Spectral signature of a Ru(ii, iii, iv) complex: a combined experimental and theoretical investigation

The electronic and geometrical features of a recently synthesized ruthenium β-diketonato complex with a protected ethynyl ligand ([Ru(dbm)2(acac-TIPSA)], dbm = dibenzoylmethanate ion, acac-TIPSA = 3-(triisopropylsilyl)acetylene-2,4-pentanedionate ion), a building block for molecular spintronic devices, were analyzed as a function of its oxidation degree using Density Functional Theory (DFT) and Time Dependent DFT (TD-DFT), for ground and excited state properties, respectively, and compared to the available experimental data. The UV-Vis spectral signature of a native Ru(III) neutral form computed at a TD-DFT level was compared to those of the oxidized Ru(IV) and reduced Ru(II) ones, allowing us to clearly identify the nature of all bands occurring in this spectral region and thus providing important photophysical insights for the use of this complex as a building block in polynuclear organometallic mixed valence molecular systems able to perform a swapping operation under light control.