Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand.
Dalton Trans. 2012 Nov 7;41(41):12720-5. doi: 10.1039/c2dt31776a.
Herein we report the synthesis, structure and magnetic properties of FeL(3)(2), 1, where L is the bidentate ligand N-(4-methoxyphenyl)-1H-imidazol-2-yl-methanimine. Complex 1 crystallises as the mer-isomer which is stabilised by intramolecular π-π interactions between the methoxyphenyl 'tail' and imidazole 'head' of adjacent ligands centred around Fe(II). The crystal lattice is devoid of any significant intermolecular π-π interactions between neighbouring complexes, although hydrogen bonding between two imidazole N-H groups and two perchlorate anions links two adjacent complexes together and allows them to buttress up against one another. Structural data collected at 116 and 292 K suggest a spin-crossover (SCO) behaviour for 1 as Fe-N bond lengths increase by ca. 10% at the higher temperature. SCO behaviour is confirmed by magnetic susceptibility measurements. The χT vs. T data reveals a complete and reversible SCO for 1 with T(1/2) of 158 K, and this is further confirmed by Mössbauer spectroscopy (at 4.2 and 293 K) and variable temperature reflectivity measurements. Indeed, upon irradiation with red light (647 nm) at 10 K, 1 shows a photo-induced spin-crossover and undergoes full switching between the LS and HS states.
在此，我们报告了 FeL(3)(2), 1 的合成、结构和磁性，其中 L 是双齿配体 N-(4-甲氧基苯基)-1H-咪唑-2-基-甲亚胺。配合物 1 以高自旋（HS）的顺式异构体结晶，这种结构由相邻配体中甲氧基苯基“尾巴”和咪唑“头”之间的分子内π-π相互作用稳定。晶体点阵中没有相邻配合物之间存在任何显著的分子间π-π相互作用，尽管两个咪唑 N-H 基团和两个高氯酸根阴离子之间的氢键将两个相邻的配合物连接在一起，并允许它们相互支撑。在 116 和 292 K 下收集的结构数据表明，1 具有自旋交叉（SCO）行为，因为 Fe-N 键长在较高温度下增加了约 10%。磁性测量证实了 SCO 行为。χT 与 T 的数据表明 1 完全和可逆的 SCO，T(1/2)为 158 K，这进一步通过穆斯堡尔光谱（在 4.2 和 293 K）和变温反射率测量得到证实。事实上，在 10 K 下用红光（647 nm）照射时，1 表现出光诱导的自旋交叉，并在 LS 和 HS 态之间完全切换。
