We report the construction of frustrated Lewis pairs (FLPs) in a metal–organic framework (MOF), where both Lewis acid (LA) and Lewis base (LB) are fixed to the backbone. The anchoring of a tritopic organoboron linker as LA and a monotopic linker as LB to separate metal oxide clusters in a tetrahedron geometry allows for the precise control of distance between them. As the type of monotopic LB linker varies, pyridine, phenol, aniline, and benzyl alcohol, a series of 11 FLPs were constructed to give fixed distances of 7.1, 5.5, 5.4, and 4.8 Å, respectively, revealed by ¹¹B–¹H solid-state nuclear magnetic resonance spectroscopy. Keeping LA and LB apart by a fixed distance makes it possible to investigate the electrostatic effect by changing the functional groups in the monotopic LB linker, while the LA counterpart remains unaffected. This approach offers new chemical environments of the active site for FLP-induced catalysis.

中文翻译：

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金属有机框架中受阻路易斯对的精确距离控制和功能调节

我们报告了金属有机骨架（MOF）中受挫路易斯对（FLP）的构建，其中路易斯酸（LA）和路易斯碱（LB）都固定在主链上。锚定三位有机硼连接体 LA 和单位连接体 LB 以分离四面体几何形状中的金属氧化物簇，从而可以精确控制它们之间的距离。由于单位 LB 连接体的类型不同（吡啶、苯酚、苯胺和苯甲醇），构建了一系列 11 个 FLP，分别给出 7.1、5.5、5.4 和 4.8 Å 的固定距离，由¹¹ B– ¹ H揭示固态核磁共振波谱。将 LA 和 LB 保持固定距离使得可以通过改变单位 LB 连接子中的官能团来研究静电效应，而 LA 对应物不受影响。这种方法为 FLP 诱导的催化活性位点提供了新的化学环境。