Conducting Polymers Containing In-Chain Metal Centers: Electropolymerization of Oligothienyl-Substituted {M(tpy)2} Complexes and in Situ Conductivity Studies, M = Os(II), Ru(II)

The electropolymn. of Ru and Os bis-terpyridine complexes that form rodlike polymers with bithienyl, quaterthienyl, or hexathienyl bridges were studied. Absorption spectroscopy, SEM, and cyclic voltammetry were used to characterize the monomers and resulting polymer films. The abs. d.c. cond. of the quaterthienyl-bridged {Ru(tpy)2} and {Os(tpy)2} polymers is unusually large and independent of the identity of the metal center at 1.6 × 10-3 S cm-1. The max. cond. occurs at the formal potential of each redox process, which typically is obsd. for systems where redox conduction is the dominant charge transport mechanism. Significantly, the d.c. cond. of the metal-based redox couple obsd. in these polymers is 2 orders of magnitude higher than that of a comparable nonconjugated system.