4-[2-(Trimethylsilyl)ethynyl]benzoates: Synthesis and evaluation for mesomorphic properties of some novel calamitic molecules

• Synthesis and mesomorphic properties of novel calamitic molecules: 4-[2-(trimethylsilyl)ethynyl]benzoates.
• The compounds were characterised by IR, 1H NMR, 13C NMR, elemental analysis, ESI-MS, DSC and POM.
• Esters of biphenyl core with short terminal alkyl chains favour liquid crystalline properties.

A series of novel terminal trimethylsilylacetylene benzoate derivatives with various linking groups were synthesized using Friedel-Craft's O-acylation reaction. The chemical structures of the novel 4-[2-(trimethylsilyl)ethynyl]benzoates were confirmed by standard spectroscopic techniques. The compounds were investigated for their liquid crystalline properties employing polarised optical microscopy and differential scanning calorimetry. The esters 5c – 5f, 5h and 5n possessing three phenyl rings exhibited liquid crystalline property of SmA/SmC phases with wide thermal range.

A new series of terminal trimethylsilylacetylene benzoate derivatives were investigated for liquid crystalline properties. During heating, 5d transformed from crystal to Smectic A phase and then to isotropic phase, but during cooling, the compound 5d transformed from isotropic phase to Smectic A phase and Smectic C phase and then crystallised.Figure optionsDownload as PowerPoint slide