- Selective and reversible adsorption of cationic dyes by mixed ligand Zn(II) coordination polymers synthesized by reactant ratio modulation
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Dye capture and separation through coordination polymers (CPs) has been a promising research field in recent times due to the toxic and nondegradable nature of organic dyes released into the environment from various industries as well as the reusability of CPs for the said purpose. Here, we report the synthesis and characterization of two mixed ligand CPs {[Zn2(HBTC)2(L)(H2O)2](C2H5OH)3}n (CP1) and {[Zn5(BTC)2(L)3(OH)4(H2O)2](H2O)4(CH3OH)11}n (CP2) (where H3BTC = 1,3,5-benzene tricarboxylic acid and L = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene) by the stoichiometric variation of the precursors. The crystal structure analysis revealed that CP1 is a 2D network composed of a [Zn2(HBTC)2(H2O)2]n motif linked via terminal nitrogen atoms of L and CP2 is a 3D framework in which symmetrically disposed two-dimensional {[Zn5(BTC)2(L)3(OH)4(H2O)2]}n sheets composed of pentanuclear [Zn5(RCO2)6(μ3-OH)2(μ2-OH)2(H2O)2] SBUs are pillared by L ligands. Adsorption and separation of cationic dyes by CP1 and the solid-state fluorescence properties of both CPs have been investigated. Cationic dyes (RhB, MB, and MV) can be effectively adsorbed by CP1 from their aqueous solution (61%, 90%, and 97%, respectively) while the anionic dye methyl orange (MO) remains uncaptured. Dye desorption studies and CP1 as a column chromatographic filler for the separation of cationic dyes in water have also been demonstrated.
- Rachuri, Yadagiri,Subhagan, Sreevalsa,Parmar, Bhavesh,Bisht, Kamal Kumar,Suresh, Eringathodi
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- Co-crystals of tetrakis-1,2,3,4-(4′-carboxyphenyl)cyclobutane with dipyridyl spacers: Design and serendipity
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Tetrakis-1,2,3,4-(4′-carboxyphenyl)cyclobutane (TCCB), a tetracarboxylic acid, has been employed for making co-crystals with linear dipyridyl spacers molecules like 4,4′-bipyridine (4,4′-bpy), 1,2-bis(4′-pyridyl)ethane (4,4′-bpethane), trans-1,2-bis(4′- pyridyl)ethylene (4,4′-bpe) and 1,4-bis(4′-pyridyl)-2,3-diaza-1,3- butadiene (4,4′-bpdb). In the case of 4,4′-bpy, a 2:1 co-crystal was obtained with TCCB having a three dimensional 5-fold interpenetrated dmp network. The diagonal-diagonal interpenetrated isostructural (4,4)-connected 2D networks were obtained in 1:1 co-crystals of TCCB with 4,4′-bpe and 4,4′-bpdb. The (4,4)-connected nets in the 1:1 co-crystal of TCCB with 4,4′-bpethane were found to stack parallel instead of interpenetrating. 1:1 co-crystals were always obtained in the last three cases regardless of molar ratio during co-crystallization, indicating the influence of kinetic factors. The structural diversity and similarities in this series of co-crystals in the context of composition variation and solvent interference are discussed. The serendipitous formation of (4,4)-connected networks is critically compared with designability of the system in presence of synthon competition.
- Kole, Goutam Kumar,Tan, Geok Kheng,Koh, Lip Lin,Vittal, Jagadese J.
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- A Water-Stable Twofold Interpenetrating Microporous MOF for Selective CO2 Adsorption and Separation
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Self-assembly of bent dicarboxylate linker 4,4′-sulfonyldibenzoic acid (H2SDB) and flexible N,N-donor spacer 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (L) with Co(NO3)2·6H2O forms a twofold interpenetrated {[Co2(SDB)2(L)]·(H2O)4·(DMF)}n, (IITKGP-6) network via solvothermal synthesis with SQL(2,6L1) topology, which is characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, powder X-ray diffraction (XRD), and single-crystal XRD. The framework is microporous with a solvent-accessible volume of 25.5% and forms a one-dimensional channel along [1-1 0] direction with the dimensions of -3.4 × 5.0 ?2. As the stability of metal-organic frameworks (MOFs) in the presence of water is a topic of significant importance while considering them for practical applications, this framework reveals its high stability toward water. The desolvated framework shows modest uptake of CO2 (50.6 and 37.4 cm3 g-1 at 273 and 295 K under 1 bar pressure, respectively), with high selectivity over N2 and CH4. Ideal adsorbed solution theory calculations show that the selectivity values of CO2/N2 (15:85) are 51.3 at 273 K and 42.8 at 295 K, whereas CO2/CH4 (50:50) selectivity values are 36 at 273 K and 5.1 at 295 K under 100 kPa. The high CO2 separation selectivity over N2 and CH4 along with its water stability makes this MOF a potential candidate for CO2 separation from flue gas mixture and landfill gas mixture as well.
- Pal, Arun,Chand, Santanu,Das, Madhab C.
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- Construction of one dimensional Co(II) and Zn(II) coordination polymers based on expanded N,N′-donor ligands
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Four new 1-D coordination polymers [Zn(acac)2(L1)] n (1), [Co(acac)2(L1)]n (2), [Co(acac)2(L2)]n (3) and [Co(acac)2(L3)]n (4) were afforded by the complexation reaction of appropriate zinc and cobalt metal salts, acetylacetone co-ligand as well as three linear electron rich and bi-functional N,N′-bipyridyl-base ligands of N,N′-bis(pyridin-4-ylmethylene)naphthalene-1,5-diamine (L1), N,N′-bis(pyridin-4-ylmethylene) phenylene-1,4-diamine (L2) and N,N′-bis(pyridin-4-ylmethylene)hydrazine (L3). The structures of these compounds were characterized by FT-IR spectroscopy, elemental analysis, X-ray powder and single crystal X-ray diffractions. X-ray crystallography analyses revealed that these compounds have 1-D linear chain structures a containing {N2O4} metal coordination environment in which the N-donor Lx (x = 1–3) bridges occupy trans positions. The acetylacetone (acac) ancillary ligands control the coordination number of the metal cation and adopt chelating binding mode on octahedral metal center. Furthermore, 1-D chains are held together with their neighboring ones by C–H?O, C–H?π and π-π stacking intermolecular interactions to stabilize 2-D supramolecular networks. The two former cases 1 and 2, containing same L1 spacer ligand generate isomorphous structures. Theoretical calculations invoking electronic properties, frontier molecular orbital description and the strength of interactions between metal ion and coordinated atoms via second order perturbation energies were carried out using natural bond orbital analysis (NBO). Finally, thermal stability of compound 2–4 was examined by thermogravimetric (TGA) analysis.
- Zahedi, Mansoureh,Shaabani, Behrouz,Aygün, Muhittin,Kazak, Canan
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- Spontaneous resolution to absolute chiral induction: Pseudo-kagomé type homochiral Zn(II)/Co(II) coordination polymers with achiral precursors
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It is observed that conglomerate crystallization of achiral precursors yielding racemate metal organic frameworks/coordination polymers (MOFs/CPs) can be driven to absolute homochiral crystallization of the desired enantiomorph by utilizing a suitable chiral induction agent. In a series of crystallization experiments isostructural Zn and Co homochiral CPs (1P, 1M and 2P, 2M) are prepared using the achiral precursors. In the presence of enantiopure camphoric acid, the crystallization process prefers absolute chiral induction over conglomerate formation which is established by single crystal X-ray diffraction and CD spectroscopy.
- Bisht, Kamal Kumar,Suresh, Eringathodi
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- Synthesis of Highly Stable Porous Metal-Iminodiacetic Acid Gels from A Novel IDA Compound
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In this work, a novel and simple flexible aromatic multi-carboxylate compound N,N′-(4,4′-biphenylyl) iminodiacetic acid (BP-IDA) was synthesized, with which two new stable metal-IDA gels (denoted as MIG1 and MIG2) with three-dimensional network structures have been prepared successfully by employing Cr3+and Al3+as the metal ions, respectively. The rheological performance was investigated by means of dynamic rheology measurement. The morphology and microstructure were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction technique. Nitrogen sorption isotherm measurement suggests that the MIG1 aerogel has considerable porosity with the Brunauer-Emmett-Teller specific surface area up to 760 m2·g?1. Owing to easy preparation, good stability, and three-dimensional network structure, the as-prepared metal-organic gels will possess potential applications in separation, catalysis, and drug delivery.
- Chen, Wenjing,Jiang, Yanhong,Ding, Xuesong,Yan, Chaoguo,Han, Baohang
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- A new pillared Cd-organic framework as adsorbent of organic dyes and as precursor of CdO nanoparticles
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A new neutral cadmium-organic framework with a pillared layer structure, [Cd3(BTC)2(4-bpdb)2] (H3BTC = benzene-1,3,5-tricarboxylic acid; 4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), has been synthesized via solvothermal reaction of cadmium nitrate with the tricarboxylic acid H3BTC and the linear bispyridyl linker 4-bpdb. The complex has been characterized by single crystal X-ray diffraction, showing to possess a 3D porous network of jcr7 topology. The capability of the prepared MOF in adsorbing the organic dyes Congo Red (CR) and Neutral Red (NR), together with kinetics and thermodynamics of their adsorption, have been investigated in detail. The adsorption process was well described by pseudo-first order and pseudo-second order kinetics for CR and NR, respectively. In addition, conversion of the MOF 3D architecture into nano-sized cadmium oxide particles has also been studied.
- Ghomshehzadeh, Samira Gholamali,Nobakht, Valiollah,Pourreza, Nahid,Mercandelli, Pierluigi,Carlucci, Lucia
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- A luminescent metal-organic framework with pre-designed functionalized ligands as an efficient fluorescence sensing for Fe3+ ions
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Metal-organic frameworks are a class of attractive materials for fluorescent sensing. Here, we report the exploration of fluorescent Zn-based amine/azine-functionalized MOF, TMU-17-NH2, ([Zn(NH2-BDC)(4-bpdb)].2DMF; NH2-BDC = amino-1,4-benzenedicarboxylic acid, 4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-2,3-butadiene) for highly selective and sensitive detection of Fe3+ in DMF solution. TMU-17-NH2 shows fast recognition of Fe3+ ion with a response time of?3 M DMF solution of Fe3+. Furthermore, the static quenching constant is calculated to be upper than 41,000 M?1 by the fluorescence titration experiment in low concentration of Fe3+. No interferences from 250 μM As3+, Cd2+, Zn2+, Co2+, Ni2+, Cu2+, Pb2+, Mn2+ and Al3+ were found for the detection of Fe3+. The efficient fluorescent quenching effect is attributed to the photoinduced electron transfer between Fe3+ ions and the amino-functionalized ligand in this MOF. Moreover, the introduced azine N donors in the 4-bpdb ligand of TMU-17-NH2 additionally donate their lone-pair electrons to the Fe3+ ions, leading to significantly enhanced detection ability. Furthermore, the regenerated TMU-17-NH2 still has high selectivity for Fe3+ ions, which suggests that the functionalized TMU-17-NH2 is a promising luminescent probe for selectively sensing of Fe3+ ions.
- Farahani, Yeganeh Davoudabadi,Safarifard, Vahid
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- Construction of five dicyanamide based coordination polymers with diverse dimensionality: Synthesis, characterization and photoluminescence study
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A family of dicyanamide bridged compounds namely {[Co(dca)4(2-abim)2]}n(1), {[Ni(dca)4(2-abim)2]}n(2), {[Cd(dca)4(2-abim)2]}n(3), {[Zn(N(CN)2)2(4-bpdb)]}n(4) and {[Cd(N(CN)2)2(4-bpdb)]}n(5); [where dca?=?dicyanamide, 2-abim?=?2-aminobenzimidazole and 4-bpdb?=?1,4-bis-(4-pyridyl)-2,3-diaza-1,3-butadiene] have been synthesized by stirring at room temperature. These compounds have been characterized by single crystal diffraction analysis, infrared spectroscopy (IR) and powder X-ray diffraction (PXRD). Complexes 1–3 are isostructural and exhibit two-dimensional (2D) metal-dca sheet with pendant 2-abim ligand. Compound 4 forms [Zn(N(CN)2)]nchains with a pendent dca and a bridging dca linker, which are further connected by bridging 4-bpdb ligands extending into a 2D layer structure. In case of compound 5 each Cd(II) centers connect with four bridging dca linkers to form [Cd(N(CN)2)]ndouble chains, which are further connected by bridging 4-bpdb ligands extending into a 2D layer structure. Here [Cd2(N(CN)2)] and 4-bpdb spacer are interpenetrated to each other and resemble polyrotaxane-type structures. Photoluminescent properties of compounds 3–5 were also studied and they exhibit nice ligands based photoluminescence properties at room temperature.
- Das, Anamika,Bhattacharya, Biswajit,Maity, Dilip Kumar,Halder, Arijit,Ghoshal, Debajyoti
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- Design, synthesis and biological evaluation of Schiff’s base derivatives as multifunctional agents for the treatment of Alzheimer’s disease
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A series of Schiff’s base derivatives was rationally designed, synthesized, and evaluated as multi-function agents for the treatment of Alzheimer’s disease (AD). The results revealed that compound 3b was a novel multifunctional agent. It acted as a highly selective monoamine oxidase-B inhibitor (IC50 = 8.4 nM), which was explained by the docking study. Compound 3b also was an antioxidant agent (2.3 eq) and could significantly inhibit self-induced Aβ1-42 aggregation (31.8%). Meanwhile, compound 3b was a selective metal chelator and could inhibit Cu2+-induced Aβ1-42 aggregation (62.3%). Furthermore, compound 3b presented good neuroprotective effects on H2O2-induced PC12 cell injury. More importantly, compound demonstrated good blood brain barrier permeability and druglike properties. Therefore, compound 3b, a promising multi-targeted active molecule, offers an attractive starting point for further study in the drug-discovery process against AD.[Figure not available: see fulltext.].
- Shi, Jian,Zhou, Yi,Wang, Keren,Ma, Qinge,Wei, Rongrui,Li, Qingfeng,Zhao, Yiyang,Qiao, Zhanpin,Liu, Shuang,Leng, Yumin,Liu, Wenmin,Sang, Zhipei
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p. 624 - 634
(2020/11/30)
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- Ruthenium(ii)-catalysed 1,2-selective hydroboration of aldazines
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Herein, an efficient and simple catalytic method for the selective and partial reduction of aldazines using ruthenium catalyst [Ru(p-cymene)Cl2]2 (1) has been accomplished. Under mild conditions, aldazines undergo the addition of pinacolborane in the presence of a ruthenium catalyst, which delivered N-boryl-N-benzyl hydrazone products. Notably, the reaction is highly selective, and results in exclusive mono-hydroboration and desymmetrization of symmetrical aldazines. Mechanistic studies indicate the involvement of in situ formed intermediate [{(η6-p-cymene)RuCl}2(μ-H-μ-Cl)] (1a) in this selective hydroboration.
- Gunanathan, Chidambaram,Pradhan, Subham,Thiyagarajan, Subramanian
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supporting information
p. 7147 - 7151
(2021/08/30)
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- Coordination Polymers of Zn and Cd Based on Two Isomeric Azine Ligands: Synthesis, Crystal Structures, and Luminescence Properties
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Abstract: Metal-organic 1D coordination polymers of Zn(II) and Cd(II), [{Zn(3-Bphz)(H2O)4}(3-Bphz)(NO3)2]n (I), [Zn(3-Bphz)I2]n (II), [Cd(3-Bphz)I2]n (III), [Cd(4-Bphz)(CH3COO)2(H2O)]n (IV), and [Cd(4-Bphz)(NO3)2(H2O)2]n (V), containing azines of the N,N' type, 1,2-bis(pyridin-3-ylmethylene)hydrazine (3-Bphz) and 1,2-bis(pyridin-4-ylmethylene)hydrazine (4-Bphz), as bridging ligands are synthesized. The compositions and structures of the compounds are confirmed by the data of elemental analysis, IR and NMR spectroscopy, and single-crystal X-ray diffraction analysis (CIF files CCDC nos.?1812634–1812638 for I–V). Coordination polymers I–III have zigzag structures. The octahedral environment of the Zn2+ ion in compound I is formed by two 3-Bphz ligands and four water molecules. The external sphere contains nitrate anions and uncoordinated 3-Bphz molecules. In isomorphous compounds II and III, the tetrahedral environment of the metal is formed by two nitrogen atoms of two bridging 3-Bphz ligands and two iodine atoms. Coordination polymers IV and V are linear. The coordination polyhedron of the Cd2+ ion in?compound IV is a pentagonal bipyramid, two vertices of which are occupied by the nitrogen atoms of two 4-Bphz molecules, and the equatorial plane is formed by two bidentate-chelating acetate anions and one water molecule. In compound V, the octahedral environment of the Сd2+ ion is formed by two molecules of the 4-Bphz ligand, two monodentate nitrate anions, and two water molecules. All complexes are weak luminophores emitting in the blue-green spectral range.
- Lozovan,Coropceanu,Bourosh,Micu,Fonari
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- Engineering a Cu-MOF Nano-Catalyst by using Post-Synthetic Modification for the Preparation of 5-Substituted 1H-Tetrazoles
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A new nano scale Cu-MOF has been obtained via post-synthetic metalation by immersing a Zn-MOF as a template in DMF solutions of copper(II) salts. The Cu-MOF serves as recyclable nano-catalyst for the preparation of 5-substituted 1H-tetrazoles via [3?+?2] cycloaddition reaction of various nitriles and sodium azide in a green medium (PEG). The post-synthetic metalated MOF were characterized by FT-IR spectroscopy, powder X-ray diffraction (PXRD), atomic absorption spectroscopy (AAS), and energy dispersive X-ray spectroscopy (EDX) techniques. The morphology and size of the nano-catalyst were determined by field emission scanning electron microscopy (FE-SEM).
- Salahshournia, Behrang,Hamadi, Hosein,Nobakht, Valiollah
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- N, N' - double-pyridine - 4 - formaldehyde shrinks the company nitrogen preparation method and application thereof
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The invention discloses a preparation method and an application of N, N'-bispyridine-4-formaldehydeazine and belongs to the field of prevention and treatment of plant diseases. By N, N'-bispyridine-4-formaldehydeazine and a mycelial growth rate method, the inhibitory effects of N, N'-bispyridine-4-formaldehydeazine on cucumber damping-off pathogenic bacteria and pyricularia grisea are studied. The concentrations of chemical agent are set at five gradients, namely, 0, 2 mu g/ml, 4 mu g/ml, 6 mu g/ml, and 8mu g/ml for experiments, the inhibitory effects of bacterial colonies are measured by the growth rate method and the median lethal concentrations EC50 and the inhibition rates are obtained by processing the data of diameters of the bacterial colonies. Compared with angles of EC50 values, the reagent N, N'-bis-4-pyridineformaldehydeazine sequentially has greater bactericidal virulence on pyricularia grisea than cucumber damping-off pathogenic bacteria. Experimental results show that N, N'-bis-4-pyridineformaldehydeazine has an inhibitory effect on the pyricularia grisea and cucumber damping-off pathogenic bacteria, especially has a good inhibitory effect on the pyricularia grisea.
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Paragraph 0027-0035
(2017/07/14)
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- Structural diversity in six mixed ligand Zn(II) metal-organic frameworks constructed by rigid and flexible dicarboxylates and different N, N′ donor ligands
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Three different N, N′-donor ligands with Zn(NO3)2·6H2O and two different dicarboxylates, flexible succinate (suc) and rigid fumarate (fum) afforded six different metal-organic frameworks (MOFs). Among the N, N′-donor ligands, one bent 1, 4-bis(3-pyridyl)-2, 3-diaza-1, 3-butadiene (3-bpdb) gives two isostructural two-dimensional MOFs, {[Zn(3-bpdb)(suc)]·(H2O)2}n (1) and {[Zn(3- bpdb)(fum)(H2O)2]}n (2). The use of a straight N, N′-donor ligand, i.e., 1, 4-bis(4- pyridyl)-2, 3-diaza-1, 3-butadiene (4-bpdb), results in two three-dimensional (3D) MOFs, {[Zn4(4-bpdb)2(suc)3(OH)2]·5(H2O)}n (3) and {[Zn(4-bpdb)(fum)]·(H2O)2}n (4). Here, 3 is a pillared layer structure, whereas 4 has a 5-fold interpenetrated dimondoid network. For both the bent and straight N, N′-donor ligands an imine alike motif is embedded in the structure. When this motif is replaced by a C-C double bond by using the ligand 1, 2-bis(4-pyridyl)ethylene (bpee), it produces two MOFs, {[Zn(bpee)(suc)]2·(H2O)3}n (5) and {[Zn2(bpee)2(fum)2]·(H2O)}n (6), having a similar structural relation like 3 and 4 respectively, 5 with a pillared layer structure and 6 with a 5-fold interpenetrated diamondoid network. All the compounds have been thoroughly characterized by powder X-ray diffraction (PXRD), elemental analysis, infrared (IR) spectroscopy, UV-vis spectroscopy, and thermogravimetric analyses. Gas/solvent vapor sorption studies have been carried out for compounds 3-6, which have 3D structures. In the case of 3, an interesting reversible crystalline to crystalline transformation was observed which has been thoroughly studied by PXRD analysis, IR spectroscopy, and UV-vis spectroscopy. Solid state emission spectral analysis for all the complexes was performed at room temperature.
- Halder, Arijit,Bhattacharya, Biswajit,Haque, Fazle,Ghoshal, Debajyoti
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p. 6613 - 6624
(2018/05/31)
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- Efficient adsorption of Europhtal onto activated carbon modified with ligands (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine (M) and (1E,2E)-1,2-bis(pyridin-3-ylmethylene)hydrazine (SCH-4); Response surface methodology
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Porous activated carbon was modified with (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine (M) and (1E,2E)-1,2-bis(pyridin-3-ylmethylene)hydrazine (SCH-4). Characterization was performed using different techniques such as SEM, FTIR and 1H NMR analysis. Then, these new adsorbents were used for the efficient removal of Europhtal (sulfonated cobalt phthalocyanine). Response surface methodology (RSM) was used to achieve operational conditions for the efficient removal of Europhtal using an activated carbon modified with novel ligands. To investigate the individual effect of variables involved and the effect of their possible interactions on the adsorption process, several systematic experiments were designed by varying the variables such as pH, sonication time, adsorbent dosage and dye concentration in the range of 2.0-11, 2-8 min, 0.005-0.035 g and 4-30 mg L-1, respectively. The optimum values of pH, sonication time, adsorbent dosage and Europhtal concentration were found to be 7, 2 min, 30 mg L-1 and 0.03 g for the sample modified with M and 7, 5 min, 30 mg L-1 and 0.03 g for the one modified with SCH-4, at which the removal percentages were more than 98%. Adsorption equilibrium data were well fitted to the Freundlich model with maximum adsorption capacities of 56.69 and 17.84 mg g-1 for M and SCH-4, respectively. The study of adsorption kinetics indicated that the dye uptake process follows the pseudo second-order and saturation type rate expressions for each ligand.
- Ghaedi,Alam Barakat,Asfaram,Mirtamizdoust,Bazrafshan,Hajati
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p. 42376 - 42387
(2015/05/20)
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- An interpenetrating amine-functionalized metal-organic framework as an efficient and reusable catalyst for the selective synthesis of tetrahydro-chromenes
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The amine group of the 2-amino-1,4-benzenedicarboxylic acid (NH2-BDC) ligand in a novel two-fold interpenetrated metal-organic framework, [Zn(NH2-BDC)(4-bpdb)]·2DMF (TMU-17-NH2) has been found to be a base catalyst active site. TMU-17-NH2 consists of both NH2-BDC and the N,N′-bipyridine-type rigid linkers (4-bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-2,3-butadiene) with ZnN2O4 secondary building units (SBUs). The MOF was characterized by FT-IR spectroscopy, elemental analysis, powder X-ray diffraction, thermal gravimetric analysis and single-crystal X-ray diffraction. The amine-functionalized framework was used as an efficient heterogeneous base catalyst for the synthesis of tetrahydro-chromenes. Excellent conversions were obtained under mild conditions in the presence of 6 mol% catalyst. The TMU-17-NH2 catalyst could be reused several times without significant degradation in catalytic activity. This journal is
- Safarifard, Vahid,Beheshti, Saeideh,Morsali, Ali
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p. 1680 - 1685
(2015/02/19)
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- Two-dimensional iron(ii) networks - Guest-dependent structures and spin-crossover behaviors
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Four compounds with general formula [Fe(4-bphz)2(NCS) 2]·X [4-bphz = 1,2-bis(pyridin-4-ylmethylene)hydrazine; X = 2H2O·2CH3CN (1·CH3CN), 4CH 3COCH3 (2·CH3COCH3), 2.5C10H8 (3·C10H8), 2C 6H5NO2 (4·C6H 5NO2)] were synthesized and characterized. These compounds contain 2D gridlike networks that are diversely stacked or self-interpenetrated depending on the inclusive guest molecules. Magnetic studies showed that 1·CH3CN undergoes a two-step and almost complete spin transition and 2·CH3COCH3 showed an incomplete transition, whereas 3·C10H8 and 4·C 6H5NO2 are paramagnetic in the whole temperature range. Correlations between structures and magnetic properties revealed that the size and shape of the guest molecules exerted great influence on the conformation of the ligand and the 3D structures of the complexes and, hence, spin-crossover behaviors. Complexes with the general formula [Fe(4-bphz)2(NCS)2]·X [4-bphz = 1,2-bis(pyridin-4-ylmethylene)hydrazine, X = guest molecules] are composed of isomeric 2D gridlike networks, but show different solvation polymorphs. Whether the complex undergoes spin crossover or is just paramagnetic depends on both the inclusive guest molecules and the conformation of the ligands.
- Yang, Feng-Lei,Chen, Ming-Guang,Li, Xiu-Ling,Tao, Jun,Huang, Rong-Bin,Zheng, Lan-Sun
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p. 4234 - 4242
(2013/09/12)
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- Chromophore containing bipyridyl ligands. Part 1: Supramolecular solid-state structure of Ag(I) complexes
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The solid-state structures of a series of azine or azo chromophore containing bipyridyl ligand complexes of Ag(i) salts have been determined by single-crystal X-ray diffraction. The supramolecular structures are dominated by one-dimensional chains formed through pyridyl-Ag-pyridyl bonding, but the packing of these chains through non-covalent intermolecular interactions is unpredictable. Ag...anion interactions are shown to be important, especially for nitrate and perchlorate species, but these may be supported or replaced by Ag...Ag, Ag...solvent, Ag...azine or Ag...π contacts. The molecular structures of the ligands show little alteration on complex formation, except for the AgNO3 complex of N,N′-bis-pyridin-4-ylmethylenehydrazine where the normally planar azine ligand adopts a twisted geometry. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Kennedy, Alan R.,Brown, Karen G.,Graham, Duncan,Kirkhouse, Jennifer B.,Kittner, Madeleine,Major, Claire,McHugh, Callum J.,Murdoch, Paul,Smith, W. Ewen
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p. 826 - 832
(2007/10/03)
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- The first controlled reduction of the high explosive RDX
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The first reduction chemistry of the high explosive RDX that allows subsequent functionalization into a SERRS active species.
- McHugh, Callum J.,Smith, W. Ewen,Lacey, Richard,Graham, Duncan
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p. 2514 - 2515
(2007/10/03)
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- Difunctional heterocycles: a convenient synthesis of bis(pyridinyl-2,3-dihydrooxadiazolyl)benzenes
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Bis(pyridynyl-2,3-dihydrooxadiazolyl)benzenes 51-e and 9a, b are obtained in 25-85 percent yields by heating the corresponding bis(hydrazones) 4a-f and 8a, d in refluxing Ac2O-AcOH for 3-5 h, while the bishydrazones 19 and 17b give 33-54 percent yields of the phthalazine derivatives 20a, b upon heating in refluxing ethanol containing acetic acid.
- Elwahy, Ahmed H. M.,Ahmed, Mohamed M.,El-sadek, Mohamed
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p. 552 - 561
(2007/10/03)
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- THERMOLYSIS OF SODIUM SALTS OF TOSYLHYDRAZONES OF SOME HETEROCYCLIC ALDEHYDES IN THE PRESENCE OF SILVER CHROMATE: 1,3 NC MIGRATION OF TOSYL GROUP
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The thermal decompositions of sodium salts of tosylhydrazones of furfural, thiophene-2-aldehyde, 1-methylpyrrole-2-aldehyde, and pyridine-2-aldehyde in the presence of silver chromate gave 2-furyl(p-toluenesulfonyl)methane, thiophene-2-(p-toluenesulfonyl)methane, 1-methylpyrrole-2-(p-toluenesulfonyl)methane, and pyridine-2-(p-toluenesulfonyl)methane, respectively, via 1,3 NC migration of tosyl group.The same type of reactions with sodium salts of tosylhydrazones of thiophene-3-aldehyde, pyridine-3-aldehyde, and pyridine-4-aldehyde also afforded the corresponding p-toluenesulfonylmethanes but the yields were slightly lower comparing to the above cases.
- Saito, Katsuhiro,Ishihara, Hiraku
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p. 1891 - 1898
(2007/10/02)
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- Synthesis and X-ray Photoelectron Spectra of Some Azines
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Arylhydrazone-N-carboxylic esters (I) were treated with hydrazine hydrate, or sodium hydroxide, to give the hydrazones (II).Acidification of the latter produced the corresponding azines (III).The structures of compounds I - III were substantiated by chemical and spectral analysis.
- El-Rayyes, Nizar R.,Katrib, Ali H.
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p. 132 - 134
(2007/10/02)
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