A series of two-dimensional (2D) spin-crossover coordination polymers (SCO-CPs) [Fe^II(TPE)(NCX)₂]·solv (1: X = BH₃, solv = H₂O·2CH₃OH·DMF; 2: X = Se, solv = H₂O·2CH₃OH·0.5DMF; 3: X = S, solv = H₂O·2CH₃OH·0.5DMF) were synthesized by employing 1,1,2,2-tetra(pyridin-4-yl)ethene (TPE) and pseudohalide (NCX⁻) coligands. Magnetic measurements indicated that complexes 1–3 exhibited SCO behaviors with diminishing thermal hysteresis (7/4/0 K) upon decreasing the ligand-field strength. The critical temperatures (T_c) during spin transition were found to be inversely proportional to the coordination ability parameters (a™) with a linear correlation. The guest effect was also investigated in the solvent-exchanged phases 1-SE/2-SE/3-SE wherein the DMF molecules were replaced by methanol molecules. Compared with 1–3, 1-SE/2-SE/3-SE displayed more abrupt and complete single-step SCO behaviors but narrower thermal hysteretic loops. The results reported here demonstrate that the T_c values of these two families were dominated by the ligand-field strength of the NCX⁻ anions (NCBH₃ > NCSe > NCS), whereas the guest effect only modulated the kinetic factor of the SCO nature in this system.

中文翻译：

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基于1,1,2,2-四(吡啶-4-基)乙烯配体的二维自旋交叉配位聚合物

一系列二维（2D）自旋交叉配位聚合物（SCO-CPs）[Fe ^II (TPE)(NCX) ₂ ]·solv ( 1 : X = BH ₃ , solv = H ₂ O·2CH ₃ OH· DMF；2：X=Se，solv=H ₂ O·2CH ₃ OH·0.5DMF；3：X=S，solv=H ₂ O·2CH ₃ OH·0.5DMF)通过使用1,1,2合成， 2-四（吡啶-4-基）乙烯（TPE）和拟卤化物（NCX ^-）共配体。磁测量表明，随着配体场强度的降低，配合物1-3表现出 SCO 行为，热滞现象逐渐减小 (7/4/0 K)。研究发现自旋跃迁过程中的临界温度（T _c ）与配位能力参数（ a ™）成反比，并呈线性相关。还在溶剂交换相1-SE / 2-SE / 3-SE中研究了客体效应，其中 DMF 分子被甲醇分子取代。与1-3相比，1-SE / 2-SE / 3-SE表现出更突然和完整的单步SCO行为，但热滞回线更窄。这里报告的结果表明，这两个家族的T _c值主要由 NCX ^-阴离子的配体场强度 (NCBH ₃ > NCSe > NCS) 决定，而客体效应仅调节 SCO 性质的动力学因子。这个系统。