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81.
82.
Barboiu M Prodi L Montalti M Zaccheroni N Kyritsakas N Lehn JM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(12):2953-2959
The terpy-derived (terpy=terpyridine) ligand 1 has an extended W shape in which the two appended photoactive pyrenyl groups are held apart. On binding of a zinc(II) ion with a terpy group, ligand 1 is converted into complex 2 whereby it adopts a U shape, thus stacking the aromatic units. This structural modification leads to a very pronounced change in photophysical properties: from a highly fluorescent free ligand to a very weakly emitting complex. The W/U structural switching can be reversibly induced by the addition of a competitive tren ligand, which binds and releases a zinc(II) ion under protonation/deprotonation cycles, thus leading to oscillations in light emission. Therefore, the present system performs periodic modulation of optical output through a nanomechanical shape-flipping motion, triggered by metal ion binding and fuelled by acid-base neutralisation energy. Overall, it represents an ion-triggered opto-mechanical supramolecular device. 相似文献
83.
Binamé J Meurice N Leherte L Glasgow J Fortier S Vercauteren DP 《Journal of chemical information and computer sciences》2004,44(4):1394-1401
In this paper, we propose a reduced representation of molecules of pharmacological interest based on their chemical functions. The proposed representations of the molecules are obtained by a topological analysis of their electron density maps at medium resolution, leading to graphs of critical points. The distribution of the different types of critical points are compared at various levels of resolution for a training set of 22 molecules in order to define the optimal resolution level leading to the best representation of the various chemical functions. The reduced representations can in the future be used for molecular similarity research and pharmacophore proposals. 相似文献
84.
The synthesis of a cofacial bis-porphyrinic tweezer bearing a tris-anthracenic spacer is reported. Its behavior as host has been evidenced as well as the ability of its cavity to adjust to guests of various sizes. 相似文献
85.
Madelin G Baril N Lewa CJ Franconi JM Canioni P Thiaudiére E de Certaines JD 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2003,161(1):108-111
A B(1) field gradient-based method previously described for the detection of mechanical vibrations has been applied to detect oscillatory motions in condensed matter originated from acoustic waves. A ladder-shaped coil generating a quasi-constant RF-field gradient was associated with a motion-encoding NMR sequence consisting in a repetitive binomial 13;31; RF pulse train (stroboscopic acquisition). The NMR response of a gel phantom subject to acoustic wave excitation in the 20-200 Hz range was investigated. Results showed a linear relationship between the NMR signal and the wave amplitude and a spectroscopic selectivity of the NMR sequence with respect to the input acoustic frequency. Spin displacements as short as a few tens of nanometers were able to be detected with this method. 相似文献
86.
Harrowven DC L'Helias N Moseley JD Blumire NJ Flanagan SR 《Chemical communications (Cambridge, England)》2003,(21):2658-2659
A new approach to eight and nine membered ring synthesis is described in which a radical ipso-substitution reaction features as a key step. 相似文献
87.
Solladié N Walther ME Gross M Duarte TM Bourgogne C Nierengarten JF 《Chemical communications (Cambridge, England)》2003,(19):2412-2413
In addition to the ammonium-crown ether recognition, pi-stacking interactions between the C60 sphere and the porphyrin moiety have been evidenced in a supramolecular complex obtained from a porphyrin-crown ether conjugate and a fullerene derivative bearing an ammonium unit. 相似文献
88.
Upon crystallisation of two bismonodentate tectons based on two pyridine units, interconnected at the meta position by a tetra- or hexa-ethylene glycol fragment and Ag+ cation, double stranded helical infinite coordination networks were formed and structurally characterised. The cationic double helical architectures obtained may be regarded as analogues of DNA in terms of topology. 相似文献
89.
Macrocyclic inhibitors of the NS3 protease as potential therapeutic agents of hepatitis C virus infection 总被引:3,自引:0,他引:3
90.
Framed Discs Operads and Batalin-Vilkovisky Algebras 总被引:1,自引:0,他引:1