Sun Qiang, Mateo Luis M, Robles Roberto, Ruffieux Pascal, Bottari Giovanni, Torres Tomás, Fasel Roman, Lorente Nicolás
nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, 8600, Switzerland.
Materials Genome Institute, Shanghai University, Shanghai, 200444, China.
Adv Sci (Weinh). 2022 Jul;9(19):e2105906. doi: 10.1002/advs.202105906. Epub 2022 Mar 18.
Magnetism is typically associated with d- or f-block elements, but can also appear in organic molecules with unpaired π-electrons. This has considerably boosted the interest in such organic materials with large potential for spintronics and quantum applications. While several materials showing either d/f or π-electron magnetism have been synthesized, the combination of both features within the same structure has only scarcely been reported. Open-shell porphyrins (Pors) incorporating d-block transition metal ions represent an ideal platform for the realization of such architectures. Herein, the preparation of a series of open-shell, π-extended Pors that contain magnetically active metal ions (i.e., Cu , Co , and Fe ) through a combination of in-solution and on-surface synthesis is reported. A detailed study of the magnetic interplay between π- and d-electrons in these metalloPors has been performed by scanning probe methods and density functional theory calculations. For the Cu and FePors, ferromagnetically coupled π-electrons are determined to be delocalized over the Por edges. For the CoPor, the authors find a Kondo resonance resulting from the singly occupied Co d orbital to dominate the magnetic fingerprint. The Fe derivative exhibits the highest magnetization of 3.67 μ (S≈2) and an exchange coupling of 16 meV between the π-electrons and the Fe d-states.
磁性通常与d族或f族元素相关，但也可能出现在具有未成对π电子的有机分子中。这极大地激发了人们对这类在自旋电子学和量子应用方面具有巨大潜力的有机材料的兴趣。虽然已经合成了几种显示d/f或π电子磁性的材料，但在同一结构中兼具这两种特性的情况却鲜有报道。包含d族过渡金属离子的开壳卟啉（Pors）是实现这种结构的理想平台。在此，报道了通过溶液内和表面合成相结合的方法制备一系列包含磁活性金属离子（即Cu、Co和Fe）的开壳、π扩展Pors。通过扫描探针方法和密度泛函理论计算对这些金属卟啉中π电子和d电子之间的磁相互作用进行了详细研究。对于Cu和FePors，确定铁磁耦合的π电子在卟啉边缘离域。对于CoPor，作者发现由单占据的Co d轨道产生的近藤共振主导了磁指纹。Fe衍生物表现出3.67 μ（S≈2）的最高磁化强度以及π电子与Fe d态之间16 meV的交换耦合。
