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991.
Hydride Migration from a Triangular Face to a Tetrahedral Cavity in Tetranuclear Iron Carbonyl Clusters upon Coordination of [AuPPh3]+ Fragments 下载免费PDF全文
Dr. Marco Bortoluzzi Dr. Iacopo Ciabatti Dr. Cristina Femoni Dr. Mohammad Hayatifar Prof. Maria Carmela Iapalucci Prof. Giuliano Longoni Prof. Stefano Zacchini 《Angewandte Chemie (International ed. in English)》2014,53(28):7233-7237
Metal hydrides are of fundamental importance in chemistry, both as solid‐state materials and molecular compounds. The first low‐valent molecular metal cluster containing an interstitial four‐coordinate hydride in a tetrahedral site is decribed, which undergoes hydride migration from the surface to the tetrahedral cavity of the cluster upon coordination of a [AuPPh3]+ fragment. The [HFe4(CO)12(AuPPh3)2]? mono‐anion, which contains a surface μ3‐H, was obtained from the reaction of [HFe4(CO)12]3? with two equivalents of [Au(PPh3)Cl]. This is, in turn, transformed into the neutral [HFe4(CO)12(AuPPh3)3] upon addition of a third [AuPPh3]+ fragment, with concomitant migration of the unique hydride from the surface of the cluster to its tetrahedral cavity. All of these species have been fully characterized in solution by means of IR and multinuclear NMR spectroscopy, and in the solid state by single‐crystal X‐ray diffractometry. 相似文献
992.
Cavitand‐Grafted Silicon Microcantilevers as a Universal Probe for Illicit and Designer Drugs in Water 下载免费PDF全文
Dr. Elisa Biavardi Dr. Stefania Federici Dr. Cristina Tudisco Dr. Daniela Menozzi Dr. Chiara Massera Andrea Sottini Prof. Guglielmo G. Condorelli Dr. Paolo Bergese Prof. Enrico Dalcanale 《Angewandte Chemie (International ed. in English)》2014,53(35):9183-9188
The direct, clean, and unbiased transduction of molecular recognition into a readable and reproducible response is the biggest challenge associated to the use of synthetic receptors in sensing. All possible solutions demand the mastering of molecular recognition at the solid–liquid interface as prerequisite. The socially relevant issue of screening amine‐based illicit and designer drugs is addressed by nanomechanical recognition at the silicon–water interface. The methylamino moieties of different drugs are all first recognized by a single cavitand receptor through a synergistic set of weak interactions. The peculiar recognition ability of the cavitand is then transferred with high fidelity and robustness on silicon microcantilevers and harnessed to realize a nanomechanical device for label‐free detection of these drugs in water. 相似文献
993.
Development of CN Coupling Using Mechanochemistry: Catalytic Coupling of Arylsulfonamides and Carbodiimides 下载免费PDF全文
Davin Tan Cristina Mottillo Athanassios D. Katsenis Dr. Vjekoslav Štrukil Prof. Dr. Tomislav Friščić 《Angewandte Chemie (International ed. in English)》2014,53(35):9321-9324
Reported herein is the mechanochemical synthesis of sulfonyl guanidines, a family of molecules which are relevant as pharmaceuticals and herbicides, by direct coupling of sulfonamides and aromatic or aliphatic carbodiimides. Attempts to conduct the coupling in solution have either failed or given very low conversions, thus demonstrating mechanochemistry as the necessary component for the discovery of this synthetic strategy. 相似文献
994.
Dr. Luminita Marin Dr. Simona Moraru Dr. Maria‐Cristina Popescu Alina Nicolescu Cristina Zgardan Prof. Dr. Bogdan C. Simionescu Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(16):4814-4821
An investigation of the constitutional adaptive gelation process of chitosan/cinnamaldehyde ( C / Cy ) dynagels is reported. These gels generate timely variant macroscopic organization across extended scales. In the first stage, imine‐bond formation takes place “in‐water” and generates low‐ordered hydrogels. The progressive formation of imine bonds further induces “ out‐of‐water” increased reactivity within interdigitated hydrophobic self‐assembled layers of Cy , with a protecting environmental effect against hydrolysis and that leads to the stabilization of the imine bonds. The hydrophobic swelling due to Cy layers at the interfaces reaches a critical step when lamellar self‐organized hybrids are generated (24 hours). This induces an important restructuration of the hydrogels on the micrometric scale, thus resulting in the formation of highly ordered microporous xerogel morphologies of high potential interest for chemical separations, drug delivery, and sensors. 相似文献
995.
Cathepsin‐B Induced Controlled Release from Peptide‐Capped Mesoporous Silica Nanoparticles 下载免费PDF全文
Cristina de la Torre Laura Mondragón Carmen Coll Félix Sancenón María D. Marcos Ramón Martínez‐Máñez Pedro Amorós Mar Orzáez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15309-15314
New capped silica mesoporous nanoparticles for intracellular controlled cargo release within cathepsin B expressing cells are described. Nanometric mesoporous MCM‐41 supports loaded with safranin O ( S1‐P ) or doxorubicin ( S2‐P ) containing a molecular gate based on a cathepsin B target peptidic sequence were synthesized. Solids were designed to show “zero delivery” and to display cargo release in the presence of cathepsin B enzyme, which selectively hydrolyzed in vitro the capping peptide sequence. Controlled delivery in HeLa, MEFs WT, and MEFs lacking cathepsin B cell lines were also tested. Release of safranin O and doxorubicin in these cells took place when cathepsin B was active or present. Cells treated with S2‐P showed a fall in cell viability due to nanoparticles internalization, cathepsin B hydrolysis of the capping peptide, and cytotoxic agent delivery, proving the possible use of these nanodevices as new therapeutic tools for cancer treatment. 相似文献
996.
Microwave‐Assisted Tandem Organocatalytic Peptide‐Coupling Intramolecular aza‐Michael Reaction: α,β‐Unsaturated N‐Acyl Pyrazoles as Michael Acceptors 下载免费PDF全文
Dr. María Sánchez‐Roselló Cristina Mulet Marta Guerola Dr. Carlos del Pozo Prof. Santos Fustero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(48):15697-15701
Conjugated N‐acyl pyrazoles have been successfully employed in the organocatalytic enantioselective intramolecular aza‐Michael reaction as ester surrogates. Bifunctional squaramides under microwave irradiation provided the best results in this transformation. Furthermore, this protocol has been combined with a peptide‐coupling reaction in a tandem sequence. The final products were easily converted into the corresponding ethyl esters. 相似文献
997.
Single‐Molecule‐Magnet Behavior in the Family of [Ln(OETAP)2] Double‐Decker Complexes (Ln=Lanthanide,OETAP=Octa(ethyl)tetraazaporphyrin) 下载免费PDF全文
Nelson Giménez‐Agulló Dr. Cristina Sáenz de Pipaón Louis Adriaenssens Dr. Marta Filibian Marta Martínez‐Belmonte Eduardo C. Escudero‐Adán Prof. Pietro Carretta Prof. Pablo Ballester Prof. José Ramón Galán‐Mascarós 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12817-12825
Double‐decker complexes of lanthanide cations can be readily prepared with tetraazaporphyrins (porphyrazines). We have synthesized and characterized a series of neutral double‐decker complexes [Ln(OETAP)2] (Ln=Tb3+, Dy3+, Gd3+, Y3+; OETAP=octa(ethyl)tetraazaporphyrin). Some of these complexes show analogous magnetic features to their phthalocyanine (Pc) counterparts. The Tb3+ and Dy3+ derivatives exhibit single‐molecule magnet (SMM) behavior with high blocking temperatures over 50 and 10 K, respectively. These results confirm that, in double‐decker complexes that involve Tb or Dy, the (N4)2 square antiprism coordination mode has an important role in inducing very large activation energies for magnetization reversal. In contrast with their Pc counterparts, the use of tetraazaporphyrin ligands endows the presented [Ln(OETAP)2] complexes with extraordinary chemical versatility. The double‐decker complexes that exhibit SMM behavior are highly soluble in common organic solvents, and easily processable even through sublimation. 相似文献
998.
Reversed‐phase high‐performance liquid chromatography method with fluorescence detection to screen nitric oxide synthases inhibitors 下载免费PDF全文
Cristina Maccallini Mauro Di Matteo Alessandra Ammazzalorso Alessandra D'Angelo Barbara De Filippis Sara Di Silvestre Marialuigia Fantacuzzi Letizia Giampietro Assunta Pandolfi Rosa Amoroso 《Journal of separation science》2014,37(12):1380-1385
Nitric oxide synthase (NOS) inhibitors are potential drug candidates due to the critical role of an excessive production of nitric oxide in a range of diseases. At present, the radiometric detection of l ‐[3H]‐citrulline produced from l ‐[3H]‐arginine during the enzymatic reaction is one of the most accepted methods to assess the in vitro activity of NOS inhibitors. Here we report a fast, easy, and cheap reversed‐phase high‐performance liquid chromatography method with fluorescence detection, based on the precolumn derivatization of l ‐citrulline with o‐phthaldialdehyde/N‐acetyl cysteine, for the in vitro screening of NOS inhibitors. To evaluate enzyme inhibition by the developed method, N‐[3‐(aminomethyl)benzyl]acetamidine, a potent and selective inhibitor of inducible NOS, was used as a test compound. The half maximal inhibitory concentration obtained was comparable to that derived by the well‐established radiometric assay. 相似文献
999.
Maura Brioschi Sonia Eligini Mauro Crisci Susanna Fiorelli Elena Tremoli Susanna Colli Cristina Banfi 《Analytical and bioanalytical chemistry》2014,406(12):2817-2825
This paper describes a microproteomic workflow that is useful for simultaneously identifying and quantifying proteins from a minimal number of morphotypically heterogeneous cultured adherent cells. The analytical strategy makes use of laser capture microdissection, an effective means of harvesting pure cell populations, and label-free mass spectrometry. We optimised the workflow with particular reference to cell fixation which is crucial for successful laser-based microdissection and also downstream molecular studies. In addition, we defined the minimum number of cells to be isolated and analysed for satisfactory proteome coverage. To set up this workflow, we choose human monocyte-derived macrophages spontaneously differentiated in vitro. These cells, under our culture conditions, show distinct morphotypes, reminiscent of the heterogeneity observed in tissues in various homeostatic and pathological states, e.g. atherosclerosis. This optimised workflow may provide new insights into biology and pathology of heterogeneous cell in culture, particularly when other cell selection approaches are not suitable. Figure
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1000.
Cristina Ruiz-Samblás José M. Cadenas David A. Pelta Luis Cuadros-Rodríguez 《Analytical and bioanalytical chemistry》2014,406(11):2591-2601
The aim of this article is to study tree-based ensemble methods, new emerging modelling techniques, for authentication of samples of olive oil blends to check their suitability for classifying the samples according to the type of oil used for the blend as well as for predicting the amount of olive oil in the blend. The performance of these methods has been investigated in chromatographic fingerprint data of olive oil blends with other vegetable oils without needing either to identify or to quantify the chromatographic peaks. Different data mining methods—classification and regression trees, random forest and M5 rules—were tested for classification and prediction. In addition, these classification and regression tree approaches were also used for feature selection prior to modelling in order to reduce the number of attributes in the chromatogram. The good outcomes have shown that these methods allow one to obtain interpretable models with much more information than the traditional chemometric methods and provide valuable information for detecting which vegetable oil is mixed with olive oil and the percentage of oil used, with a single chromatogram. Figure
? 相似文献