Synthesis and properties of luminescent liquid crystalline naphthalenes

Abstract

Some novel liquid crystalline naphthalenes were synthesized and their phase transition behaviors, optical properties were investigated. The liquid crystalline dialkoxynaphthalene derivatives were synthesized from 1,5- or 2,6-dihydroxynaphthalene and 4-cyano-4'-hydroxybiphenyl with appropriate methylene chains by Williamson or Mitsunobu eterification reaction. The transitional properties observed by thermo-controlled polarizing microscopy showed that 1,5-naphthalene derivatives had a monotropic nematic phase, while 2,6-naphthalene derivatives had an enantiotropic one. They showed an intense blue fluorescence in the liquid and liquid crystalline states.