Polymeric ruthenium bipyridine complexes : new potential materials for polymer solar cells

Methyl methacrylate-containing bipyridine monomers were synthesized with a hydoxy-functionalized bipyridine. The 4-methyl group of the 2,2-bipyridine was used to introduce hydoxy-functionalized alkyl spacers of two different lengths. Two, different synthetic routes were applied for the preparation of the hydoxy-functionalized bipyridine via a bromo-(C7 spacer) or a silylated-(C3 spacer) intermediate. A copolymer of poly(methyl methacrylate) with bipyridine units in the side chains was prepared by free-radical copolymerization and characterized with 1H NMR, ultraviolet-visible, and IR spectroscopy as well as gel permeation chromatography. The bipyridine units of the copolymer were reacted with ruthenium bipyridine precursors. The resulting graft copolymers displayed promising photophysical and electrochemical properties, opening interesting perspectives for applications in the field of solar-cell devices.