Micelles of poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) (PS-PVP-PEO) with core–shell–corona structures have been used as a scaffold for the fabrication of gold (Au) hollow nanospheres of particle size 26 ± 2 nm using HAuCl₄ and NaBH₄ as metal precursor and reducing agent, respectively. The PS core acts as a template for hollow void, the PVP shell serves as reaction sites for inorganic precursors, and PEO corona stabilizes the composite particles. Under acidic conditions, the PVP shell domain becomes positively charged pyridinum-species that electrostatically interacts with negatively charged AuCl₄⁻ ions. On reduction of these composite particles and subsequent solvent extraction leads to the formation of Au hollow nanospheres. Various analytical tools such as powder X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetric analyses (TG/DTA), dynamic light scattering of (DLS) have been employed to characterize the polymeric micelles and hollow nanoparticles. The TEM and XRD studies confirmed the formation of highly crystalline Au hollow nanospheres. The Au hollow nanosphere/H₂O₂ system efficiently catalyzes the chemoselective oxidation of allylic-type unsaturated alcohols into aldehydes and ketones under mild liquid-phase conditions. The versatility of present catalytic system for the oxidation of other substrates like aliphatic-, acylic-, aromatic-, and heteroaromatic alcohols to their respective keto compounds has also been reported.

中文翻译：

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高效金空心纳米球催化醇的化学选择性氧化

具有核-壳-电晕结构的聚苯乙烯-b -2-乙烯基吡啶-b-环氧乙烷（PS-PVP-PEO）的胶束已被用作制造金（Au）空心纳米球粒子的支架分别使用HAuCl ₄和NaBH ₄作为金属前驱体和还原剂，尺寸为26±2 nm 。PS核充当空心空隙的模板，PVP壳充当无机前体的反应位点，PEO电晕稳定复合颗粒。在酸性条件下，将PVP壳域带正电吡啶鎓-物种静电带负电荷的相互作用AUCL ₄ ^-离子。在还原这些复合颗粒并随后进行溶剂萃取时，会形成金空心纳米球。各种分析工具，例如粉末X射线衍射（XRD），透射电子显微镜（TEM），热重分析（TG / DTA），动态光散射（DLS）已用于表征聚合物胶束和中空纳米粒子。TEM和XRD研究证实了高度结晶的Au中空纳米球的形成。金纳米空心球/ H ₂ O ₂系统在温和的液相条件下有效催化烯丙基型不饱和醇化学选择性氧化为醛和酮。还已经报道了本催化系统用于将其他底物如脂族醇，酰基醇，芳族醇和杂芳族醇氧化为它们各自的酮化合物的多功能性。