Novel synthesis of protected thiol end-capped stilbenes and oligo(phenylenevinylene)s (OPVs)

The first general procedures for preparation of thiol end-capped stilbenes and oligo(phenylenevinylene)s (OPVs) with tert-butyl- and acetyl-protected thiol termini have been developed. These reactions proceed via Br/Li exchange, McMurry, and Wittig-type reactions. The thiol functionality is protected against strong basic and acidic reaction conditions as a t-Bu sulfide. As a key point in the method, reprotection of the thiol group is accomplished by means of acetyl chloride and boron tribromide. The novel strategy forms the basis for stepwise introduction of 4-mercaptostyryl units in OPVs. The new mono-, di-, and trimercapto OPVs have potential applications as one, two, and three terminal molecular devices in gold nanoparticle clusters, self-assembled monolayers, and optoelectronic devices.