Lewis acidic boron compounds are ubiquitous in chemistry due to their numerous applications, yet tuning and optimizing their properties towards different purposes is still a challenging field of research. In this work, the boron Lewis acid B[OTeF3(C6F5)2]3 was synthesized by reaction of the teflate derivative HOTeF3(C6F5)2 with BCl3 or BCl3·SMe2. This new compound presents a remarkably high thermal stability up to 300 °C, as well as one of the most sterically encumbered boron centres known in the literature. Theoretical and experimental methods revealed that B[OTeF3(C6F5)2]3 exhibits a comparable Lewis acidity to that of the well‐known B(C6F5)3 and around 85% of the Lewis acidity of the related B(OTeF5)3. The affinity of B[OTeF3(C6F5)2]3 towards pyridine was accessed by Isothermal Titration Calorimetry (ITC) and compared to that of B(OTeF5)3 and B(C6F5)3. The ligand‐transfer reactivity of this new boron compound towards different fluorides was demonstrated by the formation of an anionic Au(III) complex and a hypervalent iodine(III) species.

中文翻译：

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由有机碲基配体实现的高空间位阻硼路易斯酸

路易斯酸性硼化合物由于其广泛的应用而在化学中无处不在，但针对不同目的调整和优化其性能仍然是一个具有挑战性的研究领域。本工作通过四氟乙烯衍生物HOTeF3(C6F5)2与BCl3或BCl3·SMe2反应合成了硼路易斯酸B[OTeF3(C6F5)2]3。这种新化合物在高达 300 °C 的温度下具有极高的热稳定性，并且是文献中已知的空间阻碍最大的硼中心之一。理论和实验方法表明，B[OTeF3(C6F5)2]3 表现出与众所周知的 B(C6F5)3 相当的路易斯酸度，约为相关 B(OTeF5)3 路易斯酸度的 85%。通过等温滴定量热法 (ITC) 测定 B[OTeF3(C6F5)2]3 对吡啶的亲和力，并与 B(OTeF5)3 和 B(C6F5)3 进行比较。这种新型硼化合物对不同氟化物的配体转移反应性通过阴离子 Au(III) 络合物和高价碘 (III) 物质的形成得到证明。