Article
Chemistry, Organic
Min Liu, Haobin Jiang, Jiyuan Tang, Zenghui Ye, Fengzhi Zhang, Yanqi Wu
Summary: Here, a base-mediated, highly meta-selective O-arylation process of phenols and cyclic diaryliodonium salts without the use of transition metals is reported. This novel and practical method has been demonstrated to be useful for the synthesis of iodine-containing meta-functionalized biaryl ethers with a broad functional group tolerance and environmental friendliness. Diverse transformations of the products have been conducted to obtain various valuable functionalized biaryls. Preliminary mechanistic studies provide support for the proposed aryne generation mechanism.
Article
Chemistry, Applied
Shuo He, Yujie Chen, Zhi-Bin Huang, Bao Li, Da-Qing Shi, Yingsheng Zhao
Summary: A palladium-catalyzed cross-coupling reaction between the ortho-C(sp(2)) atom of aromatic amines and aliphatic aziridines has been developed, enabling the construction of the O-aminophenethylamine skeleton via C-H activation. The reaction shows good substrate scope and can generate the O-aminophenethylamine skeleton in drugs or bioactive compounds in a one-step process.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Review
Chemistry, Multidisciplinary
Jiarong Shi, Lianggui Li, Yang Li
Summary: Arynes are highly active organic intermediates used in the rapid synthesis of substituted arenes, with o-silylaryl triflates being the most frequently employed precursors. The resurgence in aryne chemistry over the past 20 years is largely attributed to the widespread use of Kobayashi's method, which involves fluoride-induced removal of the TMS group with concomitant departure of its ortho OTf group. This review provides an overview of the history, achievements, and applications of Kobayashi's method in the synthesis of natural products, bioactive molecules, and polycyclic aromatic hydrocarbons.
Article
Chemistry, Organic
Hongqiang Jiang, Min Liu, Zenghui Ye, Zongqiang Song, Yanqi Wu, Fengzhi Zhang
Summary: Transition metal-catalyzed ortho-functionalization of cyclic diaryliodonium salts has been well developed. Herein we present a transition-metal free meta-halogenation of readily available cyclic diaryliodonium salts for the preparation of valuable 2,3'-dihalobiaryls which can be transformed into a wide range of functionalized biaryls. The key step of this green process is the base-mediated generation of a benzyne intermediate which was successfully captured and supported the proposed mechanism.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Oliver Fischer, Markus R. Heinrich
Summary: 2-fluoro-5-nitrophenyldiazonium tetrafluoroborate is a novel Sanger-type reagent that enables the versatile functionalization of primary and secondary aliphatic alcohols. The diazonium unit on the resulting aryl-alkyl ether can be used for diverse transformations such as radical C-H activation, cyclization, and palladium catalyzed cross-coupling reactions, based on mild nucleophilic aromatic substitution under unprecedented, base-free conditions.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Shang-You Sun, Selvam Raju, Guganchandar Vedarethinam, Pei-Lin Chen, Shih-Ching Chuang
Summary: The reaction of o-benzofulvene with TfOH leads to intramolecular cyclization through novel C-C and C-N bond formation, resulting in the formation of a new molecular framework with reasonable to excellent yields. The method tolerates various electron-withdrawing/donating substituents and exhibits high diastereoselectivity. Additionally, it is free of bases, oxidants, and metals, and proceeds under mild reaction conditions favorable for synthetic organic chemistry.
Article
Chemistry, Organic
Chaoyu Zhao, Siwei Yang, Yaxuan Cheng, Ruxin Qu, Xuri Huang, Huiling Liu
Summary: DFT calculations were used to investigate the mechanism of Pd(II)-catalyzed late-stage nondirected C(sp(2))-H cyanation of toluene. The results showed that the morphology of the active species is crucial for the observed metalation/deprotonation step and regioselectivity. Interestingly, transmetalation was identified as the rate-determining and turnover-determining step with the largest overall change in free energy.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Review
Chemistry, Physical
Rajib Mandal, Bholanath Garai, Basker Sundararaju
Summary: Transition-metal-catalyzed C-H bond functionalizations have had a significant impact on organic synthesis. The use of low-abundance 4d and 5d metals is in high demand, but it is important to explore methods based on more readily available 3d metals. Weakly coordinating directing groups allow for selective activation of C-H bonds without the need for strongly coordinating directing groups.
Article
Chemistry, Multidisciplinary
Yun Xiong, Shicheng Dong, Shenglai Yao, Chenshu Dai, Jun Zhu, Sebastian Kemper, Matthias Driess
Summary: White phosphorus (P-4) undergoes degradation to produce 2,5-disila-3,4-diphosphapyrrole 2 and two novel functionalized Si=P doubly bonded compounds 3 and 4 when exposed to the new N,N-bis(silylenyl)aniline PhNSi2 1. The transformation of compound 2 into compounds 3 and 4 can be achieved depending on the molar ratio of 1 and P-4 as well as the reaction conditions. These compounds can interconvert through reactions with 1 and P-4.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Shengnan Liu, Qiong Wang, Fang Huang, Wenjuan Wang, Chong Yang, Jianbiao Liu, Dezhan Chen
Summary: A novel mechanism of arylation of arenes via norbornene relay palladation through meta- to para-selectivity was revealed using density functional theory calculations. The study showed that activation of the meta-C-H bond guided by a directing group and subsequent para-arylation through NBE relay palladation was achieved. Cooperative catalysis by Pd-Ag bimetallic complex accounted for the experimental fact that no yield was detected without Ag.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Multidisciplinary Sciences
Suman K. Barman, Meng-Yin Yang, Trenton H. Parsell, Michael T. Green, A. S. Borovik
Summary: This study explores the mechanism of metal-oxido species in C-H bond cleavage, highlighting the importance of basicity in achieving enzymatic function. The research found that proton transfer plays a more dominant role than electron transfer in these reactions.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Multidisciplinary
Sunil Kumar Sunnam, Jitendra D. Belani
Summary: Recent research has explored arylation via ortho C-H activation with the aid of directing groups, leading to the development of a palladium-catalyzed C-H arylation using 8-aminoquinoline as a bidentate directing group. This method selectively provides C-H arylation products, unlike previous methods where cyclization to isoquinolones was observed. Additionally, sequential C-H functionalization was observed under specific conditions, leading to C-H olefination with the aryl group introduced from the aryne precursor.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Organic
Kelin Wang, Xia Song, Yongdi Xin, Xinying Zhang, Xuesen Fan
Summary: In this study, a condition-controlled selective synthesis of pyranone-tethered indazoles or carbazole derivatives was achieved via cascading reactions of N-nitrosoanilines with iodonium ylides. The formation mechanisms of the products were elucidated, and the developed protocols demonstrated easily controllable selectivity, mild reaction conditions, a clean and sustainable oxidant (air), and structurally diverse valuable products. Furthermore, the utility of the products was showcased by their facile and diverse transformations into synthetically and biologically interesting compounds.
Article
Chemistry, Organic
Yi-Xin Xu, Yu-Qing Liang, Zhong-Jian Cai, Shun-Jun Ji
Summary: A novel chelation-assisted C-H arylation reaction of benzo[h]quinoline is described in this study. The reaction, using [RuCl2(p-cymene)]2 as the catalyst and cheap and easily accessible arylsulfonyl chlorides as the arylation source, exhibits simple reaction conditions, a broad substrate scope, and good functional group tolerance. The successful application of bioactive-molecule-based sulfonyl chlorides further emphasizes the potential utility and importance of this desulfitative C-H arylation protocol.
Review
Spectroscopy
Richard A. J. O'Hair
Summary: Carboxylic acids are valuable organic substrates due to their wide availability, easy handling, and structural diversity. Studies over the past two decades have explored new modes of metal-mediated reactivity of carboxylic acids and their derivatives, with mass spectrometry-based studies providing insights into these new reaction pathways. Recent research highlights the potential role of mechanistic studies integrating both gas- and condensed-phase studies.
MASS SPECTROMETRY REVIEWS
(2021)
Article
Physics, Multidisciplinary
Wen Wang, Dirk Dietzel, Andre Schirmeisen
Summary: A study was conducted on the wear tracks on ionic crystals created by reciprocating single asperity scratch tests using atomic force microscopy. It was found that the wear depth exhibited nonmonotonic behavior with temperature, transitioning between two different regimes with the occurrence of quasiperiodic ripple formation. A thermally activated bond breaking model explained the wear data at low temperatures, but failed above a certain temperature threshold, which was later resolved by geometrically separating the ripple mounds from the troughs to achieve agreement with Arrhenius kinetics over the full temperature range.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Qigang Zhong, Alexander Ihle, Sebastian Ahles, Hermann A. Wegner, Andre Schirmeisen, Daniel Ebeling
Summary: Constructing low-dimensional covalent assemblies with tailored size and connectivity is challenging but important in molecular electronics for tuning the properties of quantum materials. A versatile approach has been developed for building such structures block by block on a surface through highly selective tip-induced intermolecular reactions.
Article
Multidisciplinary Sciences
Qitang Fan, Linghao Yan, Matthias W. Tripp, Ondrej Krejci, Stavrina Dimosthenous, Stefan R. Kachel, Mengyi Chen, Adam S. Foster, Ulrich Koert, Peter Liljeroth, J. Michael Gottfried
Summary: The study introduces a new method for synthesizing a novel biphenylene network by conducting an interpolymer dehydrofluorination reaction on a surface, resulting in a metallic carbon allotrope. This method provides a new approach for synthesizing other nonbenzenoid carbon allotropes.
Article
Nanoscience & Nanotechnology
Michael G. Ruppert, Daniel Martin-Jimenez, Yuen K. Yong, Alexander Ihle, Andre Schirmeisen, Andrew J. Fleming, Daniel Ebeling
Summary: QPlus sensors are non-contact atomic force microscope probes that offer atomic-scale spatial resolution. They are commonly used to visualize the chemical structure of adsorbed organic molecules. However, recent experiments using higher-order resonance modes have shown different image contrast, suspected to be caused by unknown vibrations of the tip. This study investigates the source of these artifacts and provides guidance for future probe development.
Article
Chemistry, Multidisciplinary
Qigang Zhong, Kaifeng Niu, Long Chen, Haiming Zhang, Daniel Ebeling, Jonas Bjork, Klaus Mullen, Andre Schirmeisen, Lifeng Chi
Summary: Assembling semiconducting organic molecules into stable metal-organic frameworks using multiple aryl-metal covalent bonds is a promising approach for integrating single-molecule electronics. However, embedding multiple aryl-metal bonds into these frameworks remains a challenge. In this study, the authors demonstrate the synthesis of 1D and 2D metal-organic hybrids with multiple aryl-metal bonds, and investigate the substrate-dependent structural control of these hybrids.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Benedikt P. Klein, Alexander Ihle, Stefan R. Kachel, Lukas Ruppenthal, Samuel J. Hall, Lars Sattler, Sebastian M. Weber, Jan Herritsch, Andrea Jaegermann, Daniel Ebeling, Reinhard J. Maurer, Gerhard Hilt, Ralf Tonner-Zech, Andre Schirmeisen, J. Michael Gottfried
Summary: Defects play a critical role in the functionality and performance of materials, but their effects are often poorly understood due to their low concentrations. In this study, the focus is on topological defects in two-dimensional materials like graphene. The researchers combine theoretical analysis and experimental investigations to study the bonding and electron transfer between embedded defects in graphene and a copper surface. The results show enhanced bonding and electron transfer compared to regular graphene, suggesting the potential use of topological defect engineering for performance control.
Article
Materials Science, Multidisciplinary
Zhifang Wang, Daniel Martin-Jimenez, Yingying Zhang, Miguel Wiche, Lacheng Liu, Daniel Ebeling, Qigang Zhong, Florian Fontein, Andre Schirmeisen, Lizhen Huang, Zi Wang, Wenchong Wang, Lifeng Chi
Summary: In this study, a thin liquid crystal-like film was used as the carrier transport channel for organic field-effect transistors (OFETs) and achieved high-performance OFETs with a saturation carrier mobility of 1.62 +/- 0.26 cm(2) V-1 s(-1) and a small variation of 16% among three batches. This finding provides a new strategy to design materials and device structures to simultaneously achieve high carrier mobility and device uniformity.
SCIENCE CHINA-MATERIALS
(2023)
Article
Physics, Multidisciplinary
Ebru Cihan, Dirk Dietzel, Benedykt R. Jany, Andre Schirmeisen
Summary: Structural superlubricity refers to greatly reduced friction between incommensurate atomically flat surfaces. By measuring the friction of antimony nanoparticles on graphite, this study found a characteristic change in friction during the amorphous-crystalline phase transition above 420 K, which was irreversible upon cooling. The results validate the concept that structural superlubricity is determined by the effectiveness of atomic force canceling processes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Zhifang Wang, Daniel Martin-Jimenez, Qigang Zhong, Daniel Ebeling, Andre Schirmeisen, Hong Wang, Wenchong Wang, Lifeng Chi
Summary: A method is reported to achieve high-resolution patterning and orientation control of crystalline organic thin films using Au patterned SiO2 substrates.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Qigang Zhong, Artur Mardyukov, Ephrath Solel, Daniel Ebeling, Andre Schirmeisen, Peter R. Schreiner
Summary: On-surface synthesis is being recognized as the preferred method for generating and visualizing unconventional molecules. In this study, the structurally elusive cyclotriphosphazene (P3N3) was successfully synthesized on Cu(111) and Au(111) surfaces using molecular manipulation with unprecedented precision. The achieved atomic-level imaging revealed the planar D-3h-symmetric ring structure of cyclotriphosphazene.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Qigang Zhong, Viktor Barat, Daniel Csokas, Kaifeng Niu, Marcin Gorecki, Animesh Ghosh, Jonas Bjork, Daniel Ebeling, Lifeng Chi, Andre Schirmeisen, Mihaiela C. Stuparu
Summary: A highly distorted chiral nanographene structure composed of triple corannulene-fused [5]helicenes is prepared with an overall isolated yield of 28%. The complex three-dimensional (3D) structure of the bowl-helix hybrid nanostructure is studied by a combination of non contact atomic force microscopy (AFM) and scanning tunneling microscopy (STM) on the Cu(111) surface, density functional theory calculations, AFM/STM simulations, and high-performance liquid chromatography-electronic circular dichroism analysis.
Article
Chemistry, Multidisciplinary
Daniel Martin-Jimenez, Michael G. Ruppert, Alexander Ihle, Sebastian Ahles, Hermann A. Wegner, Andre Schirmeisen, Daniel Ebeling
Summary: This study analyzes the suitability of qPlus sensors for modern multifrequency AFM techniques and demonstrates their ability to achieve submolecular resolution imaging. The results show that using torsional and flexural higher eigenmodes can produce good imaging results and reveal specific contrast features.
Article
Materials Science, Multidisciplinary
Matthias Vorholzer, Dirk Dietzel, Ebru Cihan, Andre Schirmeisen
Summary: This study investigates the role of shear stress in contact aging phenomena, revealing that shear stress does have an impact on contact aging, especially exhibiting special effects under the influence of temperature.