Optically active and photoswitchable Tröger's base analogs

2019 ◽  
Vol 43 (20) ◽  
pp. 7751-7755 ◽  
Author(s):  
Masoud Kazem-Rostami
Keyword(s):  
Liquid Crystal ◽  
Optically Active ◽  
Troger's Base

Azo carrying Tröger's base analogs introduced chirality, thermochromic and phototunable properties to an achiral liquid crystal host.

Modular Synthesis of Optically Active Tröger’s Base Analogues

ChemPlusChem ◽  
2013 ◽  
Vol 78 (12) ◽  
pp. 1510-1516 ◽  
Author(s):  
Takuya Kamiyama ◽  
Merve Sinem Özer ◽  
Elisabeth Otth ◽  
Jan Deska ◽  
Ján Cvengroš
Keyword(s):  
Optically Active ◽  
Modular Synthesis ◽  
Troger's Base

Optically Active Smectic Liquid Crystal

1971 ◽  
Vol 14 (3-4) ◽  
pp. 289-292 ◽  
Author(s):  
W. Helfrich ◽  
Chan S. Oh
Keyword(s):  
Liquid Crystal ◽  
Optically Active ◽  
Smectic Liquid Crystal

scholarly journals Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

2020 ◽  
Vol 20 (4) ◽  
pp. 6-26
Author(s):  
V. A. Burmistrov ◽  
V. V. Aleksandriiskii ◽  
I. V. Novikov ◽  
O. I. Koifman
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
High Efficiency ◽  
Stationary Phases ◽  
Theoretical Description ◽  
Optically Active ◽  
Axial Coordination ◽  
Chiral Dopants

Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.

Optically Active Binary Liquid Crystal Thermometry

1979 ◽  
Vol BME-26 (3) ◽  
pp. 148-152 ◽  
Author(s):  
Thomas H. Windhorn ◽  
Charles A. Cain
Keyword(s):  
Liquid Crystal ◽  
Optically Active ◽  
Binary Liquid

Highly frustrated liquid crystal phases in optically active dimers: synthesis and rich phase transitional behavior

2019 ◽  
Vol 43 (5) ◽  
pp. 2148-2162 ◽  
Author(s):  
Rashmi Ashwathama Nayak ◽  
Sachin A. Bhat ◽  
G. Shanker ◽  
D. S. Shankar Rao ◽  
C. V. Yelamaggad
Keyword(s):  
Schiff Base ◽  
Liquid Crystal ◽  
Optically Active ◽  
Rich Phase ◽  
Transitional Behavior ◽  
Crystal Phases ◽  
Liquid Crystal Phases

New cholesterol-based Schiff base dimers exhibit a rich mesomorphism.

scholarly journals Development of N-F fluorinating agents and their fluorinations: Historical perspective

2021 ◽  
Vol 17 ◽  
pp. 1752-1813
Author(s):  
Teruo Umemoto ◽  
Yuhao Yang ◽  
Gerald B Hammond
Keyword(s):  
Organic Compounds ◽  
Historical Development ◽  
Historical Perspective ◽  
Optically Active ◽  
Research Areas ◽  
Troger's Base

This review deals with the historical development of all N-F fluorinating agents developed so far. The unique properties of fluorine make fluorinated organic compounds attractive in many research areas and therefore fluorinating agents are important. N-F agents have proven useful by virtue of their easy handling. This reagent class includes many types of N-F compounds: perfluoro-N-fluoropiperidine, N-fluoro-2-pyridone, N-fluoro-N-alkylarenesulfonamides, N-fluoropyridinium salts and derivatives, N-fluoroquinuclidium salts, N-fluoro-trifluoromethanesulfonimide, N-fluoro-sultams, N-fluoro-benzothiazole dioxides, N-fluoro-lactams, N-fluoro-o-benzenedisulfonimide, N-fluoro-benzenesulfonimide, 1-alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts, N-fluoropyridinium-2-sulfonate derivatives, 1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane salts, N-fluorodinitroimidazole, N-fluoro-trichloro-1,3,5-triazinium salt, N-F ethano-Tröger’s base derivatives, N-fluoro-methanesulfonimide, N-fluoro-N-arylarenesulfonamides, bisN-F salts such as N,N’-difluorobipyridinium salts and N,N’-difluoro-1,4-diazoniabicyclo[2.2.2]octane salts, and their many derivatives and analogs, including chiral N-F reagents such as optically active N-fluoro-sultam derivatives, N-fluoro-alkaloid derivatives, DABCO-based N-F derivatives, and N-F binaphthyldisulfonimides. The synthesis and reactions of these reagents are described chronologically and the review also discusses the relative fluorination power of each reagent and their mechanisms chronicling developments from a historical perspective.

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