TY - JOUR
T1 - Unusual Excimer/Dimer Behavior of a Highly Soluble C,N Platinum(II) Complex with a Spiro-Fluorene Motif
AU - Pander, Piotr
AU - Zaytsev, Andrey V.
AU - Franca, Larissa Gomes
AU - Dias, Fernando B.
AU - Kozhevnikov, Valery N.
N1 - Funding information: The authors thank Yana Dikova and J.A. Gareth Williams for assistance in recording HRMS data. P.P. thanks the National Science Centre, Poland for funding, grant ref. 2022/47/D/ST4/01496.
PY - 2023/11/13
Y1 - 2023/11/13
N2 - 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%.
AB - 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%.
UR - http://www.scopus.com/inward/record.url?scp=85176991649&partnerID=8YFLogxK
U2 - 10.1021/acs.inorgchem.3c02667
DO - 10.1021/acs.inorgchem.3c02667
M3 - Article
C2 - 37905928
SN - 0020-1669
VL - 62
SP - 18465
EP - 18473
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 45
ER -