The synthesis, structure and photophysical properties of dinuclear bis(phenylpyridine)(salicylaldiminato)Ir(III) complexes bearing polymethylene linkers are described herein. Chiral and achiral dinuclear Ir complexes bearing short ( n = 2), medium ( n = 5) and long ( n = 8) polymethylene linkers were prepared by reacting [Ir(2-phenylpyridinato)IrCl] 2 with the corresponding salicylaldimine derivatives. The facial configurations of the coordination sites and the polymethylene-linked structures were unequivocally established based on X-ray crystallography. The emission wavelengths of these polymethylene-linked binuclear complexes in 2-MeTHF in a glassy state at 77 K were found to vary with the length of the linker, such that a hypsochromic shift from yellow to green was observed upon changing from pentamethylene ( n = 5) or octamethylene ( n = 8) to ethylene ( n = 2) linkages. X-ray crystallography and 1 H nuclear magnetic resonance analysis combined with density functional theory calculations demonstrated that the present chromism arises from variations in the proximity and conformational rigidity between the two iridium cores, both of which are controlled by the length of the polymethylene linkage.

中文翻译：

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对与聚亚甲基间隔基连接的双核水杨醛基环金属化铱 (III) 配合物磷光性能的邻近效应

本文描述了带有聚亚甲基连接体的双核双(苯基吡啶)(水杨醛二氨基)Ir(III)配合物的合成、结构和光物理性质。手性和非手性双核 Ir 配合物带有短 (n = 2)、中 (n = 5) 和长 (n = 8) 多亚甲基接头，通过 [Ir(2-苯基吡啶基)IrCl] 2 与相应的水杨醛亚胺衍生物反应制备。基于 X 射线晶体学明确建立了配位点和聚亚甲基连接结构的面部构型。发现这些聚亚甲基连接的双核复合物在 77 K 下处于玻璃态的 2-MeTHF 中的发射波长随连接子的长度而变化，因此，在从五亚甲基 (n = 5) 或八亚甲基 (n = 8) 变为亚乙基 ( n = 2) 键时，观察到从黄色到绿色的变色。X 射线晶体学和 1 H 核磁共振分析结合密度泛函理论计算表明，目前的色度是由两个铱核之间的接近度和构象刚度的变化引起的，这两者都由聚亚甲基键的长度控制。