Role of higher excited states in radiative and nonradiative processes of coordination compounds of Ru(II) and Rh(III) in crystal

3MLCT of [Ru(bpy)3](PF6)2 (bpy:2,2′-bipyridine) in solid state above 350 K decays via the lowest excited d-d state lying higher with a frequency of 7 × 1013 s−1 at the high-temperature limit. Crystal water of [Ru(bpy)3]Cl2 · 6H2O lowers the energy level of an intermediate for the nonradiative decay by by≈2000 cm−1. Crystalline sample of [Rh(bpy)3Cl2](PF6) at 536 K emits an unresolved phosphorescence with a fwhm of 6000 cm−1, which comes from two closely lying excited d-d states. Nonradiative decays of the lowest excited d-d state occur via the second lowest excited d-d state with a more displaced potential curve in a higher-temperature region of 350–586 K.