- Synthesis, surface adsorption, micellization behavior and antibacterial activity of novel gemini surfactants with morpholinium headgroup and benzene-based spacer
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Two series of novel gemini surfactants with morpholinium headgroup and benzene-based rigid spacers (abbreviated as (Mor)m-P-m and (Mor)m-BP-m, where m represents the carbon numbers of hydrophobic chains) were synthesized and characterized by 1H NMR, ESI-MS, and FT-IR spectra. The effect of lengths of rigid spacer and hydrocarbon chain on their solution properties and antibacterial activities were systematically investigated. Due to the existence of morpholinium, they have a superior surface activity to the classic gemini surfactants. (Mor)m-BP-m possess lower CMC and γcmc than (Mor)m-P-m, which is assumed to be related to the conformation change of spacer. The possible arrangement models for the adsorptions of (Mor)m-P-m and (Mor)m-BP-m at the air-water interface were proposed by comparing their surface parameters with those of other similar surfactants. The pre-micellar associations occur in aqueous solutions of (Mor)16-P-16, (Mor)14-BP-14 and (Mor)16-BP-16. The thermodynamic parameters indicate the micellar processes are spontaneous, and (Mor)m-BP-m have stronger aggregation tendency than (Mor)m-P-m. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) show they spontaneously self-assemble into vesicle, and the aggregate size of (Mor)m-BP-m is larger than (Mor)m-P-m. These surfactants showed excellent antibacterial properties against Bacillus subtilis and Escherichia coli. Compared with (Mor)m-P-m, (Mor)m-BP-m exhibit a higher activity.
- Zheng, Le-Chi,Tong, Qing-Xiao
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- Making Copper(0) Nanoparticles in Glycerol: A Straightforward Synthesis for a Multipurpose Catalyst
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Small zero-valent copper nanoparticles (CuNPs) have been straightforwardly prepared from Cu(I) and Cu(II) precursors in glycerol and in the presence of polyvinylpyrrolidone as stabilizer. Thanks to the negligible vapor pressure of the solvent, these original nano-systems could be directly characterized in glycerol as well as in the solid state, exhibiting relevantly homogeneous colloidal dispersions, also even after catalysis. CuNPs coming from the well-defined coordination complex di-μ-hydroxobis[(N,N,N′,N′-tetramethylethylenediamine)copper(II)] chloride {[Cu(κ2-N,N-TMEDA)(μ-OH)]2Cl2} have been highly efficient in C–C and C–heteroatom bond formation processes. This new catalytic system has proved its performance in C–N couplings and in the synthesis of differently substituted propargylic amines through cross-dehydrogenative couplings, multi-component reactions such as A3 (aldehyde-alkyne-amine) and KA2 (ketone-alkyne-amine) couplings, as well as in the formation of heterocycles such as benzofurans, indolizines, and quinolines under smooth conditions. No significant copper amount was detected in the extracted organic compounds from the catalytic phase by inductively coupled plasma-atomic emission spectroscopic (ICP-AES) analyses, proving a highly efficient immobilization of copper nanoparticles in glycerol. From a mechanistic point of view, spectroscopic data (infrared and ultraviolet-visible spectra) agree with a surface-like catalytic reactivity. (Figure presented.).
- Dang-Bao, Trung,Pradel, Christian,Favier, Isabelle,Gómez, Montserrat
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p. 2832 - 2846
(2017/08/23)
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- Mild and selective activation and substitution of strong aliphatic C-F bonds
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A procedure for chemoselectively manipulating the strong aliphatic C-F bond with direct transformation into a C-N bond under mild conditions is reported. The activation and subsequent substitution of primary alkyl fluorides is mediated by La[N(SiMe3)2]3, and results in high to excellent yields of tertiary amines. The methodology displays high selectivity towards the C(sp3)-F bond, and a variety of secondary amines are applicable as nucleophiles. Mechanistic investigations reveal a reaction that is first order with respect to [La[N(SiMe3)2]3], [R1R2NH], and [alkyl fluoride], and a 6-membered cyclic transition state is proposed. In addition, 1H NMR spectroscopy shows that La[N(SiMe3)2]3 is the active species involved in the substitution and that protonolysis of the amine, yielding La[NR1R2]3, lowers the reactivity.
- Janjetovic, Mario,Tr?ff, Annika M.,Hilmersson, G?ran
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supporting information
p. 3772 - 3777
(2015/03/04)
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- Methylformate as replacement of syngas in one-pot catalytic synthesis of amines from olefins
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A new general approach for the one-pot hydroaminomethylation of olefins using methylformate as formylating agent instead of synthesis gas (syngas) has been proposed. Herein we report that a Ru-Rh catalytic system demonstrates high activity in a tandem conversion of a series of n-alkenes into amines using methylformate with yields 58-92% (6 h). The selectivity for the normal amine reached 96% with catalysis by the Ru carbonyl complex Ru3(CO) 12, with an overall yield of 55% with respect to amine in this instance. The addition of the Rh complex to Ru catalytic system, sharply increased the hydroaminomethylation rate of both the terminal and internal alkenes and increased the yield of amines to 82-93% (6-12 h). The Royal Society of Chemistry.
- Karakhanov, Eduard,Maksimov, Anton,Kardasheva, Yulia,Runova, Elena,Zakharov, Roman,Terenina, Maria,Kenneally, Corey,Arredondo, Victor
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p. 540 - 547
(2014/02/14)
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- Nematocidal activity of long alkyl chain amides, amines and their derivatives on dog roundworm larvae
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The nematocidal activity of amides and amines having a long alkyl chain against the second-stage larva of dog roundworm, Toxocara canis, was examined. Long chain acyl amides with smaller substituents on the nitrogen showed stronger activity and the activity of cyclic amine amides was stronger than that of acyclic ones. In a series of homologous amides, the activity was dependent on the alkyl chain length: it reached a maximum at an optimal chain length and decreased in both shorter and longer homologues. The relationship between the activity and hydrophobicity of the homologues was analysed by the use of the bilinear model. The hydrophobicity of a compound, which gives a maximal activity, was similar for all neutral amides, but amides which have an additional amine group in the molecule had different values. Tertiary amines and their salts having a long alkyl chain also showed nematocidal activities comparable to those of the corresponding amides. The salts killed the larva at concentrations lower than their critical micell concentration, suggesting that they behave as a single molecule for the nematocidal action.
- Kiuchi,Nishizawa,Kawanishi,Kinoshita,Ohsima,Uchitani,Sekino,Ishida,Kondo,Tsuda
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p. 3234 - 3244
(2007/10/02)
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- HOMOLOGATION DES DERIVES HALOGENES
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The halide R-X is converted, in two steps, to its homologous R-CH2-X.
- Yankep, Emmanuel,Charles, Georges
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p. 427 - 430
(2007/10/02)
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