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Density Functional Theory-based methods have been exploited to look into the structural, vibrational and electronic properties of antenna ligands, all of them crucial points for a reliable design of customized...

A new model with the aim to predict the temperature dependence of europium emission in coordination systems is presented. The model has been developed from a library of Eu3+ complexes of general formula EuL3A2, where L is a β‐diketone, and A is an ancillary ligand. Three possible deactivation channels have been considered: two competitive metal‐related terms describing the primary deactivation channels, i. e. back energy transfer and multiphonon quenching, and a third ligand‐related term to describe non‐radiative deactivation of the antenna triplet. As many parameters as possible are taken from measurable chemical‐physical properties, such as ligand triplet and multiphonon quenching energies. The other parameters have been deduced from selected EuL3A2 compounds and used as one‐size‐fits‐all values. The model proved to be very effective in describing the interplay between back energy transfer and multiphonon deactivation channels. Finally, the model has been implemented in a freeware standalone MATLAB application. Users need to input only the energy of the sensitizer triplet level and choose the coordinated quencher, if present. It simulates the range of applicability of the molecular thermometers and the shape of the thermometric sensitivity curve Sr employing as thermometric parameter either emission intensity or lifetime.

A theoretical protocol combining density functional theory (DFT) and multireference (CAS) calculations is proposed for a Eu3+ complex. In the complex, electronic levels of the central Eu3+ ion are correctly calculated at the CASPT2 level of theory, and the effect of introducing different numbers of states in the configuration interaction matrices is highlighted as well as the shortcomings of DFT methods in the treatment of systems with high spin multiplicity and strong spin–orbit coupling effects. For the 5D0 state energy calculation, the inclusion of states with different multiplicity and the number of states considered for each multiplicity are crucial parameters, even if their relative weight is different. Indeed, the addition of triplet and singlets is important, while the number of states is relevant only for the quintets. The herein proposed protocol enables a rigorous, full ab initio treatment of Eu3+ complex, which can be easily extended to other Ln3+ ions.