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排序方式: 共有320条查询结果,搜索用时 234 毫秒
311.
The synthesis, spectroscopic properties, and TD-DFT calculations of new aza-Boron-dipyromethene dyes featuring pendant nitrofluorenylethynyl substituents are described. This functionalization allows for moving the luminescence in the NIR, conserving a good quantum yield efficiency. 相似文献
312.
Yaouba A Tatsadjieu LN Dongmo PM Etoa FX Mbofung CM Zollo PH Menut C 《Natural product communications》2011,6(9):1367-1371
Investigations were conducted to determine the chemical composition, antifungal and antiradical activities of the essential oil extracted from the fresh leaves of Clausena anisata (Willd.) Hook. F. ex Benth (from Cameroon) against Aspergillus flavus, A. niger, A. parasiticus and Fusarium moniliforme. The essential oil obtained by hydrodistillation was analysed by GC and GC/MS. The disc diffusion method was used to evaluate the fungal growth inhibition at various concentrations of the oil while the antiradical activity of the essential oil was studied by the DPPH (diphenyl picryl hydrazyl) method. The main components obtained were E-ocimenone (15.1%), Z-ocimenone (11.5%), gamma-terpinene (11.4%) and germacrene D (10.9%). After 10 days of incubation on essential oil supplemented medium, the growth of A. flavus, A. niger, A. parasiticus and F. moniliforme were totally inhibited by 4, 5, 5 and 5 mg/mL of C. anisata essential oil, respectively. The antiradical activity of C. anisata essential oil (SC50 = 5.1 g/L) was less than that of butylated hydroxyl toluene (BHT), which was used as the reference compound (SC50 = 0.007 g/L). Results obtained in the present study indicate the possibility of exploiting C. anisata essential oil to fight strains of A. flavus, A. niger, A. parasiticus and F. moniliforme responsible for biodeterioration of stored food products. 相似文献
313.
Falzon MF Zoombelt AP Wienk MM Janssen RA 《Physical chemistry chemical physics : PCCP》2011,13(19):8931-8939
Developing new acceptor materials as alternatives to fullerene acceptors remains a challenge in the field of organic photovoltaics. We report on the synthesis and optoelectronic properties of three acceptor polymers bearing diketopyrrolopyrrole units in the main chain (PA, PB and PC). Their performance as the acceptor material in bulk heterojunction solar cells using P3HT as the donor material has been tested. The solar cells show relatively high open-circuit voltages (≥0.9 V) but low fill factors and short-circuit current densities limit the photovoltaic device performance. Formation of free charge carriers and low electron mobility are identified as the major obstacles. In blends of P3HT with PA or PB charge formation is limited, while for the P3HT:PC blend photogenerated charges recombine into the PC triplet state before they can separate, unless assisted by a reverse electric field. 相似文献
314.
Lux F Mignot A Mowat P Louis C Dufort S Bernhard C Denat F Boschetti F Brunet C Antoine R Dugourd P Laurent S Vander Elst L Muller R Sancey L Josserand V Coll JL Stupar V Barbier E Rémy C Broisat A Ghezzi C Le Duc G Roux S Perriat P Tillement O 《Angewandte Chemie (International ed. in English)》2011,50(51):12299-12303
315.
Henri-Jean Cbistau Chantal Garcia Jumah Kadoura Eliane Torreilles 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):151-154
Abstract Metallated aminophosphonium ylids, diaza-diylids and azayldiid, are investigated as reagents for primary and secondary amines synthesis. 相似文献
316.
Single step hybrid coating process to enhance the electrosteric stabilization of inorganic particles
Rufier C Reufer M Dietsch H Schurtenberger P 《Langmuir : the ACS journal of surfaces and colloids》2011,27(11):6622-6627
We report on a single-step coating process and the resulting colloidal stability of silica-coated spindle-type hematite nanoparticles (NPs) decorated with a layer of poly(acrylic acid) (PAA) polyelectrolyte chains that are partially incorporated into the silica shell. The stability of PAA coated NPs as a function of pH and salt concentration in water was compared to bare hematite particles and simple silica-coated hematite NPs, studying their electrophoretic mobility and the hydrodynamic radius by dynamic light scattering. Particles coated with this method were found to be more stable upon the addition of salt at pH 7, and their aggregation at the pH of the isoelectric point is reversible. The hybrid coating appears to increase the colloidal stability in aqueous media due to the combination of the decrease of the isoelectric point and the electrosteric stabilization. This coating method is not limited to hematite particles but can easily be adapted to any silica-coatable particle. 相似文献
317.
Maalouli N Gouget-Laemmel AC Pinchemel B Bouazaoui M Chazalviel JN Ozanam F Yang Y Burkhard P Boukherroub R Szunerits S 《Langmuir : the ACS journal of surfaces and colloids》2011,27(9):5498-5505
Monolayers of metal complexes were covalently attached to the surface of lamellar SPR interfaces (Ti/Ag/a-Si(0.63)C(0.37)) for binding histidine-tagged peptides with a controlled molecular orientation. The method is based on the activation of surface acid groups with N-hydroxysuccinimide (NHS), followed by an amidation reaction with (S)-N-(5-amino-1-carboxypentyl)iminodiacetic acid (NTA). FTIR and X-ray photoelectron spectroscopy (XPS) were used to characterize each surface modification step. The NTA modified SPR interface effectively chelated Cu(2+) ions. Once loaded with metal ions, the modified SPR interface was able to bind specifically to histidine-tagged peptides. The binding process was followed by surface plasmon resonance (SPR) in a droplet based configuration. The Cu(2+)-NTA modified interface showed protein loading comparable to commercially available NTA chips based on dextran chemistry and can thus be regarded as an interesting alternative. The sensor interface can be reused several times due to the easy regeneration step using ethylenediaminetetraacetic acid (EDTA) treatment. 相似文献
318.
Basit H Van der Heyden A Gondran C Nysten B Dumy P Labbé P 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14317-14328
Tethered bilayer lipid membranes (tBLMs) are designed on mixed self-assembled monolayers (SAMs) of a novel synthetic anchoring thiol, 2,3-di-o-palmitoylglycerol-1-tetraethylene glycol mercaptopropanoic acid ester (TEG-DP), and a new short dilution thiol molecule, tetraethylene glycol mercaptopropanoic acid ester (TEG). tBLM formation was accomplished by self-directed fusion of small unilamellar vesicles of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine. The influence of the dilution of the anchoring thiol molecule in the SAM on the vesicle fusion process and on the properties of the resulting tBLMs is studied. It is observed by quartz crystal microbalance that vesicle fusion is a one-step process for a pure TEG-DP SAM as well as for mixed SAMs containing a high concentration of the anchoring thiol. However, upon dilution of the anchoring thiol to moderate concentrations, this process is decelerated and possibly follows a pathway different from that observed on a pure TEG-DP SAM. Electrochemical impedance spectroscopy is used to qualitatively correlate the composition of the SAM to the electrical properties of the tBLM. In this paper we also delineate the necessity of a critical concentration of this anchoring TEG-DP thiol as a requisite for inducing the fusion of vesicles to form a tBLM. 相似文献
319.
Dennis Popp Dr. Sven M. Elbert Chantal Barwig Julian Petry Dr. Frank Rominger Prof. Dr. Michael Mastalerz 《Angewandte Chemie (International ed. in English)》2023,62(19):e202219277
The palladium catalyzed cyclotrimerization of ortho-silylaryl triflates as aryne precursors is meanwhile an established method to synthesize polycyclic aromatic hydrocarbons (PAHs) with triphenylene cores. During the palladium-catalyzed reaction of a pyrene with an o-silylaryl triflate moiety in the K-region higher homologues with central eight- and ten-membered rings (the pyrenylenes) were found, besides the expected trimer and a protocol was developed to isolate all members of this series. This unprecedented new class of PAHs was fully investigated by all means, including X-ray diffraction of single-crystals, UV/Vis and fluorescence spectroscopy and theoretical calculations. Supported by density-functional theory (DFT) calculations, a mechanism of all higher cyclooligomers is proposed. 相似文献
320.
Carsten E. Seyfert Christoph Porten Dr. Biao Yuan Selina Deckarm Dr. Fabian Panter Dr. Chantal D. Bader Janetta Coetzee Felix Deschner Dr. Kamaleddin H. M. E. Tehrani Prof. Dr. Paul G. Higgins Prof. Dr. Harald Seifert Prof. Dr. Thomas C. Marlovits Dr. Jennifer Herrmann Prof. Dr. Rolf Müller 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(2):e202214094