Irina D. Yushina

Complex structure tri- and polyiodides of iodocyclization products of 2-allylthioquinoline

Iodocyclization products of 2-allylthioquinoline are obtained in the form of polyiodides with different stoichiometric compositions. X-ray crystallography data are analyzed for two different crystal structures of 1-iodomethyl-1,2-dihydro[1,3]thiazolo[3,2-a]quinolinium polyiodides: triiodide C12H11INS+I3− and complex polyiodide 2(C12H11INS+I3−)·I2. A comparison is made of the nonbonding interactions of dihydrothiazoloquinolinium with atoms of the triiodide anion and complex polyiodide to show the crystal structure features attributed to the participation of molecular iodine.

Raman spectroscopy study of new thia- and oxazinoquinolinium triodides

A number of new solid polyiodides of thia- and oxa-zinoquinolinium derivatives have been characterized using a combined approach of Raman spectroscopy and periodic 3D calculations of the Raman intensities. Various cation–anion ratios, including tri- and polyiodides of the complex structure [I3⋯I2]−, have been studied. For the oriented single crystal containing the [I3⋯I2]− fragments, the polarized Raman spectra and the angular dependency of the band intensities on crystal rotation have been obtained. These techniques have allowed us to get new information on the spatial organization of the intermolecular interactions of iodine in polyiodide-anion chains. They have also shown perspectives on the geometrical characterization of complex polyiodides using Raman spectroscopy.

Nontypical iodine-halogen bonds in the crystal structure of (3E)-8-chloro-3-iodomethylidene-2,3-dihydro-1,4-oxazino[2,3,4-ij]quinolin-4-ium triiodide.

Two kinds of iodine-iodine halogen bonds are the focus of our attention in the crystal structure of the title salt, C12H8ClINO(+)·I3(-), described by X-ray diffraction. The first kind is a halogen bond, reinforced by charges, between the I atom of the heterocyclic cation and the triiodide anion. The second kind is the rare case of a halogen bond between the terminal atoms of neighbouring triiodide anions. The influence of relatively weakly bound iodine inside an asymmetric triiodide anion on the thermal and Raman spectroscopic properties has been demonstrated.

Testing the tools for revealing and characterizing the iodine–iodine halogen bond in crystals

To understand what tools are really suitable to identify and classify the iodine-iodine non-covalent interactions in solid organic polyiodides, we have examined the anisotropy of the electron density within the iodine atomic basin along and across the iodine-iodine halogen bond using the Laplacian of electron density, one-electron potential and electron localization function produced by Kohn-Sham calculations with periodic boundary conditions. The Laplacian of electron density exhibits the smallest anisotropy and yields a vague picture of the outermost electronic shells. The one-electron potential does not show such a deficiency and reveals that the valence electron shell for the halogen-bond acceptor iodine is always wider than that for the halogen-bond donor iodine along its σ-hole direction. We have concluded that the one-electron potential is the most suitable for classification of the iodine-iodine bonds and interactions in complicated cases, while the electron localization function allows to distinguish the diiodine molecule bonded with the monoiodide anion from the typical triiodide anion.

Energy properties and structure of 2- and 8-allylthioquinoline complexes with iodine

The study focuses on the energy and quantum topological properties of substituted 2- and 8-allylthioquinoline complexes with iodine, which are assumed to correspond to prereaction states in the iodocyclization reaction leading to the formation of thiazolo- and tiazinoquinoline systems. The structures of the complexes and the corresponding atomic interactions are modeled considering the different conformational states of allyl-substituted quinolinethiols (thioquinolines). The energy values are analyzed for the interactions between the iodine molecule and different donor centers of the substituted quinoline system: the nitrogen heteroatom, sulfur, and π-system of the allyl group. It is shown that the formation of stable complexes with the nitrogen of the quinoline ring is complicated by steric hindrances posed by the S-allyl group at positions 2 and 8 of the quinoline system, which in turn contributes to the convergence of the cyclization centers.

The photochemical generation of superoxide Rh(III) complexes

The photolysis products of the [Rh(NH3)5(NO2)](NO3)2 complex in aqueous solutions were studied by electron paramagnetic resonance (EPR), UV-visible (UV-vis), and 15N nuclear magnetic resonance (15N NMR) spectroscopies. Aqueous solutions of [Rh(NH3)5(NO2)](NO3)2 became blue when exposed to UV irradiation under an oxygen-containing atmosphere while aqueous solutions of [Rh(NH3)5(NO2)](NO3)2 with additives of NaNO2 turned orange under the same conditions. Photolysis of degassed [Rh(NH3)5(NO2)](NO3)2 solutions did not lead to any change of their color. It was suggested that, as a result of the photolysis, the complex decomposed with the formation of a NO2 fragment and a fragment containing Rh(II). In the presence of molecular oxygen in solution, a superoxide complex, [Rh(NH3)5O2]2+, was formed, in which electron transfer from the metal ion to O2 took place.

Modern level for properties prediction of iodine-containing organic compounds: the halogen bonds formed by iodine

The modern concepts on specific features of anisotropy of the electron density of valence shells of bound atoms and chemical bonds providing the successful description of the properties of halogen bonds formed by the iodine molecule in compounds with useful physicochemical properties are generalized in the review. The prognoses of basicity by the diiodine basicity scale for the nitrogen-containing compounds are illustrated. The regularities and peculiarities of shifting bands in Raman spectra of iodine-containing organic crystals are considered. The methodical and specific problems of modeling appeared when the electronic characteristics of the iodine compounds are estimated and briefly discussed.