Zhang Daopeng, Valverde-Muñoz Francisco Javier, Bartual-Murgui Carlos, Piñeiro-López Lucía, Muñoz M Carmen, Real José Antonio
Instituto de Ciencia Molecular (ICMol), Universitat de València , C/Catedrático José Beltrán Martínez 2, 46980 Paterna (Valencia), Spain.
College of Chemical Engineering, Shandong University of Technology , Zibo 255049, People's Republic of China.
Inorg Chem. 2018 Feb 5;57(3):1562-1571. doi: 10.1021/acs.inorgchem.7b02906. Epub 2018 Jan 16.
We report an unprecedented series of two-dimensional (2D) spin-crossover (SCO) heterobimetallic coordination polymers generically formulated as {Fe(Hg(SCN))}·Solv, where x = 2 for L = tvp (trans-(4,4'-vinylenedipyridine)) (1tvp), bpmh ((1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine) (1bpmh·nCHOH; n = 0, 1), bpeh ((1E,2E)-1,2-bis(1-(pyridin-4-yl)ethylidene)hydrazine) (1bpeh·nHO; n = 0, 1) and x = 2.33 for L = bpbz (1,4-bis(pyridin-4-yl)benzene) (1bpbz·nHO; n = 0, 2/3). The results confirm that self-assembly of Fe, [Hg(SCN)], and ditopic rodlike bridging ligands L containing 4-pyridyl moieties favors the formation of linear [Fe(μ-L)] chains and in situ generated binuclear units {Hg(SCN)}. The latter act as bridges between adjacent chains generating robust 2D layers. The [FeN] centers are equatorially surrounded by four NCS groups and two axial N atoms of the organic ligand L. The compound 1tvp and the unsolvated form of 1bpmh undergo complete SCO centered at T = 177 and 226 K, characterized by the enthalpy and entropy variations ΔH = 12.3 and 10.5 kJ mol and ΔS = 69.4 and 48 J K mol, respectively. The almost complete SCO of the unsolvated form of 1bpeh occurs at ca. T = 119 K and exhibits a complete LIESST effect. Regardless of the degree of solvation, a half-spin conversion at T < 100 K occurs for 1bpbz·nHO, which becomes almost complete at p = 0.65 GPa. The labile solvent molecules present in 1bpmh·CHOH and 1bpeh·HO have a dramatic influence on the corresponding SCO behavior.
我们报道了一系列前所未有的二维（2D）自旋交叉（SCO）异双金属配位聚合物，其通式为{Fe(Hg(SCN))}·Solv，其中当L = tvp（反式-(4,4'-乙烯基二吡啶)）（1tvp）、bpmh（(1E,2E)-1,2-双(吡啶-4-基亚甲基)肼）（1bpmh·nCHOH；n = 0, 1）、bpeh（(1E,2E)-1,2-双(1-(吡啶-4-基)亚乙基)肼）（1bpeh·nHO；n = 0, 1）时x = 2，当L = bpbz（1,4-双(吡啶-4-基)苯）（1bpbz·nHO；n = 0, 2/3）时x = 2.33。结果证实，Fe、[Hg(SCN)]和含有4-吡啶基部分的双齿棒状桥连配体L的自组装有利于形成线性[Fe(μ-L)]链和原位生成的双核单元{Hg(SCN)}。后者充当相邻链之间的桥梁，形成坚固的二维层。[FeN]中心在赤道方向被四个NCS基团和有机配体L的两个轴向N原子包围。化合物1tvp和1bpmh的非溶剂化形式在T = 177和226 K发生完全自旋交叉，其特征在于焓变和熵变分别为ΔH = 12.3和10.5 kJ mol以及ΔS = 69.4和48 J K mol。1bpeh的非溶剂化形式的几乎完全自旋交叉发生在约T = 119 K，并表现出完全的光激发诱导自旋态捕获（LIESST）效应。无论溶剂化程度如何，1bpbz·nHO在T < 100 K时发生半自旋转换，在p = 0.65 GPa时几乎完全转换。1bpmh·CHOH和1bpeh·HO中存在的不稳定溶剂分子对相应的自旋交叉行为有显著影响。
