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排序方式: 共有181条查询结果,搜索用时 328 毫秒
41.
Rodríguez Amalia Muñoz Ernestina Sánchez Francisco Moya María Luisa Burgess John 《Transition Metal Chemistry》1992,17(1):5-8
Transition Metal Chemistry - The wavelengths of absorption maxima are reported for two ligand field bands of hexathiocyanatochromate(III), $ {? Cr(NCS)_{6}^{3-}} $, over a range of... 相似文献
42.
Christophe Deraedt Amalia Rapakousiou Yanlan Wang Lionel Salmon Melanie Bousquet Didier Astruc 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(32):8585-8589
Simple “click” polycondensation metallopolymers of redox‐robust bis(ethynyl)biferrocene (biFc) and di(azido) poly(ethylene glycol) (PEG400 and PEG1000) were designed for multiple functions including improvement of water solubility and biocompatibility, the introduction of mixed valency and sensing capabilities, and as nanoparticle stabilizers for catalysis. 相似文献
43.
44.
Karolina Strakova Dr. Amalia I. Poblador-Bahamonde Dr. Naomi Sakai Prof. Stefan Matile 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14935-14942
To image the membrane tension in living cells, planarizable push–pull probes have been introduced. The first operational probe is built around two dithieno[3,2-b:2′,3′-d]thiophenes (DTTs) that are twisted out of co-planarity and polarized with donors and acceptors at either end. In this report, the chemical space available for the twisting of “flipper probes” is assessed comprehensively. The result is, not surprisingly, that every atom matters: Removal of one methyl group in the twist region yields probes that planarize already in solution and are thus less sensitive to membrane tension. Addition of one or more carbons in the same region hinders non-interfering probe alignment along lipid tails and thus partitioning into lipid bilayer membranes as well as mechanosensitivity. However, substitution of one methyl by an isosteric trifluoromethyl group in the twist region, achieved by quite substantial multistep organic synthesis, yields excitation maxima that shift over +100 nm to the red in response to increasing order of the surrounding membrane. This record redshift comes with record changes in fluorescence intensity and lifetime, high push–pull transition dipoles and higher rotational barriers. Supported by distinct dependence on viscosity and twist of the push–pull probes, kinetic competition between dark, fully twisted and bright, fully planarized relaxed excited states emerges as unifying origin of fluorescence quantum yields. 相似文献
45.
46.
Amalia M. Estévez Raquel G. Soengas José M. Otero Juan C. Estévez Robert J. Nash Ramón J. Estévez 《Tetrahedron: Asymmetry》2010,21(1):21-26
A divergent synthesis of the two novel polyhydroxylated azepanes (2R,3R,4R,5R,6R)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol and (2R,3R,4R,5R,6S)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol from d-mannose is described. The method involves a Henry reaction between dimethyl-tert-butylsilyl 2,3-O-isopropylidene-α-d-lyxo-pentodialdo-1,4-furanoside and 2-nitroethanol followed by a reductive ring closure of the resulting epimeric nitro aldols. Glycosidase inhibition tests showed that (2R,3R,4R,5R,6S)-2-(hydroxymethyl)azepane-3,4,5,6-tetraol exhibits a weak but selective inhibition against α-l-fucosides. 相似文献
47.
Mahesh Vishe Radim Hrdina Amalia I. Poblador-Bahamonde Céline Besnard Laure Guénée Thomas Bürgi Jér?me Lacour 《Chemical science》2015,6(8):4923-4928
The thermodynamically disfavored isomerization of α,β-unsaturated esters to deconjugated β,γ-unsaturated analogues occurs readily when coupled to an amidation. Within the framework of macrocyclic derivatives, it is shown that 15, 16, and 18 membered macrocycles react with tBuOK and anilines to generate, in one-pot, β,γ-unsaturated amides (yields up to 88%). Importantly, single (chiral) diastereomers are isolated (d.r. > 49 : 1, 1H NMR) irrespective of the size and nature of the rings, showing an effective transmission of remote stereochemistry during the isomerization process. CSP-chromatographic resolution and absolute configuration determination by VCD are achieved. 相似文献
48.
Criterion of multiple collisions in a simple mechanical system with viscous damping and dry friction
A criterion has been formulated for single and multiple central collisions of two rigid bodies of a simple mechanical system that can be either conservative or non-conservative. Analytical discussion has been confined to investigations of the possibility of appearance of four successive collisions between the bodies with damping neglected and two collisions when viscous damping and Coulomb dry friction are considered. 相似文献
49.
Graciani Mdel M Rodríguez A Martín VI Fernández G Moyá ML 《Langmuir : the ACS journal of surfaces and colloids》2010,26(24):18659-18668
The reaction methyl naphthalene-2-sulfonate + Br(-) was investigated in several alkanediyl-α-ω-bis(dodecyldimethylammonium) bromide, 12-s-12,2Br(-) (with s = 2, 3, 4, 5, 6, 8, 10, 12), micellar solutions in the absence and in the presence of various additives. The additives were 1,2-propylene glycol, which remains in the bulk phase, N-decyl N-methylglucamide, MEGA10, which forms mixed micelles with the dimeric surfactants, and 1-butanol, which distributes between the aqueous and micellar phases. Information about the micellar reaction media was obtained by using conductivity and fluorescence measurements. In all cases, with the exception of water-1,2-prop 12-5-12,2Br(-) micellar solutions, with 30% weight percentage of the organic solvent, a sphere-to-rod transition takes place upon increasing surfactant concentration. In order to quantitatively explain the experimental data within the whole surfactant concentration range, a kinetic equation based on the pseudophase kinetic model was considered, together with the decrease in the micellar ionization degree accompanying micellar growth. However, theoretical predictions did not agree with the experimental kinetic data for surfactant concentrations above the morphological transition. An empirical kinetic equation was proposed in order to explain the data. It contains a parameter b which is assumed to account for the medium micellar kinetic effects caused by the morphological transition. The use of this empirical equation permits the quantitative rationalization of the kinetic micellar effects in the whole surfactant concentration range. 相似文献
50.
George Agelis Panagiota Roumelioti Amalia Resvani Serdar Durdagi Maria-Eleni Androutsou Konstantinos Kelaidonis Demetrios Vlahakos Thomas Mavromoustakos John Matsoukas 《Journal of computer-aided molecular design》2010,24(9):749-758
A new 1,5 disubstituted imidazole AT1 Angiotensin II (AII) receptor antagonist related to losartan with reversion of butyl and hydroxymethyl groups at the 2-,
5-positions of the imidazole ring was synthesized and evaluated for its antagonist activity (V8). In vitro results indicated that the reorientation of butyl and hydroxymethyl groups on the imidazole template of losartan
retained high binding affinity to the AT1 receptor concluding that the spacing of the substituents at the 2,5- positions is of primary importance. The docking studies
are confirmed by binding assay results which clearly show a comparable binding score of the designed compound V8 with that of the prototype losartan. An efficient, regioselective and cost effective synthesis renders the new compound as
an attractive candidate for advanced toxicological evaluation and a drug against hypertension. 相似文献