Electroluminescence of Tetradentate Pt(II) Complexes: O^N^N^O versus C^N^N^O Coordination

Pander, Piotr; *Gomes Franca, Larissa; Dias, Fernando B.; Kozhevnikov, Valery N.

Abstract

Alkylation of one of the phenolic hydroxyl groups in a salen-type tetradentate ligand changes the coordination mode from O^N^N^O to the cyclometallating C^N^N^O type. The ligand was used to synthesize a new cyclometalated luminescent Pt(II) complex 2. While in solution the complex is poorly luminescent, in the solid state the emission is reinstated, which allowed one to evaluate complex 2 as a phosphorescent emitter in organic light-emitting diodes. 2 displays external quantum efficiency (EQE) = 9.1% and a maximum luminance of 9000 cd m–2 in a vacuum-deposited device. We carried out comparative analysis of photo- and electroluminescence of complex 2 with O^N^N^O complex 1 and demonstrated that the similar luminescent properties of the O^N^N^O and C^N^N^O complexes are rather coincidental because they display different excited-state landscapes. Surprisingly, the two complexes display a dramatically different electrochemical behavior, with O^N^N^O coordination leading to the formation of a stable electropolymer but C^N^N^O coordination fully preventing electropolymerization.

Citation

Pander, P., *Gomes Franca, L., Dias, F. B., & Kozhevnikov, V. N. (2023). Electroluminescence of Tetradentate Pt(II) Complexes: O^N^N^O versus C^N^N^O Coordination. Inorganic Chemistry, 62(14), https://doi.org/10.1021/acs.inorgchem.3c00364

• Journal Article Type: Article
• Online Publication Date: Mar 30, 2023
• Publication Date: 2023
• Deposit Date: Jul 3, 2023
• Publicly Available Date: Jul 3, 2023
• Journal: Inorganic Chemistry
• Print ISSN: 0020-1669
• Electronic ISSN: 1520-510X
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 62
• Issue: 14
• DOI: https://doi.org/10.1021/acs.inorgchem.3c00364
• Public URL: https://durham-repository.worktribe.com/output/1168932