排序方式: 共有18条查询结果,搜索用时 15 毫秒
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Hao Wang Dr. Hari Krishna Bisoyi Dr. Bing-Xiang Li Dr. Michael E. McConney Dr. Timothy J. Bunning Prof. Quan Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(7):2706-2709
Visible-light-driven molecular switches endowing reversible modulation of the functionalities of self-organized soft materials are currently highly sought after for fundamental scientific studies and technological applications. Reported herein are the design and synthesis of two novel halogen bond donor based chiral molecular switches that exhibit reversible photoisomerization upon exposure to visible light of different wavelengths. These chiral molecular switches induce photoresponsive helical superstructures, that is, cholesteric liquid crystals, when doped into the commercially available room-temperature achiral liquid crystal host 5CB, which also acts as a halogen-bond acceptor. The induced helical superstructure containing the molecular switch with terminal iodo atoms exhibits visible-light-driven reversible unwinding, that is, a cholesteric–nematic phase transition. Interestingly, the molecular switch with terminal bromo atoms confers reversible handedness inversion to the helical superstructure upon irradiation with visible light of different wavelengths. This visible-light-driven, reversible handedness inversion, enabled by a halogen bond donor molecular switch, is unprecedented. 相似文献
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Ivana Brekalo David E. Deliz Prof. Leonard J. Barbour Prof. Michael D. Ward Prof. Tomislav Friščić Prof. K. Travis Holman 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(5):2013-2018
Guanidinium organosulfonates (GSs) are a large and well-explored archetypal family of hydrogen-bonded organic host frameworks that have, over the past 25 years, been regarded as nonporous. Reported here is the only example to date of a conventionally microporous GS host phase, namely guanidinium 1,4-benzenedisulfonate ( p -G2BDS ). p -G2BDS is obtained from its acetone solvate, AcMe@ G2BDS , by single-crystal-to-single-crystal (SC-SC) desolvation, and exhibits a Type I low-temperature/pressure N2 sorption isotherm (SABET=408.7(2) m2 g−1, 77 K). SC-SC sorption of N2, CO2, Xe, and AcMe by p -G2BDS is explored under various conditions and X-ray diffraction provides a measurement of the high-pressure, room temperature Xe and CO2 sorption isotherms. Though p -G2BDS is formally metastable relative to the “collapsed”, nonporous polymorph, np -G2BDS , a sample of p -G2BDS survived for almost two decades under ambient conditions. np -G2BDS reverts to zCO2@ p -G2BDS or yXe@ p -G2BDS (y,z=variable) when pressure of CO2 or Xe, respectively, is applied. 相似文献
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Friedrich C. Simmel 《Chemie in Unserer Zeit》2013,47(3):164-173
For the past two decades the extraordinary molecular recognition properties of DNA molecules have been used for the creation of artificial molecular structures. Following the initial production of simple molecular objects and lattices, with the recent invention of the DNA origami technique the complexity of these structures has considerably increased. Now the construction of almost arbitrary molecular nanostructures from DNA in two and even three dimensions is feasible – and first concrete applications in biomedicine and nanotechnology are in reach. In addition to static molecular structures, also dynamical systems such as molecular machines, molecular motors, and molecular computers can be realized. The combination of these functions within integrated systems currently leads to the development of first molecular “robots” and assembly lines for nanotechnology. 相似文献
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