Mechanistic Investigation and Conductance Modulation of a Metal‐Molecule‐Metal Junction via Extra Acid Addition

Abstract

One important prerequisite for the fabrication of molecular functional device strongly relies on the understanding the conducting behaviors of the metal-molecule-metal junction that can respond to an external stimulus. The model Lewis basic molecule 4,4'-(pyridine-3,5-diyl)dibenzonitrile (DBP), which can react with Lewis acid and protic acid, was synthesized. Then, the molecular conducting behavior of DBP, DBP-B(C 6 F 5 ) 3 , and DBP-TfOH (DBP-B(C 6 F 5 ) 3 , and DBP-TfOH were produced by Lewis acid and protonic acid treatment of DBP) was researched and compared. Given that their identical physical paths for DBP, DBP-B(C 6 F 5 ) 3 , and DBP-TfOH to sustain charge transport, our results indicate that modifying the molecular electronic structure, even not directly changing the conductive physical backbone, can tune the charge transporting ability by nearly one order of magnitude. Furthermore, the addition of another Lewis base triethylamine (of stronger alkaline than DBP), to Lewis acid-base pair reverts the electrical properties back to that of a single DBP junction, that is constructive to propose a useful but simple strategy for the design and construction of reversible and controllable molecular device based on pyridine derived molecule.

Manipulating the charge transport via incorporating a cobalt bridge into a single-molecule junction

“…For the molecular wires terminated by the pyridine anchoring group, the dominated charge carriers are electrons. 31,32 Fig. 4b illustrates the transmission spectra across the molecular junctions composed of p-Co-p, p-Co-m, m-Co-m and their alkynyl counterparts at V = 0 V. It was found that the conductance of molecular wires with meta-linked pyridine anchors decreased.…”

Utilizing Planar σ-Aromaticity to Enhance Electron Transport Abilities

“…对于每个模型, 分子嵌入 两个金电极的空穴位点, Au-Au 键长度为 0.288 nm [24] , 硫原子与金等三角形中心之间的最佳距离采用 0.230 nm [17] . 同时采用密度泛函结合非平衡格林函数(DFT＋ NEGFs)方法优化分子结的几何结构并计算相应分子结 的电子输运性质 [25][26] . 其中, 金电极采用 3×3 Au(111) 周期性模型, 广义梯度近似(GGA-PBE)方法评估电子交 换和相关能.…”