Nature of the Ligand-Centered Triplet State in Gd³⁺ β-Diketonate Complexes as Revealed by Time-Resolved EPR Spectroscopy and DFT Calculations.

ABSTRACT: A series of Gd³⁺ complexes (Gd1-Gd3) with the general formula GdL₃(EtOH)₂, where L is a β-diketone ligand with polycyclic aromatic hydrocarbon substituents of increasing size (1-3), was studied by combining time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy and DFT calculations to rationalize the anomalous spectroscopic behavior of the bulkiest complex (Gd3) through the series. Its faint phosphorescence band is observed only at 80 K and it is strongly red-shifted (∼200 nm) from the intense fluorescence band. Moreover, the TR-EPR spectral analysis found that triplet levels of 3/Gd3 are effectively populated and have smaller |D| values than those of the other compounds. The combined use

SUBMITTER: Carlotto S 

PROVIDER: S-EPMC8763374 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature