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Basem Moosa Lukman O. Alimi Weibin Lin Aliyah Fakim Prashant M. Bhatt Mohamed Eddaoudi Niveen M. Khashab 《Angewandte Chemie (International ed. in English)》2023,62(46):e202311555
Porous molecular sorbents have excellent selectivity towards hydrocarbon separation with energy saving techniques. However, to realize commercialization, molecular sieving processes should be faster and more efficient compared to extended frameworks. In this work, we show that utilizing fluorine to improve the hydrophobic profile of leaning pillararenes affords a substantial kinetic selective adsorption of benzene over cyclohexane (20 : 1 for benzene). The crystal structure shows a porous macrocycle that acts as a perfect match for benzene in both the intrinsic and extrinsic cavities with strong interactions in the solid state. The fluorinated leaning pillararene surpasses all reported organic molecular sieves and is comparable to the extended metal–organic frameworks that were previously employed for this separation such as UIO-66. Most importantly, this sieving system outperformed the well-known zeolitic imidazolate frameworks under low pressure, which opens the door to new generations of molecular sieves that can compete with extended frameworks for more sustainable hydrocarbon separation. 相似文献
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Rawhi H. Al‐Far Salim F. Haddad Basem Fares Ali 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(8):m321-m324
In the structural motifs of two isomorphous triclinic salts, (C5H6Br2N3)2[MBr4] (M = CdII and MnII), each [MBr4]2− anion interacts with eight surrounding 2,6‐diamino‐3,5‐dibromopyridinium cations through intermolecular C/N—H...Br and Br...Br interactions, leading to a three‐dimensional framework structure. The cations show a minor degree of π–π stacking, adding extra stability to the three‐dimensional architecture. 相似文献
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Rawhi H. Al‐Far Salim F. Haddad Basem Fares Ali 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(11):m451-m454
The structures of three isomorphous compounds, namely bis(2,6‐dibromopyridinium) tetrabromidocuprate(II) dihydrate, (C5H4Br2N)2[CuBr4]·2H2O, bis(2,6‐dibromopyridinium) tetrabromidocadmate(II) dihydrate, (C5H4Br2N)2[CdBr4]·2H2O, and bis(2,6‐dibromopyridinium) tetrabromidomercurate(II) dihydrate, (C5H4Br2N)2[HgBr4]·2H2O, show a crystal supramolecularity represented by M—Br...H—O—H...Br—M intermolecular interactions along with (π)N—H...OH2 hydrogen‐bonding interactions forming layers connected via aryl–aryl face‐to‐face stacking of cations, leading to a three‐dimensional network. The anions have significantly distorted tetrahedral geometry and crystallographic C2 symmetry. The stability of this crystal lattice is evidenced by the crystallization of a whole series of isomorphous compounds. 相似文献
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Basem Abdulla Al Alwan Mumtaj Shah Mohd Danish Mohammed K. Al Mesfer Mohammed Ilyas Khan Varagunapandiyan Natarajan 《印度化学会志》2022,99(4):100393
In this study, COx-free hydrogen production via methane decomposition was studied over Cu–Zn-promoted tri-metallic Ni–Co–Al catalysts. The catalysts have been prepared by the constant pH co-precipitation method, and the nominal Ni metal loading was fixed at 50 wt % along with other metals at 10 wt% each. The catalyst activity for methane decomposition reaction was examined in a reactor between 400 °C and 700 °C and at atmospheric pressure. Different techniques such as N2-physisorption, X-ray diffraction, H2-TPR SEM, TEM, ICP-MS, TGA, and Raman spectroscopy were applied to characterize the catalysts. The relation between the catalyst composition and their catalytic activity has been investigated. The controlled synthesis has resulted in a series of catalysts with a high surface area. Ni–Co–Cu–Zn–Al was the most active and productive catalyst. Various characterizations indicate that the promotional effects of Cu–Zn interaction were the critical factor in catalysts' activity and stability. Ni–Co–Cu–Zn catalyst gave the highest methane conversion of 85% at 700 °C. Zn addition improves the stability of the catalyst by retaining the active metal size during the decomposition reaction. The catalyst was active for 80 h of stability study. The rapid deactivation of the Ni–Co catalyst was due to the sintering of the catalyst at 650 °C. Moreover, carbon species accumulated during the methane decomposition reaction depend on the catalysts' composition. Zn promotes the growth of reasonably long and thin carbon nanotubes, whereas the diameter of carbon nanotubes on unpromoted catalysts was large. 相似文献
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Amina Chnirheb Mourad Harir Basem Kanawati Agnes Fekete Mohammed El Azzouzi Norbert Hertkorn Philippe Schmitt-Kopplin 《Analytical and bioanalytical chemistry》2010,398(5):2325-2334
The hydrolysis of the herbicide safener mefenpyrdiethyl (1-(2, 4-dichlorophenyl)-4, 5-dihydro-5-methyl-1H-pyrazole-3,5-dicarboxylic acid diethyl ester) was investigated in aqueous solutions in the pH range from 2 to 9 and the temperature
range from 298 to 323 K. The kinetics of hydrolysis were pseudo first order and were found to be strongly pH and temperature
dependent. While near-constant in acidic medium, the hydrolysis rates strongly increased in alkaline pH, and total hydrolysis
was observed at pH 11. Two main hydrolysis products, mefenpyrethyl (monoester) and mefenpyr (dicarboxylic acid) were isolated
by ultrahigh-pressure liquid chromatography (UHPLC) and characterized using high-resolution Fourier transform ion cyclotron
resonance mass spectroscopy (ICR-FT/MS) as well as 1H, 13C and 2D NMR analyses. Additionally, a density functional theory (DFT) investigation explained the stability of the pesticide
at pH 7 and the high reactivity of the pesticide in alkaline medium. The key nucleophilic reaction partner is hydroxyl ions
instead of neutral water molecules. Furthermore, the calculated activation barrier for hydrolysis in alkaline medium is in
agreement with the extrapolated and experimentally determined activation barrier at pH 14. 相似文献
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Yanjun Ding Lukman O. Alimi Basem Moosa Carine Maaliki Johan Jacquemin Feihe Huang Niveen M. Khashab 《Chemical science》2021,12(14):5315
The selective separation of benzene (Bz) and cyclohexane (Cy) is one of the most challenging chemical separations in the petrochemical and oil industries. In this work, we report an environmentally friendly and energy saving approach to separate Cy over Bz using thienothiophene cages (ThT-cages) with adaptive porosity. Interestingly, cyclohexane was readily captured selectively from an equimolar benzene/cyclohexane mixture with a purity of 94%. This high selectivity arises from the C–H⋯S, C–H⋯π and C–H⋯N interactions between Cy and the thienothiophene ligand. Reversible transformation between the nonporous guest-free structure and the host–guest assembly, endows this system with excellent recyclability with minimal energy requirements.Selective adsorptive separation of cyclohexane was realized from an equimolar benzene and cyclohexane mixture via crystalline thienothiophene cages with a selectivity of 94%. 相似文献
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Rawhi Al-Far Basem F. Ali Mukarram H. Zaghal Razan M. Mhaidat Zaher Judeh Khaldoun Al-Sou'od 《Journal of chemical crystallography》2006,36(1):41-46
The title compound, cis-[Rh(biq)2Cl2]Cl·3H2O (biq = 2,2′-biquinoline) crystallized in the monoclinic space group P2
1
/n with a = 11.231(2) Å, b = 20.895(4) Å, c = 14.081(3) Å, β = 94.76(3)°, V = 3293.0(11) Å3, D
c = 1.565 g cm−3, μ = 0.806 mm−1, F(000) = 1576 and Z = 4. It contains a monomeric [Rh(biq)2Cl2]+ cation, a chloride ion and three molecules of H2O. The rhodium(III) ion is hexa coordinated forming a distorted octahedral arrangement. The mean Rh(III)–N distance for the four Rh(III)–N bonds is 2.0625 Å. The two chloride atoms are bonded in a cis configuration [Rh(III)–Cl bond distances are 2.329(3) and 2.341(4) Å]. The structure shows a curling stacks of cationic complexes interacting via offset-face-to-face (OFF) π–π aryl interaction motif. Water molecules and chloride ions are hydrogen bonded (H2O···H–OH and Cl···H–OH) and links the curling stacks by hydrogen bonding via Rh–Cl···H–OH interactions. 相似文献
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