نتایج جستجو برای: achiral

تعداد نتایج: 1375  

2015
Zhaocun Shen Tianyu Wang Lin Shi Zhiyong Tang Minghua Liu

Although the importance of circularly polarized luminescence (CPL) materials has been widely recognized, the CPL responses of supramolecular gels are still rarely studied. Moreover, developing CPL materials based on supramolecular gels is of great significance, due to their special advantages and important applications. Herein, we report the first circularly polarized supramolecular gels self-a...

2016
Bruno Gallinella Rosella Ferretti Leo Zanitti Isabella Sestili Antonina Mosca Roberto Cirilli

A simple analytical high-performance liquid chromatography (HPLC) method was applied for the enantiomeric excess determination of esomeprazole ((S)-OME), the enantiopure active ingredient contained in drug products, in the presence of its potential organic impurities A-E. The enantioselective separation was accomplished on the immobilized-type Chiralpak ID-3 chiral stationary phase (CSP) under ...

2013
Jan Labuta Shinsuke Ishihara Tomáš Šikorský Zdeněk Futera Atsuomi Shundo Lenka Hanyková Jaroslav V. Burda Katsuhiko Ariga Jonathan P. Hill

Enantiomeric excess of chiral compounds is a key parameter that determines their activity or therapeutic action. The current paradigm for rapid measurement of enantiomeric excess using NMR is based on the formation of diastereomeric complexes between the chiral analyte and a chiral resolving agent, leading to (at least) two species with no symmetry relationship. Here we report an effective meth...

Journal: :Chemical science 2015
Zhaocun Shen Tianyu Wang Lin Shi Zhiyong Tang Minghua Liu

Although the importance of circularly polarized luminescence (CPL) materials has been widely recognized, the CPL responses of supramolecular gels are still rarely studied. Moreover, developing CPL materials based on supramolecular gels is of great significance, due to their special advantages and important applications. Herein, we report the first circularly polarized supramolecular gels self-a...

2015
A Anuradha Duong Duc La Mohammad Al Kobaisi Sheshanath V. Bhosale

The induction and development of chiral supramolecular structures from hierarchical self-assembly of achiral compounds is closely related to the evolution of life and the chiral amplification found in nature. Here we show that the combination of achiral tetraphenylethene (TPE) an AIE-active luminophore bearing four long alkyl chains via amide linkage allows the entire process of induction and c...

Journal: :Nature chemistry 2012
Kohsuke Ohmatsu Mitsunori Ito Tomoatsu Kunieda Takashi Ooi

Conventional chiral ligands rely on the use of a covalently constructed, single chiral molecule embedded with coordinative functional groups. Here, we report a new strategy for the design of a chiral ligand for asymmetric transition-metal catalysis; our approach is based on the development of an achiral cationic ammonium-phosphine hybrid ligand paired with a chiral binaphtholate anion. This ion...

Journal: :Physical review letters 2016
S K Mkhonta K R Elder Zhi-Feng Huang

Chirality is known to play a pivotal role in determining material properties and functionalities. However, it remains a great challenge to understand and control the emergence of chirality and the related enantioselective process particularly when the building components of the system are achiral. Here we explore the generic mechanisms driving the formation of two-dimensional chiral structures ...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2010
Yunfeng Qiu Penglei Chen Minghua Liu

Interfacial molecular assemblies of eight atypical amphiphilic porphyrins, substituted with hydrophobic or hydrophilic substituents but without long alkyl chains on their molecular skeletons, have been investigated in terms of supramolecular chiralty generation and amplification. It is found that all of the originally organized interfacial molecular assemblies display very weak or undetectable ...

2015
Lifei Zheng Silvia Sonzini Masyitha Ambarwati Edina Rosta Oren A. Scherman Andreas Herrmann

Chiral macromolecules have been widely used as synthetic pockets to mimic natural enzymes and promote asymmetric reactions. An achiral host, cucurbit[8]uril (CB[8]), was used for an asymmetric Lewis acid catalyzed Diels-Alder reaction. We achieved a remarkable increase in enantioselectivity and a large rate acceleration in the presence of the nanoreactor by using an amino acid as the chiral sou...

Journal: :Electr. J. Comb. 2006
Éric Fusy

We completely solve the problem of enumerating combinatorially inequivalent d-dimensional polytopes with d + 3 vertices. A first solution of this problem, by Lloyd, was published in 1970. But the obtained counting formula was not correct, as pointed out in the new edition of Grünbaum’s book. We both correct the mistake of Lloyd and propose a more detailed and self-contained solution, relying on...

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