Ethyl-, vinyl- and ethynylcyanoborates: Room temperature borate ionic liquids with saturated and unsaturated hydrocarbon chains

Ethyl-, vinyl- and ethynyltricyano and dicyanofluoroborates were prepared on gram scale from commercially available potassium trifluoroborates and trimethylsilylcyanide. Salt metathesis resulted in the corresponding EMIm-salts that are hydrophobic room-temperature ionic...

Gold(I) Complexes Bearing Alkylated 1,3,5-Triaza-7-phosphaadamantane Ligands as Thermoresponsive Anticancer Agents in Human Colon Cells

Overheating can affect solubility or lipophilicity, among other properties, of some anticancer drugs. These temperature-dependent changes can improve efficiency and selectivity of the drugs, since they may affect their bioavailability, diffusion through cell membrane or activity. One recent approach to create thermosensitive molecules is the incorporation of fluorine atoms in the chemical structure, since fluor can tune some chemical properties such as binding affinity. Herein we report the anticancer effect of gold derivatives with phosphanes derived from 1,3,5-triaza-7-phosphaadamantane (PTA) with long hydrocarbon chains and the homologous fluorinated chains. Besides, we analysed the influence of temperature in the cytotoxic effect. The studied gold(I) complexes with phosphanes derived from PTA showed antiproliferative effect on human colon carcinoma cells (Caco-2/TC7 cell line), probably by inhibiting cellular TrxR causing a dysfunction in the intracellular redox state. In addition, the cell cycle was altered by the activation of p53, and the complexes produce apoptosis through mitochondrial depolarization and the consequent activation of caspase-3. Furthermore, the results suggest that this cytotoxic effect is enhanced by hyperthermia and the presence of polyfluorinated chains.

Molecular Dynamics Simulations on the Chain Fold During the Isothermal Orientation of n-Alkanes on Graphene

The orientation of hydrocarbon chains plays a key role in the applications of organic materials. And chain folding in the process of molecular orientation is also of great significance for the design of organic molecular thin films. The effect of chain length and simulation temperature on the isothermal orientation of n-alkanes on graphene surface is studied by molecular dynamics simulation in this paper. And the chain folding is also described. The n-alkanes can form perpendicular ordered structure, parallel ordered structure or perpendicular orientation at relative low temperature and parallel orientation at relative high temperature on graphene surface. The chain fold happens when long n-alkanes form perpendicular ordered structure on graphene surface. And the simulation results show the interactions of n-alkane−graphene and n-alkane−n-alkane affect chain fold.

Frozen n-Tetradecane Investigated by Cryo-Atom Probe Tomography

Atom probe tomography (APT) has been established in the microscopic chemical and spatial analysis of metallic or semiconductors nanostructures. In recent years, and especially with the development of a transfer shuttle system and adapted preparation protocols, the field of frozen liquids has been opened up. Still, very limited knowledge is available about the evaporation and fragmentation behavior of frozen liquids in APT. In this work, efforts were made to extend the method toward organic and biological soft matter, which are mostly built from hydrocarbon chains, the evaporation and fragmentation behavior of simple alkane chains (n-tetradecanes). Tetradecane shows a very complex evaporation behavior whereby peaks of C1–C15 can be observed. Based on multihit events and the representation of these in correlation plots, more detailed information about the evaporation behavior and the decay of molecules into smaller fragments in the region near the tip can be studied. A variety of different dissociation tracks of larger molecules in their excited state and their subsequent decay in low-field regions, on the way to the detector, could be observed and the dissociation zone in the low-field region was calculated.

Rare fatty acids and lipids in plant oilseeds: occurrence and bioactivity

Lipids are biomolecules which are present in plants as general metabolites with different functions such as structural, protective and also as storage material. Plants produce a high number of different fatty acids: the most common structural types are long linear hydrocarbon chains, saturated or unsaturated with an even number of carbon atoms. In addition, plants accumulate rare fatty acids with reference to their occurrence and to their structures such as number and arrangement of unsaturated bonds, chain branches, type of functional groups, cyclic structures and halogenation. Their presence is limited in plant leaves, roots or stems, while they are mostly found as components of storage seed oils. The present review aims to describe the structural features of selected unusual rare fatty acids occurring in plants, their bioactivity and applications as pharmaceutical, cosmetic, food and non-food industrial products. Cyanolipids, a group of rare natural lipids containing a cyanogenic group in the molecule and only found in seed oils of a few plant species are also commented.

EFFECT OF ZEOLITE ON THE CATALYTIC CRACKING OF TAR YIELDS MAHOGANY WOOD PYROLYSIS

In this study, the effects of zeolite were observed to investigate the formation of a pyrolysis product, which is tar yield. Tar yields receive the most attention because of their potential as a bio-oil and chemical feedstocks. For this reason, efforts to increase tar yield were made, one of which was by adding zeolite to the pyrolysis process. The role of zeolite here was a pyrolysis catalyst. This research was conducted on a real pilot plant pyrolysis reactor which utilized mahogany wood as biomass feedstock with the addition of zeolite that was 0–50% of the total mass pyrolysis feedstock. The temperatures set in this pyrolysis were 250 °C, 500 °C, and 800 °C. The test results were measured in terms of the tar yield’s volume and mass. The chemical composition of tar yield was tested using a Gas Chromatograph Mass Spectrometry (GC-MS) to measure the percentage of its chemical constituent compounds. Then, the formation mechanism of tar compounds from pyrolysis was described by using HyperChem simulation. The results showed that an increase in zeolite catalyst percentage would generate more volume of tar yields. It was due to the breaking of biomass hydrocarbon chains, increasing the production of tar yields. Zeolite also affected the formation of hydrocarbon chains in tar yields where the chains became shorter as the percentage of zeolite catalyst rose. The mechanism of increasing tar product was due to the role of zeolite as a catalyst in the catalytic cracking process which is almost similar to acid-base reactions of Brønsted-Lowry and Lewis. This reaction took place when the pyrolysis yields moved through the pores of zeolite, breaking the long hydrocarbon chains into shorter ones which were dominated by alkenes, aromatic, and acidic compounds formation. In addition, acidic compounds represented by acetic acid function as a flammable matter possess the potential of becoming oil-fuel.

Understanding the Dynamics of a Lipid Monolayer on a Water Surface under a Marangoni Flow

Biological membrane is composed of lipid molecules, because of its fluidity, it is possible to carry out physiological functions. Therefore, it is important to study the hydrodynamic properties of membranes toward understanding its function. Here, we observed the dynamical behavior of a lipid monolayer on the water surface under Marangoni flow. By using X-ray reflectometry, we obtained the tilt angle of the hydrocarbon chains of the lipid at different surface pressures. Comparing them with the dynamical surface pressure under Marangoni flow, it was found that the lipid molecules in rotational rather than translational motion. At low surface pressure, the molecular tilt angle is reduced by 20 degrees, even though the molecular area is reduced by at most 10%.

Intrinsic lipid curvatures of mammalian plasma membrane outer leaflet lipids and ceramides

We developed a global X-ray data analysis method to determine the intrinsic curvatures of lipids hosted in inverted hexagonal phases. In particular, we combined compositional modelling with molecular shape-based arguments to account for non-linear mixing effects of guest-in-host lipids on intrinsic curvature. The technique was verified by all-atom molecular dynamics simulations and applied to sphingomyelin and a series of phosphatidylcholines and ceramides with differing composition of the hydrocarbon chains. We report positive lipid curvatures for sphingomyelin and all phosphatidylcholines with disaturated and monounsaturated hydrocarbons. Substitution of the second saturated hydrocarbon with an unsaturated acyl chain in turn shifted the intrinsic lipid curvatures to negative values. All ceramides, with chain lengths varying between C2:0 and C24:0, displayed significant negative lipid curvature values. Moreover, we report non-additive mixing for C2:0 ceramide and sphingomyelin. Our findings manifest the high and manifold potential of lipids to modulate physiological membrane function.