共查询到20条相似文献,搜索用时 15 毫秒
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Kirill Nikitin Dr. Helge Müller‐Bunz Dr. Yannick Ortin Dr. Michael J. McGlinchey Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(8):1836-1843
Metal clamping in operation! Deprotonation of [η6‐2‐(9‐triptycyl)indene]tricarbonylchromium induces a haptotropic shift of the organometallic fragment from the six‐membered to the five‐membered ring, as in a→b . In the anion, rotation of the molecular paddlewheel is blocked by the bulky tripod. X‐ray crystal structures provide pictures of the system in both its “ON” and “OFF” states.
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Andreas Lohr Dr. Matthias Grüne Dr. Frank Würthner Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(15):3691-3705
Dipolar aggregation : Examples of a novel class of tweezer molecules have been constructed through the tethering of two dipolar merocyanine chromophores. The electrostatic‐interaction‐directed self‐assembly of these tweezers affords centrosymmetric bimolecular complexes with a unique aggregate geometry of four π‐stacked chromophores (see picture) with an alternating arrangement of their dipole moments and very high dimerization constants, even in the good solvating solvent chloroform.
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Gregor Hagelueken Dr. W. John Ingledew Dr. Hexian Huang Biljana Petrovic‐Stojanovska Chris Whitfield Prof. Hassane ElMkami Dr. Olav Schiemann Dr. James H. Naismith Prof. 《Angewandte Chemie (International ed. in English)》2009,48(16):2904-2906
Distance fingerprinting : Pulsed electron–electron double resonance spectroscopy (PELDOR) is applied to the octameric membrane protein complex Wza of E. coli. The data yielded a detailed distance fingerprint of its periplasmic region that compares favorably to the crystal structure. These results provide the foundation to study conformation changes from interaction with partner proteins.
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Jorge Bordello Belén Reija Dr. Wajih Al‐Soufi Prof. Dr. Mercedes Novo Prof. Dr. 《Chemphyschem》2009,10(6):931-939
Buckle up! The dimerization of small fluorescent guests is strongly enhanced in presence of a cyclodextrin host. The host cavity acts like a belt to assist the self‐assembly of guests (see picture). Small variations in the guest structure have significant influence on the stability and geometry of the aggregates.
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Mauri A. Kostiainen Dr. Henna Rosilo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(23):5656-5660
Losing the grip : The synthesis of multivalent low‐molecular‐weight dendrons with lysine branching units coupled to disulfide‐linked spermine surface groups is described. It is furthermore demonstrated that the dendrons bind DNA with good affinity (see image), but are also able to release the DNA in a reductive environment.
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Georgeta Masson David E. Herbert George R. Whittell Dr. Jason P. Holland Dr. Alan J. Lough Dr. Jennifer C. Green Prof. Ian Manners Prof. 《Angewandte Chemie (International ed. in English)》2009,48(27):4961-4964
Not blue but red‐brown : A [1]ferrocenophanium ion has been synthesized and isolated as a red‐brown crystalline salt, surprisingly different in color from characteristically blue‐green unstrained ferrocenium ions. Compared to the neutral iron(II) counterpart, the [1]ferrocenophanium ion displays a considerably higher ring tilt and an increased propensity for ring‐opening reactions.
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A convenient route with high stereo control to γ‐acetoxy dienoates is provided by the reaction of methyl propiolate with aldehydes in the presence of ZnEt2 and N‐methylimidazole at room temperature, followed by the catalytic conversion of the resulting γ‐hydroxy‐α,β‐acetylenic esters with p‐N,N‐dimethylaminopyridine (DMAP) in acetic anhydride (see scheme).
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Dimitrios A. Pantazis Dr. Maylis Orio Dr. Taras Petrenko Dr. Samir Zein Dr. Eckhard Bill Dr. Wolfgang Lubitz Dr. Johannes Messinger Prof. Frank Neese Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(20):5108-5123
Broken‐symmetry DFT calculations on transition‐metal clusters with more than two centers allow the hyperfine coupling constants to be extracted. Application of the proposed theoretical scheme to a tetranuclear manganese complex that models the S2 state of the oxygen‐evolving complex of photosystem II yields hyperfine parameters that can be directly compared with experimental data. The picture shows the metal–oxo core of the model and the following parameters; exchange coupling constant Jij, the expectation value of the site‐spin operator , and the isotropic hyperfine coupling parameters.
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Jun Shi Hiroki Shigehisa Dr. Carlos A. Guerrero Ryan A. Shenvi Chuang‐Chuang Li Dr. Phil S. Baran Prof. 《Angewandte Chemie (International ed. in English)》2009,48(24):4328-4331
One stereocenter makes all the difference : The synthesis and biological evaluation of 17‐epi‐cortistatin A is reported from a common intermediate used to procure natural cortistatin A. The synthesis features a unique stereocontrolled Raney‐Ni reduction process that can be employed to reliably produce both α‐ and β‐configured D‐ring aryl steroids. Biological evaluations of these “cortalogs” are reported for the first time.
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Ronald Siebert Denis Akimov Dr. Michael Schmitt Dr. Andreas Winter Dr. Ulrich S. Schubert Prof. Dr. Benjamin Dietzek Dr. Jürgen Popp Prof. Dr. 《Chemphyschem》2009,10(6):910-919
Ultrafast light‐induced processes in a series of π‐conjugated mono‐, bis‐, tris‐ and tetrakis(terpyridine) derivatives are investigated by femtosecond time‐resolved spectroscopy. Non‐exponential excited‐state dynamics involving singlet–triplet intersystem crossing are observed which span from picoseconds to nanoseconds (see figure).
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Saikat Mandal Dr. Atsuomi Shundo Dr. Somobrata Acharya Dr. Jonathan P. Hill Dr. Qingmin Ji Dr. Katsuhiko Ariga Dr. 《化学:亚洲杂志》2009,4(7):1055-1058
Keeping their cool : Fabrication of a 2D weblike nanonetwork of gold was successfully demonstrated through a two‐step procedure including complexation of gold precursors to a weblike supramolecular assembly of surfactant followed by in situ reduction of the precursors to gold. Molecular assemblies stabilized by hydrogen bonding provided a sound template, leading to the highly integrated structure of gold through room‐temperature (cold) nanostructure fusion.
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Guest Effect : The differences of nitrogen atom positions and the bridge bonds linked to two pyridine rings of some bipyridine guests can significantly affect the binding abilities and inclusion geometries of β‐cyclodextrin with the guests in both the solution and solid states.
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Hilkka Saal Michael Binnewies Prof. Dr. Marius Schrader Dr. Alexander Börger Dr. Klaus‐Dieter Becker Prof. Dr. Viatcheslav A. Tikhomirov Dr. Karl Jug Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(26):6408-6414
A pigment of your imagination : A range of polycrystalline solid solutions of a zinc‐rich Znx?1MnxO system (see figure) have been prepared and studied in terms of their colour, diffuse reflectance spectra, Mn valence state and electronic structure. The intense optical absorption arises from Mn2+ doping and is thought to be due to forbidden or partially forbidden transitions between the valence and the conduction band.
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Soluble InP and GaP Nanowires: Self‐Seeded,Solution–Liquid–Solid Synthesis and Electrical Properties
Zhaoping Liu Kai Sun Dr. Wen‐Bin Jian Prof. Dr. Dan Xu Yen‐Fu Lin Jiye Fang Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(18):4546-4552
A facile, self‐seeded , solution–liquid–solid growth of soluble InP and GaP nanowires with a very low amount of native point defects with respect to the carrier concentrations have been synthesized (see scheme) and characterized. They are potentially promising building blocks in optoelectronic applications.