The Fluidization Effect of a Bilayer Membrane on a Fatty Acid Vesicle by a Detergent

A bicelle, which is a bilayer molecular assembly, can be prepared by fluidizing a vesicle in the presence of a detergent. We investigated the effect of two different detergents, 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxypropane sulfonate (CHAPSO) and Triton X-100 (TX), on the formation of a bicelle from a vesicle containing oleic acid (OA) and the detergent molecules. The fluidization effect of the detergent was evaluated using the membrane packing density, which we measured using the fluorescent probe method with Laurdan, in conjunction with transmission electron microscopy to examine the morphology of the prepared bilayer molecular assemblies. As a result, it was discovered that the OA/CHAPSO system could form a heterogeneous phase with the highest packing density, implying that CHAPSO was the better detergent for a bicelle preparation, whereas the OA/TX system formed a disordered phase with the lowest packing density.

Short-Chained Platinum Complex Catalyzed Hydrosilylation under Thermomorphic Conditions: Heterogeneous Phase Separation at Ice Temperature

Homogeneous catalysts PtCl2[5,5′-bis-(n-ClCF2(CF2)3CH2OCH2)-2,2′-bpy] (2A) and PtCl2[5,5′-bis-(n-HCF2(CF2)3CH2OCH2)-2,2′-bpy] (2B), which contained short fluorous chains, were synthesized and used in catalysis of hydrosilylation of alkynes. In these reactions the thermomorphic mode was effectively used to recover these catalysts from the reaction mixture up to eight cycles by taking advantage of heterogeneous phase separation at ice temperature. This kind of catalysis had previously been observed in fluorous catalysts of platinum containing about 50% F-content, but in this work the percentage of F-content is decreased to only about 30%, by which we termed them as “very light fluorous”. Our new type of catalyst with limited number of F-content is considered as the important discovery in the fluorous technology field as the reduced number of fluorine atoms will help to be able to comply the EPA 8-carbon rule. The metal leaching after the reaction has been examined by ICP-MS, and the testing results show the leaching of residual metal to be minimal. Additionally, comparing these results to our previous work, fluorous chain assisted selectivity has been observed when different fluorous chain lengths of the catalysts are used. It has been found that there exists fluorous chain assisted better selectivity towards β-(E) form in the Pt-catalyzed hydrosilylation of non-symmetric terminal alkyne when the Pt catalyst contains short fluorous chain (i.e., 4 Cs). Phenyl acetylenes showed the opposite regioselectivity due to pi-pi interaction while using the same catalyst via Markovnikov’s addition to form terminal vinyl silane, which is then a major product for Pt-catalyzed hydrosilylation of terminal aryl acetylene with triethylsilane. Finally, the kinetic studies indicate that the insertion of alkyne into the Pt-H bond is the rate-determining step.

Study on Hydrolysis Reaction Rate of Several Chemical Warfare Agents

According to the first-order kinetic reaction equation, the hydrolysis rate constants of homogeneous and heterogeneous phase of eight poisons under different conditions were calculated, and the relationship between hydrolysis rate constants and temperature was obtained according to the arrhenius formula, and the activation energy of hydrolysis reaction of some poisons was calculated. The evolution curve of homogeneous hydrolysis rate of 0.5 g/L HD with time was collected by T-135 method, and the hydrolysis rate was 0.1 min-1 and the half-life was 7 min. Poison concentration, pH of system, environmental temperature and structural composition of soil all affect the hydrolysis rate of Chemical Warfare Agents.

Amino acids and Peptides Organocatalysts: A Brief Overview on Its Evolution and Applications in Organic Asymmetric Synthesis

: This review highlights the application of biopolymers of natural α-amino acids and its derived wild type peptides employed as an organocatalysis for the asymmetric synthesis published by researchers across the globe is described. The α-amino acids with L-stereochemistry are available commercial in pure form are played crucial role in enantioselective chiral molecule synthesis. Out of twenty natural amino acids, only one secondary amine containing proline amino acid exhibited revolution in the field of orgnocatalysis, because of its rigid structure and formation of an imine like transition state during the reaction lead more stereoselectivity. Hence, it is referred to as a simple enzyme in organocatalyst. Further discussed chiral organic molecule synthesis by employing oligopeptides derived from the natural amino acids as a robust biocatalyst replaced enzyme catalysts. The peptide includes di-, tri, tetra-, penta- and oligopeptide derived demonstrated as a potential organocatalysts, whose reaction activity and mechanistic pathways are reviewed. Several choice of families of these organocatalysts permit chemist to achieve facile and efficient stereoselective synthesis of many complex natural products with optically pure isomer. Subsequently, researcher developed green and sustainable heterogeneous catalytic system containing organocatalyst immobilized onto solid inorganic supports or porous materials, and is responsible for accelerating the reaction through heterogeneous phase. The developed heterogeneous organocatalysts-MOFs found to be used easier and employed for bulk production and flow reactor synthesis. This review compiled many outstanding discoveries in organocatalysts derived amino acids and it’s heterogenized on to MOFs together role of the organocatalysis in many organic transformations in academic and industrial applications are covered.