21829-09-4Relevant academic research and scientific papers
g-C3N4@Ce-MOF Z-scheme heterojunction photocatalyzed cascade aerobic oxidative functionalization of styrene
Karimia, Meghdad,Sadeghia, Samira,Gavinehroudi, Reza Ghahremani,Mohebali, Haleh,Mahjoub, Alireza,Heydari, Akbar
, p. 6671 - 6681 (2021/04/22)
A special composite of the cerium-based metal-organic framework (Ce-UiO-66) modified with graphitic carbon nitride nanosheets (g-C3N4) has been synthesized. In order to make a comparison, a series of composites comprising g-C3N4and Ce-MOF were synthesized as well. Their structural features were investigated using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), sorption of nitrogen (BET and BJH), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray fluorescence spectroscopy (XRF) and diffuse reflectance UV-Vis spectroscopy (UV-Vis DRS) and electron spin resonance (ESR) techniques. According to the obtained results, it was found that nanosheets of mesoporous g-C3N4act as linkers between the cerium sites, playing a critical role in the formation of composites. In fact, the embedded g-C3N4nanoparticles in the Ce-MOF cause a new kind of meso-porosity. Moreover, the coordination of nitrogen atoms in the graphitic carbon nitride structure to cerium atoms of the crystal brings about substantial changes in the optical properties, increasing the photoreactivity. On the other hand, since there is a physical contact between Ce-UiO-66 and g-C3N4in the composite, the unaltered pore volume and optical properties lead to the formation of a physical mixture rather than a composite. The g-C3N4@Ce-MOF as a photocatalyst was employed in photocatalytic aerobic oxidative Hantzsch pyridine synthesis of styrene and indicated high performance under visible light. The stability and reusability of g-C3N4@Ce-MOF were also examined and showed high efficiency up to the 5th run. Besides, the PXRD and FT-IR analyses taken from the retrieved g-C3N4@Ce-MOF nanocomposite confirmed the catalyst stability after the completion of the cascade aerobic oxidative reaction. Despite the photocatalytic performance, the synergistic effect of open metal sites in the MOF as Lewis acid and nitrogen in g-C3N4have greatly improved the efficiency of the catalyst. Moreover, the study of the reaction mechanism using ESR indicates the positive effect of composite formation on the performance of the photocatalytic aerobic oxidation reaction by the superoxide radical (O2˙—), as a selective oxidant species.
Green synthesis and characterization of novel Mn-MOFs with catalytic and antibacterial potentials
Aryanejad, Sima,Bagherzade, Ghodsieh,Moudi, Maryam
, p. 1508 - 1516 (2020/02/06)
This study focused on the synthesis of a new manganese-based metal-organic framework and the investigation of its application aspects. A Mn-MOF nanostructure, namely UoB-4, was prepared using a Schiff base organic linker (H2bbda: 4,4′-[benzene-
[Fesipmim]Cl as highly efficient and reusable catalyst for solventless synthesis of dihydropyridine derivatives through Hantzsch reaction
Agrwal, Akansha,Kasana, Virendra
, (2020/06/01)
Abstract: In the present investigation, magnetic ferrite nanoparticles (ferrite NPs) were synthesized and coated with silica (ferrite?SiO2NPs) by using the sol-gel method. After that, silica propylmethylimidazolium chloride ionic liquid [Sipmim]Cl was prepared and linked with the above-prepared ferrite?SiO2NPs to synthesize ferrite silica propylmethylimidazolium chloride [Fesipmim]Cl catalyst. The formation of [Fesipmim]Cl catalyst was confirmed by Fourier-transform infrared (FT-IR) spectroscopy analysis. X-ray diffraction (XRD) analysis confirmed the structure of ferrite NPs and ferrite?SiO2 NPs. Transmission electron microscopy (TEM) evidenced the successful formation of ferrite NPs and ferrite?SiO2 NPs. Scanning electron microscopy (SEM) results revealed the change in morphology of ferrite NPs, ferrite?SiO2NPs and [Fesipmim]Cl. The magnetic properties of [Fesipmim]Cl catalyst were measured by vibrating sample magnetometer (VSM). The efficiency of the [Fesipmim]Cl catalyst was checked by using it for the synthesis of different derivatives of dihydropyridine through Hantzsch reaction via a three-component coupling reaction of substituted benzaldehydes, ethyl/ methyl acetoacetate and ammonium acetate. The formation and structures of all the synthesized compounds were confirmed by FT-IR, 1HNMR, 13C NMR spectral analyses. The reusability of the catalyst [Fesipmim]Cl was checked up to seven cycles and found to have excellent activity up to five cycles. Graphic abstract: [Figure not available: see fulltext.].
Erbium-Organic Framework as Heterogeneous Lewis Acid Catalysis for Hantzsch Coupling and Tetrahydro-4H-Chromene Synthesis
Hajiashrafi, Taraneh,Karimi, Meghdad,Heydari, Akbar,Tehrani, Alireza Azhdari
, p. 453 - 462 (2017/02/18)
Abstract: An Erbium-organic framework was prepared by hydrothermal reaction. The prepared framework was characterized by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). The framework has open metal sites at Er(III) centers, thus providing an accessible Lewis acid center for electrophile activation. Accordingly, the synthesized framework was used as Lewis acid heterogeneous catalyst for Hantzsch coupling reaction and tetrahydro-4H-chromene synthesis. The reaction condition has been optimized by variation of the reaction time, temperature, solvent and catalyst concentration. A variety of tetrahydro-4H-chromenes was synthesized and characterized by FT-IR and1H NMR spectroscopy. Er-MOF, as a Lewis acid heterogeneous catalyst, showed excellent selectivity and high yield for these transformations. Graphical Abstract: [Figure not available: see fulltext.]
Method for synthesizing 1,4-dihydropyridines derivatives
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Paragraph 0130; 0131, (2017/10/27)
The invention relates to a method for synthesizing 1,4-dihydropyridines derivatives. According to the method, a fluorescence-marked nonmetal organic boron-nitrogen lewis acid-alkali dual-functional complex is used as a catalyst, so that the pollution of heavy metals is effectively avoided; the catalyst can be recycled, and a residual amount of the catalyst in a product can be rapidly detected; and the source of raw materials is wide, the target yield is close to 100 percent, the reaction process is a homogenous reaction, and a product is obtained by virtue of chromatographic separation. The whole reaction system can be directly amplified, and the industrialization prospect is significant.
A New Type of Magnetically-Recoverable Heteropolyacid Nanocatalyst Supported on Zirconia-Encapsulated Fe3O4 Nanoparticles as a Stable and Strong Solid Acid for Multicomponent Reactions
Zolfagharinia, Somayeh,Kolvari, Eskandar,Koukabi, Nadiya
, p. 1551 - 1566 (2017/05/17)
Abstract: A novel highly efficient magnetically retrievable catalyst was developed by the immobilization of H3PW12O40 (20–60 wt%) on the surface of zirconia-encapsulated Fe3O4 nanoparticles. The prepared HPW supported on nano-Fe3O4@ZrO2 heterogeneous acid catalyst (or n-Fe3O4@ZrO2/HPW) was fully characterized by several physicochemical techniques such as: Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, vibrating sample magnetometry and thermogravimetric analysis. The FT-IR spectroscopic data revealed that H3PW12O40 molecules on the nano-Fe3O4@ZrO2 support existed in the Keggin structure. The acidity of the catalyst was measured by the help of a potentiometric titration with n-butylamine. It was surprising that this very strong solid acid catalyst exhibited an excellent acid strength which was as a result of possessing a higher number of surface active sites compared to its homogeneous analogues. The catalytic activity of the as-prepared novel nano-Fe3O4@ZrO2/HPW was explored through the one-pot three-component synthesis of different 3,4-dihydropyrimidin-2(1H)-ones (i.e. Biginelli reaction) and 1,4-dihydropyridines (i.e. Hantzsh reaction) under solvent free condition. The sample of 40 wt% showed higher acidity and activity in the catalytic transformation. After the reaction, the catalyst/product isolation could be easily achieved with an external magnetic field and the catalyst could be easily recycled for at least five times without any decrease in its high catalytic activity. The excellent recyclability was attributed to the strong interaction between the hydroxyl groups of the nano-Fe3O4@ZrO2 support and the HPW species. Graphical Abstract: [Figure not available: see fulltext.].
Computational investigations on structural and electronic properties of CuI nanoparticles immobilized on modified poly(styrene-co-maleic anhydride), leading to an unexpected but efficient catalyzed synthesis of 1,4-dihydropyridine via Hantzsch pyridine synthesis
Heravi, Majid M.,Hosseinnejad, Tayebeh,Nazari, Niousha
, p. 530 - 536 (2017/05/31)
A, quantitative description for the interaction of Cu(I) with poly(styrene-co-maleic anhydride) modified with 4-aminopyridine (denoted as CuI/SMI complex) is presented using density functional theory (DFT) and quantum theory of atoms in molecules (QTAIM) approaches. Topological analysis of electron density revealed the existence of effective interactions between Cu(I) ions and the nitrogen in the pyridine ring. Interestingly, the results also showed that there is considerable interaction between Cu(I) and the oxygen of the carbonyl motif in the SMI ligand. Thus, CuI/SMI was examined as a heterogeneous and recyclable catalyst in Hantzsch pyridine synthesis under solvent-free conditions, affording diverse 1,4-dihydropyridines (1,4-DHPs) in excellent yields with relatively short reaction times.
Study of temperature dependent three component dynamic covalent assembly VIa Hantzsch reaction catalyzed by dioxido- and oxidoperoxidomolybdenum(VI) complexes under solvent free conditions
Maurya, Mannar R.,Saini, Neeraj,Avecilla, Fernando
, p. 12993 - 13009 (2016/02/12)
Tridentate ONO donor ligands derived from heterocyclic compound 4-acetyl-3-methyl-1-phenyl-2-pyrazoline-5-one (Hap) and aromatic hydrazides {benzoyl hydrazide (Hbhz), isonicotinoyl hydrazide (Hinh), nicotinoyl hydrazide (Hnah) and furoyl hydrazide (Hfah)} react with [MoVIO2(acac)2] (Hacac = acetylacetone) in equimolar ratio in methanol to give dioxidomolybdenum(vi) complexes, [MoO2(ap-bhz)(MeOH)] 1, [MoO2(ap-inh)(MeOH)] 2, [MoO2(ap-nah)(MeOH)] 3 and [MoO2(ap-fah)(MeOH)] 4. Reaction of these ligands with in situ generated oxidoperoxidomolybdenum(vi) precursor results in the formation of oxidoperoxidomolybdenum(vi) complexes, [MoO(O2)(ap-bhz)(MeOH)] 5, MoO(O2)(ap-inh)(MeOH)] 6, MoO(O2)(ap-nah)(MeOH)] 7 and MoO(O2)(ap-fah)(MeOH)] 8. These complexes have been characterized by elemental analysis, spectroscopic techniques (infrared, UV-vis, 1H and 13C NMR) and thermogravemetric analysis. The structures of complexes [MoVIO2(ap-bhz)(H2O)] 1a (water coordinated), [MoVIO2(ap-bhz)(DMSO)] 1b (DMSO coordinated), [MoVIO2(ap-nah)(DMF)] 3a (DMF coordinated), [MoVIO(O2)(ap-bhz)(MeOH)] 5 (methanol coordinated) and [MoVIO(O2)(Hap-nah)(OMe)]·MeOH 7a (methoxy coordinated) have been confirmed by single crystal X-ray studies. X-ray diffraction study also reveals that tridentate ligands bind to the metal center through enolic oxygen (of pyrazolol), azomethine nitrogen and enolic oxygen (of hydrazide) atoms. In complex 7a, pyridinic nitrogen is protonated. These complexes [dioxidomolybdenum(vi) as well as oxidoperoxidomolybdenum(vi)] have been tested as catalysts for temperature dependent one pot three component (methylacetoacetate, benzaldehyde and ammonium acetate) dynamic covalent assembly, via Hantzsch reaction, using 30% H2O2 as a green oxidant under solvent free conditions. Various parameters such as the amount of catalyst, oxidant and temperature of the reaction mixture have been taken into consideration to optimize the reaction conditions. In the Hantzsch reaction, the temperature and oxidant control the conversion and selectivity of the desired product.
A Simple and Efficient One-pot Synthesis of 1,4-dihydropyridines Using Nano-WO3-supported Sulfonic Acid as an Heterogeneous Catalyst under Solvent-free Conditions
Bitaraf, Mehrnoosh,Amoozadeh, Ali,Otokesh, Somayeh
, p. 336 - 344 (2016/05/09)
Nano-tungsten trioxide-supported sulfonic acid (n-WSA) was found to be an effective heterogeneous catalyst for the one-pot reaction of aromatic aldehydes, β-dicarbonyl compounds and ammonium acetate to afford 1,4-dihydropyridine derivatives in good to excellent yields. The other main advantages of the present method are short reaction times, simple workup, ease in purification and environmentally benign methodology. The reaction conditions were optimized employing Response Surface Method technique (Central Composite Design (CCD)) which is economically considerable because of the minimum number of experiments required to evaluate the effects of multiple parameters on the response.
Synthesis of 1,4-dihydropyridine esters using low-melting sugar mixtures as green solvents
Kumar, J. Ashwin,Shridhar, Gomathi,Ladage, Savita,Ravishankar, Lakshmy
supporting information, p. 1989 - 1998 (2016/12/09)
Several low-melting sugar mixtures (LMMs) were synthesized and used for preparation of 1,4-dihydropyridines with aldehydes, 1,3-dicarbonyl compounds, and a nitrogen source as starting materials. Good yields, low reaction times, recyclability of LMMs, and catalyst-free methodology are some of the highlights of this new protocol.
