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Yang Yang, Anhe Wang, Qiang Wei, Cathleen Schlesener, Rainer Haag, Qi Li, Junbai Li
Mesoporous silica-based nanoparticles are generally accepted as a potential platform for drug loading with a lot of advantages, except for their complex purification procedures and structures that are difficult to decompose. In this work, biocompatible hyperbranched polyglycerol is introduced to synthesize mesoporous silica nanoparticles (MSNs). The materials possess good biocompatibility, controlled release, and biodegradability. They also show passive targeting capability through the enhanced permeability and retention effect and can be excreted from the biological system...
February 2017: ChemistryOpen
Saroj Kumar, Xia Liu, Ferenc Borondics, Qunfeng Xiao, Renfei Feng, Erik Goormaghtigh, Fredrik Nikolajeff
The microenvironment of a tumor changes chemically and morphologically during cancer progression. Cancer-stimulated fibroblasts promote tumor growth, however, the mechanism of the transition to a cancer-stimulated fibroblast remains elusive. Here, the multi-modal spectroscopic methods Fourier transform infrared imaging (FTIRI), X-ray absorption spectroscopy (XAS) and X-ray fluorescence imaging (XFI) are used to characterize molecular and atomic alterations that occur in cancer-stimulated fibroblasts. In addition to chemical changes in lipids (olefinic and acyl chain) and protein aggregation observed with FTIRI, a new infrared biomarker for oxidative stress in stimulated fibroblasts is reported...
February 2017: ChemistryOpen
Kai Schütte, Juri Barthel, Manuel Endres, Marvin Siebels, Bernd M Smarsly, Junpei Yue, Christoph Janiak
Decomposition of transition-metal amidinates [M{MeC(NiPr)2} n ] [M(AMD) n ; M=Mn(II), Fe(II), Co(II), Ni(II), n=2; Cu(I), n=1) induced by microwave heating in the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate (triflate) ([BMIm][TfO]), and 1-butyl-3-methylimidazolium tosylate ([BMIm][Tos]) or in propylene carbonate (PC) gives transition-metal nanoparticles (M-NPs) in non-fluorous media (e...
February 2017: ChemistryOpen
Ileana Guzzetti, Monica Civera, Francesca Vasile, Daniela Arosio, Cristina Tringali, Umberto Piarulli, Cesare Gennari, Luca Pignataro, Laura Belvisi, Donatella Potenza
The interaction of a small library of cyclic DKP-RGD peptidomimetics with α5β1 integrin has been investigated by means of an integrated experimental and computational approach. Bioaffinity NMR techniques, including saturation transfer difference (STD) and transferred NOESY, were applied to the ligands in a suspension of intact MDA-MB-231 breast cancer cells, in which integrin α5β1 is highly expressed. The NMR data were compared with the docking calculations of the RGD ligands in the crystal structure of the α5β1 binding site, and were integrated with competitive binding assays to the purified α5β1 integrin...
February 2017: ChemistryOpen
Ettore Fazio, Javier Jaramillo-García, María Medel, Maxence Urbani, Michael Grätzel, Mohammad K Nazeerudin, Gema de la Torre, Tomas Torres
Unique donor-π-acceptor phthalocyanines have been synthesized through the asymmetric functionalization of an ABAB phthalocyanine, crosswise functionalized with two iodine atoms through Pd-catalyzed cross-coupling reactions with adequate electron-donor and electron-acceptor moieties. These push-pull molecules have been optically and electrochemically characterized, and their ability to perform as chromophores for dye-sensitized solar cells has been tested.
February 2017: ChemistryOpen
Mohamed E Assal, Mufsir Kuniyil, Mujeeb Khan, Abdulrahman Al-Warthan, Mohammed Rafiq H Siddiqui, Wolfgang Tremel, Muhammad Nawaz Tahir, Syed Farooq Adil
We report on the synthesis of the zirconia-manganese carbonate ZrOx(x   %)-MnCO3 catalyst (where x=1-7) that, upon calcination at 500 °C, is converted to zirconia-manganese oxide ZrOx(x   %)-Mn2O3 . We also present a comparative study of the catalytic performance of the both catalysts for the oxidation of benzylic alcohol to corresponding aldehydes by using molecular oxygen as the oxidizing agent. ZrOx(x   %)-MnCO3 was prepared through co-precipitation by varying the amounts of Zr(NO3)4 (w/w %) in Mn(NO3)2...
February 2017: ChemistryOpen
Xingrui He, Xia Chen, Songbo Lin, Xiaochang Mo, Pengyong Zhou, Zhihao Zhang, Yaoyao Lu, Yu Yang, Haining Gu, Zhicai Shang, Yonggen Lou, Jun Wu
Natural products are a major source of biological molecules. The 3-methylfuran scaffold is found in a variety of plant secondary metabolite chemical elicitors that confer host-plant resistance against insect pests. Herein, the diversity-oriented synthesis of a natural-product-like library is reported, in which the 3-methylfuran core is fused in an angular attachment to six common natural product scaffolds-coumarin, chalcone, flavone, flavonol, isoflavone and isoquinolinone. The structural diversity of this library is assessed computationally using cheminformatic analysis...
February 2017: ChemistryOpen
Alessio Paternò, Laura Goracci, Salvatore Scire, Giuseppe Musumarra
In the field of ionic liquids (ILs), theory-driven modeling approaches aimed at the best fit for all available data by using a unique, and often nonlinear, model have been widely adopted to develop quantitative structure-property relationship (QSPR) models. In this context, we propose chemoinformatic and chemometric data-driven procedures that lead to QSPR soft models with local validity that are able to predict relevant physicochemical properties of ILs, such as viscosity, density, decomposition temperature, and conductivity...
February 2017: ChemistryOpen
Yuichiro Ashida, Atsushi Honda, Yuka Sato, Hidefumi Nakatsuji, Yoo Tanabe
A highly substrate-general synthesis of all-carbon-substituted E- and Z-stereodefined olefins is performed. The method comprises two sets of parallel and stereocomplementary preparations of (E)- and (Z)-α,β-unsaturated esters involving two robust and distinctive reactions: 1) stereocomplementary enol tosylations using readily available TsCl/diamine/(LiCl) base reagents, and 2) stereoretentive Negishi cross-coupling using the catalysts [Pd(dppe)Cl2] (for E) and [Pd(dppb)Cl2] (for Z). The present parallel approach is categorized as both type I (convergent approach: 16 examples, 56-87 % yield) and type II (divergent approach: 18 examples, 70-95 % yield)...
February 2017: ChemistryOpen
Guido Orlandini, Giulio Ragazzon, Valeria Zanichelli, Lorenzo Degli Esposti, Massimo Baroncini, Serena Silvi, Margherita Venturi, Alberto Credi, Andrea Secchi, Arturo Arduini
Tris-(N-phenylureido)-calix[6]arene derivatives are heteroditopic non-symmetric molecular hosts that can form pseudorotaxane complexes with 4,4'-bipyridinium-type guests. Owing to the unique structural features and recognition properties of the calix[6]arene wheel, these systems are of interest for the design and synthesis of novel molecular devices and machines. We envisaged that the incorporation of photoactive units in the calixarene skeleton could lead to the development of systems the working modes of which can be governed and monitored by means of light-activated processes...
February 2017: ChemistryOpen
Aminu K Rabiu, Peter S Toth, Andrew N J Rodgers, Robert A W Dryfe
There is much interest in understanding the interfacial properties of carbon nanotubes, particularly at water/oil interfaces. Here, the adsorption of single-wall carbon nanotubes (SWCNTs) at the water/1,2-dichloroethane (DCE) interface, and the subsequent investigation of the influence of the adsorbed nanotube layer on interfacial ion transfer, is studied by using the voltammetric transfer of tetramethylammonium (TMA(+)) and hexafluorophosphate (PF6(-)) as probe ions. The presence of the interfacial SWCNT layer significantly suppresses the transfer of both ions across the interface, with a greater degree of selectivity towards the PF6(-) ion...
February 2017: ChemistryOpen
Aleksandra Kasprowicz, Kamila Stokowa-Sołtys, Małgorzata Jeżowska-Bojczuk, Jan Wrzesiński, Jerzy Ciesiołka
Here, we describe the characterization of new RNA-cleaving DNAzymes that showed the highest catalytic efficiency at pH 4.0 to 4.5, and were completely inactive at pH values higher than 5.0. Importantly, these DNAzymes did not require any divalent metal ion cofactors for catalysis. This clearly suggests that protonated nucleic bases are involved in the folding of the DNAzymes into catalytically active structures and/or in the cleavage mechanism. The trans-acting DNAzyme variants were also catalytically active...
February 2017: ChemistryOpen
Mengxing Zhang, Huijun Guo, Lidong Zhang
The ionization of aromatic ethylamines by photons or electrons leads to elimination of CH2NH fragments, supposedly deriving from the McLafferty rearrangement involving intramolecular γ-hydrogen transfer. Using tryptamine and phenethylamine as examples, the results reported here suggest that the McLafferty mechanism is inadequate for interpreting the observations of CH2NH elimination due to much higher calculated appearance energy than experimentally measured values. Furthermore, by considering the roaming-mediated effect, the calculated appearance energy for the elimination of CH2NH fragments is reduced and matches well with the experimental results and verifies the existence of roaming-mediated effect...
February 2017: ChemistryOpen
Alessandro Angelin, Olivier Kassel, Sepand Rastegar, Uwe Strähle, Christof M Niemeyer
The unique structure-directing properties of DNA origami nanostructures (DONs) show great potential to specifically manipulate intracellular processes. We report an innovative concept to selectively activate the transcription of a single gene in the developing zebrafish embryo. We reason that engineering a designer transcription factor in which a rigid DON imposes a fixed distance between the DNA-binding domain (DBD) and the transactivation domain (TAD) would allow the selective activation of a gene harboring the same distance between the corresponding transcription factor binding site and the core promoter...
February 2017: ChemistryOpen
Toribio F Otero, Lluis X Martinez-Soria, Johanna Schumacher, Laura Valero, Victor H Pascual
Thick films of polypyrrole/polyvinylsulfate (PPy/PVS) blends were electrogenerated on stainless-steel electrodes under potentiostatic conditions from aqueous solution. The best electropolymerization potential window was determined by cyclic voltammetry. After removing the film from the back metal, self-supported electrodes were obtained. Voltammetric, coulovoltammetric, and chronoamperometric responses from a LiClO4 aqueous solution indicated the formation of an energetically stable structure beyond a reduction threshold of the material...
February 2017: ChemistryOpen
Peng-Hua Li, Jin-Ming Yang, Yin Wei, Min Shi
An interesting silver(I)-catalyzed, one-pot intramolecular cyclization of epoxide-propargylic esters is described. A variety of 1,4-oxazine derivatives were obtained through a novel domino sequence, including three-membered ring-opening, 3,3-sigmatropic rearrangement, 6-exo-cycloisomerization and subsequent intramolecular elimination in moderate yields under mild conditions.
February 2017: ChemistryOpen
Natalia Soldatova, Pavel Postnikov, Olga Kukurina, Viktor V Zhdankin, Akira Yoshimura, Thomas Wirth, Mekhman S Yusubov
A straightforward synthesis of diaryliodonium salts is achieved by using Oxone as the stoichiometric oxidant. Slow addition is the key to obtaining good yields and purities of the reaction products, which are highly useful reagents in many different areas of organic synthesis.
February 2017: ChemistryOpen
Jeanet Conradie, Abhik Ghosh
Two-component relativistic time-dependent density functional theory calculations with spin-orbit coupling predict yellow and orange-red absorption for BiPh5 and BiMe5, respectively, providing an excellent explanation for their respective violet and blue-violet colors. According to the calculations, the visible absorption is clearly attributable to a single transition from a ligand-based HOMO to a low-energy LUMO with a significant contribution from a relativistically stabilized Bi 6s orbital. Surprisingly, scalar releativistic calculations completely fail to reproduce the observed visible absorption and place it at the violet/near-UV borderline instead...
February 2017: ChemistryOpen
Emilia Oueis, Brunello Nardone, Marcel Jaspars, Nicholas J Westwood, James H Naismith
Natural products comprise a diverse array of molecules, many of which are biologically active. Most natural products are derived from combinations of polyketides, peptides, sugars, and fatty-acid building blocks. Peptidic macrocycles have attracted attention as potential therapeutics possessing cell permeability, stability, and easy-to-control variability. Here, we show that enzymes from the patellamide biosynthetic pathway can be harnessed to make macrocycles that are hybrids of amino acids and a variety of manmade chemical building blocks, including aryl rings, polyethers, and alkyl chains...
February 2017: ChemistryOpen
Rosaria Ciriminna, Mina Ghahremani, Babak Karimi, Mario Pagliaro
The electrocatalytic oxidation of alcohols mediated by TEMPO-like nitroxyl radicals is an economically and industrially viable method that will shortly find commercial application in the synthesis of valued substances including active pharmaceutical ingredients (APIs), valued natural product derivatives, fine chemicals, and valued nanomaterials.
February 2017: ChemistryOpen
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