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61.
Raúl Pérez-Ruiz Robert Fichtler Yrene Diaz Miara Matthieu Nicoul Dominik Schaniel Helfried Neumann Matthias Beller Dirk Blunk Axel G. Griesbeck Axel Jacobi von Wangelin 《Journal of fluorescence》2010,20(3):657-664
The photophysical properties of a series of structurally related 4-aminophthalimides and the corresponding 5-aminophthalic
hydrazides (luminols) are reported. Absorption, steady-state, and time-resolved fluorescence spectra of luminols exhibited
substitution, solvent, and pH dependence. Singlet lifetimes have been determined by time-resolved laser flash spectroscopy.
UV spectra in gas phase and DMSO solution were calculated by TD-DFT which revealed the existence of two low-energy excited
singlet states with strong pH-sensitivity. 相似文献
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The highly enantiomerically enriched silyllithium compound lithiomethylphenyl(1-piperidinylmethyl)silane (4) reacts stereospecifically with chlorosilanes, but over a period of several hours slow racemization in solution at room temperature occurs, which can be suppressed by a transmetalation reaction with MgBr2(thf)4. 相似文献
65.
66.
Schreiner E Nicolini C Ludolph B Ravindra R Otte N Kohlmeyer A Rousseau R Winter R Marx D 《Physical review letters》2004,92(14):148101
The temperature-dependent behavior of a solvated oligopeptide, GVG(VPGVG), is investigated. Spectroscopic measurements, thermodynamic measurements, and molecular dynamics simulations find that this elastinlike octapeptide behaves as a two-state system that undergoes an "inverse temperature" folding transition and reentrant unfolding close to the boiling point of water. A molecular picture of these processes is presented, emphasizing changes in the dynamics of hydrogen bonding at the protein/water interface and peptide backbone librational entropy. 相似文献
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The mechanism of specific acid-catalyzed glycosidic bond formation between methanol and alpha-d-glucopyranoside in aqueous solution at 300 K was studied using Car-Parrinello molecular dynamics. The reaction was found to proceed through a non-solvent equilibrated oxocarbenium cation intermediate characterized by the loss of a hydrogen-bonding interaction between the ring oxygen and solvating water. The mechanism, which was found to be D(N)A(N) in nature, is discussed in detail. 相似文献
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Atsushi Nakagawa Dominik Fenn Andreas Koschella Thomas Heinze Hiroshi Kamitakahara 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):4964-4976
This article describes a new synthesis strategy to prepare diblock copolymers as model compounds for industrially produced cellulose ethers exemplified with methylcellulose (MC). To elucidate a key structure for thermoreversible gelation of MC, five regioselectively methylated celluloses 1 – 5 (236, 23, 26, 3, and 6 MC), five corresponding methyl‐β‐D‐glucopyranosyl‐(1→4)‐cellulosides 6 – 10 , and five equiv methyl‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐glucopyranosyl‐(1→4)‐cellulosides 11 – 15 were synthesized for the first time via combination of the glycosyl trichloroacetimidate method and the acid‐catalyzed methanolysis method. The structure of compounds 1 – 15 was confirmed by means of NMR spectroscopy and MALDI‐TOF MS. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献