- An excellently stable heterovalent copper–organic framework based on Cu4I4 and Cu(COO)2N2 SBUs: The catalytic performance for CO2 cycloaddition reaction and Knoevenagel condensation reaction
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A novel 3D heterovalent Cu-based MOF, [Cu2Cu4I4(ANA)4(DMF)4]n (denoted as complex 1), was successfully designed and synthesized by the self-assembly of CuI and 5-aminonicotinic acid (HANA)
- Jin, Feng
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- The synthesis of a bifunctional copper metal organic framework and its application in the aerobic oxidation/Knoevenagel condensation sequential reaction
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A novel one-pot aerobic oxidation/Knoevenagel condensation reaction system was developed employing a Cu(ii)/amine bifunctional, basic metal-organic framework (MOF) as the catalyst. The sequential aerobic alcohol oxidation/Knoevenagel condensation reaction was efficiently promoted by the Cu3TATAT MOF catalyst in the absence of basic additives. The benzylidenemalononitrile product was produced in high yield and selectivity from an inexpensive benzyl alcohol starting material under an oxygen atmosphere. The role of the basic functionality was studied to demonstrate its role in the aerobic oxidation and Knoevenagel condensation reactions. The reaction progress was monitored in order to identify the reaction intermediate and follow the accumulation of the desired product. Lastly, results showed that the yield was not significantly compromised by the reuse of a batch of catalyst, even after more than five cycles.
- Miao, Zongcheng,Luan, Yi,Qi, Chao,Ramella, Daniele
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- Synthesis of 5- and 7-(dicyanomethylene)-2,3-dihydrocyclohepta-1,4- dithiins, 'push-pull' heptafulvene derivatives. 8,8-Dicyanoheptafulvenes from α-bromomalononitrile and cycloheptatrienylium salt
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Treatment of 2,3-dihydro-4aH-cyclohepta-1,4-dithiin with triphenylmethyl tetrafluoroborate followed by condensation with α-promomalononitrile in pyridine afforded 5- and 7-(dicyanomethylene)-2,3-dihydrocyclohepta-1,4- dithiins in good yields. When changing the solvent to acetonitrile, the products obtained were 5- and 6-(2,2-dicyanoethyl)-2,3-dihydro-1,4- benzodithiins. This new method was applicable to the general synthesis of dicyanoheptafulvenes from tropylium salts.
- Mori,Kubo,Takeshita
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- Yolk-Shell-Structured Covalent Organic Frameworks with Encapsulated Metal-Organic Frameworks for Synergistic Catalysis
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Yolk-shell composites offer a promising platform for integrating cores into hollow shells to create unique structures and properties. However, the concomitant functionality and tunability of yolk-shell nanocomposites is still a great challenge but highly desirable. Herein, we demonstrate a rational design for the fabrication of yolk-shell-structured covalent organic framework (COF)@metal-organic framework (MOF) (YS-COF@MOF) nanocomposites with COF as the external shell and MOF as the inner yolk. Series of the YS-COF@MOF composites with different MOF cores and COF shells were readily synthesized via a template-free solvothermal method. Control experiments showed that the formation of the hollow cavity between the core and the shell originated from the amorphous-to-crystalline transformation and the simultaneous shrinkage of the shell under the pyrrolidine-catalyzed conditions. The resultant YS-COF@MOF merges the inherent structure tunability and functionality of both COFs and MOFs. The functions of YS-COF@MOF can be regulated and optimized by judicious selections of metal ions and organic building blocks. Representative YS-TpPa@UiO-66-(COOH)2 with spatially distributed acidic and basic sites exhibited synergistically enhanced catalytic activity in one-pot deacetalization-Knoevenagel cascade reactions.
- Dang, Qiang,Huang, Hanlin,Li, Liuyi,Lyu, Xiaolin,Zhong, Shenghong,Yu, Yan,Xu, Dongsheng
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- Knoevenagel condensation reaction catalysed by Al-MOFs with CAU-1 and CAU-10-type structures
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The metal-organic frameworks (MOFs) CAU-1-NH2 ([Al4(OH)2(OCH3)4(p-BDC-NH2)3], (p-BDC-NH2)2- = 2-aminoterephthalate) and CAU-10-NH2 ([Al(OH)(m-BDC-NH2)], (m-BDC-NH2)2- = 5-aminoisophthalate) which possess two different pore sizes were studied for their catalytic activity as heterogeneous solid base catalysts in the Knoevenagel condensation reaction between benzaldehyde and malononitrile under mild reaction conditions (40 °C, 7 h, ethanol). For comparison, isoreticular MOFs containing a smaller amount of -NH2 groups (CAU-1-NH2/H) or no -NH2 groups (CAU-10-H) were synthesized. A two-step synthesis route including the synthesis of CAU-1-NH2 and its use as crystal seeds was developed to obtain the mixed-linker CAU-1-NH2/H compound. Only for CAU-1-NH2, up to 100% selectivity towards the desired Knoevenagel condensation product is observed. Hence, the catalytic activity of CAU-1-NH2 was tested between various benzaldehydes containing different substituents with malononitrile. By employing benzaldehyde and malononitrile as the starting materials, it is found that the mixed-linker MOF CAU-1-NH2/H catalyses the formation of the acetal (benzaldehyde diethyl acetal), while both CAU-10 materials lead to mixtures of the two products. Furthermore, the catalyst stability was also examined through reusability and leaching experiments and it is observed that the catalyst can be reused with no significant drop in its activity.
- Dhakshinamoorthy, Amarajothi,Heidenreich, Niclas,Lenzen, Dirk,Stock, Norbert
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- 2-Methylimidazole-assisted synthesis of a two-dimensional MOF-5 catalyst with enhanced catalytic activity for the Knoevenagel condensation reaction
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We report a facile strategy to fabricate two-dimensional (2D) MOF-5 with a thickness of 4 nm with 2-methylimidazole (2-MI) as a coordination regulator. 2-MI can inhibit the growth of MOF-5 in the vertical direction by competitive coordination to obtain 2D
- Guo, Changyan,Zhang, Yonghong,Zhang, Li,Zhang, Yi,Wang, Jide
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- Chemical modification of crystal-like mesoporous phenylene-silica with amino group
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Amination of phenylene moieties in crystal-like mesoporous silica hybridized with phenylene is successfully achieved with close to 28% conversion of phenylene by a two-step chemical transformation process while preserving both the ordered mesostructure an
- Ohashi, Masataka,Kapoor, Mahendra P.,Inagaki, Shinji
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- Post-synthetic cation exchange in anionic metal-organic frameworks; A novel strategy for increasing the catalytic activity in solvent-free condensation reactions
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In recent years anionic MOFs (metal-organic frameworks) have only been scarcely explored for application in heterogeneous catalysis. In this work an anionic metal-organic framework, [HDMA]2[Zn2(BDC)3(DMA)2]·6DMF
- Beheshti, Saeideh,Morsali, Ali
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- Nitrogen-rich porphyrinic metal-organic frameworks synthesized by postsynthetic metathesis: from inert material to active catalyst
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With the aid of a postsynthetic metathesis method, an inert nitrogen-rich porphyrinic metal-organic framework can exhibit a high catalytic activity in one-pot deacetalization-Knoevenagel condensation reaction.
- Liu, Dahuan,Wang, Xuan,Chen, Ying-Pin,Yuan, Shuai,Zhong, Chongli,Zhou, Hong-Cai
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- Two-dimensional flexible Ni(II)-based porous coordination polymer showing single-crystal to single-crystal transformation, selective gas adsorption and catalytic properties
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A novel two dimensional (2D) porous coordination polymer {[Ni3(TBIB)2(BTC)2(H2O)6]·5C2H5OH·9H2O}n (1) [TBIB = 1,3,5-tri(1H-benzo[d]imidazol-1-yl)benzene, H
- Agarwal, Rashmi A.,Mukherjee, Soumya
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- Guanine-Derived Porous Carbonaceous Materials: Towards C1N1
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Herein, the basic nature of noble covalent, sp2-conjugated materials prepared via direct condensation of guanine in the presence of an inorganic salt melt as structure directing agent was studied. At temperatures below 700 °C stable and more basic additio
- Antonietti, Markus,Heil, Tobias,Kossmann, Janina,López-Salas, Nieves
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- Periodic Mesoporous Organosilicas as Efficient Nanoreactors in Cascade Reactions Preparing Cyclopropanic Derivatives
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In this work, three organosilica precursors functionalized with carbamate moieties were synthesized by condensing of 3-isocyanatopropyltriethoxysilane and coupling regents of either hydroquinone (HQ), bisphenol A (BPA), or 1,1′-bi-2-naphthol (BN). These organosilica precursors were covalently bonded in the framework of periodic mesoporous organosilicas by co-condensation and hydrolysis with tetraethyl orthosilicate (TEOS) under hydrothermal treatment. The compositions and physical properties were characterized with FTIR, XRD, thermogravimetric/differential thermal analysis (TG/DTA), 29Si NMR, 13C NMR spectroscopies, SEM, TEM, and BET technologies. These characterizations suggest that three different structures were formed as the result of different sizes and compositions of the organosilica precursors. The three mesoporous organosilicas were applied as heterogeneous catalysts in the one-pot cascade Knoevenagel and Michael cyclopropanic reactions for the synthesis of cyclopropanic derivatives and showed excellent activity and selectivity. The highest conversion was obtained with mesoporous catalyst (MC)-HQ owing to its ordered mesostructure, highest surface area, and weakest stereo effect of the organic linking groups compared with MC-BAP and MC-BN. This methodology employed cheaper and more easily obtainable raw materials as reagents over the traditional alkene additive system and these heterogeneous catalysts exhibit superior performance and recyclability than typical homogeneous organic catalysts.
- Huo, Hang,Jiang, Yanqiu,Zhao, Tingting,Wang, Junlei,Li, Defeng,Xu, Xianzhu,Lin, Kaifeng
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- Au@Cu(II)-MOF: Highly Efficient Bifunctional Heterogeneous Catalyst for Successive Oxidation-Condensation Reactions
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A new composite Au@Cu(II)-MOF catalyst has been synthesized via solution impregnation and full characterized by HRTEM, SEM-EDS, XRD, gas adsorption-desorption, XPS, and ICP analysis. It has been shown here that the Cu(II)-framework can be a useful platform to stabilize and support gold nanoparticles (Au NPs). The obtained Au@Cu(II)-MOF exhibits a bifunctional catalytic behavior and is able to promote selective aerobic benzyl alcohol oxidation-Knoevenagel condensation in a stepwise way.
- Wang, Jing-Si,Jin, Fa-Zheng,Ma, Hui-Chao,Li, Xiao-Bo,Liu, Ming-Yang,Kan, Jing-Lan,Chen, Gong-Jun,Dong, Yu-Bin
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- Design and Synthesis of an Au@MIL-53(NH2) Catalyst for a One-Pot Aerobic Oxidation/Knoevenagel Condensation Reaction
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Highly dispersed gold nanoparticles were deposited on an amino-functionalized Al-based MIL-53 metal-organic framework by a facile adsorption/reduction strategy. The aromatic amino groups were utilized for adsorption and stabilization of AuCl4- and as basic catalytic sites in the Knoevenagel reaction. The bifunctional Au@MIL-53(NH2) catalyst was utilized to develop an efficient one-pot aerobic oxidation of alcohols/Knoevenagel condensation reaction that takes advantage of Au0 and NH2 incorporation at the same time. The roles of Au and NH2 groups were systematically investigated to elucidate their functionality during the one-pot reaction. In addition, the Au@MIL-53(NH2) catalyst can be easily recycled up to five times without leaching of the active centres or significant loss of catalytic activity.
- Qi, Yue,Luan, Yi,Peng, Xiong,Yang, Ming,Hou, Junying,Wang, Ge
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- Phosphor-doped hexagonal boron nitride nanosheets as effective acid-base bifunctional catalysts for one-pot deacetalization-Knoevenagel cascade reactions
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One-pot cascade reactions over metal-free heterogeneous bifunctional catalysts have been attracting increased attention in green chemistry owing to the advantage of process intensification, as well as the elimination of wastes and metal contamination. In this paper, phosphor-doped hexagonal boron nitride nanosheets (BNP) can act as excellent metal-free acid-base bifunctional catalysts for one-pot deacetalization-Knoevenagel cascade reactions. XRD, FT-IR, XPS, and solid NMR characterizations indicate that phosphor was doped into the framework of h-BN mainly at the corner (N2PO) and bayer (N3P-OH) sites. The CO2-TPD and NH3-TPD characterizations showed that the BNP sample with optimal phosphor-doping amounts simultaneously possessed the highest amount of acid and base sites. When correlated with the catalytic performance, it can be concluded that mainly N3P-OH acts as the Br?nsted acid sites and -BNH2 and N2PO as the Lewis and Br?nsted base sites, respectively. In addition, the good recycling stability and immobilization feasibility on a monolith support confirm its potential in practical applications.
- Zhao, Jun,Lin, Baining,Zhu, Yifan,Zhou, Yonghua,Liu, Hongyang
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- Robust Bifunctional Lanthanide Cluster Based Metal-Organic Frameworks (MOFs) for Tandem Deacetalization-Knoevenagel Reaction
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A series of 12-connected lanthanide cluster based metal-organic frameworks (MOFs) have been constructed by [Ln6(μ3-OH)8(COO-)12] secondary building units (SBUs) and 2-aminobenzenedicarboxylate (BDC-NH2) ligands. These obtained materials exhibit high chemical stability and generic thermal stability, especially in acidic and basic conditions. They also present commendable CO2 adsorption capacity, and Yb-BDC-NH2 was further confirmed by a breakthrough experiment under both dry and wet conditions. Moreover, these materials possess both Lewis acid and Br?nsted base sites that can catalyze one-pot tandem deacetalization-Knoevenagel condensation reactions.
- Zhang, Yue,Wang, Yuxiang,Liu, Lin,Wei, Na,Gao, Ming-Liang,Zhao, Dan,Han, Zheng-Bo
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- A layered amino-functionalized zinc-terephthalate metal organic framework: Structure, characterization and catalytic performance for Knoevenagel condensation
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A new stable mixed-ligand metal organic framework Zn2(tpt) 2(2-atp)I2 1 (tpt = tris (4-pyridyl) triazine, 2-atp = 2-aminoterephthalate) with split channels has been synthesized and characterized. The nitrogen containing ligands tpt and 2-atp are selected to create attractive basic sites for the catalyst. The Knoevenagel condensation between benzaldehyde and the active hydrogen compound (ethyl cyanoacetate or malononitrile) is carried out using compound 1 as solid basic catalytic support. The test results indicate that 1 is an efficient base catalyst with selective catalytic properties. It gives 37% and 99% yield respectively for the condensation products ethyl (E)-α-cyanocinnamate and 2- benzylidenemalononitrile. TG data show that the solid catalyst sample is fairly thermally stable. The compound does not show any signs of decomposition until 420 °C. PXRD data support that the catalyst remains its crystalline and framework stability after the catalysis process. These characters make it easily to be regenerated for the next cycle.
- Tan, Yi,Fu, Zhiyong,Zhang, Jie
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- Nickel(II), Copper(II) and Palladium(II) Complexes with Bis-Semicarbazide Hexaazamacrocycles: Redox-Noninnocent Behavior and Catalytic Activity in Oxidation and C-C Coupling Reactions
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Nickel(II), copper(II), and palladium(II) complexes MLH, where M = Ni (1), Cu (2), Pd (3), and MLOMe, where M = Ni (4), Cu (5), Pd (6), have been prepared by reactions of NiCl2·6H2O, Cu(OAc)2·H2O, and PdCl2(MeCN)2 with 14-membered bis-semicarbazide hexaazamacrocycles H2LH and H2LOMe in dimethylformamide (DMF). The compounds were characterized by elemental analysis, ESI mass spectrometry, IR, UV-vis, and 1D (1H, 13C) and 2D (1H-1H COSY, 1H-1H TOCSY, 1H-1H NOESY, 1H-13C HSQC, 1H-13C HMBC) NMR spectra (1, 3, 4, and 6), and X-ray diffraction (2, 4-6). The complexes with MIIN4 coordination environment have S = 0, 1/2, 0 ground states for Ni, Cu, and Pd, respectively. The electrochemical behavior of 1-6 was investigated in detail. The electronic structures of 1e-oxidized species were studied by EPR, UV-vis-NIR spectroelectrochemistry, and DFT calculations, indicating the redox-noninnocent behavior of the ligands. Compounds 1-6 were tested in the oxidation of styrene and C-C coupling (Henry and Knoevenagel condensations). Compounds 2 and 5 selectively catalyze the microwave-assisted oxidation of neat styrene to benzaldehyde (up to 88% yield), whereas the 1 and 4 catalytic systems afforded up to 99% β-nitroethanol yield with an appreciable diastereoselectivity toward the formation of the anti isomer.
- Arion, Vladimir B.,Breza, Martin,Darvasiová, Denisa,Dobrov, Anatolie,Fesenko, Anastasia,Martins, Luísa M. D. R. S.,Pombeiro, Armando J. L.,Rapta, Peter,Shutalev, Anatoly,Stepanenko, Iryna,Yankov, Alexander
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- Lewis acid mediated three-component one-flask regioselective synthesis of densely functionalized 4-amino-1,2-dihydropyridines via cascade Knoevenagel/Michael/cyclization sequence This paper is dedicated to Professor Ganesh Pandey on the occasion of his 60th birthday
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A highly convergent and regioselective one-pot synthesis of hitherto unreported 4-amino-1,2-dihydropyridines has been achieved via three-component domino coupling (3CDC) of α-oxoketene-N,S-arylaminoacetals, aldehydes, and malononitrile in the presence of InCl3 under solvent-free conditions. The merit of this cascade Knoevenagel condensation/Michael addition/cyclization sequence is highlighted by its atom-economy, efficacy of forming consecutive three new bonds (two C-C and one C-N), and one ring in a single operation. Noteworthy, the presence of nitrile and amino groups at 3- and 4-positions of 1,2-dihydropyridine ring makes these compounds excellent precursors for further synthetic renovations. Remarkably, one of the newly synthesized 4-amino-1,2-dihydropyridine exhibited high selectivity and sensitivity for Fe3+ ion over other metal ions.
- Koley, Suvajit,Chowdhury, Sushobhan,Chanda, Tanmoy,Janaki Ramulu,Samai, Subhasis,Motisa, Lerato,Singh, Maya Shankar
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- Microporous assembly and shape control of a new Zn metal–organic framework: Morphology-dependent catalytic performance
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A new metal–organic framework (MOF), [Zn(ATA)(bpd)]∝ (1Zn) (ATA: 2-aminoterephthalic acid; bpd: 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), exhibiting a three-dimensional extended porous structure was successfully assembled in a MeOH–H2O solvent system. Under various controlled conditions, 1Zn was obtained in a variety of morphologies such as microspheres, microblocks, microsheets, microplates and microrods. The catalytic performance of the 1Zn microsized MOF was evaluated, and a possible catalytic mechanism was proposed. The flexibility of this MOF assembly strategy for shape control will certainly enhance new potential applications of micro?/nano?MOFs.
- Wang, Jiajia,Han, Yuqing,Xu, Haitao,Xu, Zhen-Liang
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- Synthesis, crystal structure and catalytic property of a highly stable 3D Cu(II)-organic framework
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A three-dimensional (3D) Cu(II)-based MOF, [CuL·Cl]n (namely complex 1), was successfully generated through the in-situ reaction of CuCl2, NaN3, and 4-(4-cyanostyryl)pyridine. Notably, –CN and N3 ? ca
- Chen, Chunyan
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- Self-assembly of mixed-valence and heterometallic metallocycles: efficient catalysts for the oxidation of alcohols to aldehydes in ambient air
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Two mixed-valence CuII/CuIand two heterometallic CuII/AgImetallocycles have been synthesized by the assembly of designed metalloligands and CuI/AgIions, respectively. The CuII/CuImetallocycle can catalyze the oxidation of alcohols to aldehydes mediated by a co-catalyst, TEMPO (2,2,6,6-tetramethylpiperdine-1-oxyl), with ambient air as an oxidant, while the CuII/AgImetallocycle has no catalytic effect.
- Dai, Rui-Rong,Huang, Yong-Liang,Lai, Ya-Liang,Li, Dan,Wang, Xue-Zhi,Zhou, Xian-Chao,Zhou, Xiao-Ping
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- Supported copper on a diamide-diacid-bridged PMO: an efficient hybrid catalyst for the cascade oxidation of benzyl alcohols/Knoevenagel condensation
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In this study, a novel periodic mesoporous organosilica (PMO) containing diamide-diacid bridges was conveniently prepared using ethylenediaminetetraacetic dianhydride to support Cu(ii) species and affording supramolecular Cu@EDTAD-PMO nanoparticles efficiently. Fourier transform infrared (FT-IR) and energy dispersive X-ray (EDX) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer-Emmett-Teller (BET) analysis, and high-resolution transmission electron microscopy (HRTEM) results confirmed the successful synthesis of Cu@EDTAD-PMO. The stabilized Cu(ii) nanoparticles inside the mesochannels of the new PMO provided appropriate sites for selective oxidation of different benzyl alcohol derivatives to their corresponding benzaldehydes and subsequent Knoevenagel condensation with malononitrile. Therefore, Cu@EDTAD-PMO can be considered as a multifunctional heterogeneous catalyst, which is prepared easily through a green procedure and demonstrates appropriate stability with almost no leaching of the Cu(ii) nanoparticles into the reaction medium, and easy recovery through simple filtration. The recycled Cu@EDTAD-PMO was reused up to five times without significant loss of its catalytic activity. The stability, recoverability, and reusability of the designed heterogeneous catalyst were also studied under various reaction conditions.
- Dekamin, Mohammad G.,Valiey, Ehsan
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p. 437 - 450
(2022/01/20)
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- Polyionic liquid decorated chitosan beads as versatile metal-free catalysts for catalyzing chemical reactions in aqueous media
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A new strategy is presented for enhancing the catalytic activity of cross-linked chitosan beads. More precisely, chitosan beads were cross linked with glutaraldehyde and then, vinyl functionalized. In the next step, the vinyl-functionalized beads were pol
- Koohestani, Fatemeh,Sadjadi, Samahe
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- A ru-complex tethered to a N-rich covalent triazine framework for tandem aerobic oxidation-knoevenagel condensation reactions
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Herein, a highly N-rich covalent triazine framework (CTF) is applied as support for a RuIII complex. The bipyridine sites within the CTF provide excellent anchoring points for the [Ru(acac)2(CH3CN)2]PF6 complex. The obtained robust RuIII@bipy-CTF material was applied for the selective tandem aerobic oxidation-Knoevenagel condensation reaction. The presented system shows a high catalytic performance (>80% conversion of alcohols to α, β-unsaturated nitriles) without the use of expensive noble metals. The bipy-CTF not only acts as the catalyst support but also provides the active sites for both aerobic oxidation and Knoevenagel condensation reactions. This work highlights a new perspective for the development of highly efficient and robust heterogeneous catalysts applying CTFs for cascade catalysis.
- Abednatanzi, Sara,Der Voort, Pascal Van,Derakhshandeh, Parviz Gohari,Leus, Karen,Schmidt, Johannes,Watson, Geert
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- Highly Active Copper(I)-Chalcogenone Catalyzed Knoevenagel Condensation Reaction Using Various Aldehydes and Active Methylene Compounds
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First copper(I) chalcogenones catalysed Knoevenagel Condensation reactions have been reported. No illustration of the utilization of this copper-chalcogenone complex class in Knoevenagel Condensation catalysis can be found. Thus, copper(I) bis(benzimidazole-2-chalcogenone) catalysts [Cu(L1)4]+BF4? (1) and [Cu(L2)4]+BF4? (2) (L1 = bis(1-isopropyl-benzimidazole-2-selone)-3-ethyl; L2 = bis(1-isopropyl-benzimidazole-2-thione)-3-ethyl) have been utilized as catalysts in the Knoevenagel Condensation reactions. These copper(I) chalcogenone catalysts have shown high efficiency for the catalytic Knoevenagel Condensation of aryl aldehydes and active methylene compounds. In particular, complex 2, exhibit the best catalytic activities. The scope of the catalytic reactions has been investigated with 22 different molecules. The excellent catalytic activity has been depicted for various types of substrates with either electron-rich or deficient aryl aldehydes. The present investigation features relatively mild reaction conditions with good functional group tolerance and excellent yields. Graphic Abstract: The first copper(I)-chalcogenone complexes catalysed Knoevenagel Condensation reactions?have also been investigated, and revealed the best catalytic activities. [Figure not available: see fulltext.]
- Mannarsamy, Maruthupandi,Prabusankar, Ganesan
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- Photocatalytic cascade reactions and dye degradation over CdS-metal-organic framework hybrids
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Two bifunctional CdS-MOF composites have been designed and fabricated. The hybrids exhibited synergistic photocatalytic performance toward two cascade reactions under visible light integrating photooxidation activity of CdS and Lewis acids/bases of the MO
- Chen, Yu-Zhen,Li, Shu-Rong,Ren, Feng-Di,Wang, Lin
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p. 35326 - 35330
(2021/11/30)
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- Triazole-directed fabrication of polyoxovanadate-based metal-organic frameworks as efficient multifunctional heterogeneous catalysts for the Knoevenagel condensation and oxidation of alcohols
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By introducing 4-amino-1,2,4-triazole (4-NH2-trz), three new polyoxovanadate-based metal-organic frameworks (PMOFs) [Ni3(4-NH2-trz)6][V6O18]·3H2O (1), [Co3(4-NH2-trz)6][V6O18]·3H2O (2) and [Cu3OH(4-NH2-trz)3H2O][VO3]5·H2O (3) have been synthesized and thoroughly characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis and elemental analysis (EA). Among them, PMOFs1and2had similar structures containing [V6O18]6?clusters; however, PMOF3was isolated as a structure containing a [VO3]55?cluster when the amount of the 4-NH2-trz ligand was reduced to half with the other synthesis conditions being the same as those of PMOFs1and2except for the transition-metal chlorides. Furthermore, the negative charges of polyoxovanadate [V6O18]6?and [VO3]55?anions were balanced by trinuclear complex cations [Ni3(4-NH2-trz)6]6?for1, [Co3(4-NH2-trz)6]6?for2and [Cu3OH(4-NH2-trz)3H2O]5?for3, respectively. PMOFs1-3were further used as heterogeneous catalysts in the Knoevenagel condensation under solvent-free conditions and showed high catalytic activity. PMOF1showed moderate catalytic activities in the oxidation of various aromatic alcohols using H2O2as an oxidant. Moreover, PMOF1could be reused at least three times without losing its activity.
- Cheng, Xueli,Han, Yinfeng,Hu, Changwen,Huang, Xianqiang,Li, Jikun,Mei, Yu,Wei, Chuanping
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p. 10082 - 10091
(2021/08/03)
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- Robust Mg(Ca)Zr-Doped Acid-Base Bifunctional Mesoporous Silica and Their Applications in the Deacetalization-Knoevenagel Reaction
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A series of Mg(Ca)Zr-doped acid-base bifunctional mesoporous silica were synthesized to study the impact of the one-step or two-step impregnation method on material structure. The two-step method seems to be a better way to synthesize metal-based functionalized catalyst and their catalytic performance is investigated using deacetalization-Knoevenagel reaction as the probe reaction. The coexisting dual active sites and suitable designing routes endowed highly efficient (Conv. >99.6%, Sel. >99.8%) and robust stability (10 consecutive cycles) of these materials. The present process succeeded in preparing catalysts decorated with acid-base sites by doping acidic and alkali metal species rather than grafting organic groups.
- Cai, Menglu,Wang, Xiaozhong,Fang, Yangyang,Chen, Yingqi,Dai, Liyan
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p. 8924 - 8935
(2021/06/30)
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- Efficient and recyclable solid acid-catalyzed alkylation of active methylene compound via oxonium intermediate for atom economical synthesis of organic compounds
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In the present work, we report the catalytic reaction of active methylene compounds with cyclic enol ethers and aryl acetals through oxonium intermediate under solvent-free conditions using heterogeneous solid acid catalysts. Among studied solid acid catalysts, Amberlyst-15 gave excellent yields (35–85%) of alkylated products. The catalyst showed broader substrate scope, and a recyclable catalytic cost-efficient approach of the alkylation was examined on the different types of cyclic enol ethers and aryl acetal.
- Naikwadi, Dhanaji R.,Bankar, Balasaheb D.,Ravi, Krishnan,Biradar, Ankush V.
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p. 3691 - 3703
(2021/06/12)
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- Nanochannel {InZn}-Organic Framework with a High Catalytic Performance on CO2Chemical Fixation and Deacetalization-Knoevenagel Condensation
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The rare combination of InIII 5p and ZnII 3d in the presence of a structure-oriented TDP6- ligand led to a robust hybrid material of {(Me2NH2)[InZn(TDP)(OH2)]·4DMF·4H2O}n (NUC-42) with the interlaced hierarchical nanochannels (hexagonal and cylindrical) shaped by six rows of undocumented [InZn(CO2)6(OH2)] clusters, which represented the first 5p-3d nanochannel-based heterometallic metal-organic framework. With respect to the multifarious symbiotic Lewis acid-base and Br?nsted acid sites in the high porous framework, the catalytic performance of activated NUC-42a upon CO2 cycloaddition with styrene oxide was evaluated under solvent-free conditions with 1 atm of CO2 pressure, which exhibited that the reaction could be well completed at ambient temperature within 48 h or at 60 °C within 4 h with high yield and selectivity. Moreover, because of the acidic function of metal sites and a central free pyridine in the TDP6- ligand, deacetalization-Knoevenagel condensation of acetals and malononitrile could be efficiently facilitated by an activated sample of NUC-42a under lukewarm conditions.
- Chen, Hongtai,Zhang, Zhengguo,Hu, Tuoping,Zhang, Xiutang
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p. 16429 - 16438
(2021/11/01)
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- Catalytic activity of Mg-Al hydrotalcites and derived mixed oxides for imination reactionsviaan oxidative-dehydrogenation mechanism
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The catalytic activities of Mg-Al hydrotalcites and derived Mg-Al mixed oxides were studied for the imination of benzylic substrates (benzyl amine and benzyl alcohol), with aniline as a model reaction, to establish a green and cost-effective catalytic (precious metal free) process for imination and tandem reactions utilizing alcohols as reagents. The Mg-Al mixed oxide (Mg/Al ratio = 3.0) was found to be an efficient catalyst for imination reactions to synthesize cross-imines with high selectivity as well as for tandem reactions of alcohols. Basic sites of catalysts adsorb benzylic substrates through the hydrogen of their functional groups (-NH2/-OH) and activate (weaken) benzylic C-H bonds for hydride elimination. Thus, basic sites catalyze the reaction by activating benzylic substrates for oxidative-dehydrogenation (i.e., deprotonation followed by hydride elimination with the help of oxygen) to produce reactive imine/carbonyl intermediates, which undergo subsequent nucleophilic reactions with amine.
- Vala, Naresh,Joshi, Pradyuman A.,Mishra, Manish
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p. 8859 - 8868
(2020/06/08)
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- Highly efficient FeNP-embedded hybrid bifunctional reduced graphene oxide for Knoevenagel condensation with active methylene compounds
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We have synthesized atypical highly active bifunctional FeNPs implanted on amino-modified reduced graphene oxide (FeNPs/Am@rGO) [where FeNPs = Fe nanoparticles; Am = Primary aromatic amine derivatives such as p-phenylenediamine (PPD) and/or aniline (AN)]
- Patel, Dikin,Vithalani, Ravi,Modi, Chetan K.
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p. 2868 - 2881
(2020/03/03)
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- Acidic polymer containing sulfunic acid and carboxylic acid groups heterogenized with natural clay: A novel metal free and heterogeneous catalyst for acid-catalyzed reactions
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A novel metal-free solid acid catalyst, PHSA, has been designed and synthesized through facile and environmentally benign procedure via using halloysite nanoclay as a natural and biocompatible support. The synthetic protocol included co-polymerization of
- Akbari, Maryam,Heravi, Majid M.,Kahangi, Fatemeh Ghoreyshi,Sadjadi, Samahe
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- Magnetically recoverable 2-(aminomethyl)phenols-modified nanoparticles as a catalyst for Knoevenagel condensation and carrier for palladium to catalytic Suzuki coupling reactions
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A class of magnetic nanoparticles modified by 2-(aminomethyl)phenols has been successfully designed and synthesized as a reusable catalyst for Knoevenagel reaction. What's more, such nanomaterial also proved as suitable carrier for immobilization of palladium nanoparticles and the obtained composite exerted potent catalytic activity in Suzuki coupling reactions. Both of the (aminomethyl)phenols-modified nanoparticles and its related palladium nanocatalyst could be easily separated and reused for several consecutive runs by magnetic decantation without significant loss of their catalytic efficiency.
- Wang, Gongshu,Ding, Zhiqiang,Meng, Lingxin,Yan, Guiyang,Chen, Zhangpei,Hu, Jianshe
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- The Modified Clay as a New and Eco-Friendly Catalyst for the Knoevenagel Reaction
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Abstract: This work aims the synthesis of substituted alkenes via Knoevenagel condensation using the clay collected from the Agadir region and modified by KF as a heterogeneous catalyst (KF-modified clay). In this context, the influence of various paramet
- Bentahar, S.,Dbik, A.,Khomri, M. El,Lacherai, A.,Messaoudi, N. El,Sabour, A.,Taleb, M. Ait
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p. 1438 - 1444
(2020/10/29)
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- One-pot oxidant-free dehydrogenation-Knoevenagel tandem reaction catalyzed by a recyclable magnetic base-metal bifunctional catalyst
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A new base-metal bifunctional catalyst NH-Pd(0)@MNP was prepared via a facile procedure and fully characterized. The as-prepared catalyst was used as an efficient relay catalyst for the one-pot oxidant-free dehydrogenation-Knoevenagel condensation tandem reaction from benzyl alcohol in H2O under mild conditions and generated benzalmalononitriles with yield up to 96%. Meanwhile, the catalyst could be easily recovered from the reaction system by an external magnetic field, and is reusable with little loss of activity up to 6 runs (5%).
- Yuan, Xiaofeng,Wan, Zijuan,Ning, Jinfeng,Zhang, Qiang,Luo, Jun
-
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- Acid-base bifunctional ZIF-8 catalyst with amine and sulfonic acid groups by post-synthetic modification for one-pot tandem reaction
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Zeolitic imidazolate frameworks (Zeeeeeeeate frameworks) having an activated microporous structure. ZIFIFS 2 - which has a structure similar to 1 methylimidazole which is a ligand constituting the ZIF, and is contacted with a compound comprising at least one nitrogen atom and at least one amine group substituted on the ring. The ZIF is reacted with 1,3 - propanesultone to react ZIF to which the amine group is 2 introduced, thereby introducing a sulfone group by an amine group and a ring opening reaction, and an acid-base double functional ZIF having both an amine group and a sulfone group prepared therefrom. The ZIF may perform an acid reaction with an increased conversion rate, and may perform a single-step reaction formed by a deacetylation - KnoKnoKnoKnoop condensation reaction. Further, by providing ZIF which can be reused, it is expected to apply to a large-scale business.
- -
-
Paragraph 0072-0086; 0115-0118
(2021/02/16)
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- One-pot synthesis of bimetallic metal-organic frameworks (MOFs) as acid-base bifunctional catalysts for tandem reaction
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Designing and preparing effective acid-base tandem catalysts is one of the research hotspots at present because assembling antagonistic active sites in one catalyst is still a challenge. In this work, amine-functionalized bimetallic metal-organic frameworks (MIL-101(Al/Fe)-NH2 (X)) were synthesized through a rapid reflux method and acted as acid-base bifunctional catalysts for tandem reaction (deacetalization-Knoevenagel condensation reaction). The bimetallic MOF catalysts exhibit enhanced catalytic activity when compared with monometallic catalysts either MIL-101(Al)-NH2 or MIL-101(Fe)-NH2. The superior performance of MIL-101(Al/Fe)-NH2 (X) has been attributed to the synergistic effect between Al3+ and Fe3+ ions and the hierarchical pore structure. Moreover, the as-synthesised samples showed robust stability, excellent recyclability, and durable catalytic activity.
- Hu, Yanjing,Zhang, Jian,Huo, Hang,Wang, Zhe,Xu, Xianzhu,Yang, Yulin,Lin, Kaifeng,Fan, Ruiqing
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p. 315 - 322
(2020/02/04)
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- Highly Active Bisamino Functionalized Zr(IV)-UiO-67 Metal-Organic Framework for Cascade Catalysis
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This work reports the synthesis and characterization of Zr(IV)-based UiO-67-(NH2)2 (called 1) metal-organic framework. Activated 1 (named 1') was shown to be an efficient tandem catalyst in the conversion of benzaldehydedimethyl acet
- Das, Aniruddha,Anbu, Nagaraj,Mostakim,Dhakshinamoorthy, Amarajothi,Biswas, Shyam
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supporting information
p. 2830 - 2834
(2020/07/04)
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- Synthesis and catalytic activities of a Zn(ii) based metallomacrocycle and a metal-organic framework towards one-pot deacetalization-Knoevenagel tandem reactions under different strategies: A comparative study
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Solvothermal reactions between a pyridine based amide functionalized dicarboxylic acid, 4,4′-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L), and zinc(ii) nitrate in the absence and presence of a base produced the binuclear metallomacrocyclic compound [Zn2(L)2(H2O)4]·2(H2O)·6(DMF) (1) and the metallomacrocyclic based two dimensional MOF [Zn5(L)4(OH)2(H2O)4]n·8n(DMF)·4n(H2O) (2), respectively. Compound 1 bears two tetrahedral Zn(ii) centres, whereas the 2D framework 2 includes a penta-nuclear Zn(ii) cluster as a secondary building block unit, with two of the metal cations assuming a tetrahedral type geometry and the remaining three an octahedral type geometry. The topological analyses reveal that compound 1 has a 2-connected uninodal net and framework 2 has a 2, 8-connected binodal net. These compounds heterogeneously catalyse the tandem deacetalization-Knoevenagel condensation reactions carried out under conventional heating, microwave irradiation or ultrasonic irradiation. Comparative studies show that ultrasonic irradiation (final product yield of 99percent after 2 h of reaction time) provides the most favourable method (e.g., microwave irradiation leads to a final product yield of 91percent after 3 h of reaction time). Moreover, the catalysts can be reused at least for five consecutive cycles without losing activity significantly.
- Guedes Da Silva, M. Fátima C.,Karmakar, Anirban,Pombeiro, Armando J. L.,Rúbio, Guilherme M. D. M.,Soliman, Mohamed M. A.
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p. 8075 - 8085
(2020/07/10)
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- Cascade reaction synthesis method of 2-(phenylmethylene)malononitrile or derivative thereof
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The invention discloses a cascade reaction synthesis method of 2-(phenylmethylene)malononitrile or a derivative thereof. According to the invention, a dendritic acid-alkali catalyst based on cross-linked polystyrene is synthesized, and 2-(phenylmethylene) malononitrile or a derivative thereof is synthesized in batches by successfully applying a cascade reaction into fluid chemistry, so that the method of the invention has advantages of substantially reduced, yield increase and no separation process of a catalyst and a product compared with the traditional test tube reaction.
- -
-
Paragraph 0033-0037
(2020/03/12)
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- Acid and base catalysed reactions in one pot with site-isolated polyHIPE catalysts
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The polyHIPE catalysts based on styrene, vinyl benzyl chloride, and divinylbenzene co-polymerisation were functionalised with carboxylic and tertiary amine groups. Catalyst characterisation showed covalent bonding of the graft polymers. The macroporous and highly interconnected structure of polyHIPEs allows isolation of the acid and base functional groups and allows the presence of these otherwise incompatible functionalities on the same catalyst. The functionalised polyHIPE catalysts were shown to perform two reactions; (i) acid-catalysed acetal hydrolysis and (ii) base-catalysed Knoevenagel condensation in one-pot with 97% yield. The yield obtained is substantially higher than that observed with the homogeneous or resin polymer type catalysts due to the compartmentalisation of the active sites and improved mass transfer through the open porous polyHIPE structure.
- Yavuz, Erdem,Cherkasov, Nikolay,Degirmenci, Volkan
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p. 8175 - 8183
(2019/03/21)
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- A Zn based metal organic framework as a heterogeneous catalyst for C-C bond formation reactions
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Herein, we report the synthesis and application of a Zn-Bp-BTC MOF (Bp-4,4′-bipyridine; BTC-1,3,5-benzene tricarboxylic acid; MOF-metal organic framework) as a heterogeneous catalyst for mediating organic reactions. Initially, conditions were optimized for the Knoevenagel condensation reaction using Zn-Bp-BTC as a heterogeneous catalyst by varying the solvent, temperature and catalyst loading. Although the reaction proceeded at room temperature using methanol as the solvent, 60 °C offered the best yield in a shorter duration. Under optimized reaction conditions, a wide range of α,β-unsaturated dicyano compounds were prepared from the corresponding carbonyl precursor and malononitrile, the active methylene counterpart. Systematic investigation was also carried out to assess the role of the ligand and metal salt in the Knoevenagel condensation reaction. It was found that the Zn-Bp-BTC MOF catalyzed the reaction efficiently in comparison to its analogue Zn-BTC MOF and precursor Zn(NO3)2·6H2O. Finally, catalytic recycling and stability studies showed that the catalyst is able to mediate the reaction for up to five consecutive cycles without undergoing any significant chemical or morphological changes. Further, the catalyst was tested for its efficacy in a multi-component reaction (MCR). A MCR with the Zn-Bp-BTC MOF as the catalyst afforded good yields and there was no reaction in the absence of the catalyst. Similarly, the catalyst was tested for its efficiency in benzimidazole synthesis.
- Madasamy, Kanagaraj,Kumaraguru, Shanmugasundaram,Sankar, Velayutham,Mannathan, Subramaniyan,Kathiresan, Murugavel
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p. 3795 - 3800
(2019/03/05)
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- Cadmium Naphthalenedisulfonate Complex as Heterogeneous Catalyst in the Knoevenagel Condensation
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The reaction of naphthalene-1,5-disulfonate (1,5-nds), 2,4,5-tris(pyridin-4-yl)imidazole (tpim), and cadmium(II) acetate dihydrate Cd(OAc)2·2H2O afforded a 2D coordination polymer, [Cd(tpim)(1,5-nds)]n (1). Crystal structu
- Deng,Guo,He,Ji
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p. 117 - 121
(2019/04/13)
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- Catalysis through Dynamic Spacer Installation of Multivariate Functionalities in Metal-Organic Frameworks
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We demonstrate herein a facile strategy to engineer versatile catalytically active coordination interspace in the same primitive metal-organic framework (MOF) for variable heterogeneous catalysis. Different functional ligands can be reversibly inserted into and removed from proto-LIFM-28 individually or successively to bring in single or binary catalytic sites for specific reactions and switch the parent MOF to multipurpose catalysts. Alcohol-oxidation, Knoevenagel-condensation, click, acetal, and Baylis-Hillman reactions are achievable through simple exchange of a single catalytic spacer, while sequential or stepwise reactions are designable via selective combination of two catalytic spacers with different functionalities, thus making proto-LIFM-28 a multivariate MOF for multiuse and economic catalysis.
- Cao, Chen-Chen,Chen, Cheng-Xia,Wei, Zhang-Wen,Qiu, Qian-Feng,Zhu, Neng-Xiu,Xiong, Yang-Yang,Jiang, Ji-Jun,Wang, Dawei,Su, Cheng-Yong
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supporting information
p. 2589 - 2593
(2019/03/04)
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- Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
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A series of new prolinamide polyacrylonitrile fiber catalysts with tunable length of alkyl linker and different linker group were prepared by covalent bonding for the first time and well characterized by mechanical strength, FT-IR, XRD, EA, TGA, SEM and water contact angel. The catalytic activities of these fiber catalysts were evaluated in Knoevenagel condensation and one-pot Knoevenagel-Michael multicomponent tandem reactions to synthesize α, β-unsaturated nitrile and 2-amino-4H-chromene derivatives in water. The result show that the suitable linker length attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA?2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can be easily recovered and reused for at least ten consecutive cycles without significant loss of catalytic activity and active sites leaching.
- Zhu, Hai,Xu, Gang,Du, Huimin,Zhang, Chenlu,Ma, Ning,Zhang, Wenqin
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p. 217 - 229
(2019/05/16)
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- Calix[4]arene-based polyoxometalate organic-inorganic hybrid and coordination polymer as heterogeneous catalysts for azide-alkyne cycloaddition and Knoevenagel condensation reaction
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Based on a neutral pyridyl-functional calix[4]arene ligand (L = tetrakis [(3-pyridylmethyl)oxy]-p-tertbutylcalix[4]arene), one polyoxometalate-based organic-inorganic hybrid [Cu2L(SiW12O40)0.5]·CH3CN·
- Yue, Liu-Juan,Liu, Ying-Ying,Xu, Guo-Hai,Ma, Jian-Fang
-
supporting information
p. 15871 - 15878
(2019/10/22)
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- Two Hg(II)-based Macrocycles Offering Hydrogen Bonding Cavities: Influence of Cavity Structure on Heterogeneous Catalysis
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We present synthesis and characterization of two Hg-macrocycles offering H-bonding based cavities of varying dimensions. Both Hg-macrocycles illustrate noteworthy difference in their catalytic performance that has been related to their cavity structures.
- Pachisia, Sanya,Gupta, Rajeev
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p. 6039 - 6047
(2019/10/21)
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- Oxidative Olefination of Benzylamine with an Active Methylene Compound Mediated by Hypervalent Iodine (III)
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Hypervalent iodine-mediated oxidative olefination of amines with an active methylene compound provides a rapid gateway towards the formation of electrophilic alkenes under mild reaction conditions in good to excellent yields. This is an efficient protocol for the preparation of substituted electrophilic alkenes.
- Rupanawar, Bapurao D.,Veetil, Sruthi M.,Suryavanshi, Gurunath
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p. 6232 - 6239
(2019/11/05)
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- A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
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A transition metal free expedient approach for the C[dbnd]C bond cleavage of electron deficient alkenes such as arylidene Meldrum's acid and malononitrile derivatives are discussed. The C[dbnd]C bond of these compound were cleaved to benzoic acid in good yield at high temperature. Most importantly, with oxone in CH3CN/H2O at 45 °C or m-CPBA in DCM or NaClO2 in THF/H2O or PIDA in THF at room temperature furnished benzaldehyde derivatives selectively in excellent yields.
- Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
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- Catalyst-free cascade synthesis of densely functionalized chromenes in water
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An expeditious and environmental friendly, general protocol has been developed for the synthesis of 2-amino-3-cyano-4H-chromenes via cascade Knoevenagel-Michael-intramolecular cyclization in water. Pure solid products were obtained by simple filtration technique. The aqueous catalyst-free reactions lead to high product yield at room temperature.
- Bhat, Subrahmanya Ishwar
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p. 2532 - 2536
(2019/10/02)
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- An intramolecular relay catalysis strategy for Knoevenagel condensation and 1,3-dipolar cycloaddition domino reactions
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A relay catalysis strategy was established by using a bifunctional catalyst which was prepared by immobilization of organic chains containing secondary amine and Cu(ii) complex onto silica-coated nano-Fe3O4. The simply prepared nanoparticles acted as efficient, intramolecular relays and magnetically recyclable base-metal bifunctional catalysts for Knoevenagel condensation and 1,3-dipolar cycloaddition domino reactions to prepare 5-substituted 1H-tetrazoles with excellent yields.
- Yuan, Xiaofeng,Wang, Zijuan,Zhang, Qiang,Luo, Jun
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p. 23614 - 23621
(2019/08/12)
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- Amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks as efficient catalysts for one-pot cascade reactions
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In this paper, novel amino- and sulfo-bifunctionalized hyper-crosslinked organic nanotube frameworks (H-ONTFs) were directly prepared by templating core-shell bottlebrush copolymers via a Friedel-Crafts (F-C) alkylation reaction, in which the acidic sites were anchored into the wall of nanotubes and basic sites were introduced onto the inner layer wall of nanotubes through a rational molecular design strategy. The resulting acid-base bifunctionalized H-ONTFs showed excellent catalytic activities for one-pot deacetalization-Knoevenagel cascade reactions due to their open-ended structure, large surface area and good multi-porosity interconnectivity.
- Meng, Guojie,Gao, Shengguang,Liu, Ying,Zhang, Li,Song, Chunmei,Huang, Kun
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supporting information
p. 2269 - 2273
(2019/02/05)
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- Efficient bifunctional reactivity of K-doped CrO(OH) nanosheets: Exploiting the combined role of Cr(iii) and surface -OH groups in tandem catalysis
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This work reports the bifunctional catalytic activity of layered K-doped α-CrO(OH). The combined action of the redox active Cr(iii) and the surface hydroxyl groups was efficiently used to carry out 2-3 oxidation reactions in tandem followed by condensation/coupling reactions in one pot. Oxidation of benzyl alcohol followed by Knoevenagel condensation or coupling reactions forming C-C and C-N linkages in one pot is demonstrated. The catalyst has been characterized using XRD, IR, TGA, CO2-TPD, cyclic voltammetry, XPS and microscopic techniques to gain insight into the nature of active sites. The role of O- and O2- on the CrO(OH) catalyst in the bifunctional activity was studied using analytical techniques. Recyclability and leaching tests confirmed that K-α-CrO(OH) is a stable and environmentally safe catalyst.
- Vernekar, Dnyanesh,Ratha, Satyajit,Rode, Chandrashekhar,Jagadeesan, Dinesh
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p. 1154 - 1164
(2019/03/12)
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- Co2+ immobilized on highly ordered mesoporous graphitic carbon nitride (ompg-C3N4/Co2+) as an efficient and recyclable heterogeneous catalyst for one-pot tandem selective photo-oxidation/Knoevenagel condensation
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Design and synthesis of efficient heterogeneous photocatalysts is an important task for practical applications due to the increasing environmental challenges and energy crisis. In this work, Co2+ modified highly ordered mesoporous graphitic carbon nitride (ompg-C3N4/Co2+) was prepared through a simple procedure involving sonication treatment. The obtained catalyst was characterized using FT-IR, XRD, ICP-OES, FE-SEM, UV–vis DRS, N2 adsorption-desorption, and TGA. It was found that the ompg-C3N4/Co2+ can function as a multifunctional heterogeneous photocatalyst for the one-pot tandem selective photo-oxidation/ Knoevenagel condensation. More interestingly, the obtained ompg-C3N4/Co2+ represented a high photocatalytic activity in benzyl alcohol oxidation without any oxidant under air atmosphere and visible light irradiation.
- Ghafuri, Hossein,Jafari, Ghazaleh,Rashidizadeh, Afsaneh,Manteghi, Faranak
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- Precise Control of the Oriented Layered Double Hydroxide Nanosheets Growth on Graphene Oxides Leading to Efficient Catalysts for Cascade Reactions
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In recent years, great attention has been paid to cascade reactions, which can improve efficiency and reduce waste production by implementing several consecutive reactions. Herein, two bifunctional catalysts were successfully prepared by precise control of the oriented layered double hydroxides (LDHs) growth on graphene oxides (GO) using a single-drop and co-precipitation method, respectively. The resultant Ru/LDH-GO-P and Ru/LDH-GO-V composites were characterized by EXAFS, FT-IR, XRD, TG-DTA, BET, XPS, TEM, CO2-TPD, O2-TPD, etc. The catalytic performance of Ru/LDH-GO-P and Ru/LDH-GO-V for one-pot oxidation-Knoevenagel condensation reaction showed significant difference under the same experimental conditions, in which the Ru/LDH-GO-P showed 99 % conversion and 99 % selectivity, in marked contrast of 60.7 % conversion and 47.9 % selectivity using Ru/LDH-GO-V as catalyst. The large enhancement of the catalytic performance using Ru/LDH-GO-P can be attributed to the following reasons: 1) the Co3+ centers in Ru/LDH-GO-P can promote the formation of surface oxygen vacancies that can adsorb and activate O2 to get better performance; 2) the Ru/LDH-GO-P exhibited larger BET surface and more medium-strong basic active sites than the Ru/LDH-GO-V. Moreover, the Ru/LDH-GO-P catalyst can be easily recovered from the reaction system and reused for at least five times without obvious deterioration of its catalytic activity or structural integrity.
- Zhang, Wei,Wang, Zelin,Zhao, Yufei,Miras, Haralampos N.,Song, Yu-Fei
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p. 5466 - 5474
(2019/11/13)
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- Cluster nuclearity control and modulated hydrothermal synthesis of functionalized Zr12 metal-organic frameworks
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The synthesis of chemically stable metal-organic frameworks (MOFs) in benign solvents is a key step towards their scalable production and commercialization. Extending the modulated hydrothermal (MHT) synthesis approach for zirconium (Zr) MOFs, we herein demonstrate cluster nuclearity control over the secondary building units (SBUs) to target Zr6-based and Zr12-based phases for the Zr terephthalate (Zr-BDC) system. Different functional groups (-NH2, -NO2, -Br, -F4) can be incorporated into Zr12-BDC, providing an avenue to further tune the chemical properties of these promising MOFs.
- Peh, Shing Bo,Cheng, Youdong,Zhang, Jian,Wang, Yuxiang,Chan, Ger Hui,Wang, Jian,Zhao, Dan
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supporting information
p. 7069 - 7073
(2019/06/06)
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- New Bifunctional Metal-Organic Frameworks and Their Utilization in One-Pot Tandem Catalytic Reactions
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Two new metal-organic framework (MOF) compounds were synthesized by a room temperature slow diffusion reaction. The compounds, [Cd3(C8H3SO7)2(C10H8N4)3(C3H7NO)2](C3H7NO)2·(CH3OH)4, I, and [Cd3(C8H3SO7)2(C12H10N4)3(C3H7NO)2](C12H10N4)·(C3H7NO)2, II, have comparable structures formed by Cd-sulfoisopthalate layers cross-linked by bipyridyl linkers forming three-dimensional structures. The compounds have both Lewis acidic (Cd metal centers) as well as basic (azine, free pyridine, and uncoordinated sulfo oxygens) sites, and they exhibited good catalytic activity for one-pot tandem deacetalization-Knoevenagel condensation reactions. The compounds exhibit catalytic activity both in the presence of a solvent as well as in solvent-free conditions. Compound I also exhibits good proton conductivity at room temperature.
- Mistry, Subhradeep,Sarkar, Anupam,Natarajan, Srinivasan
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p. 747 - 755
(2019/01/11)
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- Molybdenum carbide as an efficient and durable catalyst for aqueous Knoevenagel condensation
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By following green chemistry principles, various molybdenum compounds as cost-effective, commercially available, heterogeneous, and benign catalysts were used for the Knoevenagel condensation reaction. Among the compounds (Mo2C, MoS2, MoB, MoSi2), molybdenum carbide showed efficient performance for the Knoevenagel condensation in aqueous media at room temperature, affording the corresponding products in high yields within a short reaction time. Notably, using this commercially available heterogeneous catalyst, the deacetalization-Knoevenagel condensation of benzaldehyde dimethyl acetal and malononitrile at room temperature could successfully proceed in excellent yield. Molybdenum carbide could be recovered five times without loss of activity with an operationally simple procedure.
- Tavakolian, Mina,Najafpour, Mohammad Mahdi
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p. 16437 - 16440
(2019/11/11)
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- Synthesis of multifunctional polymer containing Ni-Pd NPs via thiol-ene reaction for one-pot cascade reactions
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Recently, acid–base bifunctional catalysts have been considered due to their abilities, such as the simultaneous activation of electrophilic and nucleophilic species and their high importance in organic syntheses. However, the synthesis of acid–base catalysts is problematic due to the neutralization of acidic and basic groups. This work reports a facial approach to solve this problem via the synthesis of a novel bifunctional polymer using inexpensive materials and easy methods. In this way, at the first step, heterogeneous poly (styrene sulfonic acid-n-vinylimidazole) containing pentaerythritol tetra-(3-mercaptopropionate) (PETMP) and trimethylolpropane trimethacrylate (TMPTMA) cross-linkers were synthesized in the pores of a mesoporous silica structure using click reaction as a novel bifunctional acid–base catalyst. After that, Ni-Pd nanoparticles supported on poly (styrenesulfonic acid-n-vinylimidazole)/KIT-6 as a novel trifunctional heterogeneous acid–base-metal catalyst was prepared. The prepared catalysts were characterized by various techniques like FT-IR, TGA, ICP-AES, DRS-UV, TEM, FE-SEM, EDS-Mapping, and XRD. The synthesized catalysts were efficiently used as bifunctional/trifunctional catalysts for one-pot, deacetalization-Knoevenagel condensation and one-pot, three-step and a sequential reaction containing deacetalization-Knoevenagel condensation-reduction reaction. It is important to note that the synthesized catalyst showing high chemo-selectivity for the reduction of nitro group, alkenyl double bond and ester group in the presence of nitrile. Moreover, it was found that the different nanoparticles including Ni, Pd, and alloyed Ni-Pd showing different chemo-selectivity and catalytic activity in the reaction.
- Javad Kalbasi, Roozbeh,Mesgarsaravi, Niloofar,Gharibi, Reza
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-
- Tandem synthesis method of 2-(phenylmethylene)malononitrile or derivative thereof
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A tandem synthesis method of 2-(phenylmethylene)malononitrile or a derivative thereof is disclosed. The general structural formula of the 2-(phenylmethylene)malononitrile or a derivative thereof is shown in the description, wherein R1 is hydrogen, p-methoxy, 2-bromo, 3-bromo or 4-bromo, and R2 is a cyano or ester group. A chloromethylated polystyrene microsphere acid-base functionalized catalyst is synthesized, a tandem reaction is successfully applied to the flow chemistry, and the 2-(phenylmethylene)malononitrile or a derivative thereof is synthesized in a gram scale. Compared with traditional test tube reactions, the method greatly reduces the reaction time, improves the yield and product purity, and avoids a step of separating a product from the catalyst.
- -
-
Paragraph 0029-0033
(2019/10/01)
-
- Molecular Pivot-Hinge Installation to Evolve Topology in Rare-Earth Metal–Organic Frameworks
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Linker desymmetrization has been witnessed as a powerful design strategy for the discovery of highly connected metal–organic frameworks (MOFs) with unprecedented topologies. Herein, we introduce molecular pivot-hinge installation as a linker desymmetrization strategy to evolve the topology of highly connected rare-earth (RE) MOFs, where a pivot group is placed in the center of a linker similar to a hinge. By tuning the composition of pivot groups and steric hindrances of the substituents on various linker rotamers, MOFs with various topologies can be obtained. The combination of L-SO2 with C2v symmetry and 12-connected RE9 clusters leads to the formation of a fascinating (4,12)-c dfs new topology. Interestingly, when replacing L-SO2 with a tetrahedra linker L-O, the stacking behaviors of RE-organic layers switch from an eclipsed mode to a staggered stacking mode, leading to the discovery of an intriguing hjz topology. Additionally, the combination of the RE cluster and a linker [(L-(CH3)6)] with more bulky groups gives rise to a flu topology with a new 8-c inorganic cluster. The diversity of these RE-MOFs was further enhanced through post-synthetic installation of linkers with various functional groups. Functionalization of each linker with acidic and basic units in the mesoporous RE-based PCN-905-SO2 allows for efficient cascade catalytic transformation within the functionalized channels.
- Feng, Liang,Wang, Yutong,Zhang, Kai,Wang, Kun-Yu,Fan, Weidong,Wang, Xiaokang,Powell, Joshua A.,Guo, Bingbing,Dai, Fangna,Zhang, Liangliang,Wang, Rongming,Sun, Daofeng,Zhou, Hong-Cai
-
supporting information
p. 16682 - 16690
(2019/11/11)
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- Synthesis and characterization of a Ni nanoparticle stabilized on Ionic liquid-functionalized magnetic Silica nanoparticles for tandem oxidative reaction of primary alcohols
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In this research, preparation of the magnetic nanoparticle, coating by a silica shell using (3-aminopropyl) triethoxysilane and synthesis of a novel sulfonic acid-substituted imidazolium-based ionic liquid onto the surface of these particles via a multi-component reaction, is described. The functionalized nanoparticles was loaded by Ni nanoparticles and characterized by means of techniques such as XRD, FTIR, SEM, EDX, TEM, TGA and ICP-OES. The nanostructures have spherical shapes that ranged in size from 80 to 100?nm. The catalytic activity of these nanoparticles was tested in aerobic oxidation of primary alcohols that showed good performance in the wide range of primary alcohols in water at mild reaction conditions. As a second step of this work, the tandem oxidative synthesis of alkylacrylonitriles and bisindolylmethanes were investigated using primary alcohols under oxidation conditions. This catalyst system can be recovered using external magnet and reused for five consecutive cycles without significantly less of its activity.
- Hosseinzadeh-Khanmiri, Rahim,Kamel, Yaser,Keshvari, Zahra,Mobaraki, Ahmad,Shahverdizadeh, Gholam Hossein,Vessally, Esmail,Babazadeh, Mirzaagha
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