Tetrazoles: Synthesis, Structures, Physico-Chemical Properties and Application

The paper represents a brief review of works published by the authors over a period of 1980-2003 years in the field of synthesis and investigations of properties of tetrazole derivatives. The main attention is given to problems of regioselective functionalization of the tetrazole ring and the development of simple and convenient methods for the synthesis of N- and C-substituted tetrazoles, to peculiarities of structure of crystalline tetrazoles including quaternary salts and complexes with transition metal salts as well as to the data on electronic, spatial structure and energetic characteristics of tetrazoles obtained using both quantum-chemical methods and IR-, XH , 13C and 15N NMR spectroscopy. The features of thermal decomposition and combustion of various tetrazoles and polyvinyltetrazoles determining the prospects of their use as effective components of different kind combustible and thermally decomposing systems, including those capable of liquid-flame combustion, which has been revealed for the first time, are considere

Colloidal Nanocrystals Embedded in Macrocrystals: Robustness, Photostability, and Color Purity

Cataloged from PDF version of article.The incorporation of colloidal quantum dots (QDs) into ionic crystals of various salts (NaCl, KCl, KBr, etc.) is demonstrated. The resulting mixed crystals of various shapes and beautiful colors preserve the strong luminescence of the incorporated QDs. Moreover, the ionic salts appear to be very tight matrices, ensuring the protection of the QDs from the environment and as a result providing them with extraordinary high photo- and chemical stability. A prototype of a white light-emitting diode (WLED) with a color conversion layer consisting of this kind of mixed crystals is demonstrated. These materials may also find applications in nonlinear optics and as luminescence standards

trans-Dichloridotetrakis­[1-(2-hydroxy­ethyl)-1H-tetrazole-κN 4]cobalt(II)

The title cobalt(II) complex, [CoCl2(C3H6N4O)4], was obtained from metallic cobalt by direct synthesis. There are two Co atoms in the asymmetric unit, each lying on an inversion centre and adopting a distorted octa­hedral coordination. Classical and non-classical hydrogen bonds are responsible for formation of a three-dimensional polymeric network in the crystal

Lewis acid complexes: synthesis and application in polymerization processes

The published works by the present authors on the synthesis of organoaluminium compounds and complexes there of are summarized. The study of the reactivity of these latter in stereospecific and alternating polymerization made it possible to produce effective catalysts for synthe-sizing superhigh molecular weight polyolefins, alternating copolymers. The detailed investigation of the properties of the organoaluminium complexes with ethers allowed working out new catalytic systems capable of initiating styrene living cationic polymerization. The revealed regularities of living polymerization of styrene allows to realize for the first time the controlled polymerization of industrial C9-fraction, with the obtained results being used for developing technology for production of aromatic hydrocarbon resins from C9-fraction. An industrial process was developed and employed to produce oligopiperylene and aromatic hydrocarbon resins, which are used as film-forming components in paint and varnish compositio

Macrocrystals of Colloidal Quantum Dots in Anthrancene: Exciton Trannsfer and Polarized Emission

Cataloged from PDF version of article.In this work, centimeter-scale macrocrystals of nonpolar colloidal quantum dots (QDs) incorporated into anthracene were grown for the first time. The exciton transfer from the anthracene host to acceptor QDs was systematically investigated, and anisotropic emission from the isotropic QDs in the anthracene macrocrystals was discovered. Results showed a decreasing photoluminescence lifetime of the donor anthracene, indicating a strengthening energy transfer with increasing QD concentration in the macrocrystals. With the anisotropy study, QDs inside the anthracene host acquired a polarization ratio of similar to 1.5 at 0 degrees collection angle, and this increases to similar to 2.5 at the collection angle of 60 degrees. A proof-of-concept application of these excitonic macrocrystals as tunable color converters on light-emitting diodes was also demonstrated

catena-Poly[cobalt(II)-di-μ-chlorido-κ4 Cl:Cl-μ-1,5-dimethyl-1H-tetra­zole-κ2 N 3:N 4]: an X-ray powder investigation

The asymmetric unit of the title compound, [CoCl2(C3H6N4)]n, contains two Co atoms, both lying on inversion centres, two Cl atoms and one 1,5-dimethyl­tetra­zole ligand. The coordination polyhedra of both Co atoms adopt flattened octa­hedral geometry, with two N atoms from two ligands in axial positions and four Cl atoms in equatorial sites. Neighbouring Co atoms are linked together via two bridging Cl atoms and one tetra­zole ring to form polymeric chains running along the a axis

Resonance energy transfer in self-organized organic/inorganic dendrite structures

Hybrid materials formed by semiconductor quantum dots and J-aggregates of cyanine dyes provide a unique combination of enhanced absorption in inorganic constituents with large oscillator strength and extremely narrow exciton bands of the organic component. The optical properties of dendrite structures with fractal dimension 1.7–1.8, formed from J-aggregates integrated with CdTe quantum dots (QDs), have been investigated by photoluminescence spectroscopy and fluorescence lifetime imaging microscopy. Our results demonstrate that (i)J-aggregates are coupled to QDs by F¨orster-type resonant energy transfer and (ii) there are energy fluxes from the periphery to the centre of the structure, where the QD density is higher than in the periphery of the dendrite. Such an anisotropic energy transport can be only observed when dendrites are formed from QDs integrated with J-aggregates. These QD/ J-aggregate hybrid systems can have applications in light harvesting systems and optical sensors with extended absorption spectra.Fundação para a Ciência e a Tecnologia (FCT