Noncovalently Linked Metallacarboranes on Functionalized Magnetic Nanoparticles as Highly Efficient, Robust, and Reusable Photocatalysts in Aqueous Medium
Noncovalently Linked Metallacarboranes on Functionalized Magnetic Nanoparticles as Highly Efficient, Robust, and Reusable Photocatalysts in Aqueous Medium
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DOI：
10.1021/acsami.0c17847
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发表时间：
2020-12-16
影响因子：
9.5
通讯作者：
Teixidor, Francesc
中科院分区：
文献类型：
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作者：
Guerrero, Isabel;Saha, Arpita;Teixidor, Francesc
一种成功的均相光氧化还原催化剂已在涂有二氧化硅层的磁性纳米颗粒（MNP）上进行了卓有成效的异质化，保持了其均质催化性能完整，但由于易于磁分离和可回收性而获得了其他性能。以非共价键连接到 H[3,3'-Co(1,2-C2B9H11)(2)](-) (H[1]) 的胺封端磁性二氧化硅纳米颗粒（称为 MSNPs-NH2@gH[1]）高度稳定，不会在水中产生光氧化还原催化剂 H[1] 的任何泄漏。磁铁矿 MNP 涂有 SiO2，以提供胶体稳定性和与含胺单元连接的硅烷醇基团。这些是 MSNPs-NH2，其上锚定在水中的钴双（二碳内酯）络合物 H[1]，以获得 MSNPs-NH(2)gH[1]。对 MSNPs-NH2 和 MSNPs-NH(2)gH[1] 进行评估，以研究所产生的 MNP 的形态、表征和胶体稳定性。研究了非均相 MSNP-NH2@H[1] 体系对 1-苯基乙醇、1-己醇、1,6-己二醇或环己醇等醇类的光氧化作用，催化剂负载量为 0.1 mol% 和 0.01 mol%。引入表面活性剂以防止MNPs聚集，并选择十六烷基三甲基氯化铵作为表面活性剂。这提供了足够的稳定性，而不妨碍快速磁分离。结果证明，如果防止聚集，可以加速催化。通过运行 12 次 MSNPs-NH(2)gH[1] 系统，证明了催化系统的可回收性，每一次都没有损失选择性和产率。事实证明，负载在二氧化硅涂层磁铁矿纳米粒子上的钴双（二碳内酯）催化剂是一种稳健、高效且易于重复使用的系统，可用于水中醇的光氧化，从而形成绿色且可持续的多相催化系统。
A successful homogeneous photoredox catalyst has been fruitfully heterogenized on magnetic nanoparticles (MNPs) coated with a silica layer, keeping intact its homogeneous catalytic properties but gaining others due to the easy magnetic separation and recyclability. The amine-terminated magnetic silica nanoparticles linked noncovalently to H[3,3'-Co(1,2-C2B9H11)(2)](-) (H[1]), termed MSNPs-NH2@gH[1], are highly stable and do not produce any leakage of the photoredox catalyst H[1] in water. The magnetite MNPs were coated with SiO2 to provide colloidal stability and silanol groups to be tethered to amine-containing units. These were the MSNPs-NH2 on which was anchored, in water, the cobaltabis(dicarbollide) complex H[1] to obtain MSNPs-NH(2)gH[1]. Both MSNPs-NH2 and MSNPs-NH(2)gH[1] were evaluated to study the morphology, characterization, and colloidal stability of the MNPs produced. The heterogeneous MSNP-NH2@H[1] system was studied for the photooxidation of alcohols, such as 1-phenylethanol, 1-hexanol, 1,6-hexanediol, Or cyclohexanol among others, using catalyst loads of 0.1 and 0.01 mol %. Surfactants were introduced to prevent the aggregation of MNPs, and cetyl trimethyl ammonium chloride was chosen as a surfactant. This provided adequate stability, without hampering quick magnetic separation. The results proved that the catalysis could be speeded up if aggregation was prevented. The recyclability of the catalytic system was demonstrated by performing 12 runs of the MSNPs-NH(2)gH[1] system, each one without loss of selectivity and yield. The cobaltabis(dicarbollide) catalyst supported on silica-coated magnetite nanoparticles has proven to be a robust, efficient, and easily reusable system for the photooxidation of alcohols in water, resulting in a green and sustainable heterogeneous catalytic system.