Bis(Dioxolene)Bis(Pyridine)Ruthenium Redox Series.

摘要

A series of ruthenium complexes containing non-innocent, 1,2-dioxolene ligands (dioxolene refers to any of the series catechol-semiquinone-quinone) have been prepared. These have the formula trans-(Ru(RpY)2(dioxolene)2)n where RPy are a series of substituted pyridines and n = -1,0,+1. Their electrochemical and spectroscopic (NMR,ESR,IR,PES, electronic) properties are reported and discussed in terms of their electronic structures, described using simple qualitative molecular orbital models. Their electronic structures are subtly different from those of the related cis-(Ru(bpy) (dioxolene)2)n species reported previously (bpy = 2,2'-bipyrdine). The neutral (n=0) complexes have a fully delocalized, mixed valence RuIII (RPy)2(catechol) (semiquinone) electronic structure. The oxidized (n = +1) and reduced (n = -1) species are also RuIII species. The electronic absorption data show a variety of different charge transfer (CT) bands whose assignments are based upon energy variations with change of pyridine and/or dioxolene substituent, and net oxidation state.