Thermal properties of monosubstituted ferrocene derivatives: a series of new ferrocenomesogens

Abstract

The preparation of a series of 1-substituted ferrocene derivatives is described. The structure of the substituent was varied systematically in order to determine the structural limits within which mesogenic behaviour is retained. The compounds are particularly useful for stabilizing the nematic phase, the range of which was increased substantially by extending the aromatic core of the substituent. Selective lateral fluorination was successfully used to lower the nematic temperatures as well as to suppress any smectic phases. Derivatives with no more than two rings in the core only display the crystal smectic B phase. The significance of substituents on the cyclopentadienyl rings is discussed with reference to their electronic properties and their effect on the stability of the compounds.

Solvent-free synthesis of ferrocenylimines

“…The melting behaviors of the imine products are in accordance with the guidelines provided by Imrie and Loubser [11]. Compounds containing one ferrocenyl group plus one phenyl ring have sharp melting points; those with one ferrocenyl group plus two phenyl rings show some crystal-crystal phase transitions and finally those with one ferrocenyl group and three phenyl rings exhibit liquid crystal behavior.…”

Phase behavior of some mono-substituted ferrocene- and [3]ferrocenophane-containing nematics with the cyclohexane ring in the rigid core

“…The latter fact has been already emphasized in systematic investigations of Loubser and Imrie [14]. Dissimilar to fluorinated 4b showing enantiotropic mesomorphism its non-fluorinated counterpart 5 exhibits only the monotropic nematic phase.…”

Thermotropic Liquid Crystals from Planar Chiral Compounds: [2.2]Paracyclophane as a Mesogen Core

“…Subsequent removal of the protecting group was accomplished by stirring with aq. ammonia in EtOH [28] to give the desired phenolic derivatives, which were recrystallized from EtOH.…”