Kang Soonchul, Shiota Yoshihito, Kariyazaki Akira, Kanegawa Shinji, Yoshizawa Kazunari, Sato Osamu
Institute for Materials Chemistry and Engineering, Kyushu University, 744 Motooka Nishi-ku Fukuoka, 819-0395 (Japan), Fax: (+81) 92-802-6205.
Chemistry. 2016 Jan 11;22(2):532-8. doi: 10.1002/chem.201503392. Epub 2015 Nov 13.
The anionic Fe(III) complex exhibiting cooperative spin transition with a wide thermal hysteresis near room temperature, K[Fe(5-Brthsa)2 ] (5-Brthsa-H2 =5-bromosalicylaldehyde thiosemicarbazone), is reported. The hysteresis (Δ=69 K in the first cycle) shows a one-step transition in heating mode and a two-step transition in cooling mode. X-ray structure analysis showed that the coexistence of hydrogen bond and cation-π interactions, as well as alkali metal coordination bonds, to give 2D coordination polymer structure. This result is contrary to previous reports of broad thermal hysteresis induced by coordination bonds of Fe(II) spin crossover coordination polymers (with 1D/3D structures), and by strong intermolecular interactions in the molecular packing through π-π stacking or hydrogen-bond networks. As a consequence, the importance, or the very good suitability of alkali metal-based coordination bonds and cation-π interactions for communicating cooperative interactions in spin-crossover (SCO) compounds must be reconsidered.
报道了一种阴离子型Fe(III)配合物K[Fe(5-Brthsa)2 ]（5-Brthsa-H2 =5-溴水杨醛缩硫代卡巴腙），它在室温附近表现出具有宽热滞回的协同自旋转变。热滞回（第一个循环中Δ=69 K）在加热模式下呈现一步转变，在冷却模式下呈现两步转变。X射线结构分析表明，氢键、阳离子-π相互作用以及碱金属配位键共存，形成二维配位聚合物结构。这一结果与先前关于由Fe(II)自旋交叉配位聚合物的配位键（具有一维/三维结构）以及通过π-π堆积或氢键网络在分子堆积中的强分子间相互作用引起的宽热滞回的报道相反。因此，必须重新考虑碱基金属配位键和阳离子-π相互作用在自旋交叉（SCO）化合物中传递协同相互作用方面的重要性或非常好的适用性。
