Magnesium cations as templates for the self-assembly of supramolecular luminescent {Mg@[Bφ]}-clusters.

Solvothermal reaction of magnesium nitrate and boron oxide in ,-dimethylformamide produced a number of particularly complex supramolecular magnesium borates. Five topologically different types of negatively charged {Mg@[Bφ]}-clusters, φ = O, OH, were observed with the magnesium cation as a core and octadecaborate anions as shells. The clusters assemble common borate polyhedra forming 1D chains, a 2D mesoporous layer, and 3D mesoporous frameworks with an effective channel width of up to 16 Å.

Four-parameter model of thin surface layer contribution to reflectance-absorbance spectroscopy and ellipsometry.

The contribution of the surface layer to the reflection coefficients is shown to be determined by four surface integral values, which can be interpreted as real and imaginary parts of two complex permittivity excesses. The reflectance-absorbance spectra are determined by the spectra of these parameters. The spectra of the surface excess integrals cannot be found with the angular measurements of reflection-absorption spectra, which are determined by only three angular dependent terms.

AgBOX (X = Cl, Br, I) Heptaborate Family: Comprehensive Crystal Chemistry, Thermal Stability Trends, Topology, and Vibrational Anharmonicity.

Using glass crystallization and solid-state techniques, we were able to complete the family of salt-inclusion silver halide borates, AgBOX, by the X = Cl and I members. The new compounds are characterized by differential scanning calorimetry, single-crystal and high-temperature powder X-ray diffraction, optical spectroscopy, and density functional theory calculations. In all structures, the silver atoms exhibit strong anharmonicity of thermal vibrations, which could be modeled using Gram-Charlier expansion, and its asymmetry was characterized by the skewness vector.

Field-Induced Assembly of sp-sp Carbon Sponges.

The formation of macroscale carbon structures characterised by an sp-sp2-hybridization is realised by self-assembly in colloidal solutions under an effect of laser irradiation and electromagnetic fields. The sponge-like morphology, sculptured with gold nanoparticles (NPs) was revealed by Scanning Electron Microscopy (SEM) imaging. Full structural and defect characterization of the self-assembled sponges was provided using the micro-Raman spectroscopic technique.

Angular invariance of the contribution of an anisotropic thin surface layer to reflectance and reflectance-absorbance.

The absorbance studies of the optical radiation reflection from the boundary of two soft-matter media with a thin monolayer between are performed for a number of angles of incidence. The reflectance and absorbance spectra are described in terms of a unique spectrum invariant with respect to the incidence angles. The angular dependence of the absorbance for s-polarized radiation is shown to not provide any extra information as compared with a single-angle study in line with the previously developed theoretical considerations.

Bridging the Salt-Inclusion and Open-Framework Structures: The Case of Acentric AgBOX (X = Br, I) Borate Halides.

An acentric borate family, AgBOX (X = Br, I), has been prepared by slow cooling stoichiometric melts in evacuated silica ampules. Their crystal structure is comprised of two porous interpenetrating frameworks and demonstrates a further development of the "salt-inclusion" architecture toward a "covalent-inclusion" structure. The (AgX) sublattice shows strong anharmonic vibrations.

The first silver bismuth borate, AgBiBO.

The first silver bismuth borate, AgBiBO (silver dibismuth pentaborate), has been prepared via glass crystallization in the AgO-BiO-BO system and characterized by single-crystal X-ray diffraction. Its structure is derived from that of centrosymmetric BiBO by ordered substitution of one Bi ion for Ag, which results in the disappearance of the mirror plane and inversion centre. Second harmonic generation (SHG) measurements confirm the acentric crystal structure.

Synthesis and Properties of 6-Aryl-4-azidocinnolines and 6-Aryl-4-(1,2,3-1-triazol-1-yl)cinnolines.

An efficient approach towards the synthesis of 6-aryl-4-azidocinnolines was developed with the aim of exploring the photophysical properties of 6-aryl-4-azidocinnolines and their click reaction products with alkynes, 6-aryl-4-(1,2,3-1-triazol-1-yl)cinnolines. The synthetic route is based on the Richter-type cyclization of 2-ethynyl-4-aryltriazenes with the formation of 4-bromo-6-arylcinnolines and nucleophilic substitution of a bromine atom with an azide functional group. The developed synthetic approach is tolerant to variations of functional groups on the aryl moiety.

Novel homogeneous photocatalyst for oxygen to hydrogen peroxide reduction in aqueous media.

An isoquinolinium-pyrrole donor-acceptor dyad was found to exhibit photocatalytic activity in oxygen-to-peroxide photoreduction with oxalate as a sacrificial electron donor. The concentration of hydrogen peroxide was shown to reach a plateau of 0.57 mM.

Light-Induced Reactions of Diazotetrahydrofuranone without Elimination of Nitrogen: Experimental and Mechanistic Study.

The energies and lifetimes of the excited states (S, S, S, T) of a diazotetrahydrofuranone were determined using experimental and computational methods. It was shown that direction of the diazoketone photochemical transformations without elimination of nitrogen is determined by multiplicity and energy of the excited state, generated by UV irradiation of diazo compound: isomerization to α-ketodiazirine proceeds from the singlet S state, whereas the alternative process of C-H insertion with hydrazone formation occurs through the triplet T state. The most probable excited state that leads to elimination of nitrogen and Wolff rearrangement is one of the highest singlet excited states of diazotetrahydrofuranone.

Phase Transitions in DNA/Surfactant Adsorption Layers.

The adsorption layers of complexes between DNA and oppositely charged surfactants dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB) at the solution/air interface were studied with surface tensiometry, dilational surface rheology, atomic force microscopy, Brewster angle microscopy, infrared absorption-reflection spectroscopy, and ellipsometry. Measurements of the kinetic dependencies of the surface properties gave a possibility to discover the time intervals corresponding to the coexistence of two-dimensional phases. One can assume that the observed phase transition is of the first order, unlike the formation of microaggregates in the adsorption layers of mixed solutions of synthetic polyelectrolytes and surfactants.

Synthesis of new porphyrin-fullerene dyads capable of forming charge-separated states on a microsecond lifetime scale.

A series of covalently linked axially symmetric porphyrin-fullerene dyads with a rigid pyrrolo[3,4-c]pyrrolic linker enabling a fixed and orthogonal arrangement of the chromophores has been synthesized and studied by means of transient absorption spectroscopy and cyclic voltammetry. The lifetime of the charge-separated state has been found to depend on the substituents on the porphyrin core, reaching up to 4 μs for a species with meso-(p-MeOC6H4) substituents. The ground and excited electronic states of model compounds have been calculated at the DFT and TD-DFT B3LYP(6-31G(d)) levels of theory and analyzed with regard to the effect of the substituent on the stabilization of the charge-separated state in the porphyrin-fullerene ensemble with a view to explaining the observed dependence.