Resonant transport in single-wall armchair carbon nanotubes with local mirror-symmetry-breaking deformations

2001 ◽  
Vol 63 (7) ◽  
Author(s):  
H.-S. Sim ◽  
C.-J. Park ◽  
K. J. Chang
Symmetry ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1098 ◽  
Author(s):  
Carsten Tschierske ◽  
Christian Dressel

Recent progress in mirror symmetry breaking and chirality amplification in isotropic liquids and liquid crystalline cubic phases of achiral molecule is reviewed and discussed with respect to its implications for the hypothesis of emergence of biological chirality. It is shown that mirror symmetry breaking takes place in fluid systems where homochiral interactions are preferred over heterochiral and a dynamic network structure leads to chirality synchronization if the enantiomerization barrier is sufficiently low, i.e., that racemization drives the development of uniform chirality. Local mirror symmetry breaking leads to conglomerate formation. Total mirror symmetry breaking requires either a proper phase transitions kinetics or minor chiral fields, leading to stochastic and deterministic homochirality, respectively, associated with an extreme chirality amplification power close to the bifurcation point. These mirror symmetry broken liquids are thermodynamically stable states and considered as possible systems in which uniform biochirality could have emerged. A model is hypothesized, which assumes the emergence of uniform chirality by chirality synchronization in dynamic “helical network fluids” followed by polymerization, fixing the chirality and leading to proto-RNA formation in a single process.


2021 ◽  
Author(s):  
Ohjin Kwon ◽  
Xiaoqian Cai ◽  
Azhar Saeed ◽  
Feng Liu ◽  
Silvio Poppe ◽  
...  

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...


Author(s):  
Siti Nadiah Binti Mohd Rosely ◽  
Rusnah Syahila Duali Hussen ◽  
See Mun Lee ◽  
Nathan R. Halcovitch ◽  
Mukesh M. Jotani ◽  
...  

The title diorganotin compound, [Sn(CH3)2(C28H32N2O4)], features a distorted SnC2NO2coordination geometry almost intermediate between ideal trigonal–bipyramidal and square-pyramidal. The dianionic Schiff base ligand coordinates in a tridentate fashionviatwo alkoxide O and hydrazinyl N atoms; an intramolecular hydroxy-O—H...N(hydrazinyl) hydrogen bond is noted. The alkoxy chain has an all-transconformation, and to the first approximation, the molecule has local mirror symmetry relating the two Sn-bound methyl groups. Supramolecular layers sustained by imine-C—H...O(hydroxy), π–π [between decyloxy-substituted benzene rings with an inter-centroid separation of 3.7724 (13) Å], C—H...π(arene) and C—H...π(chelate ring) interactions are formed in the crystal; layers stack along thecaxis with no directional interactions between them. The presence of C—H...π(chelate ring) interactions in the crystal is clearly evident from an analysis of the calculated Hirshfeld surface.


2010 ◽  
Vol 81 (23) ◽  
Author(s):  
H. Lin ◽  
J. Lagoute ◽  
V. Repain ◽  
C. Chacon ◽  
Y. Girard ◽  
...  

2008 ◽  
Vol 120 (20) ◽  
pp. 3741-3744
Author(s):  
Niklas Loges ◽  
Stephan E. Wolf ◽  
Martin Panthöfer ◽  
Lars Müller ◽  
Marc-Christopher Reinnig ◽  
...  

Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 28 ◽  
Author(s):  
David Hochberg ◽  
Josep Ribó

Replicators are fundamental to the origin of life and evolvability. Biology exhibits homochirality: only one of two enantiomers is used in proteins and nucleic acids. Thermodynamic studies of chemical replicators able to lead to homochirality shed valuable light on the origin of homochirality and life in conformity with the underlying mechanisms and constraints. In line with this framework, enantioselective hypercyclic replicators may lead to spontaneous mirror symmetry breaking (SMSB) without the need for additional heterochiral inhibition reactions, which can be an obstacle for the emergence of evolutionary selection properties. We analyze the entropy production of a two-replicator system subject to homochiral cross-catalysis which can undergo SMSB in an open-flow reactor. The entropy exchange with the environment is provided by the input and output matter flows, and is essential for balancing the entropy production at the non-equilibrium stationary states. The partial entropy contributions, associated with the individual elementary flux modes, as defined by stoichiometric network analysis (SNA), describe how the system’s internal currents evolve, maintaining the balance between entropy production and exchange, while minimizing the entropy production after the symmetry breaking transition. We validate the General Evolution Criterion, stating that the change in the chemical affinities proceeds in a way as to lower the value of the entropy production.


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