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Chemical Society Reviews Jan 2012Pillar[5]arenes are [1(5)]paracyclophane derivatives consisting of 1,4-disubstituted hydroquinones linked by methylene bridges in the 2,5-positions. The first report of... (Review)
Review
Pillar[5]arenes are [1(5)]paracyclophane derivatives consisting of 1,4-disubstituted hydroquinones linked by methylene bridges in the 2,5-positions. The first report of these novel macrocycles was in 2008, when 1,4-dimethoxypillar[5]arene was prepared in 22% yield, and subsequent improvements in synthetic methods have allowed the number of derivatives to expand significantly. In addition to D(5) symmetric pillar[5]arenes, asymmetric pillar[5]arenes with two different substituents in the 1- and 4-positions and copillar[5]arenes consisting of two different repeat units in a 4 : 1 ratio have been synthesised. Crystallographic, computational and spectroscopic studies are starting to shed light on the compounds' unusual inclusion phenomena, from gelation and transportation of water through nanotubes to the formation of chromogenic rotaxanes. Applications as molecular sensors are starting to appear with a focus on guest detection by fluorescence quenching. This tutorial review will provide a summary of research into the pillar[5]arenes since their recent discovery.
Topics: Calixarenes; Crystallography, X-Ray; Ethers, Cyclic; Macrocyclic Compounds; Molecular Conformation; Quaternary Ammonium Compounds
PubMed: 21804967
DOI: 10.1039/c1cs15164a -
Journal of the American Chemical Society Jun 2018A benchtop stable, bifunctional reagent for the redox-neutral cyclopropanation of olefins has been developed. Triethylammonium bis(catecholato)iodomethylsilicate can be...
A benchtop stable, bifunctional reagent for the redox-neutral cyclopropanation of olefins has been developed. Triethylammonium bis(catecholato)iodomethylsilicate can be readily prepared on multigram scale. Using this reagent in combination with an organic photocatalyst and visible light, cyclopropanation of an array of olefins, including trifluoromethyl- and pinacolatoboryl-substituted alkenes, can be accomplished in a matter of hours. The reaction is highly tolerant of traditionally reactive functional groups (carboxylic acids, basic heterocycles, alkyl halides, etc.) and permits the chemoselective cyclopropanation of polyolefinated compounds. Mechanistic interrogation revealed that the reaction proceeds via a rapid anionic 3- exo- tet ring closure, a pathway consistent with experimental and computational data.
Topics: Alkenes; Ammonium Compounds; Catalysis; Cyclization; Cyclopropanes; Halogenation; Indicators and Reagents; Light; Methylation; Oxidation-Reduction
PubMed: 29916711
DOI: 10.1021/jacs.8b05243 -
Biomaterials Advances Jul 2023The importance of the inert environment in the transmission of pathogens has been reassessed in recent years. To reduce cross-contamination, new biocidal materials used...
The importance of the inert environment in the transmission of pathogens has been reassessed in recent years. To reduce cross-contamination, new biocidal materials used in high touch surfaces (e.g., stair railings, door handles) have been developed. However, their impact on skin remains poorly described. The present study aimed to evaluate the antibacterial properties and the risk of skin irritation of two materials based on hard-anodized aluminum (AA) impregnated with quaternary ammonium compound solutions (QAC#1 or QAC#2). The QAC#1 or QAC#2 solutions vary in composition, QAC#2 being free of dioctyl dimethyl ammonium chloride (Dio-DAC) and octyl decyl dimethyl ammonium chloride (ODDAC). Unlike AA used as a control, both AA-QAC#1 and AA-QAC#2 had excellent and rapid antibacterial efficacy, killing 99.9 % of Staphylococcus aureus and Escherichia coli bacteria, in 15 s and 1 min, respectively. The impregnation solutions (QAC#1 and QAC#2) did not show any skin sensitizing effect on transformed human keratinocytes. Nevertheless, these solutions as well as the materials (AA-QAC#1, AA-QAC#2), and the liquid extracts derived from them, induced a very rapid cytotoxicity on L929 murine fibroblasts (>70 % after 1 h of contact) as shown by LDH, MTS and neutral red assays. This cytotoxicity can be explained by the fast QACs release occurring when AA-QAC#1 and AA-QAC#2 were immersed in aqueous medium. To overcome the limitation of assays based on liquid condition, an in vitro skin irritation assay on reconstructed human epidermis (RHE) was developed. The effect of the materials upon their direct contact with the epidermis grown at the liquid-air interface was determined by evaluating tissue viability and quantifying interleukin-1 alpha (IL-1α) which is released in skin during injury or infection. AA-QAC#1 induced a significant decrease in RHE viability, close to OECD and ISO 10993-10 acceptability thresholds and enhanced the pro-inflammatory IL-1α secretion compared with AA-QAC#2. Finally, these results were corroborated by in vivo assays on mice using erythema and edema visual scores, histological observations, and epidermal thickness measurement. AA had no effect on the skin, while a stronger irritation was induced by AA-QAC#1 compared with AA-QAC#2. Hence, these materials were classified as moderate and slight irritants, respectively. In summary, this study revealed that AA-QAC#2 without Dio-DAC and ODDAC could be a great candidate for high touch surface applications, showing an extremely effective and rapid bactericidal activity, without inducing adverse effects for skin tissue.
Topics: Humans; Animals; Mice; Ammonium Compounds; Aluminum; Ammonium Chloride; Epidermis; Anti-Bacterial Agents
PubMed: 37104962
DOI: 10.1016/j.bioadv.2023.213433 -
Journal of Insect Science (Online) Jan 2017Stable flies are blood feeding parasites and serious pests of livestock. The immature stages develop in decaying materials which frequently have high ammonium content....
Stable flies are blood feeding parasites and serious pests of livestock. The immature stages develop in decaying materials which frequently have high ammonium content. We added various ammonium salts to our laboratory stable fly rearing medium and measured their effect on size and survival as well as the physical properties of the used media. The addition of ammonium hydroxide, ammonium phosphate and ammonium sulfate reduced larval survival. These compounds decreased pH and increased ammonium content of the used media. Ammonium bicarbonate had no effect on pH and marginally increased ammonium while increasing survival twofold. The optimal level of ammonium bicarbonate was 50 g (0.63 mol) per pan. Larval survival decreased when pH was outside the range of 8.5 to 9.0.
Topics: Ammonium Compounds; Animal Feed; Animals; Body Size; Diet; Female; Insect Control; Larva; Longevity; Male; Muscidae; Pupa; Salts
PubMed: 28130462
DOI: 10.1093/jisesa/iew119 -
Journal of Oleo Science Sep 2020A novel jellyfish-shaped triazine hexamer quaternary ammonium chloride surfactant (THQC) was synthesized, which consisted of one triazine spacer group and six long...
A novel jellyfish-shaped triazine hexamer quaternary ammonium chloride surfactant (THQC) was synthesized, which consisted of one triazine spacer group and six long flexible hydrophobic chains. The molecular structure and aggregation behavior of THQC was investigated by nuclear magnetic resonance (NMR), surface tension, electrical conductivity, dynamic light scattering (DLS), transmission electron microscope (TEM), etc. The results show that the jellyfish-shaped THQC has better surface activity and lower surface tension than traditional ionic and Gemini surfactants in aqueous solution. There are two inflection points in the curve of conductivity versus concentration of the THQC aqueous solution, which correspond to the critical aggregation concentration (CAC) and the critical micelle concentration (CMC) respectively. The existence of CAC indicates that there is a pre-aggregation process before THQC forms micelles. The results of DLS and TEM show that network pre-aggregation, spherical aggregation and dense spherical aggregation were observed in different concentration of THQC aqueous solution, and the electrostatic equilibrium of the system subtly depends on the concentration of the solution. In addition, intramolecular and intermolecular hydrogen bonding is also an important factor. This study provides a method for studying the aggregation behavior and morphology of oligomeric surfactants with rigid spacer groups.
Topics: Ammonium Chloride; Chemical Phenomena; Dynamic Light Scattering; Electric Conductivity; Hydrogen Bonding; Micelles; Molecular Structure; Quaternary Ammonium Compounds; Solutions; Surface Tension; Surface-Active Agents; Triazines; Water
PubMed: 32788513
DOI: 10.5650/jos.ess20016 -
Journal of Plant Physiology Jul 2023The integration of external stimuli into plant cells has been extensively studied. Ammonium is a metabolic trigger because it affects plant nutrition status; on the...
The integration of external stimuli into plant cells has been extensively studied. Ammonium is a metabolic trigger because it affects plant nutrition status; on the contrary, it is also a stress factor inducing oxidative changes. Plants, upon quick reaction to the presence of ammonium, can avoid the development of toxicity symptoms, but their primary ammonium sensing mechanisms remain unknown. This study aimed to investigate the different signaling routes available in the extracellular space in response to supplying ammonium to plants. During short-term (30 min-24 h) ammonium treatment of Arabidopsis seedlings, no indication of oxidative stress development or cell wall modifications was observed. However, specific changes in reactive oxygen species (ROS) and redox status were observed in the apoplast, consequently leading to the activation of several ROS (RBOH, NQR), redox (MPK, OXI), and cell-wall (WAK, FER, THE, HERK) related genes. Therefore, it is expected that immediately after ammonium supply, a defense signaling route is initiated in the extracellular space. To conclude, the presence of ammonium is primarily perceived as a typical immune reaction.
Topics: Reactive Oxygen Species; Prospective Studies; Ammonium Compounds; Oxidative Stress; Oxidation-Reduction; Arabidopsis; Plants
PubMed: 37245458
DOI: 10.1016/j.jplph.2023.154008 -
Journal of Chemical Information and... May 2018Development of accurate force field parameters for molecular ions in the context of a polarizable energy function based on the classical Drude oscillator is a crucial...
Development of accurate force field parameters for molecular ions in the context of a polarizable energy function based on the classical Drude oscillator is a crucial step toward an accurate polarizable model for modeling and simulations of biological macromolecules. Toward this goal we have undertaken a hierarchical approach in which force field parameter optimization is initially performed for small molecules for which experimental data exists that serve as building blocks of macromolecular systems. Small molecules representative of the ionic moieties of biological macromolecules include the cationic ammonium and methyl substituted ammonium derivatives, imidazolium, guanidinium and methylguanidinium, and the anionic acetate, phenolate, and alkanethiolates. In the present work, parameters for molecular ions in the context of the Drude polarizable force field are optimized and compared to results from the nonpolarizable additive CHARMM general force field (CGenFF). Electrostatic and Lennard-Jones parameters for the model compounds are developed in the context of the polarizable SWM4-NDP water model, with emphasis on assuring that the hydration free energies are consistent with previously reported parameters for atomic ions. The final parameters are shown to be in good agreement with the selected quantum mechanical (QM) and experimental target data. Analysis of the structure of water around the ions reveals substantial differences between the Drude and additive force fields indicating the important role of polarization in dictating the molecular details of aqueous solvation. The presented parameters represent the foundation for the charged functionalities in future generations of the Drude polarizable force field for biological macromolecules as well as for drug-like molecules.
Topics: Ammonium Compounds; Hydrogen-Ion Concentration; Molecular Conformation; Molecular Dynamics Simulation; Quantum Theory; Static Electricity; Thermodynamics; Water
PubMed: 29624370
DOI: 10.1021/acs.jcim.8b00132 -
International Journal of Nanomedicine 2020Supramolecular vesicles are the most popular smart nano-drug delivery systems (SDDs) because of their unique cavities, which have high loading carrying capacity and... (Review)
Review
Supramolecular vesicles are the most popular smart nano-drug delivery systems (SDDs) because of their unique cavities, which have high loading carrying capacity and controlled-release action in response to specific stimuli. These vesicles are constructed from amphiphilic molecules via host-guest complexation, typically with targeted stimuli-responsive units, which are particularly important in biotechnology and biomedicine applications. Amphiphilic pillar[n]arenes, which are novel and functional macrocyclic host molecules, have been widely used to construct supramolecular vesicles because of their intrinsic rigid and symmetrical structure, electron-rich cavities and excellent properties. In this review, we first explain the synthesis of three types of amphiphilic pillar[n]arenes: neutral, anionic and cationic pillar[n]arenes. Second, we examine supramolecular vesicles composed of amphiphilic pillar[n]arenes recently used for the construction of SDDs. In addition, we describe the prospects for multifunctional amphiphilic pillar[n]arenes, particularly their potential in novel applications.
Topics: Animals; Cations; Drug Delivery Systems; Humans; Nanostructures; Quaternary Ammonium Compounds
PubMed: 32848395
DOI: 10.2147/IJN.S255637 -
Molecules (Basel, Switzerland) Jun 2024Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially...
Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially engenders ecological peril. Consequently, monitoring the APP concentration to ensure product integrity and facilitate the efficacious management of wastewater from production processes is of great significance. A fluorescent assay was devised to swiftly discern APP utilizing 4',6'-diamino-2-phenylindole (DAPI). With increasing APP concentrations, DAPI undergoes intercalation within its structure, emitting pronounced fluorescence. Notably, the flame retardant JLS-PNA220-A, predominantly comprising APP, was employed as the test substrate. Establishing a linear relationship between fluorescence intensity (F-F0) and JLS-PNA220-A concentration yielded the equation y = 76.08x + 463.2 (R = 0.9992), with a LOD determined to be 0.853 mg/L. The method was used to assess the degradation capacity of APP-degrading bacteria. Strain D-3 was isolated, and subsequent analysis of its 16S DNA sequence classified it as belonging to the genus. D-3 demonstrated superior APP degradation capabilities under pH 7 at 37 °C, with degradation rates exceeding 85% over a four-day cultivation period. It underscores the sensitivity and efficacy of the proposed method for APP detection. Furthermore, D-3 exhibits promising potential for remediation of residual APP through environmental biodegradation processes.
Topics: Biodegradation, Environmental; Acinetobacter; Polyphosphates; Indoles; Ammonium Compounds; Flame Retardants
PubMed: 38893541
DOI: 10.3390/molecules29112667 -
The Journal of General Physiology Nov 1951An analysis has been made of the effect of ammonium and of lithium ions upon frog nerve deprived of sodium. Ammonium ions cannot substitute for sodium ions and restore...
An analysis has been made of the effect of ammonium and of lithium ions upon frog nerve deprived of sodium. Ammonium ions cannot substitute for sodium ions and restore the excitability of the nerve fibers; nor can they increase the L fraction of the membrane potential and the efficiency of the nerve reaction. Certain observations, however, indicate that the presence of ammonium ions outside the nerve fibers may delay the development of inexcitability in a sodium-free medium of nerve fibers restored by a moderate amount of sodium ions. Lithium ions can substitute for sodium and restore to nerve fibers of the A and C groups the ability to conduct impulses; the effect upon B fibers has not been investigated. Lithium cannot substitute for sodium in the role that sodium plays in the creation of the L fraction and in the establishment of the nerve reaction. In this respect lithium and sodium have opposite effects. This fact establishes an important difference between the two physiological responses that the nerve fibers can produce, the nerve impulse and the nerve reaction. With untreated nerve the depolarization of nerve by lithium ions at high concentrations is preceded by a phase of hyperpolarization; with nerve deprived of sodium the depolarization begins without delay.
Topics: Action Potentials; Ammonium Compounds; Animals; Anura; Ions; Lithium; Membrane Potentials; Sodium
PubMed: 14898016
DOI: 10.1085/jgp.35.2.227