Ruthenium complex polymers electrochromism

Novel Near-IR Electrochromic Ruthenium Complex Polymers... 

Subsequent to isolation of the polymer, the metallization could be conducted in a similar manner as that of the complexes reported elsewhere for DCH-Ru complexes (27-28). The ruthenium complex polymers, shown in Figure 2, thus made would be expected to exhibit similar electrochromic properties as the dinuclear ruthenium complexes while possessing the film forming characteristics of the parent polymer. We report herein the synthesis and characterization of these polymers. 

The Dublin group has also reported a three-color electrochromic metallopoly mer 6 based on a ruthenium phenolate complex bound to poly(4-vinylpyridine). The reversible color changes (wine red to green) are associated with the Ru(II) oxidation, whereas the mixed redox state produces a red-orange. The charge transport parameters of the polymer were thoroughly characterized [27,28]. 

Oxidative Eiectropoiymerization of Poiypyridyi Compiexes. Oxidative electropolymerization of suitably substituted [M (bipy)3l + complexes offers an alternative approach to the preparation of electrochromic redox active polymer films. Oxidative eiectropoiymerization has been described for iron(II) and ruthenium(II) complexes containing amino-substituted (31) and pendant aniline-substituted (32) 2,2 -bipyridyl ligands, and amino- and hydroxy-substituted 2,2 6, 2"-terpyridinyl ligands (33) [ligand structures (4) and (5)]. Analysis of IR spectra suggests that the eiectropoiymerization of [Ru(L )2l + [L = (4)], via the pendant aminophenyl substituent, proceeds by a reaction mechanism similar to that of aniline (33). The resulting metallopolymer film reversibly switches from purple to pale pink on oxidation of Fe(II) to Fe(III). For polymeric films formed from [Ru(L )2l + [L = (5)], via polymerization of the pendant hydroxyphenyl group, the color switch is from brown to dark yellow (see Electropolymerization). 

Multicolour electrochromism was reported for the complex formed from tris(5,5 -dicarbo(3-acrylatoprop-l-oxy)-2,2 -bipyridine) (34) and ruthenium(II) The polymer showed a fairly rapid electrochemical response (as short as 250 ms for the total conversion through seven oxidation states). 

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