Syntheses of Several Amphiphilic Cyanine Dyes and Formation of LB Films

Abstract

Several amphiphilic cyanine dyes which have phenylcyclohexyl group as a mesogenic group, were synthesized and the formation of monolayers and LB films were studied. The mixture of p-(trans-4-pentylcyclohexyl)phenol (1 mol) and α, ω -dibromoalkane (1.1 mol) in ethanolic potassium hydroxide solution were refluxed to form w-bromoalkyl p-(trans-4-pentylcyclohexyl)phenyl ether [4] Two monomethinecyanin. e dyes [8] and four trimethinecyanine dyes [9]were obtained from [4].
Surface pressure-area (π-A) i sotherms on a cadmium containing aqueous solution showed that these dyes form stable monolayer and the limiting areas per molecule were ca.0.5 nm²for [8] and ca.0.7 nm² for [9]. The UV-Vis spectra of the LB films were measured and discussed.