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161.
Postsynthetic Improvement of the Physical Properties in a Metal–Organic Framework through a Single Crystal to Single Crystal Transmetallation
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Thais Grancha Dr. Jesús Ferrando‐Soria Prof. Dr. Hong‐Cai Zhou Prof. Dr. Jorge Gascon Dr. Beatriz Seoane Dr. Jorge Pasán Dr. Oscar Fabelo Prof. Dr. Miguel Julve Dr. Emilio Pardo 《Angewandte Chemie (International ed. in English)》2015,54(22):6521-6525
A single crystal to single crystal transmetallation process takes place in the three‐dimensional (3D) metal–organic framework (MOF) of formula MgII2{MgII4[CuII2(Me3mpba)2]3}?45 H2O ( 1 ; Me3mpba4?=N,N′‐2,4,6‐trimethyl‐1,3‐phenylenebis(oxamate)). After complete replacement of the MgII ions within the coordination network and those hosted in the channels by either CoII or NiII ions, 1 is transmetallated to yield two novel MOFs of formulae Co2II{CoII4[CuII2(Me3mpba)2]3}?56 H2O ( 2 ) and Ni2II{NiII4[CuII2(Me3mpba)2]3}? 54 H2O ( 3 ). This unique postsynthetic metal substitution affords materials with higher structural stability leading to enhanced gas sorption and magnetic properties. 相似文献
162.
Synthesis of an [(NHC)2Pd(SiMe3)2] Complex and Catalytic cis‐Bis(silyl)ations of Alkynes with Unactivated Disilanes
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Melvyn B. Ansell Dr. Debbie E. Roberts Prof. F. Geoffrey N. Cloke Dr. Oscar Navarro Dr. John Spencer 《Angewandte Chemie (International ed. in English)》2015,54(19):5578-5582
The novel complex cis‐[(ITMe)2Pd(SiMe3)2 (ITMe=1,3,4,5‐tetramethylimidazol‐2‐ylidene) has been synthesized by mild oxidative cleavage of Me3SiSiMe3 using [(ITMe)2Pd0]. The use of this complex as precatalyst for the cis‐bis(silyl)ation of alkynes using unactivated disilanes is reported. 相似文献
163.
The Synthesis of B2(SIDip)2 and its Reactivity Between the Diboracumulenic and Diborynic Extremes
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Julian Bhnke Holger Braunschweig Theresa Dellermann William C. Ewing Kai Hammond J. Oscar C. Jimenez‐Halla Thomas Kramer Jan Mies 《Angewandte Chemie (International ed. in English)》2015,54(46):13801-13805
A new compound with the formula L‐B2‐L wherein the stabilizing ligand (L) is 1,3‐bis[diisopropylphenyl]‐4,5‐dihydroimidazol‐2‐ylidene (SIDip) has been synthesized, isolated, and characterized. The π‐acidity of the SIDip ligand, intermediate between the relatively non‐acidic IDip (1,3‐bis[diisopropylphenyl]imidazol‐2‐ylidene) ligand and the much more highly acidic CAAC (1‐[2,6‐diisopropylphenyl]‐3,3,5,5‐tetramethylpyrrolidin‐2‐ylidene) ligand, gives rise to a compound with spectroscopic, electrochemical, and structural properties between those of L‐B2‐L compounds stabilized by CAAC and IDip. Reactions of all three L‐B2‐L compounds with CO demonstrate the differences caused by their respective ligands, as the π‐acidities of the CAAC and SIDip carbenes enabled the isolation of bis(boraketene) compounds (L(OC)B‐B(CO)L), which could not be isolated from reactions with B2(IDip)2. However, only B2(IDip)2 and B2(SIDip)2 could be converted into bicyclic bis(boralactone) compounds. 相似文献
164.
Oscar F. Vazquez‐Vuelvas Julia V. Hernndez‐Madrigal Armando Pineda‐Contreras Simn Hernndez‐Ortega Reyna Reyes‐Martínez David Morales‐Morales 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(3):175-180
Two isomeric pyridine‐substituted norbornenedicarboximide derivatives, namely N‐(pyridin‐2‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (I), and N‐(pyridin‐3‐yl)‐exo‐norbornene‐5,6‐dicarboximide, (II), both C14H12N2O4, have been crystallized and their structures unequivocally determined by single‐crystal X‐ray diffraction. The molecules consist of norbornene moieties fused to a dicarboximide ring substituted at the N atom by either pyridin‐2‐yl or pyridin‐3‐yl in an anti configuration with respect to the double bond, thus affording exo isomers. In both compounds, the asymmetric unit consists of two independent molecules (Z′ = 2). In compound (I), the pyridine rings of the two independent molecules adopt different conformations, i.e. syn and anti, with respect to the methylene bridge. The intermolecular contacts of (I) are dominated by C—H...O interactions. In contrast, in compound (II), the pyridine rings of both molecules have an anti conformation and the two independent molecules are linked by carbonyl–carbonyl interactions, as well as by C—H...O and C—H...N contacts. 相似文献
165.
Well‐Defined Palladium Nanoparticles Supported on Siliceous Mesocellular Foam as Heterogeneous Catalysts for the Oxidation of Water
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Dr. Oscar Verho Dr. Torbjörn Åkermark Dr. Eric V. Johnston Karl P. J. Gustafson Dr. Cheuk‐W. Tai Henrik Svengren Dr. Markus D. Kärkäs Prof. Jan‐E. Bäckvall Prof. Björn Åkermark 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(15):5909-5915
Herein, we describe the use of Pd nanoparticles immobilized on an amino‐functionalized siliceous mesocellular foam for the catalytic oxidation of H2O. The Pd nanocatalyst proved to be capable of mediating the four‐electron oxidation of H2O to O2, both chemically and photochemically. The Pd nanocatalyst is easy to prepare and shows high chemical stability, low leaching, and recyclability. Together with its promising catalytic activity, these features make the Pd nanocatalyst of potential interest for future sustainable solar‐fuel production. 相似文献
166.
Antiviral Activity of Synthetic Aminopyrrolic Carbohydrate Binding Agents: Targeting the Glycans of Viral gp120 to Inhibit HIV Entry
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Dr. Oscar Francesconi Prof. Cristina Nativi Dr. Gabriele Gabrielli Irene De Simone Sam Noppen Prof. Jan Balzarini Prof. Sandra Liekens Dr. Stefano Roelens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10089-10093
The binding abilities of a set of structurally related aminopyrrolic synthetic receptors for mannosides, endowed with antimycotic activity against yeast and yeast‐like pathogens bearing mannoproteins on their cell surface, have been investigated towards the highly mannosylated gp120 and gp41 glycoproteins of the HIV envelope. A pronounced binding interaction with both glycoproteins was observed by SPR for most of the investigated compounds. Comparison of their binding properties towards the glycoproteins with their binding affinities toward mannosides revealed a direct correlation, supporting their role as carbohydrate binding agents (CBAs). Cytostatic activity studies revealed antiproliferative activity dependent on the nature and the structure of compounds. Antiviral activity studies against a broad panel of DNA and RNA viruses showed inhibitory effect against HIV infection of the T‐lymphocyte CEM cell line for two compounds, suggesting antiviral activity similar to other CBAs, such as the nonpeptidic pradimicin antibiotics. 相似文献
167.
Pau Turon Prof. Dr. Jordi Puiggalí Dr. Oscar Bertrán Prof. Dr. Carlos Alemán 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):18892-18898
Even in the worst of conditions, such as those which occurred during mass extinction events, life on Earth never totally stopped. Aggressive chemical and physical attacks able to sterilize or poison living organisms occurred repeatedly. Surprisingly, DNA was not degraded, denatured or modified to the point of losing the capability of transferring the genetic information to the next generations. After the events of mass extinction life was able to survive and thrive. DNA was passed on despite being an extremely fragile biomolecule. The potential implications of hydroxyapatite protection of DNA are discussed in this Concept article including how DNA acts as a template for hydroxyapatite (HAp) formation, how cell death can trigger biomineralization, and how DNA can be successfully released from HAp when the conditions are favorable for life. 相似文献
168.
Artur Vashurin Vladimir Maizlish Ilya Kuzmin Oleg Petrov Mikhail Razumov Svetlana Pukhovskaya Oleg Golubchikov Oscar Koifman 《Journal of inclusion phenomena and macrocyclic chemistry》2017,87(1-2):37-43
The influence of the size of conjugated π-system on catalytic activity of cobalt complex with β-octaphenylporphyrin and its tetraaza-, tetrabenzo and tetrabenzotetraaza derivatives was studied in present work. It is found that catalytic activity for oxidation of sulfur-containing compounds increases under extension of conjugated macrocycle system according to the following series CoP < CoBP ≤ CoPz < CoPPz ? CoPc. 相似文献
169.
Oscar Hernan Madrid-Padilla James Scott 《Journal of computational and graphical statistics》2017,26(3):537-546
We present an approach for penalized tensor decomposition (PTD) that estimates smoothly varying latent factors in multiway data. This generalizes existing work on sparse tensor decomposition and penalized matrix decompositions, in a manner parallel to the generalized lasso for regression and smoothing problems. Our approach presents many nontrivial challenges at the intersection of modeling and computation, which are studied in detail. An efficient coordinate-wise optimization algorithm for PTD is presented, and its convergence properties are characterized. The method is applied both to simulated data and real data on flu hospitalizations in Texas and motion-capture data from video cameras. These results show that our penalized tensor decomposition can offer major improvements on existing methods for analyzing multiway data that exhibit smooth spatial or temporal features. 相似文献
170.
Josep O. Bernad Anna Damascelli Oscar Núñez Maria T. Galceran 《Electrophoresis》2011,32(16):2123-2130
Two in‐line enrichment procedures (large volume sample stacking (LVSS) and field amplified sample injection (FASI)) have been evaluated for the CZE analysis of haloacetic acids (HAAs) in drinking water. For LVSS, separation on normal polarity using 20 mM acetic acid–ammonium acetate (pH 5.5) containing 20% ACN as BGE was required. For FASI, the optimum conditions were 25 s hydrodynamic injection (3.5 kPa) of a water plug followed by 25 s electrokinetic injection (?10 kV) of the sample, and 200 mM formic acid–ammonium formate buffer at pH 3.0 as BGE. For both FASI and LVSS methods, linear calibration curves (r2>0.992), limit of detection on standards prepared in Milli‐Q water (49.1–200 μg/L for LVSS and 4.2–48 μg/L for FASI), and both run‐to‐run and day‐to‐day precisions (RSD values up to 15.8% for concentration) were established. Due to the higher sensitive enhancement (up to 310‐fold) achieved with FASI‐CZE, this method was selected for the analysis of HAAs in drinking water. However, for an optimal FASI application sample salinity was removed by SPE using Oasis WAX cartridges. With SPE‐FASI‐CZE, method detection limits in the range 0.05–0.8 μg/L were obtained, with recoveries, in general, higher than 90% (around 65% for monochloroacetic and monobromoacetic acids). The applicability of the SPE‐FASI‐CZE method was evaluated by analyzing drinking tap water from Barcelona where seven HAAs were found at concentration levels between 3 and 13 μg/L. 相似文献