Bilyachenko Alexey N, Khrustalev Victor N, Huang Zhibin, Dubinina Kristina D, Shubina Elena S, Lobanov Nikolai N, Sun Di, Alegria Elisabete C B A, Pombeiro Armando J L
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia.
Peoples' Friendship University of Russia (RUDN University), Miklukho-Maklay Str. 6, 117198 Moscow, Russia.
Nanoscale. 2024 Oct 24;16(41):19266-19275. doi: 10.1039/d4nr02298j.
The synthesis of a high nuclear (CuNa) complex 1 the self-assembly of copper(II) phenylsilsesquioxane induced by complexation with bis(triphenylphosphine)iminium chloride (PPNCl) was successfully achieved. This complex, which includes two bis(triphenylphosphine)iminium PPN cations, represents the first example of a metallasilsesquioxane/phosphazene compound. The CuNa-silsesquioxane cage demonstrates a nontrivial combination of two pairs of Si-cyclic/Si-acyclic silsesquioxane ligands and a fusion of two SiCuNa fragments, combined the central ninth copper ion. The catalytic efficacy of the copper(II) compound (1) was evaluated through the peroxidative oxidation of toluene using -butyl hydroperoxide (-BuOOH) as the oxidant. The primary oxidation products were benzaldehyde (BAL), benzyl alcohol (BOL), and benzoic acid (BAC), with BAC being the predominant product, especially in acetonitrile (NCMe). The formation of cresols, indicating oxidation at the aromatic ring, was observed only in water and under microwave irradiation (MW) in NCMe. Remarkably, the highest total yield of 40.3% was achieved in water with an acidic additive at 80 °C, highlighting the crucial role of the acid additive in enhancing reaction efficiency and selectivity. This study underscores our copper(II) complex as a highly effective catalyst for toluene oxidation, demonstrating its significant potential for fine-tuning reaction parameters to optimize yields and selectivity. The unprecedented structure of the complex and its promising catalytic performance pave the way for further advancements in the fields of metallasilsesquioxane chemistry and catalysis.
通过与双（三苯基膦）亚胺氯化物（PPNCl）络合成功实现了高核（CuNa）配合物1的合成，即铜（II）苯基倍半硅氧烷的自组装。该配合物包含两个双（三苯基膦）亚胺PPN阳离子，是金属倍半硅氧烷/磷腈化合物的首个实例。CuNa-倍半硅氧烷笼展示了两对Si-环状/Si-非环状倍半硅氧烷配体的非平凡组合以及两个SiCuNa片段与中心第九个铜离子的融合。使用叔丁基过氧化氢（-BuOOH）作为氧化剂，通过甲苯的过氧化氢氧化评估了铜（II）化合物（1）的催化效果。主要氧化产物为苯甲醛（BAL）、苯甲醇（BOL）和苯甲酸（BAC），其中BAC是主要产物，尤其是在乙腈（NCMe）中。仅在水中以及在NCMe中的微波辐射（MW）下观察到了表明芳环氧化的甲酚的形成。值得注意的是，在80°C下添加酸性添加剂的水中实现了40.3%的最高总产率，突出了酸性添加剂在提高反应效率和选择性方面的关键作用。这项研究强调了我们的铜（II）配合物作为甲苯氧化的高效催化剂，展示了其在微调反应参数以优化产率和选择性方面的巨大潜力。该配合物前所未有的结构及其有前景的催化性能为金属倍半硅氧烷化学和催化领域的进一步发展铺平了道路。
