Synthesis of Fused Heterocycles Based on 1-Amino-1H-tetrazole-5-thiol and α,β-Unsaturated Aldehydes

Russian Journal of General Chemistry - 8-Phenyltetrazolo[5,1-b][1,3,4]thiadiazepine was obtained as a result of intermolecular cyclization of 1-amino-1H-tetrazole-5-thiol and 3-phenyl-2-propynal....     

Effect of a third component of the anomalous volume magnetostriction of Invar alloys

An experimental study was made of the effect of Co, Cu, Al, and C on the anomalous volume magnetostriction of Fe-Ni Invar alloys. It was found that alloying with cobalt or copper shifts the (dλ_n/dH) and λ_s extrema to the left, while alloying with aluminum or carbon shifts them to the right, along the nickel concentration axis. It was also found that structural inhomogeneities strongly affect the volume magnetostriction near the Curie point.     

Interference ionization of an impurity by an electric field in a system of quantum wells

A radical change in the ionization energy of the donor impurity Si in a GaAs/AlGaAs double-well heterostructure is observed experimentally when the electronic wave function is relocated in an electric field. The ionization energy of the impurity decreases from 15.5 meV to 0 when the voltage across the structure changes by less than 1 V. The Stark effect would give a change in the ionization energy of not more than 3 meV. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 3, 194–199 (10 February 1999)     

Expanding the Averievite Family, (MX)Cu5O2(T5+O4)2 (T5+ = P,V; M = K,Rb, Cs,Cu; X = Cl,Br): Synthesis and Single-Crystal X-ray Diffraction Study

Averievite-type compounds with the general formula (MX)[Cu₅O₂(TO₄)], where M = alkali metal, X = halogen and T = P, V, have been synthesized by crystallization from gases and structurally characterized for six different compositions: 1 (M = Cs; X = Cl; T = P), 2 (M = Cs; X = Cl; T = V), 3 (M = Rb; X = Cl; T = P), 4 (M = K; X = Br; T = P), 5 (M = K; X = Cl; T = P) and 6 (M = Cu; X = Cl; T = V). The crystal structures of the compounds are based upon the same structural unit, the layer consisting of a kagome lattice of Cu²⁺ ions and are composed from corner-sharing (OCu₄) anion-centered tetrahedra. Each tetrahedron shares common corners with three neighboring tetrahedra, forming hexagonal rings, linked into the two-dimensional [O₂Cu₅]⁶⁺ sheets parallel to (001). The layers are interlinked by (T⁵⁺O₄) tetrahedra (T⁵⁺ = V, P) attached to the bases of the oxocentered tetrahedra in a “face-to-face” manner. The resulting electroneutral 3D framework {[O₂Cu₅](T⁵⁺O₄)₂}⁰ possesses channels occupied by monovalent metal cations M⁺ and halide ions X⁻. The halide ions are located at the centers of the hexagonal rings of the kagome nets, whereas the metal cations are in the interlayer space. There are at least four different structure types of the averievite-type compounds: the P-3m1 archetype, the 2 × 2 × 1 superstructure with the P-3 space group, the monoclinically distorted 1 × 1 × 2 superstructure with the C2/c symmetry and the low-temperature P2₁/c superstructure with a doubled unit cell relative to the high-temperature archetype. The formation of a particular structure type is controlled by the interplay of the chemical composition and temperature. Changing the chemical composition may lead to modification of the structure type, which opens up the possibility to tune the geometrical parameters of the kagome net of Cu²⁺ ions.     

A simple way to novel 2-dichloromethyl-5-aryl-2H-tetrazoles

A series of 2-dichloromethyl-5-aryl-2H-tetrazoles ( 3a–i ) were synthesized by the reaction of 5-aryl-NH-tetrazoles with trichloromethane in strong organic basic condition. The reaction represents a single-stage access to a new class of promising compounds, which not only can have biological activity, but can also serve as intermediates for further alkylation of halogen and the introduction of various fragments into the structure. The compounds obtained were fully characterized by means of ESI–MS, ¹H and ¹³C{¹H} NMR spectroscopies, as well as by single-crystal X-ray diffraction (for 3b ) the structural parameters as well as the vibrational corrections to enthalpies and total energies of the investigated systems were calculated using DFT B3LYP/6-31+G** approach.     

WING BUFFET CONTROL BY USING AN EJECTOR-TYPE DEVICE

Journal of Applied Mechanics and Technical Physics - A problem of the flow around a rectangular wing under the transonic buffet conditions in a wind tunnel is investigated numerically and...     

Synthesis,structure, and antiviral properties of novel 2-adamantyl-5-aryl-2H-tetrazoles

Chemistry of Heterocyclic Compounds - The reaction of 5-aryl-NH-tetrazoles with adamantan-1-ol in concentrated sulfuric acid proceeds regioselectively with the formation of the corresponding...     

Novel tris(5-aryl-1H-tetrazol-1-yl)methanes and 2-dichloromethyl-5-aryl-2H-tetrazoles and noncovalent interactions in their crystal structure

A series of tris(5-aryl-1H-tetrazol-1-yl)methanes ( 3a-3g ) and 2-dichloromethyl-5-aryl-2H-tetrazoles ( 4a-4d ) were synthesized by reaction of 5-aryl-NH-tetrazoles with trichloromethane in strong aqueous basic condition. The compounds obtained were fully characterized by means of HRESI-MS, ¹H and ¹³C{¹H} NMR spectroscopies, as well as by single-crystal X-ray diffraction (for 3a , 3b , 4d ). Inspection of the X-ray diffraction data and Hirshfeld surface analysis for tris(5-aryl-1H-tetrazol-1-yl)methanes 3a , b and 2-dichloromethyl-5-aryl-2H-tetrazole 4d showed the presence of noncovalent π-hole•••lone pair and π-hole•••π interactions involving electrophilic tetrazole carbon atom.     

Wing Buffeting Control at Transonic Flight Velocities with the Use of Ejector-Type Pulse Thermal Actuators

A new type of ducted pulse thermal actuators with a high pulse repetition frequency is proposed to control wing buffeting at transonic flight velocities. Ducted pulse thermal actuators can operate up to frequencies of about 1 kHz, which is sufficient for controlling the majority of aerodynamic processes at high subsonic flow velocities. As the use of a pulse thermal actuator in the regime of tangential injection of a jet is less efficient from the energy viewpoint than in the regime of boundary layer suction, an ejector-type pulse thermal actuator is proposed for implementation of the suction regime.