Combining the fascinating advantages of ultrathin two-dimensional (2D) nanosheets with the nanostructuration of spin-crossover (SCO) materials represents an attractive target of controlled fabrication of SCO nano-objects at the device level. Here, we demonstrate that through facile-operating ultrasonic force-assisted liquid exfoliation technology the three-dimensional (3D) van der Waals SCO bulk precursor {[Fe(1,3-bpp)₂(NCS)₂]₂ (1, 1,3-bpp = 1,3-di(4-pyridyl)-propane)} can be exfoliated into single-layered 2D nanosheets (NS-1). As a consequence, the magnetism has been tuned from complete paramagnetic (bulk precursors) to SCO transition at around 250 K (2D nanosheets). In addition, the metal-to-ligand charge transition (MLCT), the intraligand π–π* transition and the color display also have been altered both in colloidal suspension and in the solid state. These dramatic changes of physical–chemical properties at different forms and states can be attributed to the efficient cooperativity derived from the interlayer van der Waals interactions within the curly or vertically stacked 2D building blocks.

中文翻译：

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具有可调自旋交叉特性的原子薄二维纳米片

将超薄二维（2D）纳米片的引人入胜的优势与自旋交叉（SCO）材料的纳米结构相结合，代表了在设备级别控制SCO纳米物体受控制造的诱人目标。在这里，我们证明，通过容易的运营超声力辅助液体剥离技术三维（3D）范德华SCO前驱物块状{[铁（1,3- BPP）₂（NCS）₂ ] ₂（1，1 ，3-bpp = 1,3-二（4-吡啶基）-丙烷）}可以剥离成单层二维纳米片（NS- 1）。结果，磁性已从大约250 K左右的完整顺磁性（本体前体）调整为SCO跃迁（2D纳米片）。此外，在胶态悬浮液和固态状态下，金属到配体的电荷跃迁（MLCT），配体内π–π *跃迁和颜色显示也发生了变化。这些化学和化学性质在不同形式和状态下的巨大变化，可以归因于在卷曲或垂直堆叠的2D构建块中的层间范德华相互作用所产生的有效合作性。