scholarly journals Evolution of local conductance pathways in a single-molecule junction studied using the three-dimensional dynamic probe method

Nanoscale ◽  
2019 ◽  
Vol 11 (13) ◽  
pp. 5951-5959 ◽  
Author(s):  
Atsushi Taninaka ◽  
Shoji Yoshida ◽  
Yoshihiro Sugita ◽  
Osamu Takeuchi ◽  
Hidemi Shigekawa

By combining a three-dimensional dynamic probe method with density functional theory, it has become possible to simultaneously consider the effect of the dynamics of molecular structures and the bonding states at the electrodes on the local transmission pathways and conductance.

2018 ◽  
Vol 25 (03) ◽  
pp. 1850070 ◽  
Author(s):  
BAO-AN BIAN ◽  
YA-PENG ZHENG ◽  
PEI-PEI YUAN ◽  
BIN LIAO ◽  
YU-QIANG DING

We carry out first-principles calculations based on density functional theory and non-equilibrium Green’s function to investigate the electronic transport properties of a diarylethene-based molecule sandwiched between two Au electrodes. This molecular switch can be reversed between open and close forms by using light stimulation. We analyze the switch behavior of these two forms through the current–voltage curves, transmission spectra and molecular projected self-consistent Hamiltonian. It has been found that the current of the close form is significantly larger than the open form, and there is a large and stable switch ratio in a wide bias window. This result indicates that this molecule can become one of the good candidates for optical molecular switch in the future.


ACS Nano ◽  
2016 ◽  
Vol 10 (12) ◽  
pp. 11211-11218 ◽  
Author(s):  
Shoji Yoshida ◽  
Atsushi Taninaka ◽  
Yoshihiro Sugita ◽  
Tomoki Katayama ◽  
Osamu Takeuchi ◽  
...  

2019 ◽  
Vol 4 (10) ◽  
pp. 162-166
Author(s):  
Cristian Eduardo García-López ◽  
Irineo-Pedro Zaragoza Rivera ◽  
Benjamín Vargas-Arista ◽  
Verónica Estrella-Suarez

The first-principles calculations are useful for determining electronic and structural properties for a model that simulates a material composed of atomic clusters of ZnO through the analysis of interaction energies and charge distribution. The two-dimensional structural form of ZnO aggregates shows regularly flat hexagons obtained in models of 6, 27 and 54 atoms of Zinc and Oxygen. The structure of a three-dimensional system was determined by dynamics calculations by using the interaction of a pair of monolayers consisting of 108 atoms and as a result, a cage structure was formed from a cluster of Zn54 and O54 identifying only bond atoms at the ends that promote the union of monolayers. The stable structure shows modifications of the atomic bonds in whose centers hexagonal rings prevailed and at the arrangements of the end of triangles, squares, pentagons and even rings of 10 and 11 atoms were obtained. Atomic positions and charge distribution were analyzed based on the methodology used Density Functional Theory (DFT), with the becke88-LYP exchange and correlation functional.


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Miki Nakamura ◽  
Shoji Yoshida ◽  
Tomoki Katayama ◽  
Atsushi Taninaka ◽  
Yutaka Mera ◽  
...  

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 328
Author(s):  
Raquel Álvarez-Vidaurre ◽  
Alfonso Castiñeiras ◽  
Antonio Frontera ◽  
Isabel García-Santos ◽  
Diego M. Gil ◽  
...  

This work deals with the preparation of pyridine-3-carbohydrazide (isoniazid, inh) cocrystals with two α-hydroxycarboxylic acids. The interaction of glycolic acid (H2ga) or d,l-mandelic acid (H2ma) resulted in the formation of cocrystals or salts of composition (inh)·(H2ga) (1) and [Hinh]+[Hma]–·(H2ma) (2) when reacted with isoniazid. An N′-(propan-2-ylidene)isonicotinic hydrazide hemihydrate, (pinh)·1/2(H2O) (3), was also prepared by condensation of isoniazid with acetone in the presence of glycolic acid. These prepared compounds were well characterized by elemental analysis, and spectroscopic methods, and their three-dimensional molecular structure was determined by single crystal X-ray crystallography. Hydrogen bonds involving the carboxylic acid occur consistently with the pyridine ring N atom of the isoniazid and its derivatives. The remaining hydrogen-bonding sites on the isoniazid backbone vary based on the steric influences of the derivative group. These are contrasted in each of the molecular systems. Finally, Hirshfeld surface analysis and Density-functional theory (DFT) calculations (including NCIplot and QTAIM analyses) have been performed to further characterize and rationalize the non-covalent interactions.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1390 ◽  
Author(s):  
Ilya G. Shenderovich

Due to the rigid structure of 1,3,5-triaza-7-phosphaadamantane (PTA), its 31P chemical shift solely depends on non-covalent interactions in which the molecule is involved. The maximum range of change caused by the most common of these, hydrogen bonding, is only 6 ppm, because the active site is one of the PTA nitrogen atoms. In contrast, when the PTA phosphorus atom is coordinated to a metal, the range of change exceeds 100 ppm. This feature can be used to support or reject specific structural models of organometallic transition metal complexes in solution by comparing the experimental and Density Functional Theory (DFT) calculated values of this 31P chemical shift. This approach has been tested on a variety of the metals of groups 8–12 and molecular structures. General recommendations for appropriate basis sets are reported.


2019 ◽  
Vol 48 (19) ◽  
pp. 6347-6352
Author(s):  
Di Wu ◽  
Jueting Zheng ◽  
Chenyong Xu ◽  
Dawei Kang ◽  
Wenjing Hong ◽  
...  

A new family of phosphindole fused ladder-type heteroacenes with a pyrrolo[3,2-b]pyrrole core were synthesized and characterized, which show good luminescence efficiency, high thermostability and tunable conductance.


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