Engineering On-Surface Spin Crossover: Spin-State Switching in a Self-Assembled Film of Vacuum-Sublimable Functional Molecule
Engineering On-Surface Spin Crossover: Spin-State Switching in a Self-Assembled Film of Vacuum-Sublimable Functional Molecule
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DOI：
10.1002/adma.201705416
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发表时间：
2018-03-15
影响因子：
29.4
通讯作者：
Ruben, Mario
中科院分区：
文献类型：
--
作者：
Kumar, Kuppusamy Senthil;Studniarek, Michal;Ruben, Mario
基于自旋交叉（SCO）的应用的实现需要研究纳米结构环境中 SCO 复杂分子的自旋态转换特性，特别是在表面上。除极少数情况外，表面结合薄膜的 SCO 要么被淬灭，要么因以下原因而严重改变：(i) 分子-表面相互作用和 (ii) 薄膜中相对于本体的不同分子间相互作用。通过在弱相互作用表面上制造SCO复合物，可以解决界面猝灭问题。然而，在 SCO 活性薄膜中设计分子间相互作用相当困难。在这里，提出了一种分子自组装策略来制造具有可编程分子间相互作用的自旋可切换表面结合薄膜。具有十二烷基 (C-12) 烷基链的母体络合物系统 [Fe(H2B(pz)(2))(2)(bpy)]（pz = 吡唑，bpy = 2,2'-联吡啶）的分子工程产生了经典的两亲类功能性和真空升华电荷中性 Fe-II 络合物， [Fe(H2B(pz)(2))(2)(C-12-bpy)]（C-12-bpy = 十二烷基[2,2'-联吡啶]-5-羧酸酯）。升华到复合物的石英玻璃或 SiOx 表面上的散装粉末和 10 nm 薄膜都显示出由类似层状双层（如自组装/分子相互作用）介导的可比较的自旋态转换特性。这一前所未有的观察结果预示着基于 SCO 的应用的发展，特别是在分子自旋电子学领域。
The realization of spin-crossover (SCO)-based applications requires study of the spin-state switching characteristics of SCO complex molecules within nanostructured environments, especially on surfaces. Except for a very few cases, the SCO of a surface-bound thin molecular film is either quenched or heavily altered due to: (i) molecule-surface interactions and (ii) differing intermolecular interactions in films relative to the bulk. By fabricating SCO complexes on a weakly interacting surface, the interfacial quenching problem is tackled. However, engineering intermolecular interactions in thin SCO active films is rather difficult. Here, a molecular self-assembly strategy is proposed to fabricate thin spin-switchable surface-bound films with programmable intermolecular interactions. Molecular engineering of the parent complex system [Fe(H2B(pz)(2))(2)(bpy)] (pz = pyrazole, bpy = 2,2'-bipyridine) with a dodecyl (C-12) alkyl chain yields a classical amphiphile-like functional and vacuum-sublimable charge-neutral Fe-II complex, [Fe(H2B(pz)(2))(2)(C-12-bpy)] (C-12-bpy = dodecyl[2,2'-bipyridine]-5-carboxylate). Both the bulk powder and 10 nm thin films sublimed onto either quartz glass or SiOx surfaces of the complex show comparable spin-state switching characteristics mediated by similar lamellar bilayer like self-assembly/molecular interactions. This unprecedented observation augurs well for the development of SCO-based applications, especially in molecular spintronics.