Unusual Dinuclear and Mononuclear Cyclometalated Iridium Complexes of 2,5-Diaryl-1,3,4-oxadiazole Derivatives
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- 作者：Yonghao Zheng ; Andrei S. Batsanov ; Martin R. Bryce
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：April 18, 2011
- 年：2011
- 卷：50
- 期：8
- 页码：3354-3362
- 全文大小：998K
- 年卷期：v.50,no.8(April 18, 2011)
- ISSN：1520-510X
文摘
A family of new 2,5-diphenyl-1,3,4-oxadiazole (OXD) derivatives 8鈭?b>11 bearing ortho-alkyl substituents on one of the phenyl rings is reported. The reactions of these OXDs with IrCl3 under standard cyclometalating conditions did not give the usual 渭-dichloro bridged diiridium OXD complexes. Instead, the novel diiridium complexes 12鈭?b>14 and the monoiridium complex 15 were isolated and characterized by X-ray crystallography. It is proposed that the unusual structures arise because of the ortho-alkyl substituents leading to a substantial twisting of part of the OXD system which, for steric reasons, changes the normal course of the metal鈭抣igand coordination reactions. Subsequent reactions of 13 and 15 gave the mononuclear complexes 16鈭?b>18 with acac and picolinate anciliary ligands. The crystal structures of 16 and 18 are reported. Photoluminescence is observed in the green (16) and blue-green regions (17 and 18) at room temperature. Complexes 16鈭?b>18 are phosphorescent at low temperature, with triplet lifetimes of 4.2鈭?.7 渭s at 77 K.