Article
Chemistry, Organic
Baoxiang Zhu, Zhao Wang, Hui Xi, Zengqiang Feng, Binglei Wang, Wenyang Jiao, Zhongxian Li, Zechao Wang, Junliang Wu
Summary: A new synthetic method has been developed for the synthesis of various compounds via visible-light-promoted radical monofunctionalization and difunctionalization of methylenecyclopropanes. The reaction conditions are simple and convenient, with moderate to excellent yields, a wide substrate scope, and tolerance for different functional groups. The possible radical mechanism has been investigated and proven to be a single electron transfer (SET) procedure.
ORGANIC CHEMISTRY FRONTIERS
(2021)
Article
Chemistry, Physical
Xiao-Yan Qin, Fan-Tao Meng, Mian Wang, Shu-Jiang Tu, Wen-Juan Hao, Jianyi Wang, Bo Jiang
Summary: Transition metal-catalyzed skeletal rearrangement reactions have rapidly advanced in the organic community, providing versatile methods for selective synthesis of special molecular scaffolds. A gold-catalyzed skeletal rearrangement of alkenes with alkynyl bromides was reported in this study, allowing for the regioselective generation of diverse tricyclic heterocycles with good yields. Mechanistic investigations using theoretical calculations were conducted to explain the regioselectivity of the reaction.
Article
Chemistry, Multidisciplinary
Yuegang Chen, Xin Wang, Xu He, Qing An, Zhiwei Zuo
Summary: Under mild reaction conditions, inexpensive cerium and nickel catalysts enable the use of easily accessible free alcohols as robust carbon pronucleophiles in selective C(sp(3))-C(sp(2)) cross-couplings. The identification of steric benzoate ligands for robust cerium complexes facilitates the synergy of cerium catalysis in emerging metallaphotoredox catalysis. Mechanistic investigations have led to the identification of a tribenzoate cerium(III) complex as a viable intermediate in the reaction.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Pablo Rios, Matthew S. See, Rex C. Handford, Simon J. Teat, T. Don Tilley
Summary: Stable dicopper(I) boryl complexes have been isolated using a robust dinucleating ligand DPFN and have shown reactivity in catalytic C-H bond activation.
Article
Chemistry, Multidisciplinary
Jialei Du, Daili Xiang, Jie Chen, Hehuan Xia, Leichen Wang, Fushan Liu, Yiwei Zhao, Yuanyuan Zhang, Caixia Xu, Bin Wang
Summary: Nanoporous PdCu (NP-PdCu) is a competent self-supported heterogeneous catalyst prepared from a PdCuAl alloy precursor, suitable for Suzuki-Miyaura cross-coupling with high efficiency and yields, and can be reused multiple times without obvious loss of catalytic performance.
CHEMICAL COMMUNICATIONS
(2021)
Article
Chemistry, Organic
Zhi-Jia Huang, Jin-Hao Qin, Miao-Lian Huang, Qing Sun, Hai-Yang Xie, Yang Li, Jin-Heng Li
Summary: A novel noble transition metal- and external oxidant-free electrochemical cyclization/aromatization method of aniline-tethered alkylidenecyclopropanes enabled by N-H/C-H functionalization is described. Various highly functionalized benzo[c]carbazoles were synthesized in atom-economical and sustainable manners, with a broad substrate scope and excellent regioselectivity. In addition, H-2 was the only theoretical byproduct in this protocol. Mechanistic studies revealed that the reaction proceeded through nitrogen-centered radical generation, cleavage of C-C bonds, C(sp(2))-H functionalization, and aromatization cascades.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Physical
Yang Sik Yun, Claudia E. Berdugo-Diaz, David W. Flaherty
Summary: Biomass has received considerable attention as an alternative to petrochemicals in the production of valuable chemicals and fuels. This Perspective discusses significant advancements in understanding the reaction networks and mechanisms, reactive intermediates, and active site motifs for selective production of desired compounds through hydrogenolysis over heterogeneous catalysts. Continuing research into hydrogenolysis reactions faces current challenges and provides opportunities for future exploration.
Article
Chemistry, Physical
Helgi Freyr Jonsson, Daniel Sethio, Julian Wolf, Stefan M. Huber, Anne Fiksdahl, Mate Erdelyi
Summary: Gold catalysis provides innovative organic transformations with high chemoselectivity under mild conditions. A silver-free route utilizing halogen bonding is presented for gold activation, reducing metal waste and enabling large-scale generation of complex molecules. The recyclability of gold is of supreme importance.
Article
Chemistry, Multidisciplinary
Xin-Lian Liu, Han-Ze Lin, Lu-Qi Tan, Jin-Bao Peng
Summary: In this article, an enantio-, site-, and E/Z-selective addition of ACPs with imines for the synthesis of dienyl substituted amines has been developed via palladium- and Bronsted acid co-catalysis. A range of synthetically valuable dienyl substituted amines were effectively prepared with good to excellent yields and excellent enantio- and E/Z-selectivities.
Article
Chemistry, Physical
Chun Gu, Weiqiang Yu, Hanqing Zhao, Song Shi, Penghua Che, Jie Xu, Jin Gao
Summary: Ru/porous silica regulated by templates with different carbon chain lengths exhibit the ability to control the methane yield in biomass polyols hydrogenolysis.
Article
Chemistry, Multidisciplinary
Jiaoyu Wu, Linqiang Li, Mengtian Liu, Lu Bai, Xinjun Luan
Summary: A novel Pd-0-catalyzed [2+2+1] annulation was proposed for the rapid assembly of tricyclic indoles in a single-step transformation. Experimental results showed that large tert-butyl and benzyl groups were selectively cleaved via an S(N)1 pathway in the presence of smaller alkyl groups.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Daniel A. Strassfeld, Chia-Yu Chen, Han Seul Park, D. Quang Phan, Jin-Quan Yu
Summary: The functionalization of C-H bonds in organic molecules is a direct approach for chemical synthesis. Recent advances in catalysis have allowed various chemical groups to control and direct C(sp(3))-H activation, but alcohols, a common functionality, have remained difficult to react due to their low affinity for catalysts. This study describes ligands that enable alcohol-directed arylation of C(sp(3))-H bonds through charge balance and hydrogen-bonding interactions, thus enhancing substrate-catalyst affinity and enabling previously unknown reactivity.
Editorial Material
Chemistry, Multidisciplinary
Rui Zhang, Guangbin Dong
Summary: In this issue of Chem, Morandi and coworkers describe an exciting reversible transfer hydroarylation reaction between ketones and unstrained arylated alcohols. The reaction involves a Rh-catalyzed beta-aryl elimination process, allowing for the transfer of an aryl group from the alcohol to the ketone substrate and providing a milder alternative to conventional Grignard and organolithium addition chemistry.
Article
Chemistry, Organic
Han Ding, Shuwei Zhang, Zheng Sun, Qiyuan Ma, Yuemei Li, Yu Yuan, Xiaodong Jia
Summary: Using a waste-utilized-type initiator, the aerobic oxidation of proline esters was achieved via C-H activation relay, leading to the formation of halogenated pyrroles in high yields. The mechanistic study revealed the involvement of the counterion, SbCl6-, in the radical chlorination process, providing insights into the role of counterions.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Wentao Xu, Fang Liu, Jiajun Li, Muzi Li, Jin Xie, Chengjian Zhu
Summary: Deconstructive functionalization of cyclic amines provides access to chemicals with diverse skeletons. Tertiary amines are converted to thiocarbamoyl fluorides using photoredox catalysis, enabling the synthesis of trifluoromethylamines from AgF in a one-pot method. The synthesized thiocarbamoyl fluorides can be further converted into esters.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Engineering, Electrical & Electronic
Kevin Kipruto Mutai, Hiroyasu Sato, Qiang Chen
Summary: This letter introduces a leaky-wave focusing antenna with a tapered dielectric constant distribution. The structure's main appeal lies in the simplicity and low cost of achieving the tapering in the fabrication process, where three-dimensional printing is used with polylactic acid material in less than an hour. The paper presents a detailed design method and demonstrates the desired focusing effect through simulation and experimental results at Ku-band.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Xianbo Cao, Qiang Chen, Toru Tanaka, Masaki Kozai, Hiroya Minami
Summary: A 1-bit time-modulated reflectarray (TMRA) was designed based on a conventional 1-bit reflectarray and time modulation technology. Experimental verification showed that the proposed 1-bit TMRA can achieve additional time modulation characteristics without significantly increasing system complexity, making it suitable for existing wireless communication systems.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Xianbo Cao, Hiroyasu Sato, Kai-Da Xu, Wen Jiang, Shuxi Gong, Qiang Chen
Summary: Wireless power transfer technology has played a crucial role in the development of biomedical devices. A systematic method to improve the efficiency of wireless power transfer is proposed, which includes the application of a Fresnel zone plate and an air layer-artificial matching layer to reduce propagation loss and interface reflection. Simulation and experimental results demonstrate that the proposed method significantly enhances the efficiency of wireless power transfer.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Chemistry, Organic
Hidenori Matsuyama, Xuan Zhang, Masahiro Terada, Tienan Jin
Summary: A versatile method for synthesizing alkylidene fluorenes and their heteroarene derivatives has been successfully developed by using a Pd(II)-catalyzed direct C-H/C-H coupling of o-alkenyl biaryls. Under aerobic oxidation conditions, the use of Pd(OAc)2 catalyst produces alkylidene fluorenes with various functional groups and diverse polycyclic systems. These resulting products can be utilized as versatile synthetic building blocks for constructing structurally diverse polycyclic arenes and heteroarenes.
Article
Chemistry, Multidisciplinary
Ye Lu, Ying Wang, He Li, Peihe Li, Xiujuan Feng, Yoshinori Yamamoto, Ming Bao, Jinghai Liu
Summary: An efficient and highly selective heterogeneous catalyst system using unsupported gold nanopores (AuNPore) was developed for the hydroamination of alkynes. The AuNPore catalyst enabled regioselective hydroamination of alkynes under mild conditions (rt-50 degrees C) without any additives or solvents, yielding Markovnikov imines in satisfactory to excellent yields. The catalyst showed no leaching of gold during the reaction and could be easily recovered and reused without any loss of catalytic activity. A one-pot, two-step procedure using a single AuNPore catalyst was established for the high atom efficiency synthesis of secondary amines from readily available alkynes and anilines.
Article
Engineering, Electrical & Electronic
Zhirui Zheng, Daotong Li, Xiaoheng Tan, Qiang Chen
Summary: A single-layer dual-/tri-band substrate integrated waveguide (SIW) filtenna based on multifunctional cavity-backed slots is proposed. The cavity-backed slots can function as radiators and resonators. By designing a pair of back-to-back open-loop slots embedded with a straight slot on the SIW cavity, three resonant modes combine with the TE101 mode to achieve superior dual-band filtering performance. Furthermore, four radiation nulls located at the sides of the operational passbands result in sharp roll-offs and deep stopband rejection.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Takuya Kaji, Hiroyasu Sato, Qiang Chen, Shimpei Nagae, Akira Kumagai, Osamu Kagaya
Summary: This article proposes a leaky wave antenna with a dielectric superstrate (LWADS) on a perforated dielectric spacer. The LWADS has an asymmetric structure with a half-filled dielectric spacer and a non-filled spacer, creating a quasi-cutoff region. The beam direction of the leaky wave is controlled by changing the hole radius of the periodically perforated, half-filled dielectric spacer. Measurements at X-band confirm the effectiveness of the design, demonstrating a high gain tilted beam pattern with peak gains of 14 dBi at theta = 20 degrees, 40 degrees, and even at a wide-angle of theta = 60 degrees. The ability to control the effective permittivity through the hole radius allows for the realization of an array of LWADS with different beam angles and a multibeam antenna with switched feeding.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Wenyi Shao, Qiang Chen
Summary: This paper proposes an all-dielectric surface focusing Mikaelian lens that achieves high-resolution focusing in the X- and Ka-band. The lens, made using 3D printing, is low-cost and exhibits excellent imaging performance in high-resolution microwave and millimeter-wave imaging, as demonstrated through numerical simulations and experiments.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Engineering, Electrical & Electronic
Zhirui Zheng, Daotong Li, Xiaoheng Tan, Qiang Chen
Summary: This paper proposes a compact, low-profile differential dual-polarized filtenna without an external filter circuit for vehicular communications. The antenna has a compact, low-profile, simple, and symmetrical structure, consisting of four identical quarter circular patches with a pair of crossed feeding lines symmetrically and orthogonally embedded. Good filtering performance with three radiation nulls (RNs) generated without extra filtering structure is achieved, and the production mechanisms of three RNs are studied numerically. The proposed antenna is suitable for in-vehicle local area networks (WLAN), in-vehicle Wi-Fi 6E, vehicle-to-vehicle (V2V) communication and 5G vehicle-to-basestation communication applications.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Sirao Wu, Junyi Xu, Qiang Chen
Summary: This paper reports a novel omnidirectional horizontally polarized dipole antenna array with wide bandwidth and high gain operating at sub-6 GHz band. The antenna array incorporates a major improvement in the feeding method for omnidirectional radiation patterns inspired by the classic turnstile antenna array. The antenna is simply machined with 1 mm diameter copper wire and exhibits good agreement between measured and simulated results, with a measured -10 dB impedance bandwidth of 1.19 GHz and a measured peak realized gain value of 7.44 dBi.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Kevin Kipruto Mutai, Qiang Chen
Summary: In this letter, a frequency-scanning leaky-wave array antenna is proposed to achieve a significantly increased scanning range. The structure consists of a pair of rectangular-waveguide-fed leaky-wave slot array antennas, which achieve focusing in the backward and forward quadrants at 26.5 and 23 GHz, respectively. By simply changing the frequency, a total scanning range of about 73 degrees is achieved. The proposed design allows the use of a single feed for both waveguides, with the focusing gain varying between 23 and 25 dBi.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Chemistry, Organic
Sheng Zhang, Hidenori Matsuyama, Itaru Nakamura, Masahiro Terada, Tienan Jin
Summary: A tandem oxidative ring expansion was developed to construct negatively curved polycyclicarenes with oxepine and thiepine. Mechanistic studies revealed that a unexpected [4+2] cycloadduct of o-biphenyl-linked methylenexanthenes and o-chloranil played a crucial role in the FeCl3-mediated expansion process.
Article
Engineering, Manufacturing
Daotong Li, Wei Luo, Xiaoquan Chen, Ying Liu, Kai-Da Xu, Qiang Chen
Summary: This article presents a design strategy for dual-/tri-/quad-band substrate-integrated waveguide bandpass filters based on a single perturbed multimode SIW cavity. Multiple resonant modes are achieved by loading perturbed structures in the cavity, and different filters with flexible controllable parameters are successfully realized using this approach.
IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Kai-Da Xu, Xiaoyu Weng, Qiang Chen, Haijun Fan
Summary: This article presents a direct synthesis method for designing a wideband filtering switch by incorporating p-i-n diodes into each resonator. An ideal transformer is introduced in each resonator to provide freedom in selecting values for inductances and capacitances. A new circuit model extraction procedure is used to simplify the network topology, and the lumped circuit model is converted into a distributed circuit model to maintain the filtering response in a wide frequency range. The proposed method is validated through the fabrication and measurement of two filtering switches with different fractional bandwidths.
IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES
(2023)
Article
Telecommunications
Chang Ge, Sijie Xia, Qiang Chen, Fumiyuki Adachi
Summary: In a cellular system with distributed MU-MIMO, the application of cluster-wise distributed MU-MIMO reduces computational complexity but results in both intracell and intercell interference. To address this, a fully decentralized interference coordination method combining the graph coloring algorithm and deep reinforcement learning is proposed in this letter. Through online training considering the time-varying wireless environment, the joint interference coordination can quickly adapt to changes and significantly improve system capacity compared to the absence of interference coordination.
IEEE COMMUNICATIONS LETTERS
(2023)
