We disclose a suite of Ni(II) complexes featuring secondary sphere Lewis acids of varied Lewis acidity and tether lengths. Several of these complexes feature atypical behavior of Ni(II): reactivity with O₂ that occurs only in the presence of a tethered Lewis acid. In situ UV–vis spectroscopy revealed that, although adducts are stable at −40 °C, complexes containing 9-borabicyclo[3.3.1]nonane (9-BBN) Lewis acids underwent irreversible oxidative deborylation when warmed to room temperature. We computationally and experimentally identified that oxidative instability of appended 9-BBN moieties can be mitigated using weaker Lewis acids such as pinacolborane (BPin). These insights enabled the realization of catalytic reactions: hydrogen atom abstraction from phenols and room temperature oxygen atom transfer to PPh₃.

中文翻译：

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附加的路易斯酸可实现双氧反应并与 Ni(II) 进行催化氧化

我们公开了一套Ni(II)络合物，其特征在于具有不同路易斯酸度和链长度的次级球路易斯酸。其中一些配合物具有 Ni(II) 的非典型行为：仅在存在束缚路易斯酸的情况下才会发生与 O _{2 的}反应。原位紫外可见光谱显示，虽然加合物在-40°C下稳定，但含有9-硼双环[3.3.1]壬烷(9-BBN)路易斯酸的络合物在升温至室温时会发生不可逆的氧化脱硼化。我们通过计算和实验发现，附加的 9-BBN 部分的氧化不稳定性可以使用较弱的路易斯酸（例如频哪醇硼烷 (BPin)）来减轻。这些见解使得催化反应得以实现：从苯酚中提取氢原子以及室温下氧原子转移至 PPh ₃。