Synthesis of fluorine-containing disazo dyes extended with ester linkages and their application to guest-host liquid crystal displays

Abstract

The solubility of known azo dyes was in the order of dye skeleton: trisazo and aryloxycarbonyl disazo dyes < aryloxy disazo dyes < disazo dyes. The perfluoroalkyl derivatives were synthesized and found to be more soluble than the corresponding alkyl analogues except for a series of aryloxycarbonyl disazo dyes. Dichroism (order parameter,S)was in the order of dye skeleton: disazo dyes < aryloxycarbonyl and aroyloxy disazo dyes < trisazo dyes. No marked difference in the dichroism among perfluorobutyl, hexyl and octyl derivatives was observed. All the ester-type disazo dyes showed good S values (> 0.76).