Sterically Encumbered Bipyridyl-Derivatized Conjugated Polymers and Metallopolymers Incorporating Phenylenevinylene, Phenyleneethynylene, and Fluorenylene Segments

This work reports the preparation of a series of 2,2′-bipyridyl (bipy) modified π-conjugated polymers having an average of one or three monomer units (p-arylene ethynylene for PPE1 and PPE3 or 7,7-dihexylfluorene for PF1 and PF3) between metal-binding sites. Spectroscopic data demonstrate that strategic placement of sterically encumbered mesityl groups about the metal binding sites enforces a 1:1 metal to bipy binding ratio. This steric coordination control ensures that the metalated polymers remain solution processable rather than forming insoluble networks via coordinative cross-linking. The solution photophysical and electrochemical properties of metal-free and metalated materials are reported and compared with those of related conjugated polymers and conducting metallopolymers.