scholarly journals Spontaneous and directed symmetry breaking in the formation of chiral nanocrystals

2019 ◽  
Vol 116 (23) ◽  
pp. 11159-11164 ◽  
Author(s):  
Uri Hananel ◽  
Assaf Ben-Moshe ◽  
Haim Diamant ◽  
Gil Markovich
Keyword(s):  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Natural World ◽  
Colloidal Synthesis ◽  
Aqueous Environment ◽  
Chemical Systems ◽  
Chiral Amplification ◽  
Circularly Polarized Luminescence ◽  
Left And Right ◽  
Crucial Part

Symmetry plays a crucial part in our understanding of the natural world. Mirror symmetry breaking is of special interest as it is related to life as we know it. Studying systems which display chiral amplification, therefore, could further our understanding of symmetry breaking in chemical systems, in general, and thus also of the asymmetry in Nature. Here, we report on strong chiral amplification in the colloidal synthesis of intrinsically chiral lanthanide phosphate nanocrystals, measured via circularly polarized luminescence. The amplification involves spontaneous symmetry breaking into either left- or right-handed nanocrystals below a critical temperature. Furthermore, chiral tartaric acid molecules in the solution direct the amplified nanocrystal handedness through a discontinuous transition between left- and right-handed excess. We analyze the observations based on the statistical thermodynamics of critical phenomena. Our results demonstrate how chiral minerals with high enantiopurity can form in a racemic aqueous environment.

scholarly journals Chiral Oscillations and Spontaneous Mirror Symmetry Breaking in a Simple Polymerization Model

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1388
Author(s):  
William Bock ◽  
Enrique Peacock-López
Keyword(s):  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Chiral Symmetry Breaking ◽  
Enantiomeric Excess ◽  
Chemical Species ◽  
Preferential Formation ◽  
Chiral Amplification ◽  
Sustained Oscillations ◽  
Wide Range ◽  
The Origin Of Life

The origin of biological homochirality—defined as the preference of biological systems for only one enantiomer—has widespread implications in the study of chemical evolution and the origin of life. The activation—polymerization—epimerization—depolymerization (APED) model is a theoretical model originally proposed to describe chiral symmetry breaking in a simple dimerization system. It is known that the model produces chiral and chemical oscillations for certain system parameters, in particular, the preferential formation of heterochiral polymers. In order to investigate the effect of higher oligomers, our model adds trimers, tetramers, and pentamers. We report sustained oscillations of all chemical species and the enantiomeric excess for a wide range of parameter sets as well as the periodic chiral amplification of a small initial enantiomeric excess to a nearly homochiral state.

Mirror symmetry breaking and chiral amplification in foldamer-based supramolecular helical aggregates

2012 ◽  
Vol 48 (17) ◽  
pp. 2292 ◽  
Author(s):  
Simon Azeroual ◽  
Jamie Surprenant ◽  
Thomas D. Lazzara ◽  
Marta Kocun ◽  
Ye Tao ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Mirror Symmetry ◽  
Chiral Amplification

scholarly journals Handed Mirror Symmetry Breaking at the Photo-Excited State of π-Conjugated Rotamers in Solutions

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 272 ◽  
Author(s):  
Puhup Puneet ◽  
Sajan Singh ◽  
Michiya Fujiki ◽  
Bhanu Nandan
Keyword(s):  
Symmetry Breaking ◽  
Parity Violation ◽  
Mirror Symmetry ◽  
Molecular Level ◽  
Time Resolved ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
Consistent Increase ◽  
Life On Earth ◽  
Time Resolved Photoluminescence

The quest to decode the evolution of homochirality of life on earth has stimulated research at the molecular level. In this study, handed mirror symmetry breaking, and molecular parity violation hypotheses of systematically designed π-conjugated rotamers possessing anthracene and bianthracene core were evinced via circularly polarized luminescence (CPL) and circular dichroism (CD). The CPL signals were found to exhibit a (−)-sign, and a handed dissymmetry ratio, which increased with viscosity of achiral solvents depending on the rotation barrier of rotamers. The time-resolved photoluminescence spectroscopy and quantum efficiency measurement of these luminophores in selected solvents reinforced the hypothesis of a viscosity-induced consistent increase of the (−)-sign handed CPL signals.

2,6-Dibromogallates as a new building block for controlling π-stacking, network formation and mirror symmetry breaking

2021 ◽  
Author(s):  
Ohjin Kwon ◽  
Xiaoqian Cai ◽  
Azhar Saeed ◽  
Feng Liu ◽  
Silvio Poppe ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Building Block ◽  
Mirror Symmetry ◽  
Network Formation ◽  
Network Structures ◽  
Π Stacking ◽  
Bicontinuous Cubic ◽  
Substituted 1 ◽  
End Group

Achiral multi-chain (polycatenar) compounds based on the 2,7-diphenyl substituted [1]benzothieno[3,2-b]benzothiophene (BTBT) unit and a 2,6-dibromo-3,4,5-trialkoxybenzoate end group lead to materials forming bicontinuous cubic liquid crystaline phases with helical network structures...

scholarly journals Questions of Mirror Symmetry at the Photoexcited and Ground States of Non-Rigid Luminophores Raised by Circularly Polarized Luminescence and Circular Dichroism Spectroscopy: Part 1. Oligofluorenes, Oligophenylenes, Binaphthyls and Fused Aromatics

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2606 ◽  
Author(s):  
Michiya Fujiki ◽  
Julian Koe ◽  
Takashi Mori ◽  
Yoshihiro Kimura
Keyword(s):  
Circular Dichroism ◽  
Mirror Symmetry ◽  
Neutral Current ◽  
Visible Region ◽  
Cd Spectroscopy ◽  
Mirror Image ◽  
Circularly Polarized ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence ◽  
Circular Dichroïsm

We report experimental tests of whether non-rigid, π-conjugated luminophores in the photoexcited (S1) and ground (S0) states dissolved in achiral liquids are mirror symmetrical by means of circularly polarized luminescence (CPL) and circular dichroism (CD) spectroscopy. Herein, we chose ten oligofluorenes, eleven linear/cyclic oligo-p-arylenes, three binaphthyls and five fused aromatics, substituted with alkyl, alkoxy, phenyl and phenylethynyl groups and also with no substituents. Without exception, all these non-rigid luminophores showed negative-sign CPL signals in the UV-visible region, suggesting temporal generation of energetically non-equivalent non-mirror image structures as far-from equilibrium open-flow systems at the S1 state. For comparison, unsubstituted naphthalene, anthracene, tetracene and pyrene, which are achiral, rigid, planar luminophores, did not obviously show CPL/CD signals. However, camphor, which is a rigid chiral luminophore, showed mirror-image CPL/CD signals. The dissymmetry ratio of CPL (glum) for the oligofluorenes increased discontinuously, ranging from ≈ −(0.2 to 2.0) × 10−3, when the viscosity of the liquids increased. When the fluorene ring number increased, the glum value extrapolated at [η] = 0 reached −0.8 × 10−3 at 420 nm, leading to (–)-CPL signals predicted in the vacuum state. Our comprehensive CPL and CD study should provide a possible answer to the molecular parity violation hypothesis arising due to the weak neutral current mediated by the Z0-boson.

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