Qiwei Chen

Peking University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Stepwise on-surface dissymmetric reaction to construct binodal organometallic network

Nature Communications (2019)

Jing Liu Qiwei Chen Kang Cai Jie Li Yaru Li

Abstract Dissymmetric reactions, which enable differentiated functionalization of equivalent sites within one molecule, have many potential applications in synthetic chemistry and materials science, but they are very challenging to achieve. Here, the dissymmetric reaction of 1,4-dibromo-2,5-diethynylbenzene (2Br-DEB) on Ag(111) is realized by using a stepwise activation strategy, leading to an ordered two-dimensional organometallic network containing both alkynyl–silver–alkynyl and alkynyl–silver–phenyl nodes. Scanning tunneling microscopy and density functional theory calculations are employed to explore the stepwise conversion of 2Br-DEB, which starts from the H-passivation of one Br-substituted site at 300 K in accompaniment with an intermolecular reaction to form one-dimensional organometallic chains containing alkynyl–silver–alkynyl nodes. Afterwards, the other equivalent Br-substituted site undergoes metalation reaction at 320–450 K, resulting in transformation of the chains into the binodal networks. These findings exemplify the achievement of the dissymmetric reaction and its practical application for controlled fabrications of complicated yet ordered nanostructures on a surface.

Binodal

Organometallic Chemistry

Metalation

Passivation

10.1038/s41467-019-10522-4

Cite

Citations (37)

An ion soft-landing apparatus for ion transport study with surface potential measurement

Review of Scientific Instruments (2024)

Qiwei Chen Lingyan He Xianzheng Liu Zhen Zhu Yuchen Bai

An apparatus for explorations of ion transport in a medium and across an interface has been constructed. The ion soft-landing technique is used to deposit low-energy ions onto a pre-adsorbed medium layer on a metal substrate. The designed low-energy ion source can produce a mass-filtered ion beam with tens of nanoampere from solid sources such as bulk metals and salts. The kinetic energy of the ion beam can be lower than 1.0 eV, enabling the ions to be soft-landed onto the medium at the surface. A Kelvin probe with a resolution of less than 32 mV is incorporated to measure the surface potential (SP) variation of the ion-landed sample to monitor the ion transport process in the medium. Temperature-programmed SP measurements on an Ag+-adsorbed ice film prepared on Pt(111) reveal that the temperature threshold for the Ag+-induced SP change of the ice film is about 110 K. The apparatus performance demonstrates its potential in studies of ion transport and related phenomena at both macroscopic and microscopic levels.

Ion gun

Ion beam mixing

10.1063/5.0228896

Cite

Citations (0)

Molecular insight into on-surface chemistry of an organometallic polymer

Physical Chemistry Chemical Physics (2022)

Yuxuan Lin Mengxiao Diao Jingxin Dai Zhen Xu Xinwei Zhao

A molecular investigation of Cu-elimination and subsequent C-C coupling of DCTP (4,4''-dichloro-1,1':3',1''-terphenyl)-Cu organometallic (OM) polymers on Cu(111) is conducted by scanning tunneling microscopy and spectroscopy, revealing that the Cu adatoms embedded in the DCTP-Cu chains are located at the hollow and bridge sites on the Cu(111) surface. The difference in the catalytic activities of these surface sites leads to stepwise elimination of Cu adatoms in the OM chains. Moreover, the interchain interaction plays an important role in the Cu-elimination process of the DCTP-Cu chains as well. The interchain steric hindrance, on the one hand, induces the formation of Cu-eliminated intermediates that are scarcely observed in other Ullmann coupling systems, and on the other hand, promotes the cooperative Cu-elimination and C-C coupling of the OM segments in neighboring chains. These findings demonstrate the key role of the molecule-substrate and intermolecular interactions in mediating the reaction processes of the extended molecular systems on the surface.

Organometallic Chemistry

10.1039/d2cp04858b

Cite

Citations (3)

Selective Intramolecular Dehydrocyclization of Co-Porphyrin on Au(111)

Molecules (2020)

Cen Yin Zhantao Peng Dan Liú Huanjun Song Hao Zhu

The on-surface C–H bond activation and coupling reaction is a powerful approach to constructing fine-tuned surface nanostructures. It is quite challenging to control its regioselectivity due to the inertness of the C–H bond involved. With scanning tunneling microscopy/spectroscopy and theoretical calculations, the C–H activation and sequential intramolecular dehydrocyclization of meso-tetra(p-methoxyphenyl)porphyrinatocobalt(II) was explored on Au(111), showing that the methoxy groups in the molecule could kinetically mediate the selectivity of the intramolecular reaction over its intermolecular coupling counterpart. The experimental results demonstrate that the introduced protecting group could help augment the selectivity of such on-surface reaction, which can be applied to the precise fabrication of functional surface nanostructures.

10.3390/molecules25173766

Cite

Citations (7)

Surface-mediated ordering of pristine Salen molecules on coinage metals

Inorganic Chemistry Frontiers (2020)

Dan Liu Bin Di Zhantao Peng Cen Yin Hao Zhu

The conformational isomers of Salen molecules and their self-assembled structures on coinage metal surfaces.

Metal salen complexes

10.1039/d0qi00874e

Cite

Citations (4)

Value Added Conversion of Ethanol on Morphologically Controlled and Defect‐Engineered Titanium Dioxide Nanorods

ChemPhysChem (2023)

Zining Wang Yumei Qin Yu Chen Yuchen Zhang Qiwei Chen

Abstract Developing an environmentally benign and highly effective strategy for the value‐added conversion of biomass platform molecules such as ethanol has emerged as a significant challenge and opportunity. This challenge stems from the need to harness renewable solar energy and conduct thermodynamically unfavorable reactions at room temperature. To tackle this challenge, one‐dimensional titanium dioxide photocatalysts have been designed and fabricated to achieve a remarkable photocatalytic selectivity of almost 100 % for transforming ethanol into value‐added 1,1‐diethoxyethane, contrasting the primary production of acetaldehyde in titanium dioxide nanoparticles. By incorporating a Pt co‐catalyst and infusing oxygen vacancies into the one‐dimensional catalyst, the ethanol transformation rate was doubled to 128.8 mmol g −1 h −1 with respect to that of its unmodified counterpart (about 66.7 mmol g −1 h −1 ). The underlying mechanism for this high conversion and selectivity resides in the narrowed bandgap of the catalyst and the prolonged lifetime of the photo‐generated carriers. This is a promising strategy for the photocatalytic transformation of essential biomass platform molecules that intertwines morphological control and defect engineering.

Titanium Dioxide

Nanorod

10.1002/cphc.202300564

Cite

Citations (0)