Antibacterial poly(ethylene terephthalate) surfaces obtained from thymyl methacrylate polymerization

Thymol, an antibacterial agent was used for the preparation of a methacrylic monomer. The conventional and atom transfer radical (ATRP) polymerizations of this monomer were studied using different conditions. Then, the functionalization of poly(ethylene terephthalate) (PET) films by “grafting from” ATRP using this monomer was investigated. In this aim, a three steps procedure was developed. The surfaces were first treated by NH₃ plasma treatment to incorporate primary amino functions. Then, in a second step, ATRP initiator was grafted by reaction with bromoisobutyryl bromide. Surface initiated ATRP of thymyl methacrylate was performed in solution in the presence of a sacrificial initiator. The efficiency of these reactions was confirmed by X‐ray photoelectron spectroscopy. Wetting properties and surface energy were found to vary systematically depending to the type of functionalization and grafting. The poly(thymyl methacrylate)‐grafted PET surfaces exhibit resistance to bacterial adhesion toward Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus strains. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1975–1985     

Interaction of a bounded ultrasonic beam with a thin inclusion inside a plate

A theoretical study of the reflection of a two-dimensional Gaussian ultrasonic beam, incident at a Lamb angle of a plate containing a thin rectangular inclusion at an arbitrary position, is presented on the basis radiation mode theory. The inclusion is parallel to the plate surface and its thickness is assumed to be much smaller than the ultrasonic wavelength. It is shown that the amplitude and phase of the reflected beam profile can be used for accurate inclusion characterization. However, this only holds for certain internal positions of the inclusion and for material combinations that do not strongly perturb the excitation of Lamb waves in the plate. When these conditions are satisfied, it is possible to define the Lamb waves and the associated experimental conditions for which good estimates can be obtained of the position of the beginning point of the inclusion as well as of the length and the thickness of the inclusion.     

The synthesis of 2-chloro-1-(β-D-ribofuranosyl)benzimidazole and certain related derivatives

The synthesis of 2-chloro-1-(β-D-ribofuranosyl)benzimidazole (4b) has been accomplished by a condensation of 2-chloro-1-trimethylsilylbenzimidazole (1) with 2,3,5-tri-O-acetyl-D-ribofuranosyl bromide (2) followed by subsequent deacetylation. Nucleophilic displacement of the 2-chloro group has furnished several interesting 2-substituted-1-(β-D-ribofuranosyl)benzimidazoles. 1-(β-D-Ribofuranosyl)benzimidazole (5) and 1-(β-D-ribofuranosyl)benzimidazole-2-thione (6) were prepared from 4b and 6 was also prepared by condensation of 2 with silylated benzimidazole- 2-thione (3). Alkylation of 6 furnished certain 2-alkylthio-1-(β-D-ribofuranosyl)benzimidazoles and oxidation of 6 with alkaline hydrogen peroxide produced 1-(β-D-ribofuranosyl)benzimidazole-2-one (9). The assignment of anomeric configuration for all nucleosides reported is discussed.     

Etude théorique de quelques cycles à quatre pièces

Résumé On décrit des calculs ab initio de la fonction d'onde de l'état fondamental de la cyclobutanone, de la -propiolactone, de l'anhydride malonique, de l'amino-2 méthylène-4 oxétène et de l'amino-2 méthylène-4 azétine. On discute les relations entre la structure électronique et les propriétés statiques et dynamiques de ces molécules.

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Theoretical study of some four member cycles

In this work, we report an all-electrons SCF-LCGO-MO computation for the ground state wave-functions of the cyclobutanone, -propiolactone, malonic anhydrid, amino-2 methylen-4 oxetene and amino-2 methylen-4 azetine molecules. Theoretical results are compared with experimental ones.

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Zusammenfassung Die Wellenfunktion des Grundzustandes von Cyclobutanon, -Propiolakton, Malonsäureanhydrid, 2-Amino 4-Methylen oxeten und 2-Amino 4-Methylen wird nach einem Rechenverfahren ab initio beschrieben. Die Beziehungen zwischen der Elektronenverteilung und der statischen sowie dynamischen Eigenschaften dieser Molekule wird untersucht.

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Chargé de Recherches du «Fonds National Belge de la Recherche Scientifique».     

Etude theorique des proprietes thermodynamiques du radical CN et de ses dimeres

Using the ab initio LCAO—SCF—MO method and the 6–31G extended basis set, the CN radical and its possible dimers (NCCN, CNNC or CNCN) have been studied in terms of nuclear equilibrium geometries, normal modes of vibration, IR spectrum and thermodynamic properties. The results show that quantum chemical calculations enable these parameters to be obtained with adequate accuracy. Working properly, one can build a local potential energy surface on which to perform a harmonic vibrational analysis. Hence all the required information to apply the principles of statistical thermodynamical analysis is available.     

Nature of the interference of nitric acid in the determination of nickel and vanadium by atomic absorption spectrometry with electrothermal atomization

Effects of the concentration of nitric acid in the determination of nickel and vanadium in the presence of other metals by flarneless atomic absorption spectrometry have been studied. Specific complexation of the metals in the aqueous phase suppresses the interferences. A method has been developed which allows the use of calibration curves from dilute acidic solutions in the determination of samples with high nitrate concentrations. The method is suitable for solutions reproducing the mineralization of airborne particulates.     

Pyrazolopyrimidine nucleosides. Part VII. The synthesis of certain pyrazolo [3,4-d] pyrimidine nucleosides related to the nucleoside antibiotics toyocamycin and sangivamycin

The condensation of 4-acetamido-3-cyanopyrazolo[3,4-d]pyrimidine ( 5 ) with crystalline 2,3,5-tri-O-acetyl-β- D -ribofuranosyl chloride ( 6 ) has furnished a good yield of nucleoside material ( 7 ) which on treatment with sodium methoxide in methanol provided a high yield of nucleoside which was subsequently established as methyl 4-amino-1-(β- D -ribofuranosyl)pyrazolo[3,4-d]-pyrimidine-3-formimidate monohydrate ( 11 ). The formimidate function of 11 was found to be highly reactive and 11 was readily converted into the corresponding carhoxamidine ( 8 ), carboxamidoxime ( 14 ) and carboxamidrazone ( 15 ) when treated with the appropriate nucleophiles. Treatment of the imidate ( 11 ) with sodium hydrogen sulfide gave a high yield of the thiocarboxamide ( 12 ) which was then readily converted into 4-amino-3-cyano-1-(β- D -ribofuranosyl)pyrazolo[3,4-d]pyrimidine ( 16 ). Aqueous base transformed 11 into 4-amino-1-(β- D -ribofuranosyl)-pyrazolo[3,4-d]pyrimidine-3-carboxamide ( 10 ) while more vigorous basic hydrolysis provided the corresponding carboxylic acid ( 9 ) in nearly quantitative yield. Decarboxylation of 9 proceeded smoothly in hot sulfolane to provide the known 4-amino-1-(β- D -ribofuranosyl)pyrazolo[3,4-d]pyrimidine ( 13 ) in 68% yield which unequivocally established the site of ribosylation and anomeric configuration for all nucleosides reported in this investigation.     

Evaluation of the bond energy terms for the various types of boron-nitrogen bonds

Summary We have determined a series of bond energy terms in compounds containing dative, single, double and/or triple boron-nitrogen bonds. We describe various interesting applications based on these bond energy terms namely the determination of enthalpies of atomization and stabilization energies. More particularly, the conventional ring strain energies of three- and four-membered small ring containing boron and nitrogen atoms could be determined and the aromaticity of borazine, reexamined.Dedicated to Professor Alberte Pullman     

The synthesis of certain ribofuranosylindazoles

The synthesis of 1-(β-D-ribofuranosyl)indazole (4), 2-(β-D-ribofuranosyl)indazole (5) and 6-, 5-, and 4-nitro-2-(β-D-ribofuranosyl)indazole (8a, 8b, and 8c, respectively), has been accomplished in good yield by the condensation of the appropriate N-trimethylsilylindazole (1, 6a, 6b, and 6c) with 2,3,5-tri-O-acetyl-D -ribofuranosyl bromide (2) followed by subsequent deacetylation of the reaction products. The site of ribosylation and the assignment of anomeric configuration for all nucleosides reported is discussed. This has furnished the first indazole nucleosides with assigned anomeric configurations and the site of ribosylation has been established on the basis of uv comparisons with model methyl compounds.     

Kinetics of reduction of cinnamaldehyde by means of hydrido- and deuteridocobalt tetracarbonyl

The reaction of HCo(CO)₄ ( HT ) or DCo(CO)₄ ( DT ) with excess cinnamaldehyde ( CA ) in methylcyclohexane ( RH ) at 22.2° and under 1 atm of CO follows pseudo-first-order kinetics in HT or DT with an inverse isotopic effect of 0.54. Identified products of the reaction are hydrocinnamaldehyde ( HCA ) and styrene ( STY ). The STY is believed to be an artifact of the thermal decomposition of the true product PhCH₂CH₂C( (DOUBLE BOND) O)Co(CO)₄ ( X ) or its isomer. Reduction of the carbon-carbon double bond in CA is effected by hydrogen from both the cobalt compound and RH. It is proposed that the reaction involves a free-radical chain mechanism in which the rate of the slow step is proportional to [ CA ], the initial molar concentration of CA raised to a power of 1.5− 1.8. Additionally the rate of conversion of CA to HCA and X meets the criteria of a homocompetitive reaction with [ CA ], [ HCA ], and [ STY ] simple functions of t^0.5 (where t is reaction time) for use of DT or (in a single case) a function of (t^0.5 + t) for use of HT. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 473–481, 1997.