- Controlling Mirror Symmetry Breaking and Network Formation in Liquid Crystalline Cubic, Isotropic Liquid and Crystalline Phases of Benzil-Based Polycatenars
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Spontaneous development of chirality in systems composed of achiral molecules is important for new routes to asymmetric synthesis, chiral superstructures and materials, as well as for the understanding of the mechanisms of emergence of prebiotic chirality. Herein, it is shown that the 4,4′-diphenylbenzil unit is a universal transiently chiral bent building block for the design of multi-chained (polycatenar) rod-like molecules capable of forming a wide variety of helically twisted network structures in the liquid, the liquid crystalline (LC) and the crystalline state. Single polar substituents at the apex of tricatenar molecules support the formation of the achiral (racemic) cubic double network phase with Ia (Formula presented.) d symmetry and relatively small twist along the networks. The combination of an alkyl chain with fluorine substitution leads to the homogeneously chiral triple network phase with I23 space group, and in addition, provides a mirror symmetry broken liquid. Replacing F by Cl or Br further increases the twist, leading to a short pitch double gyroid Ia (Formula presented.) d phase, which is achiral again. The effects of the structural variations on the network structures, either leading to achiral phases or chiral conglomerates are analyzed.
- Reppe, Tino,Poppe, Silvio,Tschierske, Carsten
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supporting information
p. 16066 - 16079
(2020/11/02)
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- Semiheterogeneous Dual Nickel/Photocatalytic (Thio)etherification Using Carbon Nitrides
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A carbon nitride material can be combined with homogeneous nickel catalysts for light-mediated cross-couplings of aryl bromides with alcohols under mild conditions. The metal-free heterogeneous semiconductor is fully recyclable and couples a broad range of electron-poor aryl bromides with primary and secondary alcohols as well as water. The application for intramolecular reactions and the synthesis of active pharmaceutical ingredients was demonstrated. The catalytic protocol is applicable for the coupling of aryl iodides with thiols as well.
- Cavedon, Cristian,Madani, Amiera,Seeberger, Peter H.,Pieber, Bartholom?us
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supporting information
p. 5331 - 5334
(2019/07/08)
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- FLUOROALKANE DERIVATIVE, GELLING AGENT AND GEL COMPOSITION
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The present invention provides a fluoroalkane derivative represented by the following general formula (1): ????????R-SO2-Ar-O-R1?????(1) wherein Ar denotes a substituted or nonsubstituted divalent aromatic group having 8 to 30 atoms
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Page/Page column 13-14
(2013/02/28)
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- Surface modification of self-assembled one-dimensional organic structures: White-light emission and beyond
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Surface modification is an important method to functionalize micro-/nanostructures, but substrates are mainly confined to robust inorganic compounds. We develop here a facile method to modify the surface of a fragile organic 1D microstructure. The bulk mo
- Wang, Xiao,Yan, Jing,Zhou, Yan,Pei, Jian
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supporting information; scheme or table
p. 15872 - 15874
(2011/01/11)
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- Hyperbranched polymers with a degree of branching of 100% prepared by catalyst transfer Suzuki-Miyaura polycondensation
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(Chemical Equation Presented) Hyperbranched polymers with a degree of branching of 100% were prepared by catalyst transfer Suzuki-Miyaura polymerization of AB2 monomers carrying one boronic acid and two aromatic bromo functional groups; in contrast, Suzuki-Miyaura polymerization of the same AB2 monomers using a traditional catalyst afforded hyperbranched polymers with a branching degree of only ~56%. This is a nice example of controlling the topology of hyperbranched polymers via the catalyst.
- Huang, Weiguo,Su, Linjie,Bo, Zhishan
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supporting information; experimental part
p. 10348 - 10349
(2009/12/03)
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