Herein, to elucidate the effect of substituent electronic properties on the photophysical properties of indium‐based organometallic luminophores, we prepare a series of indium complexes (1–5) with salen ligands bridged by an electron‐withdrawing 4,5‐dichlorophenylene (Cl₂Ph) unit. The structures of all the complexes are fully confirmed by ¹H and ¹³C NMR spectroscopy as well as elemental analysis. In particular, the molecular structure of 3, confirmed by X‐ray crystallography, is monomeric and the central indium atom adopts a square‐pyramidal geometry. The UV/Vis and fluorescence spectra of 1–5 show typically salen‐centered intramolecular charge transfer transitions with gradual bathochromic shifts as the electron‐donating ability of the substituents increases. This feature is further supported by electrochimical studies. Furthermore, the lowest unoccupied molecular orbital energy levels of 1–5 are considerably lower (approximately −3.70 eV) than those of salen‐based indium complexes with other aryl‐bridging units owing to the reduced electron‐donating effect of the (Cl₂Ph)salen group.

中文翻译：

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（Cl2Ph）Salen基铟配合物的合成及其光物理性质

这里，为了阐明在基于铟-有机金属发光材料的光物理性质的取代基的电子特性的影响，我们准备（一系列铟配合物1 - 5）与配体的沙仑桥接由吸电子-4,5- dichlorophenylene（CL ₂ Ph）单位。所有配合物的结构都通过¹ H和¹³ C NMR光谱以及元素分析得到了充分证实。特别是，通过X射线晶体学证实的3的分子结构是单体的，并且中心铟原子采用方锥几何形状。的UV /可见光光谱和荧光光谱1 - 5显示出随着取代基的供电子能力的增加，以Salen为中心的分子内电荷转移跃迁，并伴随着红移。电化学研究进一步支持了此功能。此外，最低未占有分子轨道能级的能量水平的1 - 5比用由于（Cl组成的还原的电子给体作用的其它芳基桥连单元基于萨伦-铟复合物的显着较低（约-3.70电子伏特）₂博士）salen组。