Li Yue, Kong Qing-Rong, Guo Ying, Tang Zheng
College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, People's Republic of China.
Key Laboratory of Cluster Science of Ministry of Education, School of Chemistry and Chemical Engineering, Liangxiang Campus, Beijing Institute of Technology, Beijing 102488, People's Republic of China.
Dalton Trans. 2021 Feb 7;50(4):1384-1389. doi: 10.1039/d0dt03796f. Epub 2021 Jan 12.
Two isostructural 3D Hofmann-type frameworks, [Fe(dbdpe)M(CN)]·4HO (M = Pt for 1 and Pd for 2), were synthesized based on a bis-monodentate ligand dbdpe (1,2-dibromo-1,2-di(pyridin-4-yl)ethane). Both compounds underwent similar one-step incomplete spin crossover (SCO) processes in the presence of lattice water molecules, i.e., T↓ = 185 K for 1 and 187 K for 2 without any hysteresis loop, while their dehydrated products exhibited paramagnetic behaviours. The application of pressure on 1 broadened the hysteresis loop to 13-25 K and shifted the transition temperature from 185 to 298 K, whereas the SCO completeness was not well improved. Variable temperature X-ray crystallographic studies clearly confirmed the incomplete SCO behaviors, and the intermolecular hydrogen bonds might promote the cooperativity in the SCO processes.
基于双单齿配体dbdpe（1,2 - 二溴 - 1,2 - 二（吡啶 - 4 - 基）乙烷）合成了两种同构的三维霍夫曼型框架化合物[Fe(dbdpe)M(CN)]·4H₂O（M = Pt时为1，M = Pd时为2）。在晶格水分子存在的情况下，这两种化合物都经历了类似的一步不完全自旋交叉（SCO）过程，即1的T↓ = 185 K，2的T↓ = 187 K，且没有任何滞后回线，而它们的脱水产物表现出顺磁行为。对1施加压力使滞后回线拓宽至13 - 25 K，并使转变温度从185 K移至298 K，然而SCO的完整性并未得到很好的改善。变温X射线晶体学研究清楚地证实了不完全SCO行为，并且分子间氢键可能促进了SCO过程中的协同性。
