Russell-Webster Bradley, Lopez-Nieto Javi, Abboud Khalil A, Christou George
Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA,
Dalton Trans. 2021 Nov 9;50(43):15524-15532. doi: 10.1039/d1dt02667d.
Two new Ce/O clusters, (pyH)[CeO(OH)(OPPh)(NO)] (1) and [CeO(OH)(OPPh)(OCBu)] (2), have been prepared that contain P-based ligands for the first time. They were obtained from the reaction of (NH)[Ce(NO)], PhPOH or PhPOH, and BuCOH in a 2 : 1 : 2 molar ratio in pyridine/MeOH (10 : 1 mL). Both compounds contain a {CeO(OH)} face-capped octahedral core, with 1 containing an additional four Ce on the outside to give a supertetrahedral Ce topology; the {CeO} unit is the smallest recognizable fragment of the fluorite structure of CeO. The HO˙ radical scavenging activities of 1 and 2 were measured by UV/vis spectral monitoring of methylene blue oxidation by HO˙ radicals in the presence and absence of the Ce/O clusters, and the results compared with those for larger Ce and Ce molecular nanoparticles of CeO prepared in previous work. 1 and 2 are both very poor HO˙ radical scavengers compared with Ce and Ce, a result that is consistent with reports in the literature that PO ions inhibit the radical scavenging ability of traditional CeO nanoparticles and putatively assigned to PO binding to the surface.
首次制备了两个新的铈/氧簇合物，(pyH)[CeO(OH)(OPPh)(NO)] (1) 和 [CeO(OH)(OPPh)(OCBu)] (2)，它们含有基于磷的配体。它们是通过(NH)[Ce(NO)]、PhPOH 或 PhPOH 与 BuCOH 以 2∶1∶2 的摩尔比在吡啶/甲醇（10∶1 mL）中反应得到的。两种化合物都含有一个{CeO(OH)}面封端的八面体核心，其中 1 在外部还含有另外四个铈，形成超四面体铈拓扑结构；{CeO}单元是 CeO 萤石结构中最小的可识别片段。通过在有和没有铈/氧簇合物存在的情况下，对 HO˙自由基氧化亚甲基蓝的紫外/可见光谱监测，测量了 1 和 2 的 HO˙自由基清除活性，并将结果与先前工作中制备的较大的 Ce 和 CeO 分子纳米颗粒的结果进行了比较。与 Ce 和 CeO 相比，1 和 2 都是非常差的 HO˙自由基清除剂，这一结果与文献报道一致，即 PO 离子会抑制传统 CeO 纳米颗粒的自由基清除能力，推测这是由于 PO 与表面结合所致
