Synthesis and Properties of Chiral Chromophore-Functionalized Polybinaphthalenes for Nonlinear Optics: Influence of Chromophore Concentration

Abstract

A series of chromophore-functionalized polybinaphthalenes have been prepared and characterized for their (nonlinear optical) properties. The polymers were prepared by direct polymerization using a Stille coupling between a bis(trimethyltin) compound and dibromo-substituted binaphthalene monomers. The chromophores were attached to the binaphthalene unit via an alkyl spacer. The influence of the chromophore concentration, spacer length, and number of chromophores per binaphthalene unit was studied. The typical treelike macromolecular architecture of these molecules gives rise to a unique behavior in the glass transition temperature, NMR, and nonlinear optical properties. The nonlinear optical response shows a continuous increase in function of the chromophore content. In this way, the nonlinear optical properties can be increased in a way that is not possible with other chromophore-functionalized polymer materials.