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531.
Sudarat Yadnum Dr. Jérome Roche Eric Lebraud Philippe Négrier Patrick Garrigue Dr. Darren Bradshaw Dr. Chompunuch Warakulwit Prof. Jumras Limtrakul Prof. Alexander Kuhn 《Angewandte Chemie (International ed. in English)》2014,53(15):4001-4005
Herein, bipolar electrochemistry is applied in a straightforward way to the site‐selective in situ synthesis of metal–organic framework (MOF) structures, which have attracted tremendous interest in recent years because of their significant application potential, ranging from sensing to gas storage and catalysis. The novelty of the presented work is that the deposit can be intentionally confined to a defined area of a substrate without using masks or templates. The intrinsic site‐selectivity of bipolar electrochemistry makes it a method of choice to generate, in a highly controlled way, hybrid particles that may have different functionalities combined on the same particle. The wireless nature of electrodeposition allows the potential for mass production of such Janus‐type objects. 相似文献
532.
Selective and Potent Proteomimetic Inhibitors of Intracellular Protein–Protein Interactions
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Dr. Anna Barnard Dr. Kérya Long Dr. Heather L. Martin Dr. Jennifer A. Miles Dr. Thomas A. Edwards Dr. Darren C. Tomlinson Dr. Andrew Macdonald Prof. Andrew J. Wilson 《Angewandte Chemie (International ed. in English)》2015,54(10):2960-2965
Inhibition of protein–protein interactions (PPIs) represents a major challenge in chemical biology and drug discovery. α‐Helix mediated PPIs may be amenable to modulation using generic chemotypes, termed “proteomimetics”, which can be assembled in a modular manner to reproduce the vectoral presentation of key side chains found on a helical motif from one partner within the PPI. In this work, it is demonstrated that by using a library of N‐alkylated aromatic oligoamide helix mimetics, potent helix mimetics which reproduce their biophysical binding selectivity in a cellular context can be identified. 相似文献
533.
Synthesis and Functional Reconstitution of Light‐Harvesting Complex II into Polymeric Membrane Architectures
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Thomas Zapf Dr. Cherng‐Wen Darren Tan Tobias Reinelt Dr. Christoph Huber Dr. Ding Shaohua Prof. Dr. Susana Geifman‐Shochat Prof. Dr. Harald Paulsen Prof. Dr. Eva‐Kathrin Sinner 《Angewandte Chemie (International ed. in English)》2015,54(49):14664-14668
One of most important processes in nature is the harvesting and dissipation of solar energy with the help of light‐harvesting complex II (LHCII). This protein, along with its associated pigments, is the main solar‐energy collector in higher plants. We aimed to generate stable, highly controllable, and sustainable polymer‐based membrane systems containing LHCII–pigment complexes ready for light harvesting. LHCII was produced by cell‐free protein synthesis based on wheat‐germ extract, and the successful integration of LHCII and its pigments into different membrane architectures was monitored. The unidirectionality of LHCII insertion was investigated by protease digestion assays. Fluorescence measurements indicated chlorophyll integration in the presence of LHCII in spherical as well as planar bilayer architectures. Surface plasmon enhanced fluorescence spectroscopy (SPFS) was used to reveal energy transfer from chlorophyll b to chlorophyll a, which indicates native folding of the LHCII proteins. 相似文献
534.
Anna F. Oliveri Lindsay A. Wills Caitlyn R. Hazlett Matthew E. Carnes I-Ya Chang Paul Ha-Yeon Cheong Darren W. Johnson 《Chemical science》2015,6(7):4071-4085
NMR spectroscopy is the go-to technique for determining the solution structures of organic, organometallic, and even macromolecular species. However, structure determination of nanoscale aqueous inorganic clusters by NMR spectroscopy remains an unexplored territory. The few hydroxo-bridged inorganic species well characterized by 1H Nuclear Magnetic Resonance spectroscopy (1H-NMR) do not provide enough information for signal assignment and prediction of new samples. 1H-NMR and quantum mechanical (QM) computations were used to characterize the NMR spectra of the entire array of inorganic flat-Ga13–xInx (0 ≤ x ≤ 6) nanoscale clusters in solution. A brief review of the known signals for μ2-OH and μ3-OH bridges gives expected ranges for certain types of protons, but does not give enough information for exact peak assignment. Integration values and NOESY data were used to assign the peaks of several cluster species with simple 1H-NMR spectra. Computations agree with these hydroxide signal assignments and allow for assignment of the complex spectra arising from the remaining cluster species. This work shows that 1H-NMR spectroscopy provides a variety of information about the solution behavior of inorganic species previously thought to be inaccessible by NMR due to fast ligand and/or proton exchange in wet solvents. 相似文献
535.
We consider the asymptotic behavior and local structure of solutions to the nonlocal variational problem developed in the
companion article to this work, On a Model of Nonlocal Continuum Mechanics Part I: Existence and Regularity. After a brief
review of the basic setup and results of Part I, we conduct a thorough analysis of the phase plane related to an integro-differential
Euler--Lagrange equation and classify all admissible structures that arise as energy minimizing strain states. We find that
for highly elastic materials with relatively weak particle-particle interactions, the maximum number of internal phase boundaries
is two. Moreover, we also develop explicit bounds for the number of internal phase boundaries supported by any material and
show that this bound is essentially inversely related to the particle size. To understand the question of asymptotics, we
utilize the Young measure and show that in the sense of energetics and averages, minimizers of the full nonlocal problem converge
to minimizers of two limiting problems corresponding to both the large and small particle limits. In fact, in the small particle
limit, we find that the minimizing fields converge, up to a subsequence in strong-Lp, for 1 ≤ p < ∞, to fields that support either a single internal phase boundary, or two internal phase boundaries that are
distributed symmetrically about the body midpoint. We close this work with some computations that illustrate these asymptotic
limits and provide insight into the notion of nonlocal metastability.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
536.
For any field 𝕂 and integer n ≥ 2, we consider the Leavitt algebra L 𝕂(n); for any integer d ≥ 1, we form the matrix ring S = M d (L 𝕂(n)). S is an associative algebra, but we view S as a Lie algebra using the bracket [a, b] = ab ? ba for a, b ∈ S. We denote this Lie algebra as S ?, and consider its Lie subalgebra [S ?, S ?]. In our main result, we show that [S ?, S ?] is a simple Lie algebra if and only if char(𝕂) divides n ? 1 and char(𝕂) does not divide d. In particular, when d = 1, we get that [L 𝕂(n)?, L 𝕂(n)?] is a simple Lie algebra if and only if char(𝕂) divides n ? 1. 相似文献
537.
538.
Joseph A. Potenza Thomas J. Emge Jennifer Albaneze Spencer Knapp Harvey J. Schugar 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1494-1495
The title molecule, 2′‐pyrenylspiro[2,3‐dihydro‐1H‐cyclopenta[b]naphthalene‐2,5′‐1′,3′‐dioxane]‐4,9‐dione, C32H22O4, contains an electron‐donating pyrene group spiro‐linked to an electron‐accepting naphthoquinone. The molecules are V‐shaped in profile and stack to form columns along b with alternating, approximately coplanar, pyrene and naphthoquinone fragments. Intermolecular contacts within a column are consistent with some degree of π contact and possible long‐range delocalization. Individual columns form a herringbone pattern when the crystal is viewed along b . 相似文献
539.
Let S be a finite set of points in the plane and let be the set of intersection points between pairs of lines passing through any two points in S. We characterize all configurations of points S such that iteration of the above operation produces a dense set. We also discuss partial results on the characterization of those finite point-sets with rational coordinates that generate all of through iteration of . 相似文献
540.
Expeditious and Divergent Total Syntheses of Aspidosperma Alkaloids Exploiting Iridium(I)‐Catalyzed Generation of Reactive Enamine Intermediates
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Peng Wen Tan Dr. Jayasree Seayad Prof. Dr. Darren J. Dixon 《Angewandte Chemie (International ed. in English)》2016,55(43):13436-13440
A new approach for the divergent total syntheses of (±)‐vincaminorine, (±)‐N‐methylquebrachamine, (±)‐quebrachamine, (±)‐minovine and (±)‐vincadifformine, each in less than 10 linear steps starting from a single δ‐lactam building block, is reported. Key to our route design is the late‐stage generation of reactive enamine functionality from stable indole‐linked δ‐lactams via a highly chemoselective iridium(I)‐catalyzed reduction. The efficiently formed secodine intermediates subsequently undergo either a formal Diels–Alder cycloaddition or a competitive Michael addition/reduction to access aspidosperma‐type alkaloids in excellent diastereoselectivities. Product selectivity could be controlled by changing the indole N‐protecting group in the reductive cyclization precursors. An asymmetric variant of this synthetic strategy for the synthesis of (+)‐20‐epi‐ibophyllidine is also described. 相似文献