New Liquid Crystal Assemblies Based on Cyano-Hydrogen Bonding Interactions.

Area of Science:

• Supramolecular Chemistry
• Liquid Crystals
• Materials Science

Background:

• Hydrogen bonding is a key interaction for forming supramolecular structures.
• Liquid crystals exhibit properties between conventional liquids and solid crystals.

Purpose of the Study:

• To synthesize and characterize novel supramolecular liquid crystal complexes.
• To investigate the influence of molecular structure, specifically alkoxy chain length, on liquid crystalline properties.

Main Methods:

• Complex formation using 4-n-alkoxybenzoic acid (An) and N-4-cyanobenzylidene-4-n-(hexyloxy)benzenamine (I).
• Spectroscopic analysis (FT-IR, NMR, Mass Spectrometry, HPLC) to confirm complexation.
• Thermal analysis (Differential Scanning Calorimetry, Polarized Optical Microscopy) for phase characterization.
• Binary phase diagrams and computational modeling (Density Functional Theory) for validation and explanation.

Main Results:

• Successful synthesis of supramolecular liquid crystal complexes via hydrogen bonding.
• Enantiotropic mesophases were observed, with type dependent on alkoxy chain length.
• Mesomorphic temperature ranges decreased linearly with increasing alkoxy chain length (I/A6 > I/A8 > I/A10 > I/A16).

Conclusions:

• The study demonstrates a structure-property relationship in hydrogen-bonded liquid crystal complexes.
• Alkoxy chain length is a critical factor controlling mesophase behavior and stability.
• Computational modeling supports experimental findings on molecular interactions and mesophase stability.