Electrochemical stability and transformations of fluorinated poly(2,6-dimethyl-1,4-phenylene oxide)

Fluorination of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) leads to narrowing of its window of electrochemical stability in a cathodic range of potentials. It is found this is connected with appearance of both perfluorinated and incompletely fluorinated units in the polymer. The former units are liable to electrochemical reduction (at potentials <−2.0 V) followed by elimination of fluorine anions and the latter react with basic products (generated at potentials <−1.8 V) of electrochemical reduction of the background solution. In the both cases this results in appearance of conjugated multiple bonds in the fluorinated macromolecules. Quantities of these units in fluorinated PPO were determined with a help of direct and indirect electrochemical reductive degradation techniques

Reactions and stability of fluorinated poly(vinyl trimethylsilane) in electrochemical systems

Fluorinated poly(vinyl trimethylsilane) (FPVTMS) unlike virgin PVTMS is able to participate in electrochemical reactions and undergoes direct and indirect electrochemical reductive degradation. Specifically, its perfluorinated units are reduced irreversibly at a glass carbon electrode in a 0.05-M (C4H9)4ClO4 solution in dimethylformamide with subsequent splitting of C–F bonds and formation of conjugated double bonds in macromolecules at the polymer surface. On the other hand, the incompletely fluorinated units at the FPVTMS surface interact with the previously electrochemically reduced background solution to be dehydrofluorinated. This is accompanied by the formation of conjugated double bonds and dissolution of the dehydrofluorinated layer also. The data obtained allowed distinguishing the incompletely fluorinated units from the perfluorinated ones in the fluorinated layer of FPVTMS. Moreover, the quantity of the incompletely fluorinated units in FPVTMS can be determined. It was found that the strengthening of fluorination conditions led to an enhancement of the electrochemically induced FPVTMS transformations

Theoretical and experimental studies of phosphonium ionic liquids as potential antibacterials of MDR <em>Acinetobacter baumannii</em>.

A previously developed model to predict antibacterial activity of ionic liquids against a resistant A. baumannii strain was used to assess activity of phosphonium ionic liquids. Their antioxidant potential was additionally evaluated with newly developed models, which were based on public data. The accuracy of the models was rigorously evaluated using cross-validation as well as test set prediction. Six alkyl triphenylphosphonium and alkyl tributylphosphonium bromides with the C8, C10, and C12 alkyl chain length were synthesized and tested in vitro. Experimental studies confirmed their activity against A. baumannii as well as showed pronounced antioxidant properties. These results suggest that phosphonium ionic liquids could be promising lead structures against A. baumannii

Structure-activity relationship modeling and experimental validation of the imidazolium and pyridinium based ionic liquids as potential antibacterials of mdr<em> Acinetobacter baumannii </em>and <em>Staphylococcus aureu</em>s.

Online Chemical Modeling Environment (OCHEM) was used for QSAR analysis of a set of ionic liquids (ILs) tested against multi-drug resistant (MDR) clinical isolate Acinetobacter baumannii and Staphylococcus aureus strains. The predictive accuracy of regression models has coefficient of determination q2 = 0.66 − 0.79 with cross-validation and independent test sets. The models were used to screen a virtual chemical library of ILs, which was designed with targeted activity against MDR Acinetobacter baumannii and Staphylococcus aureus strains. Seven most promising ILs were selected, synthesized, and tested. Three ILs showed high activity against both these MDR clinical isolates

Composite "graphene nanoplatelets - fluorine-containing polyamide": synthesis, properties and quantum-chemical simulation of electroconductivity

Considered in the article is the basic possibility of increasing of electric conductivity of thermostable fluorine-containing aromatic polyamide by its doping with graphene platelets. The raised concentration of a conducting graphene phase (78 wt.%) in the top layer (~ 50 μm) of the film composite is established. The microstructure of cross-section of the film and topography of its surface are studied by SEM and AFM. Corresponding volt-ampere characteristics are resulted. Carried out here are quantum-chemical calculations of model system &qout;a polyamide fragment + graphene strip&qout;: localization of boundary and close molecular orbitals in the composite and also distribution of spin density of the composite in electric field. Conductivity of the composite is explained within the framework of stacking interaction between π-systems of the polymer and graphene