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Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Chiral symmetry breaking and polymorphism in 1,1'-binaphthyl melt crystallization
C Ignacio Sainz-Díaz1, Africa P Martín-Islan, Julyan H E Cartwright
1Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra (CSIC)-Edificio BIC Granada, Avenida de la Innovacion, 1, P.T. Ciencias de la Salud, E-18100 Armilla, Granada, Spain. sainz@lec.ugr.es
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Stirring 1,1'-binaphthyl melt during crystallization induces chiral symmetry breaking. This process, involving whisker crystal formation and secondary nucleation, leads to enantiomorphic crystal structures.
Area of Science:
- Crystallography
- Materials Science
- Chemical Physics
Background:
- Chiral symmetry breaking is crucial in crystallization processes.
- 1,1'-binaphthyl exhibits complex crystallization behavior.
- Polymorphism and enantiomorphism are key characteristics of 1,1'-binaphthyl.
Purpose of the Study:
- To investigate chiral symmetry breaking in 1,1'-binaphthyl melt crystallization.
- To understand the role of stirring and whisker formation in inducing chirality.
- To elucidate the structural differences between melt and vapor crystallized polymorphs.
Main Methods:
- Melt crystallization experiments with controlled stirring.
- Vapor crystallization analysis.
- X-ray diffraction for crystallographic studies.
- Conformational analysis of molecular structures.
Main Results:
- Stirring induces chiral symmetry breaking in melt crystallization.
- Two polymorphs of 1,1'-binaphthyl were identified: chiral tetragonal (melt) and racemic monoclinic (vapor).
- Melt crystals contain transoid conformers, while vapor crystals contain cisoid conformers of both enantiomers.
- Weak aromatic CH/pi hydrogen bonds mediate enantiomeric discrimination.
Conclusions:
- Chiral symmetry breaking in 1,1'-binaphthyl is confirmed and influenced by stirring.
- Whisker formation and fragmentation act as an autocatalytic mechanism for chiral induction.
- Polymorphism arises from different conformers and crystallization conditions (melt vs. vapor).
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