- Comparison between the Acidification of Acidic and Alkalic Groups
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The protonation of different functional acidic and alkalic groups is of utmost importance for the crystal engineering field. By using hydrochloric acid, in this work, the amine group of 3-aminobenzoic acid (1, C7H7NO2) and the hydroxy group of (E)-4-hydroxy-3,5-dimethoxybenzaldehyde oxime (2, C9H11NO4) have been protonated, giving birth to the organic salts [C7H8NO2]+·[Cl]- ([1H]+·[Cl]-) and [C9H12NO4]+·[Cl]- ([2H]+·[Cl]-). Results revealed that both salts display similar 1D "stair-like" ribbon models via the formation of intermolecular hydrogen bonding contacts between chloride ion and the protonated groups into four-membered squares. Note that the protonated acidic groups have shown much closer and stronger intermolecular interactions than the alkalic groups. In addition, 3D Hirshfeld surfaces, 2D fingerprint plots, and crystal void calculations have been performed, which have suggested 21.4% and 17.5% interactions around the protonated acidic and alkalic groups, respectively. This work will provide a new insight into the rational design and control of molecular crystal with protonated functional groups.
- He, Xiao-Tong,Hong, Dan-Li,Chen, Chen,Chen, Fang-Hui,Zhai, Li-Hai,Guo, Li-Hong,Luo, Yang-Hui,Sun, Bai-Wang
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- Selective and Additive-Free Hydrogenation of Nitroarenes Mediated by a DMSO-Tagged Molecular Cobalt Corrole Catalyst
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We report on the first cobalt corrole that effectively mediates the homogeneous hydrogenation of structurally diverse nitroarenes to afford the corresponding amines. The given catalyst is easily assembled prior to use from 4-tert-butylbenzaldehyde and pyrrole followed by metalation of the resulting corrole macrocycle with cobalt(II) acetate. The thus-prepared complex is self-contained in that the hydrogenation protocol is free from the requirement for adding any auxiliary reagent to elicit the catalytic activity of the applied metal complex. Moreover, a containment system is not required for the assembly of the hydrogenation reaction set-up as both the autoclave and the reaction vessels are readily charged under a regular laboratory atmosphere.
- Sch?fberger, Wolfgang,Timelthaler, Daniel,Topf, Christoph
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supporting information
p. 2114 - 2120
(2021/07/22)
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- The ortho effect on the acidic and alkaline hydrolysis of substituted formanilides
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The kinetics of formanilides hydrolysis were determined under first-order conditions in hydrochloric acid (0.01-8 M, 20-60°C) and in hydroxide solutions (0.01-3 M, 25 and 40°C). Under acidic conditions, second-order specific acid catalytic constants were used to construct Hammett plots. The ortho effect was analyzed using the Fujita-Nishioka method. In alkaline solutions, hydrolysis displayed both first- and second-order dependence in the hydroxide concentration. The specific base catalytic constants were used to construct Hammett plots. Ortho effects were evaluated for the first-order dependence on the hydroxide concentration. Formanilide hydrolyzes in acidic solutions by specific acid catalysis, and the kinetic study results were consistent with the AAC2 mechanism. Ortho substitution led to a decrease in the rates of reaction due to steric inhibition of resonance, retardation due to steric bulk, and through space interactions. The primary hydrolytic pathway in alkaline solutions was consistent with a modified BAC2 mechanism. The Hammett plots for hydrolysis of meta- and para-substituted formanilides in 0.10 M sodium hydroxide solutions did not show substituent effects; however, ortho substitution led to a decrease in rate constants proportional to the steric bulk of the substituent.
- Desai, Salil Dileep,Kirsch, Lee E.
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p. 471 - 488
(2015/06/30)
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- Organoimido-derivatized hexamolybdates with a remote carboxyl group: Syntheses and structural characterizations
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Four novel organoimido derivatives of hexamolybdate containing a remote carboxyl group have been synthesized: [Bu4N]2[Mo 6O18(N-C6H4-3-COOH)] (1), [Bu 4N]2[Mo6O18(N-C6H 4-2-CH3-4-COOH)] (2), [Bu4N] 2[Mo6O18(N-C6H4-2-CH 3-5-COOH)] (3), and [Bu4N]2[Mo 6O18(N-C6H4-2-CH3-3-COOH) ] (4) with 3-aminobenzoic acid, 4-amino-3-methylbenzoic acid, 3-amino-4-methylbenzoic acid, and 3-amino-2-methylbenzoic acid as the imido-releasing agents, respectively. Their structures have been characterized by IR, UV-vis, 1H NMR, ESI-MS, and single-crystal X-ray diffraction techniques. Hydrogen bonding interactions play an important role in the supramolecular assemblies of these compounds in the solid state. Although the incorporated organic ligands are similar to each other, their supramolecular assembly behaviors are quite different. For compound 1, the dimer structure is formed via hydrogen bonding between the carboxyl group and the POM cluster of two neighboring cluster anions. For compound 2, the 1D chain structure is formed via hydrogen bonding between the carboxyl groups and the POM clusters of the cluster anions. For compound 3, the 2D plane structure is formed via two types of hydrogen bonding between the aromatic rings and the POM clusters of the cluster anions. For compound 4, the 1D plus 2D structures are formed via three types of hydrogen bonding between the aromatic rings and the POM clusters of the two types of cluster anions with different orientations.
- Sima, Guohui,Li, Qiang,Zhu, Yi,Lv, Chunlin,Khan, Rao Naumaan Nasim,Hao, Jian,Zhang, Jin,Wei, Yongge
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p. 6551 - 6558
(2013/07/11)
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