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Open accessJournal ArticleDOI: 10.1021/ACSCATAL.1C00209

Heterogenization of a Molecular Ni Catalyst within a Porous Macroligand for the Direct C-H Arylation of Heteroarenes

04 Mar 2021-ACS Catalysis (American Chemical Society (ACS))-Vol. 11, Iss: 6, pp 3507-3515
Abstract: Direct C–H functionalization catalyzed by a robust and recyclable heterogeneous catalyst is highly desirable for sustainable fine chemical synthesis. Bipyridine units covalently incorporated into the backbone of a porous organic polymer were used as a porous macroligand for the heterogenization of a molecular nickel catalyst. A controlled nickel loading within the porous macroligand is achieved, and the nickel coordination to the bipyridine (bpy) sites is assessed at the molecular level using IR and solid-state NMR spectroscopy. The heterogenized Ni-bpy catalyst was successfully applied to the direct and fully selective C2 arylation of benzothiophenes, thiophene, and selenophene, as well as for the arylation of free NH-indole. Recyclability of the catalyst was achieved by employing hydride activators to reach a cumulative turnover number of more than 300 after seven cycles of catalysis, which corresponds to a total productivity of 12 g of 2-phenylbenzothiophene, chosen as model target biaryl, per gram of catalyst.

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Topics: Catalysis (54%), Heterogeneous catalysis (53%), Bipyridine (52%)
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9 results found



Open accessJournal ArticleDOI: 10.1002/ANIE.202107032
17 Jul 2021-Angewandte Chemie
Abstract: We present a toolbox for the rapid characterisation of powdered samples of paramagnetic metal-organic frameworks at natural abundance by 1 H-detected solid-state NMR. Very fast MAS rates at room and cryogenic temperatures and a set of tailored radiofrequency irradiation schemes help overcome the sensitivity and resolution limits often associated with the characterisation of MOF materials. We demonstrate the approach on DUT-8(Ni), a framework containing Ni2+ paddle-wheel units which can exist in two markedly different architectures. Resolved 1 H and 13 C resonances of organic linkers are detected and assigned in few hours with only 1-2 mg of sample at natural isotopic abundance, and used to rapidly extract information on structure and local internal dynamics of the assemblies, as well as to elucidate the metal electronic properties over an extended temperature range. The experiments disclose new possibilities for describing local and global structural changes and correlating them to electronic and magnetic properties of the assemblies.

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1 Citations



Journal ArticleDOI: 10.1039/D1GC02490F
20 Sep 2021-Green Chemistry
Abstract: We have reported a waste-minimized protocol for the Sonogashira cross-coupling exploiting the safe use of a CPME/water azeotropic mixture and the utilization of a heterogeneous hybrid palladium catalyst supported onto a silica/β-cyclodextrin matrix in continuous flow. The use of the aq CPME azeotrope has proven to be crucial to enhance the catalyst performance including very low metal leaching. In addition, we have also completed the flow protocol by setting a downstream in-line liquid/liquid separation that allows the continuous recovery and reuse of the CPME fraction leading to consistent waste reduction. Finally, E-factor distribution and safety/hazard analysis have been performed highlighting the chemical and environmental efficiency of our protocol.

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Topics: Sonogashira coupling (51%)

1 Citations


Journal ArticleDOI: 10.1002/ASIA.202100695
Yongquan Tang1, Zhifeng Dai2, Sai Wang1, Fang Chen1  +2 moreInstitutions (2)
Abstract: Direct C-H bond activation of heterocycles as a step-economical and environmentally friendly approach to build the heterobiaryls motifs is highly attractive, but it still has a challenge to design and prepare a cheap and regioselective heterogeneous catalyst. To tackle this challenge, we have introduced Ni species into a porous phenanthroline-based organic polymer donated as POP-Phen@Ni. This heterogeneous catalyst shows excellent catalytic performances in regioselective C-H activation of heterocycles, even better than those of the corresponding homogenous catalyst. H/D exchange experiments show that the lithium bis(trimethylsilyl)amide (LiHMDS), a base added in the reaction, play a very important role during the reaction processes. We believe that this heterogeneous catalyst would open a new door for design of heterogeneous catalysts to efficiently catalyze the regioselective C-H activation of heterocycles.

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1 Citations


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66 results found


Journal ArticleDOI: 10.1002/MRC.984
Dominique Massiot1, Franck Fayon1, Mickaël Capron1, Ian King2  +7 moreInstitutions (4)
Abstract: With the description of more and more complex one- and two-dimensional NMR experiments comes the need to develop methods to make a comprehensive interpretation of the various different experiments that can be carried out on the same sample or series of related samples. We present some examples of modelling one- and two-dimensional solid-state NMR spectra of I = ½ spin and quadrupolar nuclei, using laboratory-developed software that is made available to the NMR community. Copyright © 2001 John Wiley & Sons, Ltd.

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3,176 Citations


Journal ArticleDOI: 10.1021/CR100380Z
Chengliang Wang1, Huanli Dong1, Wenping Hu1, Yunqi Liu1  +1 moreInstitutions (1)
11 Apr 2012-Chemical Reviews
Abstract: Since the discovery of highly conducting polyacetylene by Shirakawa, MacDiarmid, and Heeger in 1977, π-conjugated systems have attracted much attention as futuristic materials for the development and production of the next generation of electronics, that is, organic electronics. Conceptually, organic electronics are quite different from conventional inorganic solid state electronics because the structural versatility of organic semiconductors allows for the incorporation of functionality by molecular design. This versatility leads to a new era in the design of electronic devices. To date, the great number of π-conjugated semiconducting materials that have either been discovered or synthesized generate an exciting library of π-conjugated systems for use in organic electronics. 11 However, some key challenges for further advancement remain: the low mobility and stability of organic semiconductors, the lack of knowledge regarding structure property relationships for understanding the fundamental chemical aspects behind the structural design, and realization of desired properties. Organic field-effect transistors (OFETs) are a kind of device consisting of an organic semiconducting layer, a gate insulator layer, and three terminals (drain, source, and gate electrodes). OFETs are not only essential building blocks for the next generation of cheap and flexible organic circuits, but they also provide an important insight into the charge transport of πconjugated systems. Therefore, they act as strong tools for the exploration of the structure property relationships of πconjugated systems, such as parameters of field-effect mobility (μ, the drift velocity of carriers under unit electric field), current on/off ratio (the ratio of the maximum on-state current to the minimum off-state current), and threshold voltage (the minimum gate voltage that is required to turn on the transistor). 17 Since the discovery of OFETs in the 1980s, they have attracted much attention. Research onOFETs includes the discovery, design, and synthesis of π-conjugated systems for OFETs, device optimization, development of applications in radio frequency identification (RFID) tags, flexible displays, electronic papers, sensors, and so forth. It is beyond the scope of this review to cover all aspects of π-conjugated systems; hence, our focus will be on the performance analysis of π-conjugated systems in OFETs. This should make it possible to extract information regarding the fundamental merit of semiconducting π-conjugated materials and capture what is needed for newmaterials and what is the synthesis orientation of newπ-conjugated systems. In fact, for a new science with many practical applications, the field of organic electronics is progressing extremely rapidly. For example, using “organic field effect transistor” or “organic field effect transistors” as the query keywords to search the Web of Science citation database, it is possible to show the distribution of papers over recent years as shown in Figure 1A. It is very clear

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Topics: Organic electronics (56%)

2,571 Citations


Journal ArticleDOI: 10.1002/ANIE.200701595
Jia-Xing Jiang1, Fabing Su1, Abbie Trewin1, Colin D. Wood1  +7 moreInstitutions (1)
19 Nov 2007-Angewandte Chemie
Abstract: Rigid wiry nets: Conjugated microporous polymer networks are formed by Sonogashira–Hagihara coupling. Although these materials are amorphous, the micropore size and surface area can be controlled by varying the length of the phenyleneethynylene struts (see picture; the network is shown in blue, and one 1,3,5-substituted benzene node and three connected struts are highlighted with C gray and H white).

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1,109 Citations


Journal ArticleDOI: 10.1021/ACS.CHEMREV.8B00507
27 Feb 2019-Chemical Reviews
Abstract: C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C–H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C–H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C–H activation until summer 2018.

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892 Citations


Journal ArticleDOI: 10.1021/JA074841I
Hideaki Ebata1, Takafumi Izawa1, Eigo Miyazaki1, Kazuo Takimiya1  +3 moreInstitutions (1)
Abstract: 2,7-Dialkyl[1]benzothieno[3,2-b]benzothiophenes were tested as solution-processible molecular semiconductors. Thin films of the organic semiconductors deposited on Si/SiO2 substrates by spin coating have well-ordered structures as confirmed by XRD analysis. Evaluations of the devices under ambient conditions showed typical p-channel FET responses with the field-effect mobility higher than 1.0 cm2 V-1 s-1 and Ion/Ioff of ∼107.

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Topics: Organic semiconductor (59%), Spin coating (57%), Benzothiophene (56%) ... read more

791 Citations