Hydroxyl Radical Generation and DNA Nuclease Activity: A Mechanistic Study Based on a Surface‐Immobilized Copper Thioether Clip‐Phen Derivative

Coordination compounds of copper have been invoked as major actors in processes involving the reduction of molecular oxygen, mostly with the generation of radical species the assignment for which has, so far, not been fully addressed. In the present work, we have carried out studies in solution and on surfaces to gain insights into the nature of the radical oxygen species (ROS) generated by a copper(II) coordination compound containing a thioether clip‐phen derivative, 1,3‐bis(1,10‐phenanthrolin‐2‐yloxy)‐N‐(4‐(methylthio)benzylidene)propan‐2‐amine (2CP‐Bz‐SMe), enabling its adsorption/immobilization to gold surfaces. Whereas surface plasmon resonance (SPR) and electrochemistry of the adsorbed complex indicated the formation of a dimeric Cu^I intermediate containing molecular oxygen as a bridging ligand, scanning electrochemical microscopy (SECM) and nuclease assays pointed to the generation of a ROS species. Electron paramagnetic resonance (EPR) data reinforced such conclusions, indicating that radical production was dependent on the amount of oxygen and H₂O₂, thus pointing to a mechanism involving a Fenton‐like reaction that results in the production of OH^..     

Single‐pulse pulsed laser polymerization–electron paramagnetic resonance investigations into the termination kinetics of n‐butyl acrylate macromonomers

The termination of model mid‐chain radicals (MCRs), which mimic radicals that occur in acrylate polymerization over a broad range of reaction conditions, has been studied by single‐pulse pulsed laser polymerization (SP‐PLP) in conjunction with electron paramagnetic resonance spectroscopy. The model radicals were generated by initiator‐fragment addition to acrylic macromonomers that were preformed prior to the kinetic experiments, thus enabling separation of termination from the propagation reaction, for these model radicals propagate sparingly, if at all, on the timescale of SP‐PLP experiments. Termination rate coefficients of the MCRs were determined in the temperature range of 0–60°C in acetonitrile and butyl propionate solution as well as in bulk macromonomer over the range of 0–100 °C. Termination rate coefficients slightly below those of the corresponding secondary radicals were deduced, demonstrating the relatively high termination activity of this species, even when undergoing MCR–MCR termination. For chain length of 10, a reduction by a factor of 6 is observed. Unusually high activation energies were found for the termination rate coefficient in these systems, with 35 kJ mol^?1 being determined for bulk macromonomer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Organic Syntheses Without Solvent: Preparation of Alkoxyphthalimides and of Alkoxylamines

Alkoxyphthalimides are prepared by alkylation of N-hydroxyphthalimide under solid-liquid phase transfer catalysis without solvent. When conversion of alkoxyphthalimides into alkoxylamines is nearly complete, neat hydrazine hydrate is added at room temperature.     

Carbenes,related intermediates,and small-sized cycles: contribution from Professor Nefedov’s laboratory

The review summarizes some of the most prominent results obtained in the laboratory headed by Academician Oleg M. Nefedov at the N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences in the field of chemistry of carbenes, their heavy analogs, and related intermediates, as well as small-sized cycles. Those include elaboration of safe methodology of cyclopropanation using diazomethane, development and extension of synthetic applications of diazoesters and other diazo compounds in the preparation of valuable chemical products, design of functionalized alkynylcyclopropanes on the basis of alkynylcarbene reactions, creation of versatile synthetic approaches to preparation of various practically useful fluoroorganic compounds on the basis of reactions of fluorocarbenes, development of synthetic applications of heavy carbene analogs and synthesis of small-sized heterocycles containing silicon and germanium atoms, analysis of mechanisms of some important reactions of carbenes, their analogs and related intermediates on the basis of physicochemical studies, direct spectroscopic studies of various labile intermediates of chemical reactions.