Iridium Cyclometalated Complexes in Host–Guest Chemistry: A Strategy for Maximizing Quantum Yield in Aqueous Media

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• 作者：Lubna R. Alrawashdeh ; Michael P. Cronin ; Clifford E. Woodward ; Anthony I. Day ; Lynne Wallace
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：July 5, 2016
• 年：2016
• 卷：55
• 期：13
• 页码：6759-6769
• 全文大小：509K
• 年卷期：0
• ISSN：1520-510X

文摘

The weaker emission typically seen for iridium(III) cyclometalated complexes in aqueous medium can be reversed via encapsulation in cucurbit[10]uril (Q[10]). The Q[10] cavity is shown to effectively maximize quantum yields for the complexes, compared to any other medium. This may provide significant advantages for a number of sensor applications. NMR studies show that the complexes are accommodated similarly within the host molecule, even with cationic substituents attached to the ppy ligands, indicating that the hydrophobic effect is the dominant driving force for binding. Cavity-encapsulated 1:1 host–guest species dominate the emission, but 1:2 species are also indicated, which also give some enhancement of intensity. Results demonstrate that the enhancement is due primarily to much lower rates of nonradiative decay but also suggest that the encapsulation can cause a change in character of the emitting state.