A simple model for the water o-H2 complex

The infrared spectrum of the complex between o-H2 and H2O, D2O, or HDO, isolated in a matrix of solid p-H2, has been studied between 20 and 4500 cm(-1). In addition the infrared spectrum of the complex between p-D2 and H2O in solid o-D2 has been studied. The spectral shifts are interpreted as the result of the quadrupole-dipole interaction between hydrogen and water.     

Production of [11C]Carbon Labelled Flumazenil and L-Deprenyl Using the iMiDEV™ Automated Microfluidic Radiosynthesizer

In the last decade, microfluidic techniques have been explored in radiochemistry, and some of them have been implemented in preclinical production. However, these are not suitable and reliable for preparing different types of radiotracers or dose-on-demand production. A fully automated iMiDEV™ microfluidic radiosynthesizer has been introduced and this study is aimed at using of the iMiDEV™ radiosynthesizer with a microfluidic cassette to produce [¹¹C]flumazenil and [¹¹C]L-deprenyl. These two are known PET radioligands for benzodiazepine receptors and monoamine oxidase-B (MAO-B), respectively. Methods were successfully developed to produce [¹¹C]flumazenil and [¹¹C]L-deprenyl using [¹¹C]methyl iodide and [¹¹C]methyl triflate, respectively. The final products 1644 ± 504 MBq (n = 7) and 533 ± 20 MBq (n = 3) of [¹¹C]flumazenil and [¹¹C]L-deprenyl were produced with radiochemical purities were over 98% and the molar activity for [¹¹C]flumazenil and [¹¹C]L-deprenyl was 1912 ± 552 GBq/µmol, and 1463 ± 439 GBq/µmol, respectively, at the end of synthesis. All the QC tests complied with the European Pharmacopeia. Different parameters, such as solvents, bases, methylating agents, precursor concentration, and different batches of cassettes, were explored to increase the radiochemical yield. Synthesis methods were developed using 3–5 times less precursor than conventional methods. The fully automated iMiDEV™ microfluidic radiosynthesizer was successfully applied to prepare [¹¹C]flumazenil and [¹¹C]L-deprenyl.     

ESR applications to photochemical polymer reactions

ESR spectroscopy combined with spin-trapping technique is a selective and powerful method for studies of reaction mechanisms and intermediates in free radical reactions of polymer systems. The method has been applied to several problems in our research program of which three are presented in this paper. - The mechanism of photo-initiation with aromatic ketone/tert. amine and subsequent photocuring of acrylic coatings has been largely resolved. - The mechanism of photocrosslinking of ethylene-propylenediene copolymers (EPDM elastomers) studied by model compounds has been shown to involve formation of allyl radicals in the diene groups and crosslinking by allyl radical combination. - The photoinitiated crosslinking of polyethylenes (LD, LLD and HD) has been studied using model compounds. It involves formation of primary alkyl and allyl radicals which crosslink the polymer by radical combination. - The mechanism of photocrosslinking indicates a second order reaction, i.e. rate of crosslinking depends of the square of irradiation intensity which has been verified experimentally. This result is the basis for development of rapid crosslinking processes of technical and industrial interest.