Mixed dysprosium-lanthanide nitride clusterfullerenes DyM2N@C80-Ih and Dy2MN@C80-Ih (M = Gd, Er, Tm, and Lu): synthesis, molecular structure, and quantum motion of the endohedral nitrogen atom.
Mixed dysprosium-lanthanide nitride clusterfullerenes DyM2N@C80-Ih and Dy2MN@C80-Ih (M = Gd, Er, Tm, and Lu): synthesis, molecular structure, and quantum motion of the endohedral nitrogen atom.
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DOI：
10.1039/c9nr03593a
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发表时间：
2019-07
期刊：
影响因子：
6.7
通讯作者：
Christin Schlesier;Fupin Liu;V. Dubrovin;L. Spree;Bernd Büchner;S. Avdoshenko;Alexey A. Popov
中科院分区：
文献类型：
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作者：
Christin Schlesier;Fupin Liu;V. Dubrovin;L. Spree;Bernd Büchner;S. Avdoshenko;Alexey A. Popov
对混合金属Dy-M氮化物团簇富勒烯（NCFs，M = Gd，Er，Tm，Lu）的合成进行了系统的探索，并评估了第二金属对相对产率的影响。我们表明，金属的离子半径似乎是主要因素，允许解释的相对产量在Dy-M混合金属系统与M = Sc，Lu，Er，和Gd。同时，Dy-Tm NCF显示出非常低的产率，这与Tm 3+的相对小的离子半径不一致，但可以通过Tm的高第三电离势来解释。通过循环HPLC实现了Dy-Gd和Dy-Er的完全分离以及Dy-Lu M3N@C80氮化物簇合物富勒烯的部分分离。用X射线单晶衍射分析了DyGd_2N@C_（80）和DyEr_2N@C_（80）的分子结构。一个显着的混合金属氮化物簇的顺序被发现，尽管类似的大小和电子性质的金属。在这些和其他nitridclusterfullerenes中的氮化物簇的可能的结晶是批判性的分析与DFT计算的帮助下，在M3N@C80分子中的氮反转势垒的重建进行。虽然一个双阱势与金字塔集群结构被发现是常见的，其中大多数，反转势垒的小尺寸往往导致一个明显的平面结构的集群。这种情况被发现为那些M3N@C80分子中的最低振动能级的能量超过的反转势垒，包括Dy3N@C80和DyEr2N@C80。只有当最低振动能级低于反转势垒时，才能通过X射线衍射观察到真正的金字塔结构，例如在Gd 3N@C80和DyGd 2N@C80中发现的那些。当反转势垒的大小与最低振动能级的能量相当时，分子振动的量子性质变得特别明显。
Systematic exploration of the synthesis of mixed-metal Dy-M nitride clusterfullerenes (NCFs, M = Gd, Er, Tm, Lu) is performed, and the impact of the second metal on the relative yield is evaluated. We demonstrate that the ionic radius of the metal appears to be the main factor allowing explanation of the relative yields in Dy-M mixed-metal systems with M = Sc, Lu, Er, and Gd. At the same time, Dy-Tm NCFs show anomalously low yields, which is not consistent with the relatively small ionic radius of Tm3+ but can be explained by the high third ionization potential of Tm. Complete separation of Dy-Gd and Dy-Er, as well as partial separation of Dy-Lu M3N@C80 nitride clusterfullerenes, is accomplished by recycling HPLC. The molecular structures of DyGd2N@C80 and DyEr2N@C80 are analyzed by means of single-crystal X-ray diffraction. A remarkable ordering of mixed-metal nitride clusters is found despite similar size and electronic properties of the metals. Possible pyramidalization of the nitride clusters in these and other nitride clusterfullerenes is critically analyzed with the help of DFT calculations and reconstruction of the nitrogen inversion barrier in M3N@C80 molecules is performed. Although a double-well potential with a pyramidal cluster structure is found to be common for most of them, the small size of the inversion barrier often leads to an apparent planar structure of the cluster. This situation is found for those M3N@C80 molecules in which the energy of the lowest vibrational level exceeds that of the inversion barrier, including Dy3N@C80 and DyEr2N@C80. The genuine pyramidal structure can be observed by X-ray diffraction only when the lowest vibrational level is below the inversion barrier, such as those found in Gd3N@C80 and DyGd2N@C80. The quantum nature of molecular vibrations becomes especially apparent when the size of the inversion barrier is comparable to the energy of the lowest vibrational levels.