Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
J Am Chem Soc. 2012 Feb 1;134(4):2292-304. doi: 10.1021/ja209844r. Epub 2012 Jan 19.
Employing a scanning tunneling microscopy based beak junction technique and mechanically controlled break junction experiments, we investigated tolane (diphenylacetylene)-type single molecular junctions having four different anchoring groups (SH, pyridyl (PY), NH(2), and CN) at a solid/liquid interface. The combination of current-distance and current-voltage measurements and their quantitative statistical analysis revealed the following sequence for junction formation probability and stability: PY > SH > NH(2) > CN. For all single molecular junctions investigated, we observed the evolution through multiple junction configurations, with a particularly well-defined binding geometry for PY. The comparison of density functional theory type model calculations and molecular dynamics simulations with the experimental results revealed structure and mechanistic details of the evolution of the different types of (single) molecular junctions upon stretching quantitatively.
采用基于扫描隧道显微镜的叉指结技术和机械控制的断结实验，我们研究了在固/液界面上具有四种不同锚固基团（SH、吡啶基（PY）、NH2 和 CN）的噻吩（二苯基乙炔）型单分子结。电流-距离和电流-电压测量及其定量统计分析的结合揭示了结形成概率和稳定性的以下顺序：PY > SH > NH2 > CN。对于所有研究的单分子结，我们观察到通过多种结构型的演变，其中 PY 具有特别明确的结合几何形状。密度泛函理论类型模型计算和分子动力学模拟与实验结果的比较定量揭示了不同类型（单）分子结在拉伸时演变的结构和机制细节。
