Shin Jong Won, Jeong Ah Rim, Jeong Jong Hwa, Zenno Hikaru, Hayami Shinya, Min Kil Sik
Department of Chemistry, Kyungpook National University Daegu 41566 Republic of Korea
Department of Chemistry, Kumamoto University Kumamoto 860-8555 Japan.
RSC Adv. 2020 Jan 31;10(9):5040-5049. doi: 10.1039/c9ra09782a. eCollection 2020 Jan 29.
Two Fe(ii)-based coordination polymers [Fe(tpmd)(NCS)]·5.5HO (1) and [Fe(tpmd)(NCSe)]·7HO (2) with the framework of square-grid type have been assembled from FeSO·7HO, ,,','-tetrakis(pyridin-4-yl)methanediamine (tpmd), and KNCS/KNCSe in methanol and characterized. By utilizing two pyridine groups of a tpmd ligand, 1 and 2 are formed in two-dimensional layered structures through coordination of octahedral iron(ii) ions with the tpmd to NCS/NCSe ligands in which they have a supramolecular isomorphous conformation. 1 shows a paramagnetic behavior between 2 and 300 K, while 2 exhibits two-step spin crossover ( 145 and 50 K) in the temperature range due to the coordination of NCSe ligands. At 300 K 2 is fully high-spin state. However, at 100 K 2 becomes 50% high spin and 50% low spin iron(ii) ions, which is verified by magnetic moments. In the structural analysis of 2 at 100 K, two different layers are observed with different bond distances around iron(ii) ions in which the layers are stacked alternately.
两种具有方格型结构的基于Fe(ii)的配位聚合物[Fe(tpmd)(NCS)]·5.5H₂O (1)和[Fe(tpmd)(NCSe)]·7H₂O (2)已通过FeSO₄·7H₂O、1,1',1'',1'''-四(吡啶-4-基)甲烷二胺(tpmd)以及KSCN/KSeCN在甲醇中组装而成并进行了表征。通过利用tpmd配体的两个吡啶基团，1和2通过八面体铁(ii)离子与tpmd至NCS/NCSe配体的配位作用形成二维层状结构，其中它们具有超分子同构构象。1在2至300 K之间表现出顺磁行为，而2由于NCSe配体的配位作用在该温度范围内呈现两步自旋交叉(145 K和50 K)。在300 K时2处于完全高自旋态。然而，在100 K时2变为50%高自旋和50%低自旋的铁(ii)离子，这通过磁矩得到验证。在100 K下对2进行结构分析时，观察到围绕铁(ii)离子具有不同键距的两个不同层，这些层交替堆叠。
