Li Xiang, Yin Yongheng, Yan Hong, Lu Changsheng, Zhao Qiang
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
Dalton Trans. 2017 Aug 14;46(30):10082-10089. doi: 10.1039/c7dt02009k. Epub 2017 Jul 21.
A novel series of heteroleptic iridium complexes with 2-phenyl-pyridine as a main ligand and carborane-functionalized 2,2'-bipyridine as an ancillary ligand were synthesized, and characterized as [Ir(ppy)(By)]PF (where ppy is 2-phenyl-pyridine, By is 5-(2-R-Cb)-2,2'-bipyridine, R = H (2a), CH (2b), Ph (2c), iPr (2d) and iBu (2e), or By is 4-(2-R-Cb)-2,2'-bipyridine while R = H (3a), CH (3b), Ph (3c), iPr (3d) and iBu (3e), Cb = o-carboran-1-yl). The R groups and the substitution sites of carborane on the pyridine ring have caused differences in the emission properties of these complexes. In addition, the quantum efficiency of [Ir(ppy)(By)]PF complexes has been tuned as well through the introduction of various 2-R-substituted o-carboranes into the ancillary ligand 2,2'-bipyridine, no matter in the solid state (from 0.12 to 0.25) or in solution (from 0.04 to 0.25). The emission color was tuned from yellow to red by the o-carboranyl unit because of its inductive effect. Density functional theory (DFT) and time dependent DFT (TD-DFT) calculations have been applied to investigate excited-state electronic structures of the newly synthesized complexes, which are consistent with the observed red-shift emissions.
合成了一系列以2-苯基吡啶为主配体、碳硼烷官能化的2,2'-联吡啶为辅助配体的新型杂配铱配合物，并将其表征为[Ir(ppy)(By)]PF（其中ppy为2-苯基吡啶，By为5-(2-R-Cb)-2,2'-联吡啶，R = H（2a）、CH（2b）、Ph（2c）、iPr（2d）和iBu（2e），或者By为4-(2-R-Cb)-2,2'-联吡啶，而R = H（3a）、CH（3b）、Ph（3c）、iPr（3d）和iBu（3e），Cb = 邻碳硼烷-1-基）。吡啶环上的R基团和碳硼烷的取代位点导致了这些配合物发射性质的差异。此外，通过在辅助配体2,2'-联吡啶中引入各种2-R-取代的邻碳硼烷，[Ir(ppy)(By)]PF配合物的量子效率在固态（从0.12到0.25）和溶液（从0.04到0.25）中都得到了调节。由于邻碳硼烷基元的诱导效应，发射颜色从黄色调至红色。已应用密度泛函理论（DFT）和含时密度泛函理论（TD-DFT）计算来研究新合成配合物的激发态电子结构，其与观察到的红移发射一致。
