Comparative Study of the Reactivity of Iodinating Agents in Solution and Solid Phase

The results of reactions of a series of aromatic substrates with iodine, iodine(I) chloride, and N-iodosuccinimide in solution and solid phase were compared for the first time. In all cases, the general relations holding in the iodination process were similar. Iodine(I) chloride was found to chlorinate anthracene. A high efficiency of solid-phase iodination of β-diketones was demonstrated using dibenzoylmethane as an example.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 876–880.Original Russian Text Copyright © 2005 by Krasnokutskaya, Lesina, Gorlushko, Filimonov.     

Generation of Electrophilic Iodine from Iodine Monochloride in Neutral Media. Iodination and Protodeiodination of Carbazole

In reaction of iodine monochloride with CF₃COOAg, CH₃COONa or (CH₃COO)₂Pb in acetonitrile and acetic acid the chloride is bonded by metal cations, and electrophilic iodine is generated able to easily iodinate anthracene and carbazole. However at the iodination of anthracene in the presence of oxygen the prevailing process is anthracene oxidation to anthraquinone. In the presence of sulfuric acid protodeiodination of 3-iodocarbazole was found to occur resulting in rearranged products.     

Electronic structures and reactivities of iodinating agents in the gas phase and in solutions: A density functional study

The electronic and spatial structures of a broad spectrum of neutral compounds with X-Hal (X = N, O, Cl; Hal = Cl, Br, I) bonds and their protonated forms and of different electronic states of triiodide cation, I₃ ⁺, were determined from density functional B3LYP/6 311G* quantum chemical calculations. The effects of the structure of these compounds on the parameters of electrophilic reactivity were revealed and the thermochemical characteristics of homolytic and heterolytic X-Hal bond dissociation and of iodine transfer in hydroxyl-containing solvents were calculated. Due to low homolytic bond dissociation energies of X-I, the formation of molecular iodine and triiodide cation I₃ ⁺ becomes thermodynamically favorable and the cation should act as iodinating agent alternative to acylhypoiodites and N-iodoimides. The solvation effects of MeOH and CH₂Cl₂ on the X-Hal bond homolysis and heterolysis were determined using the PCM model. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1280–1288, August, 2006.     

The experience in production of composite refraction lenses from beryllium

The choice of beryllium-based material for the use in X-ray optics has been substantiated based on electron microscopy and X-ray diffraction data. The first results of applying refraction lenses made of this material are reported.     

Theoretical analysis of reactions of electrophilic iodination and chlorination of benzene and polycyclic arenes in density functional theory approximation

Quantum-chemical method DFT B3LYP/6-311G* was applied to stage by stage thermodynamic calculation of reactions of electrophilic iodination of benzene, naphthalene, phenanthrene, and anthracene with iodine and iodine monochloride, and comparison with chlorination reactions was performed. The main distinction of iodination process from chlorination was an enhanced reversibility owing to protodeiodination. The reversibility of iodination grows with the electron-donor properties of aromatic substrates. The calculations permit an assumption that the chlorination of anthracene and phenanthrene with iodine monochloride occurs most probably through stages of electrophilic iodination-dehydroiodination.