Measurement and model calculation of the temperature dependence of ligand-to-metal energy transfer rates in lanthanide complexes

Temperature dependent transient curves of excited levels of a model Eu3+ complex have been measured for the first time. A coincidence between the temperature dependent rise time of the 5D0 emitting level and decay time of the 5D1 excited level in the [Eu(tta)3(H2O)2] complex has been found, which unambiguously proves the T1→5D1→5D0 sensitization pathway. A theoretical approach for the temperature dependent energy transfer rates has been successfully applied to the rationalization of the experimental data. ► Temperature dependent transient curves related to intramolecular energy transfer in a Eu3+ complex directly measured for the first time. ► A test of selection rules and an experimental/ theoretical proof of the T1→5D1→5D0 sensitization pathway in Eu3+ coordination compounds. ► A theoretical approach for the temperature dependent energy transfer rates has been successfully applied to the rationalization of the experimental data.