Syntheses and Some Properties of Deep Colored Dichroic Polyazo Dyes

Abstract

Non-ionic blue trisazo dyes having the same acceptor and conjugating bridge, and different kinds of donor with intramolecular charge-transfer chromophores were synthesized and their color-constitution relationship, dichroism and solubility in liquid crystal were investigated.
Their λ_max lie at 626-645 nm and dyes absorbed in the broad region of 500-800 nm in LC. The deep blue dyes, which have 1-heptyl-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline as a donor, have an appropriate dichroism and solubility in LC and can be practically used. On the other hand, the dyes derived from 1-alkylaminonaphthalene and julolidine have better dichroism, but generally have lower solubility and their applications are restricted.