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71.
Lu Luo Shuai Tang Jiangyue Wu Shiwei Jin Hua Zhang 《Chemical record (New York, N.Y.)》2023,23(4):e202300023
Aromatic organoboron compounds are highly valuable building blocks in organic chemistry. They were mainly synthesized through aromatic C−H and C−Het borylation, in which transition metal-catalysis dominate. In the past decade, with increasing attention to sustainable chemistry, numerous transition metal-free C−H and C−Het borylation transformations have been developed and emerged as efficient methods towards the synthesis of aromatic organoboron compounds. This account mainly focuses on recent advances in transition metal-free aromatic C−H, C−N, C−S, and C−O borylation transformations and provides insights to where further developments are required. 相似文献
72.
Dr. Peng Dong Tingna Shao Jinlian Li Xiaohui Zhang Prof. Yu Zhao Prof. Xinhong Zhao Prof. Guixian Li 《欧洲无机化学杂志》2023,26(33):e202300483
Cyclohexane epoxide, which contains highly active epoxy groups, plays a crucial role as an intermediate in the preparation of fine chemicals. However, controlling the epoxidation pathway of cyclohexene is challenging due to issues such as the allylic oxidation of cyclohexene and the ring opening of cyclohexane epoxide during the cyclohexene epoxidation process to form cyclohexane oxide. This review focuses on the structure-activity relationships and synthesis processes of various heterogeneous transition metal-based catalysts used in cyclohexene epoxidation reactions, including molybdenum(Mo)-based, tungsten(W)-based, vanadium(V)-based, titanium(Ti)-based, cobalt(Co)-based, and other catalysts. Initially, the mechanism of cyclohexene epoxidation by transition metal-based catalysts is examined from the perspective of catalytic active centers. Subsequently, the current research of cyclohexene epoxidation catalysts is summarized based on the perspective of catalyst support. Additionally, the differences between alkyl hydroperoxide, hydrogen peroxide (H2O2), and oxygen (O2) as oxidants are analyzed. Finally, the main factors influencing catalytic performance are summarized, and reasonable suggestions for catalyst design are proposed. This work provides scientific support for the advancement of the olefin epoxidation industry. 相似文献
73.
ChemInform Abstract: Explaining Stability of Transition Metal Carbides — and Why TcC Does Not Exist.
Qinggao Wang Konstantin E. German Artem R. Oganov Huafeng Dong Oleg D. Feya Ya. V. Zubavichus V. Yu. Murzin 《ChemInform》2016,47(18):no-no
The formation of transition metal (M) carbides MxCy and trends of their stability are systematically investigated using the USPEX code within the DFT. 相似文献
74.
Yarabally R Girish Kanchipura R Raghavendra Dasappa Nagaraja Kothanahally S Sharath Kumar Sheena Shashikanth 《中国化学》2015,33(2):181-184
An efficient, inexpensive and simple method for the reduction of various α,β‐unsaturated ketones to corresponding saturated ketones using tosyl hydrazide as a hydrogen donor in DMF using calcium oxide powder has been reported. A variety of enones underwent reduction without forming undesirable side products. High chemoselectivity, broad functional group tolerance and good yields are the noteworthy features of this protocol. 相似文献
75.
Yahui Zhang Lingwei Kong Jianbing Shi Bin Tong Junge Zhi Xiao Feng Yuping Dong 《中国化学》2015,33(7):701-704
A new type of AIE molecules based on hexaphenyl‐1,3‐butadienes was reported with respect to the synthesis and characterization. This material exhibited different maximum emission wavelength and enhanced emission intensity at different aggregate state (amorphous and crystalline state). 相似文献
76.
Ai‐Hua Zhou Fei Pan Dr. Chunyin Zhu Prof. Dr. Long‐Wu Ye 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10278-10288
Fluorenes are a commonly encountered structural motif in materials science, pharmaceutical chemistry, and organic synthesis. Among various strategies towards the synthesis of this unique structure, transition metal‐catalyzed functionalization has emerged as one of the most efficient methods. This Minireview presents an overview of the recent advances in this emerging area by highlighting the reactions’ specificity and applicability and, where possible, provides a mechanistic rationale. 相似文献
77.
Covalent Grafting of Coordination Polymers on Surfaces: The Case of Hybrid Valence Tautomeric Interphases 下载免费PDF全文
Pablo González‐Monje Dr. Fernando Novio Dr. Daniel Ruiz‐Molina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10094-10099
We have developed a novel approach for grafting coordination polymers, structured as nanoparticles bearing surface reactive carboxylic groups, to amino‐functionalized surfaces through a simple carbodiimide‐mediated coupling reaction. As a proof‐of‐concept to validate our approach, and on the quest for novel hybrid interphases with potential technological applications, we have used valence tautomeric nanoparticles exhibiting spin transition at or around room temperature. SEM and AFM characterization reveal that the nanoparticles were organized chiefly into a single monolayer while X‐ray photoelectron spectroscopy (XPS) measurements confirm that the nanoparticles retain a temperature‐induced electronic redistribution upon surface anchorage. Our results represent an effective approach towards the challenging manufacture of coordination polymers. 相似文献
78.
Frontispiece: Entropy‐Driven 1,2‐Type Friedel–Crafts Reaction of Phenols with N‐tert‐Butoxycarbonyl Aldimines 下载免费PDF全文
79.
Dr. Dongdi Zhang Fan Cao Pengtao Ma Chao Zhang Prof. Dr. You Song Zhijie Liang Xiaojing Hu Prof. Jingping Wang Prof. Dr. Jingyang Niu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17683-17690
By deliberately using a metastable polyanion [(NbO2)6P2W12O56]12? ( 1 ), which was formed in situ, we have discovered the unprecedented hexameric cluster {Mn15(Nb6P2W12O62)6} ( 2 ), in which the six polyanions [Nb6P2W12O61]10? are alternately connected by four intriguing trinuclear {MnIII3} moieties and four {MnII} linkers. This discovery is the first in which the phosphoniobotungstate has been made accessible by using transition‐metal ions; furthermore, polyanion 2 represents the largest niobotungstate cluster reported to date. Analysis by means of electrospray ionization mass spectrometry (ESI‐MS ) provides insight into the self‐assembly process, and the peaks observed relate to the different charge states of the parent cluster, thus confirming the stability of 2 . In addition, magnetic‐susceptibility measurements reveal that each {MnIII3} subunit is a separate single‐molecule magnet (SMM). This discovery results from the exploration of the reverse effect of metastable polyanion 1 possessing high reactivity, thereby turning a disadvantage into an advantage. This finding could define a new synthetic strategy for the design and synthesis of magnetic polyoxometalate (POM) clusters. 相似文献
80.
Gas‐phase copper and silver complexes with phosphorothioate and phosphorodithioate pesticides investigated using electrospray ionization mass spectrometry 下载免费PDF全文
Efforts to improve agricultural productivity have led to a growing dependency on organophosphorus pesticides. Phosphorothioate and phosphorodithioate pesticides are organophosphorus pesticide subclasses with widespread application for the control of insects feeding on vegetables and fruits. However, even low doses of these pesticides can cause neurological problems in humans; thus, their determination and monitoring in agricultural foodstuffs is important for human health. Phosphorothioate and phosphorodithioate pesticides may be poorly ionized during electrospray, adversely affecting limits of detection. These pesticides can form complexes with Cu2+ and Ag+, however, potentially improving ionization. In the present work, we used electrospray ionization/mass spectrometry (ESI/MS) to study fenitrothion, parathion, diazinon, and malathion coordination complexes with silver and copper ions. Stable 1 : 1 and 1 : 2 metal/pesticide complexes were detected. Mass spectra acquired from pesticide solutions containing Ag+ or Cu2+ showed a significant increase in signal‐to‐background ratio over those acquired from solutions containing only the pesticides, with Ag+ improving detection more effectively than Cu2+. Addition of Ag+ to a pesticide solution improved the limit of detection by ten times. The relative affinity of each pesticide for Ag+ was related to complex stability, following the order diazinon > malathion > fenitrothion > parathion. The formation of Ag+–pesticide complexes can significantly improve the detection of phosphorothioate and phosphorodithioate pesticides using ESI/MS. The technique could potentially be used in reactive desorption electrospray ionization/mass spectrometry to detect phosphorothioate and phosphorodithioate pesticides on fruit and vegetable skins. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献