Zuo Tianming, Olmstead Marilyn M, Beavers Christine M, Balch Alan L, Wang Guangbin, Yee Gordon T, Shu Chunying, Xu Liaosa, Elliott Bevan, Echegoyen Luis, Duchamp James C, Dorn Harry C
Chemistry Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA.
Inorg Chem. 2008 Jun 16;47(12):5234-44. doi: 10.1021/ic800227x. Epub 2008 Apr 30.
We report an efficient method for the preparation and purification of the Ih and the D5h isomers of Tm3N@C80. Following preparation in a Kratschmer-Huffman electric-arc generator, the Tm3N@C80 isomers were obtained by a chemical separation process followed by a one-stage isomer selective chromatographic high-performance liquid chromatography (HPLC) separation (pyrenyl, 5PYE column). The HPLC chromatographic retention behavior on a pentabromobenzyl (5PBB) column suggests a charge transfer of approximately 6 electrons; [M3N] 6+@C80(6-) and the chromatographic retention mechanisms of the Ih and the D5h isomers of Tm3N@C80 on both 5PBB and 5PYE columns are discussed. Single-crystal X-ray diffraction data demonstrate that the Tm3N cluster has a planar structure but represents a tight fit for trapping the Tm3N cluster inside the I h - and the D 5h -C 80 cages. Specifically, the Tm atoms punch out the cage carbon atoms adjacent to them. The "punched out" effect can be demonstrated by cage radii and pyramidal angles at cage carbon atoms near the Tm atoms. The magnetic susceptibility (chiT) for Tm3N@ Ih -C80 was found to exhibit Curie-Weiss behavior with C = 23.4 emu.K/mol, which is consistent with the calculated value for three uncoupled Tm3+ ions by considering the spin and orbital contributions with no quenching of the orbital angular momentum ( L = 5, S = 1, and J = 6; Ccalcd = 23.3 emu.K/mol). The electrochemical measurements demonstrate that both the Ih and the D5h isomers of Tm3N@C80 have a large electrochemical gap.
我们报道了一种制备和纯化Tm3N@C80的Ih和D5h异构体的有效方法。在Kratschmer-Huffman电弧发生器中制备后，通过化学分离过程，然后进行单阶段异构体选择性色谱高效液相色谱（HPLC）分离（芘基，5PYE柱），获得了Tm3N@C80异构体。在五溴苄基（5PBB）柱上的HPLC色谱保留行为表明电荷转移约6个电子；[M3N]6+@C80(6-)，并讨论了Tm3N@C80的Ih和D5h异构体在5PBB和5PYE柱上的色谱保留机制。单晶X射线衍射数据表明，Tm3N团簇具有平面结构，但对于将Tm3N团簇捕获在Ih-和D5h-C80笼内来说是紧密匹配的。具体而言，Tm原子将与其相邻的笼碳原子挤出。“挤出”效应可以通过Tm原子附近笼碳原子处的笼半径和锥角来证明。发现Tm3N@Ih-C80的磁化率（χT）表现出居里-外斯行为，C = 23.4 emu·K/mol，通过考虑自旋和轨道贡献且轨道角动量无淬灭（L = 5，S = 1，J = 6；计算值Ccalcd = 23.3 emu·K/mol），这与三个未耦合的Tm3+离子的计算值一致。电化学测量表明，Tm3N@C80的Ih和D5h异构体都有较大的电化学能隙。
