Syntheses and Properties of Emissive Iridium(III) Complexes with Tridentate Benzimidazole Derivatives
详细信息 查看全文
- 作者：Tomona Yutaka ; Shinya Obara ; Satoshi Ogawa ; Koichi Nozaki ; Noriaki Ikeda ; Takeshi Ohno ; Youichi Ishii ; Ken Sakai ; and Masa-aki Haga
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：June 27, 2005
- 年：2005
- 卷：44
- 期：13
- 页码：4737 - 4746
- 全文大小：182K
- 年卷期：v.44,no.13(June 27, 2005)
- ISSN：1520-510X
文摘
A series of novel emissive Ir(III) complexes having the coordination environments of [Ir(N
NN)2]3+, [Ir(NNN)(NN)Cl]2+, and [Ir(NNN)(NCN)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, NNN), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, NCN), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, NNN), and2,2'-bipyridine (bpy, NN) have been synthesized and their photophysical and electrochemical properties studied.The Ir(III) complexes exhibited phosphorescent emissions in the 500-600 nm region, with lifetimes ranging fromapproximately 1-10 
s at 295 K. Analysis of the 0-0 energies and the redox potentials indicated that the lowestexcited state of [Ir(L1)(L2)]2+ possessed the highest contribution of 3MLCT (MLCT = metal-to-ligand charge transfer)among the Ir(III) complexes, reflecting the 
-donating ability of the tridentate ligand, ttpy < L1 < L2. The emissionquantum yields (
) of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest value (0.19) was obtainedfor [Ir(L1)(bpy)Cl]2+. Radiative rate constants (kr) were 1.2 × 104 s-1 for [Ir(ttpy)2]3+, 3.7 × 104 s-1 for [Ir(L1)(bpy)Cl]2+, 3.8 × 104 s-1 for [Ir(ttpy)(bpy)Cl]2+, 3.9 × 104 s-1 for [Ir(L1)2]3+, and 6.6 × 104 s-1 for [Ir(L1)(L2)]2+. Thehighest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of thesinglet-triplet mixing induced by spin-orbit coupling of 5d electrons in the MLCT electronic configurations.
NN)2]3+, [Ir(NNN)(NN)Cl]2+, and [Ir(NNN)(NCN)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, NNN), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, NCN), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, NNN), and2,2'-bipyridine (bpy, NN) have been synthesized and their photophysical and electrochemical properties studied.The Ir(III) complexes exhibited phosphorescent emissions in the 500-600 nm region, with lifetimes ranging fromapproximately 1-10 s at 295 K. Analysis of the 0-0 energies and the redox potentials indicated that the lowestexcited state of [Ir(L1)(L2)]2+ possessed the highest contribution of 3MLCT (MLCT = metal-to-ligand charge transfer)among the Ir(III) complexes, reflecting the -donating ability of the tridentate ligand, ttpy < L1 < L2. The emissionquantum yields () of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest value (0.19) was obtainedfor [Ir(L1)(bpy)Cl]2+. Radiative rate constants (kr) were 1.2 × 104 s-1 for [Ir(ttpy)2]3+, 3.7 × 104 s-1 for [Ir(L1)(bpy)Cl]2+, 3.8 × 104 s-1 for [Ir(ttpy)(bpy)Cl]2+, 3.9 × 104 s-1 for [Ir(L1)2]3+, and 6.6 × 104 s-1 for [Ir(L1)(L2)]2+. Thehighest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of thesinglet-triplet mixing induced by spin-orbit coupling of 5d electrons in the MLCT electronic configurations.