Unusual Excimer/Dimer Behavior of a Highly Soluble C,N Platinum(II) Complex with a Spiro-Fluorene Motif

Piotr Pander*, Andrey V. Zaytsev, Larissa Gomes Franca, Fernando B. Dias*, Valery N. Kozhevnikov*

*Corresponding author for this work

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Abstract

In this work, we introduce a spiro-fluorene unit into a phenylpyridine (CN)-type ligand as a simple way to deplanarize the structure and increase the solubility of the final platinum(II)···complex. Using a spiro-fluorene unit, orthogonal to the main coordination plane of the complex, reduces intermolecular interactions, leading to increased solubility but without significantly affecting the ability of the complex to form Pt···Pt dimers and excimers. This approach is highly important in the design of platinum(II) complexes, which often suffer from low solubility due to their mainly planar structure, and offers an alternative to the use of bulky alkyl groups. The nonplanar structure is also beneficial for vacuum-deposition techniques as it lowers the sublimation temperature. Importantly, there are no sp3 hybridized carbon atoms in the cyclometalating ligand that contain hydrogens, the undesired feature that is associated with the low stability of the materials in OLEDs. The complex displays high solubility in toluene, ∼10 mg mL–1, at room temperature, which allows producing solution-processed OLEDs in a wide range of doping concentrations, 5–100%, and EQE up to 5.9%, with a maximum luminance of 7400 cd m–2. Concurrently, we have also produced vacuum-deposited OLEDs, which display luminance up to 32 500 cd m–2 and a maximum EQE of 11.8%.
Original languageEnglish
Pages (from-to)18465-18473
Number of pages9
JournalInorganic Chemistry
Volume62
Issue number45
Early online date31 Oct 2023
DOIs
Publication statusPublished - 13 Nov 2023

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