Fine tuning of emission color of iridium(III) complexes from yellow to red via substituent effect on 2-phenylbenzothiazole ligands: synthesis, photophysical, electrochemical and DFT study.
Fine tuning of emission color of iridium(III) complexes from yellow to red via substituent effect on 2-phenylbenzothiazole ligands: synthesis, photophysical, electrochemical and DFT study.
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DOI：
10.1039/c1dt10305a
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发表时间：
2011-07
影响因子：
4
通讯作者：
Ming Li;H. Zeng;Yanyan Meng;Huiqin Sun;Song Liu;Zhiyun Lu;Y. Huang;X. Pu
中科院分区：
文献类型：
--
作者：
Ming Li;H. Zeng;Yanyan Meng;Huiqin Sun;Song Liu;Zhiyun Lu;Y. Huang;X. Pu
合成了四种含联苯（7a-7 c）或芴（7 d）修饰的苯并噻唑环金属配合物。与黄母杂岩相比，（2-苯基苯并噻唑合-N，C（2 '））铱（III）（乙酰丙酮化物）[（pbt）（2）Ir（acac）]（λ（PL max）= 557 nm，φ（PL）= 0.26），7a-7 d在溶液中显示20-43 nm红移的橙子或红色磷光，最大光致发光（PL）量子产率为0.62，PL寿命为1.8-2.0 μs。同时，在固体薄膜中，配合物也呈现出强烈的橙子或红色磷光，λ（PL_（max））= 588-611 nm。含两个叔丁基取代基的配合物7 c在稀溶液和固体薄膜中均具有最高的磷光效率，因此有望成为掺杂和主体发光的电致磷光材料。此外，尽管观察到7a-7 d在溶液中严重的氧猝灭，但由于晶体中存在空隙通道，7a和7 c甚至显示出在其固态下被氧猝灭的有效发射强度;因此，它们是有前途的分子氧传感器试剂。电化学测量和密度泛函理论计算结果表明，由于苯基取代基的作用，所有这些螯合物的LUMO都比（pbt）（2）Ir（acac）降低了0.1 eV，而只有7 d的HOMO比母体螯合物更不稳定（约0.1 eV）.
Four novel iridium(III) complexes bearing biphenyl (7a-7c) or fluorenyl (7d) modified benzothiazole cyclometallate ligands are synthesized. In comparison with the yellow parent complex, bis(2-phenylbenzothiozolato-N,C(2')) iridium(III) (acetylacetonate) [(pbt)(2)Ir(acac)] (λ(PLmax) = 557 nm, φ(PL) = 0.26), 7a-7d show 20-43 nm bathochromic shifted orange or red phosphorescence in solution, with maximum photoluminescence (PL) quantum yield of 0.62, and PL lifetime of 1.8-2.0 μs. Meanwhile, the resulting complexes also exhibit intense orange or red phosphorescence of λ(PLmax) = 588-611 nm in solid films. The complex 7c with two tert-butyl substituents possesses the highest phosphorescent efficiency both in dilute solution and thin solid films, therefore may be a prospective candidate for both doping and host emitting electrophosphorescent material. Furthermore, despite the observation of severe oxygen quenching for 7a-7d in solution, 7a and 7c even show efficient emission intensity quenching by oxygen in their solid state due to the existence of void channels in crystals; consequently, they are promising molecular oxygen sensor reagents. Electrochemical measurement and DFT calculation results suggest that all these chelates own declined LUMOs of 0.1 eV relative to that of (pbt)(2)Ir(acac) owing to the contribution of the phenyl substituents; whereas only 7d shows a more destabilized HOMO (∼0.1 eV) compared with the parent chelate.