Ultrafast transient spectroscopy of bi-metal charge-transfer complexes

SHIORI YAMAZAKI; ALEJANDRO CADRANEL; DAIANA CAPDEVILA; LUIS M. BARALDO; VALERIA D. KLEIMAN

Congreso; Meeting of the Amercan Chemical Society; 2010

American Chemical Society

Transition metal complexes have captured significant attention due to their electronic and optical properties with potential applications in organic light emitting diodes (OLEDs) and dye-sensitized solar cells (DSCs). We study a family of RuII , RuII -(m-NC)- Ru, RuII -(m-NC)- Fe, RuII -(m-NC)- Os, and RuII -(m-NC)- Cr with bpy (2,2´-bipyridine), tpy (2,2´:6´,2´´-terpyridine), and tpm (tris(1-pyrazolyl)methane) ligands. Full steady-state characterization as well as ultrafast transient absorption spectra are collected and used to understand the dynamics of electron transfer including metal-to-ligand charge transfer (MLCT) and metal-to-metal charge transfer (MMCT). We also examine the effect of solvent and geometry on the dynamics of electron transfer. In the ultrafast transient absorption experiments, we observe bands corresponding to bleach and photoinduced absorption (PIA) and we are able to identify recombination rates for the dimers and compare them to those of the corresponding monomers.