Supporting Information Theoretical investigation of the photophysical properties of model ruthenium complexes with a diazabutadiene ligand [Ru(bpy) 3–x (dab) x ] 2+ (with x=1–3) Thomas Guillon, Martial Boggio-Pasqua,* Fabienne Alary, Jean-Louis Heully, Emilie Lebon, Pierre Sutra, and Alain Igau Laboratoire de Chimie et Physique Quantiques, UMR 5626, IRSAMC, CNRS et Université de Toulouse, 118 route de Narbonne, 31062 Toulouse, France. Laboratoire de Chimie de Coordination, UPR 8241, CNRS, 205 route de Narbonne, 31077 Toulouse, France. Table of Contents DFT optimized Cartesian coordinates and energies for [Ru(bpy) 2 (dab)] 2+ S2 DFT optimized Cartesian coordinates and energies for [Ru(bpy)(dab) 2 ] 2+ S4 DFT optimized Cartesian coordinates and energies for [Ru(dab) 3 ] 2+ S5 Ab initio optimized Cartesian coordinates and energies S6 Table S1 for complete absorption spectrum obtained with TD-DFT S9 Figure S1 for the active space chosen in the CASSCF approach S10 Figure S2 for the trigonal prismatic D 3h MP2 geometry S11