Leibniz Institute for Solid State and Materials Research (IFW-Dresden) , Helmholtzstrasse 20, 01171 Dresden, Germany.
Institut für Anorganische Chemie, Universität Leipzig , 04103 Leipzig, Germany.
Langmuir. 2016 May 10;32(18):4464-71. doi: 10.1021/acs.langmuir.6b00772. Epub 2016 May 2.
Molecular anchoring and electronic properties of macrocyclic complexes fixed on gold surfaces have been investigated mainly by using scanning tunnelling microscopy (STM) and complemented with X-ray photoelectron spectroscopy (XPS). Exchange-coupled macrocyclic complexes Ni2L(Hmba) were deposited via 4-mercaptobenzoate ligands on the surface of a Au(111) single crystal from a mM solution of the perchlorate salt [Ni2L(Hmba)]ClO4 in dichloromethane. The combined results from STM and XPS show the formation of large monolayers anchored via Au-S bonds with a height of about 1.5 nm. Two apparent granular structures are visible: one related to the dinickel molecular complexes (cationic structures) and a second one related to the counterions ClO4(-) which stabilize the monolayer. No type of short and long-range order is observed. STM tip-interaction with the monolayer reveals higher degradation after 8 h of measurement. Spectroscopy measurements suggest a gap of about 2.5 eV between HOMO and LUMO of the cationic structures and smaller gap in the areas related to the anionic structures.
主要通过扫描隧道显微镜（STM）和X 射线光电子能谱（XPS）研究了固定在金表面的大环配合物的分子锚定和电子性质。通过 4-巯基苯甲酸配体，将[Ni2L（Hmba）]（+）交换偶联大环配合物从二氯甲烷中[Ni2L（Hmba）]ClO4 的 mM 溶液沉积在 Au（111）单晶表面上。STM 和 XPS 的综合结果表明，通过 Au-S 键形成了约 1.5nm 高的大单层。可以看到两种明显的颗粒状结构：一种与二镍分子配合物（阳离子结构）有关，另一种与稳定单层的反离子 ClO4（-）有关。没有观察到短程和长程有序。STM 针尖与单层的相互作用表明，在测量 8 小时后，降解程度更高。光谱测量表明，阳离子结构的 HOMO 和 LUMO 之间的能隙约为 2.5eV，与阴离子结构相关的区域的能隙较小。
