12081-05-9Relevant academic research and scientific papers
Electron-donating abilities and luminescence properties of tolane-substituted: Nido -carboranes
Nishino, Kenta,Morisaki, Yasuhiro,Tanaka, Kazuo,Chujo, Yoshiki
, p. 10550 - 10554 (2017)
The luminescence properties of nido-carborane (7,8-dicarba-nido-carborate anion)-substituted tolane derivatives were investigated. It was shown that the nido-carborane unit acted as an electron-donating group in all derivatives, and their emission colors
Phosphorescence color tuning of cyclometalated iridium complexes by o-carborane substitution
Kim, Taewon,Kim, Hyungjun,Lee, Kang Mun,Lee, Yoon Sup,Lee, Min Hyung
supporting information, p. 160 - 168 (2013/02/23)
Heteroleptic (Ca?N)2Ir(acac) (C a?N = 4-CBppy (1); 5-CBppy (2), 4-fppy (4) CB = ortho-methylcarborane; ppy = 2-phenylpyridinato-C2,N, 4-fppy = 2-(4-fluorophenyl)pyridinato-C2,N, acac = acetylacetonate) complexes were prepared and characterized. While 1 exhibits a phosphorescence band centered at 531 nm, which is red-shifted compared to that of unsubstituted (ppy)2Ir(acac) (3) (λem = 516 nm), the emission spectrum of 2 shows a blue-shifted band at 503 nm. Comparison with the emission band for the 4-fluoro-substituted 4 (λem = 493 nm) indicates a substantial bathochromic shift in 1. Electrochemical and theoretical studies suggest that while carborane substitution on the 4-position of the phenyl ring lowers the 3MLCT energy by a large contribution to lowest unoccupied molecular orbital (LUMO) delocalization, which in turn assigns the lowest triplet state of 1 as [dπ(Ir)→π*(C a?N)] 3MLCT in character, the substitution on the 5-position raises the 3MLCT energy by the effective stabilization of the highest occupied molecular orbital (HOMO) level because of the strong inductive effect of carborane. An electroluminescent device incorporating 1 as an emitter displayed overall good performance in terms of external quantum efficiency (6.6%) and power efficiency (10.7 lm/W) with green phosphorescence.
