- Synthesis, Characterization, Surface, and Thermodynamic Studies of Alkyl Tetrachloroferrates: Performance Evaluation of Their Nanostructures as Biocides
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Decyl and dodecylamino tetrachloroferrates were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), elemental analysis, X-ray diffraction (XRD), nuclear magnetic resonance (1H-NMR), and atomic absorption spectroscopy (AAS). The surface properties of the cationic surfactants including critical micelle concentration, effectiveness, minimum surface area, and maximum surface excess were determined using surface tension measurements. The effectiveness of surface tension reduction (πcmc) was found to increase as the hydrophobic chain length increases with values of 30 and 34 mN m?1 for C10 and C12, respectively. Moreover, the effect of temperature on micellization was determined over the range of 35–55?°C. Thermodynamic parameters (ΔG°, ΔS°, and ΔH°) were calculated and the results indicate a spontaneous process for both micellization and adsorption. The nanoparticles (NC10 and NC12) of the prepared surfactants were obtained using the ball mill technique. The particle size and morphology of the nanoparticles were determined using transmission electron microscope measurements. The antibacterial study of the nanoparticle surfactants revealed their strong efficiency against fungi and different pathogenic bacteria compared with the original surfactants.
- El-Shamy, Omnia A. A.,Habib, Amr O.,Mohamed, Dalia E.,Badawi, Abdelfattah M.
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- A Vibrational and Structural Study of the Solid-Solid Phase Transitions in C10H21NH3Cl
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The joint vibrational and structural study of n-decylammonium chloride results in a fair description of the solid phases and their interconversions during the thermotropic phase transitions.Phase i (stable below 312 K) crystallizes as a well-ordered, interdigitated layer structure, whereas phases α (stable above 318 K), β (stable between 318 and 316 K), δ (stable between 316 and 302 K), and ε (metastable below 302 K) represent intermediate states between a very disordered smectic B and a quite densely packed smectic H.The i -> δ transition consists in a reconstructive separation of the n-decylammonium chains, whereas the other transitions entail a successive disordering of the organic layers and the polar lattice.Disorder in the aliphatic chains takes the form of chain defects (G forms, GTG sequences, and kinks).Disorder in the polar lattice consists of jumps of the ammonium groups between several equivalent potential wells inside an appropriately distorted tetragonal chlorine pyramid.Only short-range order exists in phase α, whereas there are some intralayer correlations in phases β, δ, and ε (phase ε reaches an almost completely ordered state at about 80 K).Comparable populations of G forms, GTG sequences and kinks are observed in phases δ, β, and α; different chain tiltings and packings are realized, however.This difference is also reflected in different molecular motions in phases δ, β, and α.
- Schenk, K. J.,Ogle, C. A.,Chapuis, G.,Cavagnat, R.,Jokic, A.,Rey-Lafon, M.
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- Synthesis of Molybdenum Pincer Complexes and Their Application in the Catalytic Hydrogenation of Nitriles
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A series of molybdenum(0), (I) and (II) complexes ligated by different PNP and NNN pincer ligands were synthesized and structurally characterized. Along with previously described Mo?PNP complexes Mo-1 and Mo-2, all prepared compounds were tested in the catalytic hydrogenation of aromatic nitriles to primary amines. Among the applied catalysts, Mo-1 is particularly well suited for the hydrogenation of electron-rich benzonitriles. Additionally, two aliphatic nitriles were transformed into the desired products in 80 and 86 percent, respectively. Moreover, catalytic intermediate Mo-1a was isolated and its role in the catalytic cycle was subsequently demonstrated.
- Leischner, Thomas,Spannenberg, Anke,Junge, Kathrin,Beller, Matthias
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p. 4543 - 4549
(2020/07/13)
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- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
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Hydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO2-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions. Lifetime experiments showed that this catalyst remained active for more than 300 h (TON≥10 000) without loss of selectivity and no metal leaching from the catalyst occurred. By using this continuous-flow hydrogenation, synthesis of venlafaxine, an antidepressant drug, has been accomplished.
- Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
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p. 211 - 215
(2017/04/21)
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- Designing Simple Lipidated Lysines: Bifurcation Imparts Selective Antibacterial Activity
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In the global effort to thwart antimicrobial resistance, lipopeptides are an important class of antimicrobial agents, especially against Gram-negative infections. In an attempt to circumvent their synthetic complexities, we designed simple membrane-active agents involving only one amino acid and two lipid tails. Herein we show that the use of two short lipid tails instead of a single long one significantly increases selective antibacterial activity. This study yielded several selective antibacterial compounds, and investigations into the properties of this compound class were conducted with the most active compound. Fluorescence spectroscopic studies revealed the capacity of the representative compound to cause depolarization and permeabilization of bacterial cell membranes. This membrane-active nature of the compound imparts superior activity against persister cells, biofilms, and planktonic cells. Topical application of the compound decreased bacterial burden in mice inflicted with burn-infections caused by Acinetobacter baumannii. We anticipate that the design principles described herein will direct the development of several antimicrobial agents of clinical importance.
- Ghosh, Chandradhish,Konai, Mohini Mohan,Sarkar, Paramita,Samaddar, Sandip,Haldar, Jayanta
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supporting information
p. 2367 - 2371
(2016/11/13)
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- Selective Catalytic Hydrogenations of Nitriles, Ketones, and Aldehydes by Well-Defined Manganese Pincer Complexes
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Hydrogenations constitute fundamental processes in organic chemistry and allow for atom-efficient and clean functional group transformations. In fact, the selective reduction of nitriles, ketones, and aldehydes with molecular hydrogen permits access to a green synthesis of valuable amines and alcohols. Despite more than a century of developments in homogeneous and heterogeneous catalysis, efforts toward the creation of new useful and broadly applicable catalyst systems are ongoing. Recently, Earth-abundant metals have attracted significant interest in this area. In the present study, we describe for the first time specific molecular-defined manganese complexes that allow for the hydrogenation of various polar functional groups. Under optimal conditions, we achieve good functional group tolerance, and industrially important substrates, e.g., for the flavor and fragrance industry, are selectively reduced.
- Elangovan, Saravanakumar,Topf, Christoph,Fischer, Steffen,Jiao, Haijun,Spannenberg, Anke,Baumann, Wolfgang,Ludwig, Ralf,Junge, Kathrin,Beller, Matthias
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supporting information
p. 8809 - 8814
(2016/07/29)
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