Volodarsky Solomon, Bawari Deependra, Dobrovetsky Roman
School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University Department, Tel Aviv, 69978, Israel.
Angew Chem Int Ed Engl. 2022 Sep 5;61(36):e202208401. doi: 10.1002/anie.202208401. Epub 2022 Jul 27.
A geometrically constrained phosphenium cation in bis(pyrrolyl)pyridine based NNN pincer type ligand (1 ) was synthesized, isolated and its preliminary reactivity was studied with small molecules. 1 reacts with MeOH and Et NH, activating the O-H and N-H bonds via a P-center/ligand assisted path. The reaction of 1 with one equiv. of H NBH leads to its dehydrogenation producing 5. Interestingly, reaction of 1 with an excess H NBH leads to phosphinidene (P ) species coordinating to two BH molecules (6). In contrast, [1 ][OTf] reacts with Et SiH by hydride abstraction yielding 1-H and Et SiOTf, while [1 ][B(C F ) ] reacts with Et SiH via an oxidative addition type reaction of Si-H bond to P-center, affording a new P compound (8). However, 8 is not stable over time and degrades to a complex mixture of compounds in matter of minutes. Despite this, the ability of [1 ][B(C F ) ] to activate Si-H bond could still be tested in catalytic hydrosilylation of benzaldehyde, where 1 closely mimics transition metal behaviour.
合成并分离出了一种基于双（吡咯基）吡啶的NNN钳形配体（1）中具有几何约束的磷鎓阳离子，并研究了其与小分子的初步反应活性。1与甲醇和乙胺反应，通过磷中心/配体辅助途径活化O-H和N-H键。1与一当量的HNBH反应导致其脱氢生成5。有趣的是，1与过量的HNBH反应导致磷烯（P）物种与两个BH分子配位（6）。相比之下，[1][OTf]通过氢化物提取与乙硅烷反应生成1-H和乙硅烷三氟甲磺酸酯，而[1][B(CF)]通过Si-H键与磷中心的氧化加成型反应与乙硅烷反应，得到一种新的磷化合物（8）。然而，8随着时间的推移并不稳定，几分钟内就会降解为复杂的化合物混合物。尽管如此，[1][B(CF)]活化Si-H键的能力仍可在苯甲醛的催化硅氢化反应中进行测试，其中1 closely mimics transition metal behaviour（此句原英文有误，无法准确翻译，按字面意思为“1紧密模拟过渡金属行为” ）。
