Electronic energy transduction from the forgotten {Ru(py)4} chromophores

ALEJANDRO CADRANEL; LUIS M. BARALDO; PAOLA S. OVIEDO; DIRK M. GULDI; PABLO ALBORÉS; JOSÉ H. HODAK

Otro; Artículo enviado a Inorganic Chemistry; 2017

ACS

Despite of the large body of work on {Ru(bpy)2} sensitizers, not the same attention has been devoted to their {Ru(py)4} analogues. In this context, we explored the electron donor-acceptor trans-[Ru(L)4{(μNC)Cr(CN)5}2]4-,where L = pyridine, 4-methoxypyridine or 4-dimethylaminopyridine. We report on the synthesis and the crystal structure as well as the electrochemical, spectroscopical, and photophysical properties of these trimetallic complexes, including transient absorption measurements. We observed emission from chromium-centered dd states upon illuminating into either the MLCT or MM?CT absorptions of {Ru(L)4}. The underlying energy transfer is as fast as 600 fs and with quantum efficiencies ranging from 10% to 100%. These results document that {Ru(py)4} sensitizers are as efficient as {Ru(bpy)2}.