discussed...
January 17, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29341264/a-facile-method-to-fabricate-anisotropic-hydrogels-with-perfectly-aligned-hierarchical-fibrous-structures
#8
Md Tariful Islam Mredha, Yun Zhou Guo, Takayuki Nonoyama, Tasuku Nakajima, Takayuki Kurokawa, Jian Ping Gong
Natural structural materials (such as tendons and ligaments) are comprised of multiscale hierarchical architectures, with dimensions ranging from nano- to macroscale, which are difficult to mimic synthetically. Here a bioinspired, facile method to fabricate anisotropic hydrogels with perfectly aligned multiscale hierarchical fibrous structures similar to those of tendons and ligaments is reported. The method includes drying a diluted physical hydrogel in air by confining its length direction. During this process, sufficiently high tensile stress is built along the length direction to align the polymer chains and multiscale fibrous structures (from nano- to submicro- to microscale) are spontaneously formed in the bulk material, which are well-retained in the reswollen gel...
January 17, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29340385/coordination-supramolecular-assemblies-of-a-monohydroxycucurbit-7-uril-and-their-potential-applications-in-gas-sorption
#9
Rui Han Gao, Zi-Yi Hua, Kai Chen, Jing Xu, Qian-Jiang Zhu, Zhu Tao, Jiang-Lin Zhao
Coordination supramolecular assemblies of monohydroxycucurbit[7]uril ((HO)Q[7]) with alkaline earth metal ions (AE2+) have been formed in aqueous HCl solution in the presence of tetrachloride cadmium anions ([CdCl4]2-) as a structure directing agent. The driving force for the assembly could be attributed to the interaction of the positive electro-potential outer-surface of (HO)Q[7] molecules with [CdCl4]2- anions and ionic dipole interaction of the hydroxyl of (HO)Q[7] molecules with [CdCl4]2- anions. Moreover, the porous structure of the (HO)Q[7]/AE2+-based coordination supramolecular assemblies could result in potential applications in the selective sorption of polar volatile organic molecules, which may be useful in molecular sieves, sensors, absorption and separation...
January 17, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29340383/alamethicin-self-assembling-in-lipid-membranes-concentration-dependence-from-pulsed-epr-of-spin-labels
#10
Victoria N Syryamina, Marta De Zotti, Claudio Toniolo, Fernando Formaggio, Sergei A Dzuba
The antimicrobial action of the peptide antibiotic alamethicin (Alm) is commonly related to peptide self-assembling resulting in the formation of voltage-dependent channels in bacterial membranes, which induces ion permeation. To obtain a deeper insight into the mechanism of channel formation, it is useful to know the dependence of self-assembling on peptide concentration. With this aim, we studied Alm F50/5 spin-labeled analogs in a model 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membrane, for peptide-to-lipid (P/L) ratios varying between 1/1500 and 1/100...
January 17, 2018: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29340222/direct-molecular-fishing-of-new-protein-partners-for-human-thromboxane-synthase
#11
A V Svirid, P V Ershov, E O Yablokov, L A Kaluzhskiy, Yu V Mezentsev, A V Florinskaya, T A Sushko, N V Strushkevich, A A Gilep, S A Usanov, A E Medvedev, A S Ivanov
Thromboxane synthase (TBXAS1) catalyzes the isomerization reaction of prostaglandin H2 producing thromboxane A2, the autocrine and paracrine factor in many cell types. A high activity and metastability by these arachidonic acid derivatives suggests the existence of supramolecular structures that are involved in the regulation of the biosynthesis and directed translocation of thromboxane to the receptor. The objective of this study was to identify TBXAS1 protein partners from human liver tissue lysate using a complex approach based on the direct molecular fishing technique, LC-MS/MS protein identification, and protein-protein interaction validation by surface plasmon resonance (SPR)...
October 2017: Acta Naturae
https://www.readbyqxmd.com/read/29339288/hyaluronic-acid-in-pluronic-f-127-f-108-hydrogels-for-postoperative-pain-in-arthroplasties-influence-on-physico-chemical-properties-and-structural-requirements-for-sustained-drug-release
#12
M H M Nascimento, M K K D Franco, F Yokaichyia, E de Paula, C B Lombello, D R de Araujo
In this study, we reported the hyaluronic acid (HA) on supramolecular structure of Pluronic F-127 (PLF-127) and/or Pluronic F-108 (PLF-127) hydrogels, as well as their effects on release mechanisms, looking forward their application as lidocaine (LDC) drug-delivery systems in arthroplastic surgeries. We have studied the HA-micelle interaction using Dynamic Light Scattering (DLS), the micellization and sol-gel transition processes by Differential Scanning Calorimetry (DSC) and Rheology., of PL-based hydrogels and...
January 12, 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/29339187/doxorubicin-loaded-dendritic-fe3o4-supramolecular-nanoparticles-for-magnetic-drug-targeting-and-tumor-regression-in-spheroid-murine-melanoma-model
#13
Saumya Nigam, D Bahadur
This work evaluates the magnetically-guided delivery of DOX-loaded dendritic-Fe3O4 nanoparticles and their tumor regression efficacy in subcutaneous melanoma in C57BL/6 mice. The hematological, biochemical and histopathological parameters were minimally affected. The nanoparticles localized in lungs, liver and spleen suggesting non-specific uptake. However, in tumor-bearing mice, substantially higher localization in magnetically-targeted tumor was observed when compared to passive localization in non-targeted tumor...
January 12, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/29338096/controlling-selectivity-in-aliphatic-c-h-oxidation-via-supramolecular-recognition
#14
Diego Vidal, Giorgio Olivo, Miquel Costas
Aliphatic C-H oxidation is the most attractive approach to functionalize hydrocarbon skeletons. The main challenge of this reaction is the control of regioselectivity since organic molecules contain multiple C-H bonds. This control is perfectly achieved in natural enzymes by means of a web of interactions that orient the substrate in a specific geometry and override intrinsic reactivity patterns. Replication of this control by combination of molecular catalysts and supramolecular recognition is highly desirable in this regard...
January 16, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29337581/light-harvesting-by-equally-contributing-mechanisms-in-a-photosynthetic-antenna-protein
#15
Matthew J Guberman-Pfeffer, Jordan A Greco, Robert Richards Birge, Harry A Frank, José A Gascón
We report supramolecular quantum mechanics/molecular mechanics simulations on the peridinin-chlorophyll a protein (PCP) complex from the causative algal species of red tides. These calculations reproduce for the first time quantitatively the distinct peridinin absorptions, identify multichromophoric molecular excitations, and elucidate the mechanisms regulating the strongly-allowed S0 (11Ag-) → S2 (11Bu+) absorptions of the bound peridinins that span a 58 nm spectral range in the region of maximal solar irradiance...
January 16, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29337563/magic-angle-stacking-and-strong-intermolecular-%C3%AF-%C3%AF-interaction-in-a-perylene-bisimide-crystal-an-approach-for-efficient-near-infrared-nir-emission-and-high-electron-mobility
#16
Jiadong Zhou, Wenqiang Zhang, Xiao-Fang Jiang, Cong Wang, Xuehong Zhou, Biao Xu, Linlin Liu, Zengqi Xie, Yuguang Ma
A single crystal of perylene bisimide possesses novel magic-angle stacking and strong intermolecular π-π interaction is achieved by physical vapor transport (PVT), which shows attractive optoelectronic functions such as efficient NIR emission and high electron mobility. In this special M-type staking, the elimination of long-distance Förster energy transfer enables the minimization of the possible fluorescence quenching, which ensures the highly efficient emission. Moreover, the strong π-π interaction elongates the "supramolecular conjugation" to reduce the energy gap and also benefit the electron mobility of the crystal...
January 16, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29337415/self-healing-in-supramolecular-polymers
#17
REVIEW
Antonella Campanella, Diana Döhler, Wolfgang H Binder
Adaption and self-healing are two major principles in material science, often coupled with the placement of supramolecular moieties within a material. Proper molecular design can enable self-healing within such materials, displaying enormous potential in technology and application. Here, basic physicochemical aspects as well as new material developments in the field are described, published after a recent review in Macromolecular Rapid Communications in 2013.
January 16, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29336518/seeded-polymerization-through-the-interplay-of-folding-and-aggregation-of-an-amino-acid-based-diamide
#18
Soichiro Ogi, Kentarou Matsumoto, Shigehiro Yamaguchi
Amino-acid-based diamides are widely used as a substructure in supramolecular polymers, and also represent key components of polypeptides that help to understand protein folding. Herein, we report that the interplay of folding and aggregation of a diamide can be used to achieve seed-initiated supramolecular polymerization. For that purpose, a pyrene-substituted diamide was synthesized, in which pyrene is used as a tracer to monitor the supramolecular polymerization. Thermodynamic and time-dependent studies revealed that the folding of the diamide moiety, via the formation of intramolecular hydrogen bonds, effectively prevents a spontaneous nucleation that leads to supramolecular polymerization...
January 16, 2018: Angewandte Chemie
https://www.readbyqxmd.com/read/29336510/hierarchy-of-asymmetry-at-work-chain-dependent-helix-to-helix-interactions-in-supramolecular-polymers
#19
Sandra Díaz-Cabrera, Yeray Dorca, Joaquín Calbo, Juan Aragó, Rafael Gómez, Enrique Ortí, Luis- Sanchez
A detailed investigation of the hierarchy of asymmetry operating in the self-assembly of achiral (1) and chiral ((S)-2 and (R)-3) 1,3,5-triphenylbenzenetricarboxamides (TPBAs) is reported. The aggregation of these TPBAs is conditioned by the point chirality at the peripheral side chains for (S)-2 and (R)-3. An efficient helix-to-helix interaction that goes further in the organization of fibrillar bundles has been experimentally detected and theoretically supported only for the achiral TPBA 1. The effective interdigitation of the achiral aliphatic side chains produces a social self-sorting to form preferentially heterochiral macromolecular aggregates...
January 16, 2018: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29336146/coordination-triggered-hierarchical-folate-zinc-supramolecular-hydrogels-leading-to-printable-biomaterials
#20
Kaerdun Liu, Shihao Zang, Rongrong Xue, Jinghui Yang, Lizhi Wang, Jianbin Huang, Yun Yan
Printable hydrogels desired in bioengineering have extremely high demands on biocompatibility and mechanic strength, which can hardly be achieved in conventional hydrogels made with biopolymers. Here we show that on employment of the strategy of coordination triggered hierarchical self-assembly of naturally occurred small molecule folic acid, supramolecular hydrogels with robust mechanical elastic modulus comparable to synthetic double network (DN) polymer gels can be made at concentrations below 1 %. A sequence of hierarchical steps are involved in the formation of this extraordinary hydrogel: petrin rings on folate form tetramers through hydrogen bonding, tetramers stack into nanofibers by π-π stacking, zinc ions cross-link the nanofibers into larger scale fibrils, and further crosslink the fibril network to gel water...
January 16, 2018: ACS Applied Materials & Interfaces
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