Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
J Am Chem Soc. 2010 Sep 29;132(38):13519-24. doi: 10.1021/ja105958p.
{Cp*(dppe)Fe(C≡C-)}(2)(1,3-C(6)H(4)) is studied both as a neutral molecule, Fe(II)-Fe(II), and as a mixed-valence complex, Fe(II)-Fe(III). Scanning tunneling microscopy (STM) is used to image these species at 77 K under ultrahigh-vacuum conditions. The neutral molecule Fe(II)-Fe(II) has a symmetric, "dumbbell" appearance in STM images, while the mixed-valence complex Fe(II)-Fe(III) demonstrates an asymmetric, bright-dim double-dot structure. This asymmetry results from localization of the electron to one of the iron-ligand centers, a result which is confirmed through comparison to theoretical STM images calculated using constrained density-functional theory (CDFT). The observation of charge localization in mixed-valence complexes outside of the solution environment opens up new avenues for the control and patterning of charge on surfaces, with potential applications in smart materials and molecular electronic devices.
{Cp*(dppe)Fe(C≡C-)}(2)(1,3-C(6)H(4)) 既被研究为中性分子 Fe(II)-Fe(II)，也被研究为混合价态配合物 Fe(II)-Fe(III)。在超高真空条件下，扫描隧道显微镜 (STM) 用于在 77 K 下对这些物种进行成像。中性分子 Fe(II)-Fe(II)在 STM 图像中呈现对称的“哑铃”外观，而混合价态配合物 Fe(II)-Fe(III)则表现出不对称的亮暗双点结构。这种不对称性是由于电子局域到一个铁配体中心，这一结果通过与使用约束密度泛函理论 (CDFT) 计算的理论 STM 图像的比较得到了证实。在溶液环境之外观察到混合价态配合物中的电荷局域化，为表面上的电荷控制和图案化开辟了新的途径，在智能材料和分子电子器件中有潜在的应用。
