Solvent effects on the metal-to-ligand charge transfer transition of the complex [Ru(NH3)5(Pyrazine)]2+

In this work the solvent effects on the structure and metal-to-ligand charge transfer (MLCT) transition of the complex [Ru(NH3)5(Pyrazine)]2+ was investigated in aqueous solution, using the hybrid Density Functional Theory/Effective Fragment Potential Hamiltonian (DFT/EFP/MD) approach. The MLCT transition causes a large charge separation in the complex and produces a dipole moment variation of 8.3 ± 1.1 Debye upon excitation in solution and causes a large red-shift of 0.55 ± 0.15 eV. The solvatochromic shift can be attributed to the large charge separation accompanying the MLCT transition in solution.