Photophysical Properties of Bimetallic Cyanide-Bridged Ru(II) Polypyridines. Evidence of delocalization in the Excited State

GERMAN E. PIESLINGER; PAOLA S. OVIEDO; JOSÉ H. HODAK; ALEJANDRO CADRANEL; LUIS M. BARALDO

Santiago de Chile

Congreso; 25th Inter-American Photochemical Society Meeting; 2016

Inter-American Photochemical Society

We present the photophysical properties of a cyanide-bridged ruthenium polypyridine whose formula is [(bpy)(tpy)Ru(µ-CN)Ru(py)4Cl]2+ (tpy = 2,2?;6?,2??-terpyridine; bpy = 2,2?-bipyridine) (1). Near infrared transient absorption spectra of this complex reveal that the first populate state present a band that we assign as a metal to metal charge transfer (MMCT) and indicates a mixed-valence character for this state. By comparison with the properties of related mixed-valence complexes a delocalized nature can be assigned to the excited state of (1). It is interesting to note that the reverse tendency is observed for the ground state mixed-valence form of this complex revealing the role of the radical-anion in the photoinduced state. On the other hand, the first populate state decays to the emissive state which does not present a transition in the NIR pointing to a different configuration for the latter.