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Your search keyword '"Zang, Yaping"' showing total 160 results
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160 results on '"Zang, Yaping"'

8. A reversible single-molecule switch based on activated antiaromaticity.

Author

Yin, Xiaodong, Zang, Yaping, Zhu, Liangliang, Low, Jonathan Z, Liu, Zhen-Fei, Cui, Jing, Neaton, Jeffrey B, Venkataraman, Latha, and Campos, Luis M

Abstract

Single-molecule electronic devices provide researchers with an unprecedented ability to relate novel physical phenomena to molecular chemical structures. Typically, conjugated aromatic molecular backbones are relied upon to create electronic devices, where the aromaticity of the building blocks is used to enhance conductivity. We capitalize on the classical physical organic chemistry concept of Hückel antiaromaticity by demonstrating a single-molecule switch that exhibits low conductance in the neutral state and, upon electrochemical oxidation, reversibly switches to an antiaromatic high-conducting structure. We form single-molecule devices using the scanning tunneling microscope-based break-junction technique and observe an on/off ratio of ~70 for a thiophenylidene derivative that switches to an antiaromatic state with 6-4-6-π electrons. Through supporting nuclear magnetic resonance measurements, we show that the doubly oxidized core has antiaromatic character and we use density functional theory calculations to rationalize the origin of the high-conductance state for the oxidized single-molecule junction. Together, our work demonstrates how the concept of antiaromaticity can be exploited to create single-molecule devices that are highly conducting.

Published
2017

9. Dibenzothiophene Sulfone‐Based Ambipolar‐Transporting Blue‐Emissive Organic Semiconductors Towards Simple‐Structured Organic Light‐Emitting Transistors

Author

Li, Qingbin, primary, Zhang, Yihan, additional, Lin, Junfeng, additional, Zou, Ye, additional, Wang, Pu, additional, Qin, Zhengsheng, additional, Wang, Yongshuai, additional, Li, Yang, additional, Zhang, Yu, additional, Gao, Can, additional, Zang, Yaping, additional, Hu, Wenping, additional, and Dong, Huanli, additional

Published
2023
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14. Miniaturized matrix solid‐phase dispersion and solid‐phase clear‐up combined with capillary electrophoresis for efficient determination of trace bioactive components in complicated sample matrix: Take Wubi Shanyao Pill as an example.

Author

Gao, Wei, Qin, Yaxin, Zang, Yaping, Zhu, Jiaming, Chen, Wei, Tong, Shengqiang, Zeng, Yuqun, and Chu, Chu

Subjects
CAPILLARY electrophoresis, SOLID phase extraction, BIOACTIVE compounds, DISPERSION (Chemistry), ANALYTICAL chemistry, PILLS, TRACE analysis
Abstract

Accurate quantitative analysis of trace analytes in a complicated matrix is a challenge in modern analytical chemistry. An appropriate analytical method is considered to be one of the most common gaps during the whole process. In this study, a green and efficient strategy based on miniaturized matrix solid‐phase dispersion and solid‐phase extraction combined with capillary electrophoresis was first proposed for extracting, purifying and determining target analytes from complicated matrix, using Wubi Shanyao Pill as an example. In detail, 60 mg of samples were dispersed on MCM‐48 to obtain high yields of analytes, then the extract was purified with a solid‐phase extraction cartridge. Finally, four analytes in the purified sample solution were determined by capillary electrophoresis. The parameters affecting the extraction efficiency of matrix solid‐phase dispersion, purification efficiency of solid‐phase extraction and separation effect of capillary electrophoresis were investigated. Under the optimized conditions, all analytes demonstrated satisfactory linearity (R2>0.9983). What's more, the superior green potential of the developed method for the determination of complex samples was confirmed by the Analytical GREEnness Metric Approach. The established method was successfully applied in the accurate determination of target analytes in Wubi Shanyao Pill and thus provided reliable, sensitive, and efficient strategy support for its quality control. [ABSTRACT FROM AUTHOR]

Published
2023
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18. Online preconcentration and determination of anthraquinones in Cassiae Semen tea by salting-out assisted liquid‒liquid extraction coupled with dynamic pH junction-sweeping-large volume sample stacking in capillary electrophoresis

Author

Chu, Chu, primary, Zang, Yaping, additional, Li, Jiaxu, additional, Zou, Yanfang, additional, Gao, Wei, additional, Lv, Yangbin, additional, Li, Chenyue, additional, Tong, Shengqiang, additional, Liu, E-Hu, additional, Peng, Xin, additional, and Tang, Lan, additional

Published
2022
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21. Formation of covalent metal–carbon contacts assisted by Ag+ for single molecule junctions.

Author

Song, Kai, Lin, Junfeng, Song, Xuwei, Yang, Bowen, Zhu, Jia, Zang, Yaping, and Zhu, Daoben

Subjects
SINGLE molecules, IONS, CHEMICAL reactions, COVALENT bonds, METAL ions
Abstract

Covalent metal–carbon (M–C) contacts have long been pursued for constructing robust and high-performance molecular devices. Existing methods for creating such contacts usually rely on direct chemical reactions between metal electrodes and designed molecular ligands. An inherent limitation of this approach is that the commonly used metal electrodes (e.g., Au) are chemically inert, making it generally difficult to form covalent M–C bonds with molecules. Intriguingly, employing the scanning tunneling microscope-break junction technique, we find that simply adding Ag+ ions to molecular solution enables direct covalent bonding of terminal alkynes to Au electrodes. The bonding process is driven by Ag+ ion coupled in situ reactions and efficiently creates covalent Au/Ag–C interfaces in single molecule junctions. This metal ion assisted method avoids the need for complex synthesis of molecular ligands and works robustly for a wide range of alkyne-terminated molecules, offering a facile and versatile approach for precisely tuning the metal–molecule interface. [ABSTRACT FROM AUTHOR]

Published
2023
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27. Cleavage of non-polar C(sp2)‒C(sp2) bonds in cycloparaphenylenes via electric field-catalyzed electrophilic aromatic substitution.

Author

Lin, Junfeng, Lv, Yaxin, Song, Kai, Song, Xuwei, Zang, Hongjun, Du, Pingwu, Zang, Yaping, and Zhu, Daoben

Abstract

Electrophilic aromatic substitution (EAS) is one of the most fundamental reactions in organic chemistry. Using an oriented external electric field (OEEF) instead of traditional reagents to tune the EAS reactivity can offer an environmentally friendly method to synthesize aromatic compounds and hold the promise of broadening its scope. Despite these advantages, OEEF catalysis of EAS is difficult to realize, due to the challenge of microscopically orienting OEEF along the direction of electron reorganizations. In this work, we demonstrate OEEF-catalyzed EAS reactions in a series of cycloparaphenylenes (CPPs) using the scanning tunneling microscope break junction (STM-BJ) technique. Crucially, the unique radial π-conjugation of CPPs enables a desired alignment for the OEEF to catalyze the EAS with Au STM tip (or substrate) acting as an electrophile. Under mild conditions, the OEEF-catalyzed EAS reactions can cleave the inherently inert C(sp2)-C(sp2) bond, leading to high-yield (~97%) formation of linear oligophenylenes terminated with covalent Au-C bonds. These results not only demonstrate the feasibility of OEEF catalysis of EAS, but also offer a way of exploring new mechanistic principles of classic organic reactions aided by OEEF.Novel methodologies for cleaving inherently inert C(sp2)‒ C(sp2) bonds are desirable. Here, the authors report the use of an oriented electric field to cleave C(sp2)‒ C(sp2) in cycloparaphenylenes via electrophilic aromatic substitution. [ABSTRACT FROM AUTHOR]

Published
2023
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29. Voltage-Induced Single-Molecule Junction Planarization

Author

Zang, Yaping, Fung, E-dean, Fu, Tianren, Ray, Suman, Garner, Marc H., Borges, Anders, Steigerwald, Michael L., Patil, Satish, Solomon, Gemma, Venkataraman, Latha, Zang, Yaping, Fung, E-dean, Fu, Tianren, Ray, Suman, Garner, Marc H., Borges, Anders, Steigerwald, Michael L., Patil, Satish, Solomon, Gemma, and Venkataraman, Latha

Abstract

Probing structural changes of a molecule induced by charge transfer is important for understanding the physicochemical properties of molecules and developing new electronic devices. Here, we interrogate the structural changes of a single diketopyrrolopyrrole (DPP) molecule induced by charge transport at a high bias using scanning tunneling microscope break junction (STM-BJ) techniques. Specifically, we demonstrate that application of a high bias increases the average nonresonant conductance of single Au–DPP–Au junctions. We infer from the increased conductance that resonant charge transport induces planarization of the molecular backbone. We further show that this conformational planarization is assisted by thermally activated junction reorganization. The planarization only occurs under specific electronic conditions, which we rationalize by ab initio calculations. These results emphasize the need for a comprehensive view of single-molecule junctions which includes both the electronic properties and structure of the molecules and the electrodes when designing electrically driven single-molecule motors.

Published
2021

30. An Efficient Matrix Solid-Phase Dispersion Extraction Combined with Online Preconcentration by Electrokinetic Supercharging in Capillary Electrophoresis for the Sensitive Determination of Two Alkaloids in Complicated Samples Matrix

Author

Chu, Chu, primary, Lian, Linmin, additional, Gao, Wei, additional, Zang, Yaping, additional, Zou, Yanfang, additional, Lv, Yangbin, additional, Li, Chenyue, additional, Tong, Shengqiang, additional, Yan, Jizhong, additional, and Chen, Suhong, additional

Published
2021
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31. Voltage-Induced Single-Molecule Junction Planarization

Author

Zang, Yaping, primary, Fung, E-Dean, additional, Fu, Tianren, additional, Ray, Suman, additional, Garner, Marc H., additional, Borges, Anders, additional, Steigerwald, Michael L., additional, Patil, Satish, additional, Solomon, Gemma, additional, and Venkataraman, Latha, additional

Published
2020
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32. Cyclopropenylidenes as Strong Carbene Anchoring Groups on Au Surfaces

Author

Doud, Evan A., primary, Starr, Rachel L., additional, Kladnik, Gregor, additional, Voevodin, Anastasia, additional, Montes, Enrique, additional, Arasu, Narendra P., additional, Zang, Yaping, additional, Zahl, Percy, additional, Morgante, Alberto, additional, Venkataraman, Latha, additional, Vázquez, Héctor, additional, Cvetko, Dean, additional, and Roy, Xavier, additional

Published
2020
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36. Resonant Transport in Single Diketopyrrolopyrrole Junctions

Author

Zang, Yaping, Ray, Suman, Fung, E-Dean, Borges, Anders, Garner, Marc H., Steigerwald, Michael L., Solomon, Gemma C., Patil, Satish, Venkataraman, Latha, Zang, Yaping, Ray, Suman, Fung, E-Dean, Borges, Anders, Garner, Marc H., Steigerwald, Michael L., Solomon, Gemma C., Patil, Satish, and Venkataraman, Latha

Published
2018

37. Resonant tunneling transport in single-molecule junctions

Author

Zang, Yaping, Ray, Suman, Borges, Anders Christian, Fung, E-Dean, Solomon, Gemma C., Patil, Satish, Venkataraman, Latha, Zang, Yaping, Ray, Suman, Borges, Anders Christian, Fung, E-Dean, Solomon, Gemma C., Patil, Satish, and Venkataraman, Latha

Published
2018

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