On-surface synthesis is becoming an increasingly popular approach to obtain new organic materials. In this context, metallic surfaces are the most commonly used substrates. However, their hybridization with the adsorbates often hinder a proper characterization of the molecule’s intrinsic electronic and magnetic properties. Here we report a route to electronically decouple molecules from their supporting substrates. In particular, we have used a Ag(001) substrate and hydrogenated heptacene molecules, in which the longest conjugated segment determining its frontier molecular orbitals amounts to five consecutive rings. The non-planarity that sp³ atoms impose on the carbon backbone results in electronically decoupled molecules, as demonstrated by scanning tunneling spectroscopy measurements. The charging resonances of the latter imply the presence of double tunneling barriers. We further explain the existing relation between the charging resonance energy and their contrast, as well as with the presence or absence of additional Kondo resonances.

表面合成正成为获得新的有机材料的日益流行的方法。在这种情况下，金属表面是最常用的基底。但是，它们与被吸附物的杂交通常会妨碍分子固有电子和磁性的正确表征。在这里，我们报告了一种将分子与其支持底物进行电子脱偶联的途径。特别是，我们使用了Ag（001）底物和氢化的庚烯分子，其中确定其前沿分子轨道的最长共轭链段为五个连续的环。sp ³的非平面性如扫描隧道光谱法测量所证实，施加在碳主链上的原子导致电子去耦分子。后者的充电共振表明存在双隧道势垒。我们进一步解释了充电共振能量与其对比度之间的现有关系，以及是否存在其他近藤共振。