Syntheses and properties of emissive iridium(III) complexes with tridentate benzimidazole derivatives.
Syntheses and properties of emissive iridium(III) complexes with tridentate benzimidazole derivatives.
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DOI：
10.1021/ic048622z
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发表时间：
2005-05
影响因子：
4.6
通讯作者：
T. Yutaka;Shinya Obara;S. Ogawa;K. Nozaki;N. Ikeda;T. Ohno;Y. Ishii;K. Sakai;Masa-aki Haga
中科院分区：
文献类型：
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作者：
T. Yutaka;Shinya Obara;S. Ogawa;K. Nozaki;N. Ikeda;T. Ohno;Y. Ishii;K. Sakai;Masa-aki Haga
用2，6-二(1-甲基苯并咪唑-2-基)吡啶(L1，N-N)、1，3-双(1-甲基苯并咪唑-2-基)吡啶(L1，N-N)、1，3-双(1-甲基苯并咪唑-2-基)苯(L2H，N-C-N)、合成了4‘-(4-甲基苯基)-2，2’：6‘，2’-联吡啶(ttpy，N-N-N)和2，2‘-联吡啶(bpy，N-N)，并研究了它们的光物理和电化学性质。在295K下，Ir(III)配合物在500-600 nm区域显示出磷光发射，寿命约为1-10微秒。0-0能级和氧化还原电势分析表明，在Ir(III)配合物中，[Ir(L1)(L2)]2+的最低激发态具有最高的3MLCT(MLCT=金属-配体电荷转移)，反映了三齿配体tpy<；tpy<；l1<；L2。Ir(III)配合物的发射量子产率(Phi)在0.037~0.19之间，其中[Ir(L1)(Bpy)Cl]2+的发射量子产率最高(0.19)。辐射速率常数(k(R))[Ir(Ttpy)2]3+为1.2x10(4)S(-1)，[Ir(L1)(Bpy)Cl2+]2+为3.7x10(4)S(-1)，[Ir(Ttpy)(Bpy)Cl2+]2+为3.8x10(4)S(-1)，[Ir(L1)2]3+为3.9x10(4)S(-1)，和[Ir(L1)(L2)]2+的6.6x10(4)S(-1)。具有最大3MLCT贡献的[Ir(L1)(L2)]2+的最高辐射率可以用MLCT电子组态中5d电子的自旋-轨道耦合引起的单-三重态混合来解释。
A series of novel emissive Ir(III) complexes having the coordination environments of [Ir(N--N--N)2]3+, [Ir(N--N--N)(N--N)Cl]2+, and [Ir(N--N--N)(N--C--N)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, N--N--N), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, N--C--N), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, N--N--N), and 2,2'-bipyridine (bpy, N--N) 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 from approximately 1-10 micros at 295 K. Analysis of the 0-0 energies and the redox potentials indicated that the lowest excited 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 sigma-donating ability of the tridentate ligand, ttpy < L1 < L2. The emission quantum yields (phi) of the Ir(III) complexes ranged from 0.037 to 0.19, and the highest phi value (0.19) was obtained for [Ir(L1)(bpy)Cl]2+. Radiative rate constants (k(r)) were 1.2 x 10(4) s(-1) for [Ir(ttpy)2]3+, 3.7 x 10(4) s(-1) for [Ir(L1)(bpy)Cl]2+, 3.8 x 10(4) s(-1) for [Ir(ttpy)(bpy)Cl]2+, 3.9 x 10(4) s(-1) for [Ir(L1)2]3+, and 6.6 x 10(4) s(-1) for [Ir(L1)(L2)]2+. The highest radiative rate for [Ir(L1)(L2)]2+ with the highest contribution of 3MLCT could be explained in terms of the singlet-triplet mixing induced by spin-orbit coupling of 5d electrons in the MLCT electronic configurations.