Energy Migration Processes in Re(I) MLCT Complexes Featuring a Chromophoric Ancillary Ligand
Energy Migration Processes in Re(I) MLCT Complexes Featuring a Chromophoric Ancillary Ligand
复制标题
具有发色辅助配体的 Re(I) MLCT 配合物中的能量迁移过程
DOI：
10.1021/acs.inorgchem.0c00644
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发表时间：
2020
影响因子：
4.6
通讯作者：
Castellano, Felix N.
中科院分区：
文献类型：
--
作者：
Wells, Kaylee A.;Yarnell, James E.;Palmer, Jonathan R.;Lee, Tia S.;Papa, Christopher M.;Castellano, Felix N.
本文报道了一系列具有金属-配体电荷转移（MLCT）激发态的五种Re（I）双发色团的合成、结构表征、电子结构计算和超快和超纳秒电子物理性质，其中PNI-py为4-哌啶基-1，8-萘酰亚胺吡啶，N-N-N为二亚胺配体（Re 1 -5），沿着它们相应的模型发色团，其中4-乙基吡啶取代PNI-py（Mod 1 -5）。所用的二亚胺配体包括1，10-菲咯啉（phen，1）、2，9-二甲基-4，7-二苯基-1，10-菲咯啉（bcp，2）、4，4 ′-二叔丁基-2，2 ′-联吡啶（dtbb，3）、4，4 ′-二乙酯-2，2 ′-联吡啶（deeb，4）和2，2 ′-联喹啉（biq，5）。在这些金属-有机bichromophores，结构修饰的二亚胺配体导致的两个发色团之间的能量转移效率作为一个结果的变化in 3 MLCT激发态能量的实质性变化。平行地研究了模型发色团的物理性质和能量途径，以准确地跟踪从引入辅助配体上的有机发色团侧基所引起的变化。使用时间分辨光致发光光谱、超快和纳秒瞬态吸收光谱以及含时密度泛函理论计算，探测和表征了所有相关的光物理和能量转移过程。在本研究中的五个双发色团中，四个（Re 1 -4）在3 PNI-py和3 MLCT激发态之间表现出热平衡，大大延长了母体模型发色团的寿命。
We present the synthesis, structural characterization, electronic structure calculations, and ultrafast and supra-nanosecond photophysical properties of a series of five Re(I) bichromophores exhibiting metal to ligand charge transfer (MLCT) excited states based on the general formulafac-[Re(N∧N)(CO)3(PNI-py)]PF6,where PNI-py is 4-piperidinyl-1,8-naphthalimidepyridine and N∧N is a diimine ligand (Re1–5), along with their corresponding model chromophores where 4-ethylpyridine was substituted for PNI-py (Mod1–5). The diimine ligands used include 1,10-phenanthroline (phen,1), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bcp,2), 4,4′-di-tert-butyl-2,2′-bipyridine (dtbb,3), 4,4′-diethyl ester-2,2′-bipyridine (deeb,4), and 2,2′-biquinoline (biq,5). In these metal–organic bichromophores, structural modification of the diimine ligand resulted in substantial changes to the observed energy transfer efficiencies between the two chromophores as a result of the variation in3MLCT excited-state energies. The photophysical properties and energetic pathways of the model chromophores were investigated in parallel to accurately track the changes that arose from introduction of the organic chromophore pendant on the ancillary ligand. All relevant photophysical and energy transfer processes were probed and characterized using time-resolved photoluminescence spectroscopy, ultrafast and nanosecond transient absorption spectroscopy, and time-dependent density functional theory calculations. Of the five bichromophores in this study, four (Re1–4) exhibited a thermal equilibrium between the3PNI-py and the3MLCT excited state, drastically extending the lifetimes of the parent model chromophores.