Os(II) Phosphors with Near-Infrared Emission Induced by Ligand-to-Ligand Charge Transfer Transition

• Published in: Inorganic chemistry Vol. 53; no. 17; pp. 9366 - 9374
• Main Authors: Liao, Jia-Ling, Chi, Yun, Liu, Shih-Hung, Lee, Gene-Hsiang, Chou, Pi-Tai, Huang, Hao-Xiang, Su, Yu-De, Chang, Chih-Hao, Lin, Jin-Sheng, Tseng, Meu-Rurng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.09.2014
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/ic501474r

Heating of Os3(CO)12 with 6 equiv of 2-(3-(trifluoromethyl)-1H-1,2,4-triazol-5-yl) pyridine (fptzH) in refluxing diethylene glycol monomethyl ether, followed by sequential treatment with stoichiometric Me3NO and addition of PPhMe2, afforded two isomeric mixtures of red-emitting [Os(fptz)2(PPhMe2)2] (1T and 1C), for which the notations T and C stand for the trans and cis-oriented fptz chelates, respectively. Alternatively, preparation of Os(II) complex using a 1:1 mixture of 5,5′-di(trifluoromethyl)-3,3′-di-1,2,4-triazole (dttzH2) and 2,2′-bipyridine (bpy), instead of fptzH, gave isolation of a mononuclear Os(II) complex [Os(bpy)(dttz)(CO)2] (2) in moderate yield. Replacement of CO with PPhMe2 on 2 afforded near-infrared (NIR)-emitting Os(II) complex [Os(bpy)(dttz)(PPhMe2)2] (3). The single-crystal X-ray structural analyses were executed on 1C, 2, and 3 to reveal the structural influence imposed by the various chelates. The photophysical and electrochemical properties were measured and discussed using the results of density functional theory (DFT) and time-dependent DFT calculations. Complex 3 is selected as the dopant to probe its electroluminescent properties by fabrication of the NIR emitting organic light-emitting diodes.