p-Phenylene sulfide oligomers and their properties. Ar–S couplings mediated by copper or by fluorine substitutions

A series of monodisperse p-phenylene sulfide oligomers were efficiently synthesized by using a bidirectional growth. A strategy combining Cu-catalyzed Ar–S couplings for small oligomers and fluorine aromatic substitutions by aryl thiolates for longer ones was put forward. The latter method is superior to Cu-catalyzed reactions for longer oligomers. Fluorine chemistry brings some new advantages such as solubility and reactivity. Qualitative crystallinity studies were reported according to the oligomer size and the functional series, by using a microscope equipped with a heating stage and a camera.