Neutral RuII-based emitting materials: A prototypical study on factors governing radiationless transition in phosphorescent metal complexes

Elise Y. Li, Yi Ming Cheng, Cheng Chih Hsu, Pi Tai Chou, Gene Hsiang Lee, I. Hui Lin, Yun Chi, Chao Shiuan Liu

研究成果: 雜誌貢獻文章同行評審

46 引文 斯高帕斯(Scopus)

摘要

In addition to the metal-centered dd transition that is widely accepted as a dominant radiationless decay channel, other factors may also play important roles in governing the loss of phosphorescence efficiency for heavy-transition-metal complexes. To conduct our investigation, we synthesized two dicarbonylruthenium complexes with formulas [Ru(CO)2(BQ) 2] (1) and [Ru(CO)2(DBQ)2] (2), for which the cyclometalated ligands BQ and DBQ denote benzo-[h]quinoline and dibenzo[f,h]quinoxaline, respectively. Replacing one CO ligand with a P donor ligand such as PPh2Me and PPhMe2 caused one cyclometalated ligand to undergo a 180° rotation around the central metal atom, giving highly luminous metal complexes [Ru(CO)L(BQ)2] and [Ru(CO)L(DBQ) 2], where L = PPh2Me and PPhMe2 (3-6), with emission peaks λmax in the range of 571-656 nm measured in the fluid state at room temperature. It is notable that the S0-T 1 energy gap for both 1 and 2 is much higher than that of 3-6, but the corresponding phosphorescent spectral intensity is much weaker. Using these cyclometalated Ru metal complexes as a prototype, our experimental results and theoretical analysis draw attention to the fact that, for complexes 1 and 2, the weaker spin-orbit coupling present within these molecules reduces the T 1-S0 interaction, from which the thermally activated radiationless deactivation may take place. This, in combination with the much smaller 3MLCT contribution than that observed in 3-6, rationalizes the lack of room-temperature emission for complexes 1 and 2.

原文英語
頁(從 - 到)8041-8051
頁數11
期刊Inorganic Chemistry
45
發行號20
DOIs
出版狀態已發佈 - 2006 十月 2

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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