Synthesis and zinc(ii) complexation modulated fluorescence emission properties of two pyrene-oligo(phenylene vinylene)-2,2′-bipyridine conjugated molecular rods

Abstract

A series of conjugated rods in which the pyrene chromophore is connected to a 2,2′-bipyridine unit via an oligo(phenylene vinylene) bridge have been synthesized and their photophysical properties in solution investigated. They are shown to display intense visible electronic absorption and fluorescence emission properties. The excited-states characteristics are compared to analogous systems containing an oligo(phenylene ethynylene) spacer. The zinc complexes of the new molecules possess very polar excited states, which lead to strong solvatochromic shifts. Semi empirical calculations were performed which confirmed the experimental data. The X-ray analysis of a pyrene-containing π-conjugated bipyridine ligand is described.