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ChemistryOpen

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https://www.readbyqxmd.com/read/30003007/transformation-and-stability-of-n-nitrodiethanolamine-dinitrate-nitration-liquid-system-under-thermal-and-mechanical-stimulation
#1
Jing Zhou, Li Ding, Xiaofeng Wang, Yanlong Zhu, Bozhou Wang, Junlin Zhang
To obtain a deeper understanding of the process involved in the synthesis of N -nitrodiethanolamine dinitrate (DINA), in this work we carried out systematic studies on the transformation and stability of the N -nitration liquid and DINA. The thermal decomposition processes and dynamic characteristics for both the N -nitration liquid and DINA were carried out by thermal analysis methods and the mechanism for the decrease of stability of the N -nitration liquid was proposed according to experimental results. Mechanical stimulation of the N -nitration liquid and DINA were also studied by friction and impact sensitivity testing...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003006/direct-access-by-mechanochemistry-or-sonochemistry-to-protonated-merocyanines-components-of-a-four-state-molecular-switch
#2
Melwin Colaço, Andrea Carletta, Mégane Van Gysel, Koen Robeyns, Nikolay Tumanov, Johan Wouters
Direct access to the protonated merocyanine forms of two substituted spiropyrans by mechanosynthesis or sonochemistry was explored. The compounds were formed by the condensation reaction of the methyleneindolium iodide salt with salicylaldehyde derivatives. X-ray crystallography, 1 H NMR spectroscopy, ab initio geometry optimization, and absorption spectroscopy were combined to provide a better understanding of the four-state molecular switch system in which the newly synthesized protonated merocyanines were found to play a central role...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003005/understanding-the-molecular-structure-of-the-sialic-acid-phenylboronic-acid-complex-by-using-a-combined-nmr-spectroscopy-and-dft-study-toward-sialic-acid-detection-at-cell-membranes
#3
Shoichi Nishitani, Yuki Maekawa, Toshiya Sakata
The origin of the unusually high stability of the sialic acid (SA) and phenylboronic acid (PBA) complex was investigated by a combined nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) study. SA is a glycan-terminating monosaccharide, and its importance as a clinical target has long been recognized. Inspired by the fact that the binding properties of SA-PBA complexation are anomalously high relative to those of typical monosaccharides, great effort has been made to build a clinical platform with the use of PBA as a SA-selective receptor...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003004/partial-substitution-of-potassium-with-sodium-in-the-k-2-ti-2-po-4-3-langbeinite-type-framework-synthesis-and-crystalline-structure-of-k-1-75-na-0-25-ti-2-po-4-3
#4
Igor V Zatovsky, Nataliia Yu Strutynska, Yuriy A Hizhnyi, Sergiy G Nedilko, Nickolai S Slobodyanik, Nickolai I Klyui
The interaction of TiN with Na2 O-K2 O-P2 O5 melts was investigated at (Na+K)/P molar ratios of 0.9, 1.0, and 1.2 and at Na/K molar ratios of 1.0 and 2.0. Interactions in the system led to the loss of nitrogen and the partial loss of phosphorus and resulted in the formation of KTiP2 O7 and langbeinite-type K2- x Na x Ti2 (PO4 )3 ( x= 0.22-0.26) solid solutions over the temperature range of 1173 to 1053 K. The phase compositions of the obtained samples were determined by using X-ray diffraction (including Rietveld refinement), scanning electron microscopy (using energy-dispersive X-ray spectroscopy and element mapping), FTIR spectroscopy, and thermogravimetric analysis/differential thermal analysis...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003003/synthesis-and-characterization-of-novel-fluoro-glycosylated-porphyrins-that-can-be-utilized-as-theranostic-agents
#5
Katriann Arja, Mathias Elgland, Hanna Appelqvist, Peter Konradsson, Mikael Lindgren, K Peter R Nilsson
Small molecules with modalities for a variety of imaging techniques as well as therapeutic activity are essential, as such molecules render opportunities to simultaneously conduct diagnosis and targeted therapy, so called theranostics. In this regard, glycoporphyrins have proven useful as theranostic agents towards cancer, as well as noncancerous conditions. Herein, the synthesis and characterization of heterobifunctional glycoconjugated porphyrins with two different sugar moieties, a common monosaccharide at three sites, and a 2-fluoro-2-deoxy glucose (FDG) moiety at the fourth site are presented...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003002/exploring-the-interactions-of-oxygen-with-defective-zno
#6
Xuan Wang, Bin Lu, Ling Li, Hengshan Qiu
Exploring the interactions of oxygen with defective oxide is of importance to understand the microscopic process and performance of ZnO-based oxygen sensors. The interactions of environmental oxygen with vacuum-annealed defective ZnO have been studied by electrical methods, vacuum Fourier transform infrared spectroscopy, and in situ adsorption experiments. It was found that the vacuum-annealed defective ZnO exhibits varied electrical response at different temperatures, which, by vacuum IR investigation, was ascribed to the subtle balance between formation of oxygen vacancies and their interactions with environmental oxygen...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/30003001/synthesis-and-characterization-of-novel-fluoro-glycosylated-porphyrins-that-can-be-utilized-as-theranostic-agents
#7
Katriann Arja, Mathias Elgland, Hanna Appelqvist, Peter Konradsson, Mikael Lindgren, K Peter R Nilsson
Invited for this month's cover picture is the group of Professor Peter Nilsson at the Department of Physics, Chemistry and Biology at Linköping University (Sweden). The cover picture shows a fluoro-glycoporphyrin that selectively targets cancer cells. The selectivity towards cancer cells are afforded due to proper functionalization of the porphyrin scaffold with specific carbohydrates, and the cancer cells can be visualized because of the intrinsic fluorescence from the porphyrin. The molecule also exhibits properties for photodynamic therapy and the incorporation of fluorine, in the form of 2-fluoro-2-deoxy glucose (FDG), offers the possibility to apply these compounds as 18F positron emission tomography (PET) tracers...
July 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29938160/memory-of-chirality-as-a-prominent-pathway-for-the-synthesis-of-natural-products-through-chiral-intermediates
#8
Tomas Hardwick, Nisar Ahmed
The ability of a chiral molecule to be able to transform from one structure to another, whilst remembering its original molecular information by means of an appropriate transition state is an abstract notion that may very well play a key role in important synthetic processes, and has thus attracted a considerable amount of attention among the chemistry community. Here, we have highlighted this concept of "memory of chirality" (MOC) and extended it beyond the case of a simple molecule to larger and more complex natural products...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29938159/hydrogen-bonding-regulates-the-rigidity-of-liposome-encapsulated-chlorin-photosensitizers
#9
Martina De Vetta, Leticia González, Juan J Nogueira
Liposomal formulations facilitate the administration of hydrophobic drugs, avoiding precipitation and aggregation phenomena when injected in polar solvents. The integration of the photosensitizer into the liposome may alter the fluidity of the system and, thus, modify the delivery process of the drug. Such a change has been observed for the liposomal formulation of Temoporfin, which is one of the most potent chlorin photosensitizers employed in photodynamic therapy. Here, all-atom molecular dynamics simulations have been performed to identify the nature of the intermolecular interactions that might be responsible of the different lipids freedom of motion when the drug is introduced in the bilayer...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29938158/a-multiple-stimuli-sensitive-low-molecular-weight-gel-with-an-aggregate-induced-emission-effect-for-sol-gel-transition-detection
#10
Hao Wang, Qihong Liu, Yalong Hu, Miaochang Liu, Xiaobo Huang, Wenxia Gao, Huayue Wu
A low-molecular-weight gel (LMWG) with a hydrazone moiety and an aggregate-induced emission (AIE) unit was fabricated; the self-assembly and disassembly of the LMWG under different stimuli conditions were studied. The LMWG exhibited multiple stimuli sensitivity with temperature, light, ions, and ionic strength. The hydrazone was integrated into the gelator to act as ion sensing sites and hydrogen bond donor groups to fulfil the task of ion recognition of Ni2+ , BH4 - , and OH- , as well as ion-controlled reversible sol-gel recovery by adding H+ for deprotonation; it also broke under UV irradiation to evoke light-sensitivity...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29930893/uranium-vi-complexes-with-a-calix-4-arene-based-8-hydroxyquinoline-ligand-thermodynamic-and-structural-characterization-based-on-calorimetry-spectroscopy-and-liquid-liquid-extraction
#11
Anne Bauer, Astrid Jäschke, Sebastian Schöne, Robert Barthen, Juliane März, Katja Schmeide, Michael Patzschke, Berthold Kersting, Karim Fahmy, Jana Oertel, Vinzenz Brendler, Thorsten Stumpf
The environmental aspects of ore processing and waste treatment call for an optimization of applied technologies. There, understanding of the structure and complexation mechanism on a molecular scale is indispensable. Here, the complexation of UVI with a calix[4]arene-based 8-hydroxyquinoline ligand was investigated by applying a wide range of complementary methods. In solution, the formation of two complex species was proven with stability constants of log  ß 1:1 =5.94±0.02 and log  ß 2:1 =6.33±0.01, respectively...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29930892/the-effect-of-polymer-structures-on-complete-degradation-a-first-principles-study
#12
Yu Zhu, Depeng Zhang, Zhanwen Zhang, Zhigang Wang
The widespread application of hydrocarbon polymer materials has spurred an increasing interest in the study of their dissociation mechanism, which is related to key issues such as environmental protection. In this work, the last-step dissociation characteristics of carbon chain polymers were investigated. By using density functional theory, we considered all possible structures, including three typical normal linkage polymers and four typical abnormal linkage ones. In these structures, it can be found that the energy barrier required for the complete degradation of chain-end saturated and unsaturated polymers are in the range of 3...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29928568/sulfonated-compounds-bind-with-prostatic-acid-phosphatase-pap-248-286-to-inhibit-the-formation-of-amyloid-fibrils
#13
Tingting Zhang, Haikui Yang, Zichao Yang, Suiyi Tan, Jiabin Jin, Shuwen Liu, Jiajie Zhang
The peptide segment of prostatic acid phosphatase (PAP248-286 ) aggregates to form SEVI (semen-derived enhancer of virus infection) amyloid fibrils. These are characteristic seminal amyloids that have the ability to promote the effect of HIV infection. In this paper, we explore the binding of sulfonated compounds with PAP248-286 through an in silico study. Three derivatives of suramin, NF110, NF279, and NF340, are selected. All of these sulfonated molecules bind to PAP248-286 and alter the conformation of the peptide, even though they have various structures, sizes, and configurations...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29928567/solid-phase-synthesis-of-fluorinated-analogues-of-glycosyl-1-phosphate-repeating-structures-from-leishmania-using-the-phosphoramidite-method
#14
Rintaro Iwata Hara, Aya Yaoita, Katsuya Takeda, Hiroaki Ueki, Ayumu Ishii, Hideyuki Imoto, Satoshi Kobayashi, Michi Sano, Mihoko Noro, Kazuki Sato, Takeshi Wada
Bacterial and protozoan sugar chains contain glycosyl 1-phosphate repeating structures; these repeating structures have been studied for vaccine development. The fluorinated analogues of [β-Gal-(1→4)-α-Man-(1→6)-P-] n , which are glycosyl 1-phosphate repeating structures found in Leishmania , were synthesised using the solid-phase phosphoramidite method. This method has been less extensively studied for the synthesis of glycosyl 1-phosphate units than H -phosphonate chemistry. A stepwise synthesis of a compound containing five such repeating units has been conducted using the phosphoramidite method herein, which is the longest glycosyl 1-phosphate structures to be chemically constructed in a stepwise manner...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29928566/modified-calix-4-crowns-as-molecular-receptors-for-barium
#15
Janine Steinberg, David Bauer, Falco Reissig, Martin Köckerling, Hans-Jürgen Pietzsch, Constantin Mamat
A series of modified calix[4]crown-6 derivatives was synthesized to chelate the heavy group 2 metal barium, which serves as a non-radioactive surrogate for radium-223/-224; radionuclides with promising properties for radiopharmaceutical use. These calixcrowns were functionalized with either cyclic amide moieties or with deprotonizable groups, and the corresponding barium complexes were synthesized. Stability constants of these complexes were measured by using NMR and UV/Vis titration techniques to determine log K values of >4...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29928565/modified-calix-4-crowns-as-molecular-receptors-for-barium
#16
Janine Steinberg, David Bauer, Falco Reissig, Martin Köckerling, Hans-Jürgen Pietzsch, Constantin Mamat
Invited for this month's cover picture is the group around Dr. Constantin Mamat at the Institute of Radiopharmaceutical Cancer Research at the Helmholtz-Zentrum Dresden-Rossendorf (Germany) together with Prof. Martin Köckerling from the University of Rostock (Germany). The cover picture shows the ability of special functionalized calix[4]crown-6 derivatives to stably bind group 2 metals like barium. This binding mode is highly important for radiopharmaceutical applications not to lose the respective radiometal in vivo to avoid high background signals and/or false positive results and damages in other tissues...
June 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29872615/chromogenic-and-fluorogenic-probes-for-the-detection-of-illicit-drugs
#17
REVIEW
Eva Garrido, Luis Pla, Beatriz Lozano-Torres, Sameh El Sayed, Ramón Martínez-Máñez, Félix Sancenón
The consumption of illicit drugs has increased exponentially in recent years and has become a problem that worries both governments and international institutions. The rapid emergence of new compounds, their easy access, the low levels at which these substances are able to produce an effect, and their short time of permanence in the organism make it necessary to develop highly rapid, easy, sensitive, and selective methods for their detection. Currently, the most widely used methods for drug detection are based on techniques that require large measurement times, the use of sophisticated equipment, and qualified personnel...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29872614/cascade-reaction-by-chemo-and-biocatalytic-approaches-to-obtain-chiral-hydroxy-ketones-and-anti-1-3-diols
#18
Raffaella Gandolfi, Giorgio Facchetti, Michael S Christodoulou, Marco Fusè, Fiorella Meneghetti, Isabella Rimoldi
A chemo- and biocatalytic cascade approach was applied for the stereoselective synthesis of hydroxy ketones and the corresponding 1,3-diols. A new class of tridentate N,N,O ligands was used with copper(II) complexes for the asymmetric β-borylation of α,β-unsaturated compounds. The complex containing ligand L5 emerged as the best performer, and it gave the organoborane derivatives with good ee values. The corresponding keto-alcohol compounds were then bioreduced by yeasts. The biotransformation set up with Rhodotorula rubra allowed ( R )-keto-alcohols and ( S , S )-diols to be obtained with up to 99 %  ee and up to 99 %  de in favor of the anti enantiomers...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29872613/synthesis-of-novel-aza-aromatic-curcuminoids-with-improved-biological-activities-towards-various-cancer-cell-lines
#19
Atiruj Theppawong, Tim Van de Walle, Charlotte Grootaert, Margot Bultinck, Tom Desmet, John Van Camp, Matthias D'hooghe
Curcumin, a natural compound extracted from the rhizomes of Curcuma longa , displays pronounced anticancer properties but lacks good bioavailability and stability. In a previous study, we initiated structure modification of the curcumin scaffold by imination of the labile β-diketone moiety to produce novel β-enaminone derivatives. These compounds showed promising properties for elaborate follow-up studies. In this work, we focused on another class of nitrogen-containing curcuminoids with a similar objective: to address the bioavailability and stability issues and to improve the biological activity of curcumin...
May 2018: ChemistryOpen
https://www.readbyqxmd.com/read/29872612/coupled-optical-and-electrochemical-probing-of-silver-nanoparticle-destruction-in-a-reaction-layer
#20
Christopher A Little, Christopher Batchelor-McAuley, Kamonwad Ngamchuea, Chuhong Lin, Neil P Young, Richard G Compton
The oxidation of silver nanoparticles is induced to occur near to, but not at, an electrode surface. This reaction at a distance from the electrode is studied through the use of dark-field microscopy, allowing individual nanoparticles and their reaction with the electrode product to be visualized. The oxidation product diffuses away from the electrode and oxidizes the nanoparticles in a reaction layer, resulting in their destruction. The kinetics of the silver nanoparticle solution-phase reaction is shown to control the length scale over which the nanoparticles react...
May 2018: ChemistryOpen
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