Article
Chemistry, Multidisciplinary
Maria Alvarez, Francisco Molina, Pedro J. Perez
Summary: Control of regioselectivity in the functionalization of linear alkanes' C-H bonds can be achieved using silver complexes as catalysts. This alternative approach mainly relies on the choice of the diazo reagent to govern the regioselectivity, leading to functionalization at primary or secondary sites of the linear alkanes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Kailun Liang, Dongmei Zhang, Yanming Su, Lijun Lu, Jun Hu, Yi-Hung Chen, Xinxing Zhang, Aiwen Lei, Hong Yi
Summary: The direct alpha-C(sp(3))-H functionalization of tertiary amines is a promising method for constructing complex amine structures. Various activation methods, such as electron transfer, proton transfer, oxidants, photoredox catalysis, and electrochemical oxidation, have been studied extensively. However, the capture and identification of short-lived reactive radical intermediates in these reactions have been challenging. In this study, an online electrochemical mass spectrometry method was used to detect the short-lived intermediates in the electrochemical oxidative alpha-C(sp(3))-H functionalization of tertiary amines. The results revealed the presence of alpha-amino radical cations and iminium cations. Based on the understanding of the reactivity of the alpha-amino radical, a scalable electrochemical radical vinylation methodology was developed, leading to the synthesis of a wide range of allylic amines with broad functional group tolerance.
Article
Chemistry, Multidisciplinary
Wenzheng Fan, Xueyao Zhao, Yunshun Deng, Pinhong Chen, Fei Wang, Guosheng Liu
Summary: A highly efficient and sustainable method for enantioselective benzylic C-H cyanation has been reported by merging electrophoto-and copper catalysis. The novel catalytic system allows independent regulation of key steps to achieve high selectivity, suitable for enantioselective benzylic C-H cyanation of diverse alkylarenes and late-stage functionalization of bioactive molecules.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Polymer Science
Chengfei Yue, Changkun Ding, Ning Yang, Ying Luo, Jieliang Su, Lele Cao, Bowen Cheng
Summary: In this study, collagen/cellulose nanofibril composite films were fabricated using solution casting and solvent evaporation. The composite films showed excellent mechanical strength, thermal stability, bioactivity, and antimicrobial activity, making them promising for tissue engineering and regenerative medicine applications.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Chemistry, Physical
Jian Li, Jinsheng Sun, Kaihe Lv, Yuxi Ji, Xianbin Huang, Yingrui Bai, Jintang Wang, Jiafeng Jin, Shenglong Shi, Jingping Liu
Summary: This study introduces a novel concept of PU vitrimers with self-healing and recyclability properties, along with enhanced mechanical performance through multiple crosslinking strategies. By incorporating dynamic covalent and non-covalent bonds, the comprehensive enhancement of PUs for various industrial applications is achieved.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Multidisciplinary
Andreas C. Hans, Patrick M. Becker, Johanna Haussmann, Simon Suhr, Daniel M. Wanner, Vera Lederer, Felix Willig, Wolfgang Frey, Biprajit Sarkar, Johannes Kaestner, Rene Peters
Summary: This article discloses a catalyst type that enables highly efficient direct 1,4-additions. The catalyst is a zwitterionic entity, with acetate binding to negatively charged Cu-II and serving as a counterion for benzimidazolium. All three functionalities are involved in the catalytic activation. The productivity of maleimides increased by a factor greater than 300 compared to the literature (TONs up to 6700). High stereoselectivity and productivity were achieved for a wide range of other Michael acceptors as well. The polyfunctional catalyst, accessible in only 4 steps from N-Ph-benzimidazole with an overall yield of 96%, remained robust during catalysis, allowing for multiple reuse with nearly constant efficiency. Mechanistic studies, particularly using DFT, provided a detailed understanding of how the catalyst operates. The benzimidazolium unit stabilizes the coordinated enolate nucleophile and prevents the dissociation of acetate/acetic acid from the catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Polymer Science
Yi Nan, Chuanzhuang Zhao, Guillaume Beaudoin, X. X. Zhu
Summary: This review summarizes recent progress in the synergistic design strategy for thermoresponsive polymers with an upper critical solution temperature (UCST) in aqueous systems. The precise control of the responsive behavior of the UCST polymers can be achieved through a synergistic effect of hydrogen bonding with other interactions or modification of the chemical structures. The combination of UCST behavior with other stimuli-responsive properties of the polymers may lead to new functional materials with potential applications such as sensors, actuators, and controlled release devices.
MACROMOLECULAR RAPID COMMUNICATIONS
(2023)
Article
Polymer Science
Jiaoyang Chen, Jiajie Jing, Cheng Wang, Tao Chen, Jianhua Xu, Bowen Yao, Jiajun Fu
Summary: In this study, an ultra-strong and ultra-tough sustainable polymer composite was developed by dispersing cellulose nanofiber in a poly(vinyl alcohol) matrix. The composite exhibited excellent mechanical properties and dynamic properties, such as high toughness, good healing ability, recyclability, and biodegradability. It also showed great potential for food packaging and preservation due to its gas barrier ability and water vapor permeability. The mechanism behind the impressive performances is expected to inspire the design of other healable and green polymers in the future.
Article
Engineering, Electrical & Electronic
Sherif Elbasuney, M. Yehia, Gharieb S. El-Sayyad
Summary: This study presents a method for achieving intimate mixing between MnO2 NPs and Al NPs through surface modification. Surface modification of Al NPs with PDA was accomplished via in situ polymerization, leading to successful preparation of MnO2/PDA/Al nanocomposite.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Engineering, Multidisciplinary
Hanjun Gong, Yan Song, Guo Liang Li, Lin Zhang, Dan Guo, Guoxin Xie
Summary: An intelligent polymer composite with self-lubricating and self-healing functionalities was developed. The composite utilized a high strength intrinsic self-healing material as the matrix and surface functionalized poly-alpha-olefin oil-containing microcapsules as lubricant fillers. This combination achieved both self-lubricating and self-healing capabilities, resulting in improved tensile and compressive strengths, reduced friction coefficient and wear rate, as well as excellent scratch self-healing ability. This high strength polymer material with self-lubricating and self-healing functionalities holds great potential for engineering applications.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Polymer Science
Wangjian Cheng, Dongjie Liao, Chenhe Feng, Fubing Gao, Minjie Li, Xiawei Zhang, Lingyu Deng, Chuanhao Xu, Baoyun Ye, Chongwei An
Summary: Adhesives with exceptional toughness and self-healing properties are essential for the practical application of energetic composite materials (ECMs). This study demonstrates the synthesis of PUDS-3 films with remarkable toughness and self-healing capabilities. The incorporation of specific ring structures in the polymer enhances the interfacial interaction and accelerates crack healing, making it promising for enhancing the safety and longevity of ECMs.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Chemistry, Organic
Zhao-Yang Ju, Li-Na Song, Ming-Ben Chong, Dang-Guo Cheng, Yang Hou, Xi-Ming Zhang, Qing-Hua Zhang, Lan-Hui Ren
Summary: Nitrogen, phosphorus, and oxygen codoped carbon catalysts derived from dried yeast powder showed remarkable performance in the oxidation of C(sp)3-H bonds to ketones and esters. The catalysts exhibited high product yields without the use of organic solvents and operated under low O-2 pressure. They also demonstrated good reusability and stability after multiple recycling.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Changyuan Yan, Zixuan Chen, Hao Huang, Xianyu Deng
Summary: A Cu(BF4)(2) electrolyte capable of spontaneously generating protons is developed for ultralow-temperature copper metal batteries. It is found that the hydrolysis of BF4- generates more protons, making Cu(BF4)(2) one of the most effective aqueous electrolytes capable of breaking hydrogen bonds in water molecules. This electrolyte enables a polyaniline/Cu battery to deliver a short charging time, high charge/discharge capability, high discharge specific capacity, and a power density comparable to supercapacitors at low temperatures.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Applied
Song Jiang, Congde Qiao, Runpeng Liu, Qinze Liu, Jing Xu, Jinshui Yao
Summary: Composite films of poly(vinyl alcohol) and citric acid cross-linked chitosan were prepared and their structure and properties were investigated. The crosslinking of chitosan with citric acid was confirmed by infrared spectra and X-ray photoelectron spectra. The 1:1 CS/PVA film exhibited excellent mechanical properties, good creep resistance, and hydrophobicity, making it a potential material for food packaging and preservation.
CARBOHYDRATE POLYMERS
(2023)
Article
Chemistry, Physical
Sergii A. Sergiienko, Daniela Lopes, Gabriel Constantinescu, Marta C. Ferro, Nataliya D. Shchaerban, Obid B. Tursunov, Viacheslav Shkepu, Hanna Pazniak, Nataliya Yu Tabachkova, Enrique Rodriguez Castellon, Jorge R. Frade, Andrei Kovalevsky
Summary: This study explores the processing possibilities of Ni- and Ti3C2Tx-containing composite electrodes through co-pressing, plastic deformation, or etching. Various material design approaches were also explored, including the introduction of additional Al to tune the Ti3C2 interlayer distance. The electrochemical studies focused on hydrogen evolution showed the potential for boosting the electrochemical reaction in Ni and MXene-containing composite electrodes.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)