Hetero tri metallic Precursor with 2:2:1 Metal Ratio Requiring at Least a Pentanuclear Molecular Assembly
Hetero tri metallic Precursor with 2:2:1 Metal Ratio Requiring at Least a Pentanuclear Molecular Assembly
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DOI：
10.1021/jacs.0c05139
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发表时间：
2020-07-22
影响因子：
15
通讯作者：
Dikarev, Evgeny, V
中科院分区：
文献类型：
--
作者：
Han, Haixiang;Carozza, Jesse C.;Dikarev, Evgeny, V
这项工作代表了寻求制造具有特定金属类型和复杂金属比例的异多金属分子的重要一步。介绍了用于下一代钠离子电池正极材料Na 2 Mn 2FeO 6的复杂异三金属单源分子前体的合理设计、合成和表征。通过混合配体、不对称配体和混合价等一系列复杂的设计方法，从已知的聚合物结构[NaMnII（acac）（3）]（infinity）衍生出独特的五金属平台[Mn-II（ptac）（3）-Na-Mn-III（acac）（3）-Na-Mn-II（ptac）（3）]（1）。重要的是，这些技术的应用导致在配体环境和氧化态方面具有明显不同的过渡金属位置的分子。Fe-III对中心Mn-III离子的等价取代形成目标异三金属前体[Mn-II（ptac）（3）-Na-Fe-III（acac）（3）-Na-Mn-II（ptac）（3）]（3），其中适当的金属比为Na：Mn：Fe = 2：2：1。通过单晶X-射线研究证实了在该五金属组装体中金属离子和配体的排列。明确的位置和氧化态的元素周期表的邻居铁和锰在3已经实现了结合的调查技术，包括同步辐射共振衍射，X射线多波长异常衍射，X射线荧光光谱，穆斯堡尔光谱，气相DART质谱。异质三金属单源前体3显示出干净的分解图案，产生具有高均匀性的金属离子分布的相纯P2-Na 2 Mn 2FeO 6四元氧化物，如通过电子显微镜证实的。
This work represents an important step in the quest to make heteromultimetallic molecules featuring specific metal types and complicated metal ratios. The rational design, synthesis, and characterization of a complex heterotrimetallic single-source molecular precursor for the next generation sodium-ion battery cathode material, Na2Mn2FeO6, is described. A unique pentametallic platform [Mn-II(ptac)(3)-Na-Mn-III(acac)(3)-Na-Mn-II(ptac)(3)] (1) was derived from the known polymeric structure of [NaMnII(acac)(3)](infinity), through a series of elaborate design procedures, such as mixed-ligand, unsymmetric ligand, and mixed-valent approaches. Importantly, the application of those techniques results in a molecule with distinctively different transition metal positions in terms of ligand environment and oxidation states. An isovalent substitution of Fe-III for the central Mn-III ion forms the target heterotrimetallic precursor [Mn-II(ptac)(3)-Na-Fe-III(acac)(3)-Na-Mn-II(ptac)(3)] (3) with an appropriate metal ratio of Na:Mn:Fe = 2:2:1. The arrangement of metal ions and ligands in this pentametallic assembly was confirmed by single crystal X-ray investigation. The unambiguous assignment of the positions and oxidation states of the Periodic Table neighbors Fe and Mn in 3 has been achieved by a combination of investigative techniques that include synchrotron resonant diffraction, X-ray multiwavelength anomalous diffraction, X-ray fluorescence spectroscopy, Mossbauer spectroscopy, and gas-phase DART mass spectrometry. The heterotrimetallic single-source precursor 3 was shown to exhibit a clean decomposition pattern yielding the phase-pure P2-Na2Mn2FeO6 quaternary oxide with high uniformity of metal ion distribution as confirmed by electron microscopy.