Experimental and geometrical structure characterizations of new synthesized laterally fluorinated nematogenic system

ABSTRACT

New mesomorphic homologue series of laterally fluorinated azo/esters, 2-fluoro-4-((4-alkoxy)phenyl)diazenyl)phenyl 4-(alkoxy)benzoate (I_n/m), were synthesized and investigated their behaviour via experimental and computational tools. The prepared series bearing eight derivatives that differ from each other by the terminally attached alkoxy chain groups at their ends. Elemental analyses, FT-IR and NMR spectroscopy were carried out to elucidate their molecular structures. Mesophase and optical examinations of the synthesized homologues are conducted using differential scanning calorimetry (DSC) and polarised optical microscopy (POM). Mesomorphic characterisations revealed that all the laterally F substituted derivatives are monomorphic exhibiting nematic (N) mesophase with enantiotropic properties, except the longest terminal chain member possesses N phase monotropically. The comparative studies between the present group, I_6/m, and the laterally-neat series revealed that the type and stability of the produced phase are dependent upon the influenced molecular dipole moment of the mesogenic core which is mainly dependent on the insertion of the lateral F atom. Computational approaches were carried by DFT calculations and the optimised structures of present investigated series have been deduced. DFT results revealed that, the incorporation of lateral F atom has essential effects on the stability of possible geometries as well as their thermal and physical parameters.

GRAPHICAL ABSTRACT

KEYWORDS:

• Azo/ester
• lateral fluorine
• nematic phase
• geometrical structure
• DFT

Disclosure statement

No potential conflict of interest was reported by the author(s).

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