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Tetrahedratic Mesophases, Ambidextrous Chiral Domains and Helical Superstructures Produced by Achiral 1,1′‐Disubstituted Ferrocene Derivatives
Author(s) -
Kim Eun Ho,
Kadkin Oleg Nikolaevich,
Kim So Yeon,
Choi MoonGun
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201100165
Subject(s) - chemistry , crystallography , mesophase , liquid crystal , ferrocene , supramolecular chemistry , mesogen , molecule , lamellar structure , moiety , enantiomer , chirality (physics) , crystal structure , stereochemistry , organic chemistry , materials science , liquid crystalline , polymer , phase (matter) , nambu–jona lasinio model , optoelectronics , electrode , chiral symmetry breaking , quantum mechanics , physics , quark , electrochemistry
A series of symmetrically and asymmetrically 1,1′‐disubstituted mesogenic ferrocene derivatives exhibiting nonconventional lamellar and nematic phases has been synthesized. Liquid‐crystal properties of these compounds were investigated by polarizing optical microscopy (POM), thermal analysis (DSC) and X‐ray scattering methods (XRD). XRD patterns and optical textures of the mesophases have a complex appearance, standing apart from the signatures of previously classified liquid crystals. The most important features of the new mesophases are their spontaneous separation into large macroscopic chiral domains of opposite handednesses, intricate helical and myelinic supramolecular structures and a few signs of possible optical biaxiality. A reasonable explanation of these findings can be drawn from the tetrahedral liquid crystal order. Free rotation of the cyclopentadiene rings in the ferrocene moiety around their normal axis makes viable bent conformations of the rod‐like molecules and further stabilization of the conformational enantiomers through assembly into tetrahedral molecular associates. Thus, fundamentally new types of mesophases arise from such a molecular arrangement. In addition, a nontrivial case of mixed packing of bent and nonbent molecules into columnar mesophases was detected in one of the symmetrically substituted ferrocene derivatives. Basic relationships between mesomorphic properties, supramolecular organization and chemical structures of the ferrocenomesogens have been outlined.