Khrizanforov Mikhail N, Fedorenko Svetlana V, Mustafina Asia R, Khrizanforova Vera V, Kholin Kirill V, Nizameev Irek R, Gryaznova Tatyana V, Grinenko Valeriya V, Budnikova Yulia H
Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center, Russian Academy of Sciences 420088 Arbuzov str. 8 Kazan Russian Federation
RSC Adv. 2019 Jul 23;9(39):22627-22635. doi: 10.1039/c9ra03421h. eCollection 2019 Jul 17.
The present work introduces a facile synthetic route for efficient doping of [Ni(bpy) ] into silica nanoparticles with various sizes and architectures. Variation of the latter results in different concentrations of the Ni complexes at the interface of the composite nanoparticles. The UV-Vis analysis of the nanoparticles reveals changes in the inner-sphere environment of the Ni complexes when embedded into the nanoparticles, while the inner-sphere of Ni is invariant for the nanoparticles with different architecture. Comparative analysis of the electrochemically generated redox transformations of the Ni complexes embedded in the nanoparticles of various architectures reveals the latter as the main factor controlling the accessibility of Ni complexes to the redox transitions which, in turn, controls the electrochemical behavior of the nanoparticles. The work also highlights an impact of the nanoparticulate architecture in catalytic activity of the Ni complexes within the different nanoparticles in oxidative C-H fluoroalkylation of caffeine. Both low leakage and high concentration of the Ni complexes at the interface of the composite nanoparticles enables fluoroalkylated caffeine to be obtained in high yields under recycling of the nanocatalyst five times at least.
本工作介绍了一种简便的合成路线，用于将[Ni(bpy) ]高效掺杂到具有各种尺寸和结构的二氧化硅纳米颗粒中。后者的变化导致复合纳米颗粒界面处镍配合物的浓度不同。对纳米颗粒的紫外-可见分析表明，当镍配合物嵌入纳米颗粒时，其内球环境会发生变化，而对于具有不同结构的纳米颗粒，镍的内球是不变的。对嵌入各种结构纳米颗粒中的镍配合物的电化学产生的氧化还原转变进行比较分析，结果表明后者是控制镍配合物进行氧化还原转变的可及性的主要因素，而这又反过来控制了纳米颗粒的电化学行为。该工作还强调了纳米颗粒结构对不同纳米颗粒中镍配合物在咖啡因氧化C-H氟烷基化反应中的催化活性的影响。复合纳米颗粒界面处镍配合物的低泄漏率和高浓度使得在纳米催化剂至少循环使用五次的情况下能够高产率地获得氟烷基化咖啡因。
