Lin Qisheng, Aguirre Kaiser, Saunders Scott M, Hackett Timothy A, Liu Yong, Taufour Valentin, Paudyal Durga, Budko Sergey, Canfield Paul C, Miller Gordon J
Division of Materials Science & Engineering, Ames Laboratory, U.S. Department of Energy, 2416 Pammel Drive, Ames, IA, 50011-2416, USA.
Department of Chemistry, Iowa State University, 2415 Osborn Drive, 1605 Gilman Hall, Ames, IA, 50011-1021, USA.
Chemistry. 2017 Aug 4;23(44):10516-10521. doi: 10.1002/chem.201702798. Epub 2017 Jul 18.
Planar hydrocarbon-like metal clusters may foster new insights linking organic molecules with conjugated π-π bonding interactions and inorganic structures in terms of their bonding characteristics. However, such clusters are uncommon in polar intermetallics. Herein, we report two polar intermetallic phases, Pr Co Ge and Pr Co Ge , both of which feature such planar metal clusters, namely, ethylene-like [Co Ge ] clusters plus the concatenated forms and polyacene-like [Co Ge ] ribbons in Pr Co Ge , and 1,2,4,5-tetramethylbenzene-like [Co Ge ] cluster in Pr Co Ge . Just as in the related planar organic structures, these metal-metalloid species are dominated by covalent bonding interactions. Both compounds magnetically order at low temperature with net ferromagnetic components: Pr Co Ge through a series of transitions below 150 K and Pr Co Ge through a single ferromagnetic transition at 19 K. Spin-polarized electronic structure calculations for Pr Co Ge reveal strong spin-orbit coupling within Pr and considerable magnetic contributions from Co atoms. This work suggests that similar structural chemistry can emerge for other rare-earth/late-transition-metal/main-group systems.
平面类烃金属簇合物可能会在有机分子与具有共轭π-π键相互作用的无机结构之间的键合特性方面带来新的见解。然而，这类簇合物在极性金属间化合物中并不常见。在此，我们报道了两种极性金属间相，PrCoGe和PrCoGe，它们都具有此类平面金属簇合物，即在PrCoGe中，类似乙烯的[CoGe]簇合物及其连接形式和类似并五苯的[CoGe]带，以及在PrCoGe中类似1,2,4,5-四甲基苯的[CoGe]簇合物。正如在相关的平面有机结构中一样，这些金属-类金属物种主要由共价键相互作用主导。这两种化合物在低温下都呈现出磁有序，具有净铁磁成分：PrCoGe在150 K以下通过一系列转变，PrCoGe在19 K通过单一铁磁转变。对PrCoGe的自旋极化电子结构计算表明，Pr内存在强自旋-轨道耦合，且Co原子有相当大的磁贡献。这项工作表明，其他稀土/晚期过渡金属/主族体系可能会出现类似的结构化学。
