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Updated: Mar 21, 2026

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Synthesis, structural characterization and rigidity dependent dual phosphorescence behavior of high-energy
Mousree Mitra1, Ondřej Mrózek1, Andrey Belyaev1
1Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Str. 6, 44227 Dortmund, Germany. andreas.steffen@tu-dortmund.de.
Abstract:
The study explores the synthesis, structural characterization, and photophysical properties of cyclic (alkyl)(amino)carbene (cAAC) zinc(II) complexes, focusing on their unique rigidity-dependent dual phosphorescence behavior. Starting from previously reported dimeric [Zn2X2(μ-X)2(cAAC)2] (X = Cl, Br), halide abstraction with Et3Si+ gives dicationic tetramers with an adamantyl-like Zn4X6 core, while the reaction with Na(acac) (acac = acetylacetonate) or KCz (Cz = carbazolate) leads to ligand exchange and isolation of [ZnCl(acac)(cAAC)] (11) and [ZnCl(Cz)(THF)(cAAC)] (12), respectively. While 12 displays orange phosphorescence from 3LLCT (LLCT = ligand-to-ligand charge transfer) states both at room temperature and at 77 K, complex 11 and the tetrameric compounds exhibit excitation wavelength-dependent unusual high-energy UV-blue phosphorescence and green-yellow luminescence. The experimental data suggest that high-energy excitation leads to emission primarily from high-energy states due to strong Franck-Condon overlaps, while low-energy excitation enables direct triplet state population and geometry-driven transitions. This behavior, influenced by the molecular rigidity, appears to be the result of an equilibrium between different excited states and emphasizes the impact of the molecular structure on the emission profiles.
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