Photoluminescence of Seven-Coordinate Zirconium and Hafnium Complexes with 2,2'-Pyridylpyrrolide Ligands.

Author(s) Zhang, Y.; Akhmedov, N.G.; Petersen, J.L.; Milsmann, C.
Journal Chemistry
Date Published 2019 Feb 26

Luminescent seven-coordinated zirconium and hafnium complexes bearing three mono-anionic 2,2'-pyridylpyrrolide ligands and one chloride were synthesized. Solid-state structures and the dynamic behaviors in solution were probed by X-ray crystallography and variable temperature H NMR experiments, respectively. Absorption spectroscopy and time-dependent density functional theory (TD-DFT) calculations supported a hybrid of ligand-to-metal charge transfer (LMCT)/ligand-to-ligand charge transfer (LLCT) for the visible light absorption band. The complexes ( PMP ) MCl (M=Zr, Hf, PMP =3,5-dimethyl-2-(2-pyridyl)pyrrolide) are emissive in solution at room temperature upon irradiation with visible light due to a combination of phosphorescence and fluorescence characterized by excited state lifetimes in the μs and low to sub-ns timescale, respectively. Electrochemical experiments revealed that the zirconium complex possesses a reversible redox event under highly reducing condition (-2.29 V vs. Fc ).

DOI 10.1002/chem.201804671
ISSN 1521-3765
Citation Chemistry. 2019;25(12):30423052.

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