Watanabe Yuichiro, Washer Benjamin M, Zeller Matthias, Savikhin Sergei, Slipchenko Lyudmila V, Wei Alexander
Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States.
Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, Indiana 47907, United States.
J Am Chem Soc. 2022 Jun 15;144(23):10186-10192. doi: 10.1021/jacs.1c13462. Epub 2022 May 20.
We describe a novel manifestation of rigidochromic behavior in a series of tetranuclear Cu(I)-pyrazolate (Cupz) macrocycles, with implications for solid-state luminescence at deep-blue wavelengths (<460 nm). The Cupz emissions are remarkably sensitive to structural effects far from the luminescent core: when 3,5-di--butylpyrazoles are used as bridging ligands, adding a C4 substituent can induce a blue shift of more than 100 nm. X-ray crystal and computational analyses reveal that C4 units influence the conformational behavior of adjacent -butyl groups, with a subsequent impact on the global conformation of the Cupz complex. Emissions are mediated primarily through a cluster-centered triplet (CC) state; compression of the Cu cluster into a nearly close-packed geometry prevents the reorganization of its excited-state structure and preserves the CC energy at a high level. The remote steric effect may thus offer alternative strategies toward the design of phosphors with rigid excited-state geometries.
我们描述了一系列四核铜（I）-吡唑酸盐（Cupz）大环化合物中一种新型的刚性变色行为表现，这对深蓝色波长（<460 nm）的固态发光具有重要意义。Cupz的发射对远离发光核心的结构效应非常敏感：当使用3,5-二叔丁基吡唑作为桥连配体时，添加一个C4取代基可导致超过100 nm的蓝移。X射线晶体分析和计算分析表明，C4单元影响相邻叔丁基的构象行为，进而对Cupz配合物的整体构象产生影响。发射主要通过以簇为中心的三重态（CC）状态介导；将铜簇压缩成近乎紧密堆积的几何形状可防止其激发态结构的重组，并将CC能量保持在较高水平。因此，远程空间效应可能为设计具有刚性激发态几何形状的磷光体提供替代策略。
