Synthesis and mesomorphic properties of banana-shaped monomers containing 2,7-naphthalene as central core

Abstract

Two banana-shaped monomers containing 2,7-dihydroxynaphthalene as central unit were synthesized and their mesophase behavior was investigated. The liquid crystals monomers containing azobenzene chromophores were prepared as target molecules, 1,3-naphthalene bis-{4-[(4-allyloxy)phenylazo]benzoate} 4a and 1,3-naphthalene bis-{4-[3-(4-allyloxy)fluorophenylazo] benzoate} 4b. The polarizing optical microscopy and DSC measurements reveal that both compounds exhibited nematic mesophases. The presence of allyl bonds to the both wins could be contributed as precursors of polymers for a wide mesophase compounds during photo-polymerization under UV irradiation.