5-Vinyl-1H-tetrazole

Lisakova A.D., Ryabukhin D.S., Trifonov R.E., Ostrovskii V.A., Vasilyev A.V.

In a series of publications [2, 3] the synthesis of styryltetrazoles, containing substituents with strong electron-acceptor properties (F, NO2, CN, CO2H) in the aryl fragment based on cross-coupling of С-, Nvinyltetrazole with halobenzenes by Heck reaction is described. However no information exists on the synthesis of similar compounds containing electrondonor substituents. The electronic effect of the substituent in the aromatic fragment may significantly affect the efficiency of this reaction. The nature of the halogen present in the haloarene and the composition of the catalytic system are also of fundamental importance [4–7].

Nataraj A., Balachandran V., Karthick T.

In this work, the vibrational spectral analysis was carried out using Raman and infrared spectroscopy in the range 4000–400 cm −1 and 3500–100 cm −1 , respectively, for the 2-hydroxy-5-bromobenzaldehyde (HBB). The experimental spectra were recorded in the solid phase. The fundamental vibrational frequencies and intensity of vibrational bands were evaluated using density functional theory (DFT) with the standard B3LYP/6-311G++(d,p) method and basis set. Normal co-ordinate calculations were performed with the DFT force field corrected by a recommended set of scaling factors yielding fairly good agreement between observed and calculated frequencies. Simulation of infrared and Raman spectra utilizing the results of these calculations led to excellent overall agreement with the observed spectral patterns. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The optimized geometric parameters (bond lengths and bond angles) were compared with experimental values of related compound. The stability of the molecule arising from hyper conjugative interactions and the charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The directly calculated ionization potential (IP), electron affinity (EA), electronegativity ( χ ), electrophilicity index ( ω ), hardness ( η ), chemical potential ( μ ), and first electron excitation ( τ ) are all correlated with the HOMO and LUMO energies with their molecular properties. These show that charge transfer occurs within the molecule. Furthermore, molecular electrostatic potential maps (MESP) of the molecule have been calculated.

Aleshunin P.A., Esikov K.A., Dolgushin F.M., Ostrovskii V.A.

New functionalization procedure was developed for C- and N-vinyltetrazoles based on Heck reaction. Applying this method diverse (E)-styryl- and (E)-distyryltetrazoles were obtained for the first time in 76–85% yields. C-Vinyltetrazoles are more reactive in Heck cross-coupling than N-vinyltetrazoles. The arylation of 1-vinyltetrazole along Heck reaction proceeds with a C-H-activation and leads to the formation of 5-phenyl-1-[2-(E)-phenylethenyl]tetrazole.

Lu T., Chen F.

Multiwfn is a multifunctional program for wavefunction analysis. Its main functions are: (1) Calculating and visualizing real space function, such as electrostatic potential and electron localization function at point, in a line, in a plane or in a spatial scope. (2) Population analysis. (3) Bond order analysis. (4) Orbital composition analysis. (5) Plot density-of-states and spectrum. (6) Topology analysis for electron density. Some other useful utilities involved in quantum chemistry studies are also provided. The built-in graph module enables the results of wavefunction analysis to be plotted directly or exported to high-quality graphic file. The program interface is very user-friendly and suitable for both research and teaching purpose. The code of Multiwfn is substantially optimized and parallelized. Its efficiency is demonstrated to be significantly higher than related programs with the same functions. Five practical examples involving a wide variety of systems and analysis methods are given to illustrate the usefulness of Multiwfn. The program is free of charge and open-source. Its precompiled file and source codes are available from http://multiwfn.codeplex.com.

Glendening E.D., Landis C.R., Weinhold F.

Natural bond orbital (NBO) methods encompass a suite of algorithms that enable fundamental bonding concepts to be extracted from Hartree‐Fock (HF), Density Functional Theory (DFT), and post‐HF computations. NBO terminology and general mathematical formulations for atoms and polyatomic species are presented. NBO analyses of selected molecules that span the periodic table illustrate the deciphering of the molecular wavefunction in terms commonly understood by chemists: Lewis structures, charge, bond order, bond type, hybridization, resonance, donor–acceptor interactions, etc. Upcoming features in the NBO program address ongoing advances in ab initio computing technology and burgeoning demands of its user community by introducing major new methods, keywords, and electronic structure system/NBO communication enhancements. © 2011 John Wiley & Sons, Ltd.

Ostrovskii V.A., Aleshunin P.A., Zubarev V.Y., Popova E.A., Pavlyukova Y.N., Shumilova E.A., Trifonov R.E., Artamonova T.V.

The NH-unsubstituted 5-vinyltetrazole was obtained in 55% yield by exhaustive methylation of 5-(β-dimethylaminoethyl)tetrazole with dimethyl sulfate at the terminal dimethylamino group with the subsequent elimination of a proton from the α-CH2 group and Hofmann β-cleavage of the intermediate 5-(β-trimethylammoniumethyl)tetrazolide methyl sulfate. The microwave irradiation was shown to reduce 5-fold the time of the synthesis of the initial substrate, 5-(β-dimethylaminoethyl)tetrazole.

Ostrovskii V.A., Podkameneva M.E., Poplavskii V.S., Trifonov R.E.

The alkylation of 5-(β-dimethylaminoethyl)tetrazole (1) with dimethyl sulfate afforded 5-(β-dimethylaminoethyl)-1-methyltetrazole (2) and 5-(β-dimethylaminoethyl)-2-methyltetrazole (3). The exhaustive alkylation of compounds 2 and 3 at the terminal dimethylamino group gave 1-methyl-(4) and 2-methyl-5-(β-trimethylammonioethyl)tetrazole (5) methyl sulfates. The proton elimination from the α-methylene (with respect to the tetrazole cycle) groups of the quaternary ammonium cations of salts 4 and 5 by the action of a base leads to the corresponding zwitterions 4± and 5±, which in the rate-determining step undergo the cleavage of the nitrogen—carbon bond with the formation of 1-methyl-5-vinyl- (6) and 2-methyl-5-vinyltetrazole (7). The true constant of the transformation of zwitterion 4± into tetrazole 6 is 21 times higher than that for the transformation of zwitterion 5± into tetrazole 7.

Dolomanov O.V., Bourhis L.J., Gildea R.J., Howard J.A., Puschmann H.

New software,OLEX2, has been developed for the determination, visualization and analysis of molecular crystal structures. The software has a portable mouse-driven workflow-oriented and fully comprehensive graphical user interface for structure solution, refinement and report generation, as well as novel tools for structure analysis.OLEX2seamlessly links all aspects of the structure solution, refinement and publication process and presents them in a single workflow-driven package, with the ultimate goal of producing an application which will be useful to both chemists and crystallographers.

Pavlyukova Y.N., Trifonov R.E., Yugai E.V., Aleshunin P.A., Tselinskii I.V., Ostrovskii V.A.

Alkylation of NH-unsubstituted 5-vinyltetrazole with methyl iodide in the presence of triethylamine in acetonitrile solution led to the formation of isomeric 1- and 2-methyl-5-vinyltetrazoles in 1:1 ratio. The reaction rate constants were measured at 25–55°C. According to the thermodynamic parameters of the reaction [ΔH ≠ 66 kJ mol−1, ΔS≠-74 (mol K)−1, 298 K] the limiting stage of the reaction consists in the electrophilic attack of methyl iodide on an H-complex of the heterocycle with triethylamine.

Merrick J.P., Moran D., Radom L.

Scale factors for obtaining fundamental vibrational frequencies, low-frequency vibrational frequencies, zero-point vibrational energies (ZPVEs), and thermal contributions to enthalpy and entropy have been derived through a least-squares approach from harmonic frequencies determined at more than 100 levels of theory. Wave function procedures (HF, MP2, QCISD, QCISD(T), CCSD, and CCSD(T)) and a large and representative range of density functional theory (DFT) approaches (B3-LYP, BMK, EDF2, M05-2X, MPWB1K, O3-LYP, PBE, TPSS, etc.) have been examined in conjunction with basis sets such as 6-31G(d), 6-31+G(d,p), 6-31G(2df,p), 6-311+G(d,p), and 6-311+G(2df,p). The vibrational frequency scale factors were determined by a comparison of theoretical harmonic frequencies with the corresponding experimental fundamentals utilizing a standard set of 1066 individual vibrations. ZPVE scale factors were generally obtained from a comparison of the computed ZPVEs with experimental ZPVEs for a smaller standard set of 39 molecules, though the effect of expansion to a 48 molecule data set was also examined. In addition to evaluating the scale factors for a wide range of levels of theory, we have also probed the effect on scale factors of varying the percentage of incorporated exact exchange in hybrid DFT calculations using a modified B3-LYP functional. This has revealed a near-linear relationship between the magnitude of the scale factor and the proportion of exact exchange. Finally, we have investigated the effect of basis set size on HF, MP2, B3-LYP, and BMK scale factors by deriving values with basis sets ranging from 6-31G(d) up to 6-311++G(3df,3pd) as well as with basis sets in the cc-pVnZ and aug-cc-pVnZ series and with the TZV2P basis.

Kizhnyaev V.N., Vereshchagin L.I.

The published data on the synthesis of C- and N-vinyltetrazoles and their chemical transformations (homo- and copolymerisation) involving the heterocycle and the vinyl group are systematised and generalised. The areas of possible application of these compounds are considered. The bibliography includes 194 references.

Demko Z.P., Sharpless K.B.

The addition of sodium azide to nitriles to give 1H-tetrazoles is shown to proceed readily in water with zinc salts as catalysts. The scope of the reaction is quite broad; a variety of aromatic nitriles, activated and unactivated alkyl nitriles, substituted vinyl nitriles, thiocyanates, and cyanamides have all been shown to be viable substrates for this reaction.

Espinosa E., Molins E., Lecomte C.

Abstract Interatomic interactions such as hydrogen bonds (HB) can be adequately described and classified by the topological properties of the electron density ρ(r) at the (3,−1) critical points rCP where the gradients of ρ(r) vanish. We have analysed the topological properties of ρ(r) at the intermolecular critical points of 83 experimentally observed HBs [X–H⋯O (X=C,N,O)], using accurate X-ray diffraction experiments. In spite of different models, methods and experimental conditions employed to obtain the topological properties of ρ(r), we show that, for closed-shell interactions, the kinetic energy density G(rCP) and the potential energy density V(rCP) at the critical point depend exponentially on the H⋯O distance. Moreover, theoretical calculations for several HB dissociation energies follow the same law as does V(rCP), with a simple change of scale.

Becke A.D.

Current gradient-corrected density-functional approximations for the exchange energies of atomic and molecular systems fail to reproduce the correct 1/r asymptotic behavior of the exchange-energy density. Here we report a gradient-corrected exchange-energy functional with the proper asymptotic limit. Our functional, containing only one parameter, fits the exact Hartree-Fock exchange energies of a wide variety of atomic systems with remarkable accuracy, surpassing the performance of previous functionals containing two parameters or more.

Ostrovskii Vladimir A., Chernova Ekaterina N., Zhakovskaya Zoya A., Pavlyukova Yulia N., Ilyushin Mikhail A., Trifonov Rostislav E.

Rapid processes of tetrazole decomposition serve as sources of chemical energy stored in the five-membered ring, as well as gaseous products, primarily molecular nitrogen. Due to these properties, energetic tetrazole derivatives have found applications in various fields of science, engineering and technology, for example as components of energetic materials and products, as well as in emergency rescue equipment. The review presents an alternative view of the processes of tetrazoles decomposition, focusing on the diversity, differences, and similarities of the mechanisms and degradation products formed under the action of external energy sources. Some of these products are valuable reagents for the synthesis of previously inaccessible substances, as well as promising objects of analytical, medical, and bioorthogonal chemistry.The bibliography includes 140 references.

Baigildin V., Shakirova J., Zharskaia N., Ivanova E., Silonov S., Sokolov V., Tunik S.

AbstractIn the present report, a novel dual pH‐O2 sensor based on covalent conjugate of rhodamine 6G and cyclometalated iridium complex with poly(vinylpyrrolidone‐block‐vinyltetrazole) copolymer is reported. In model physiological solutions the sensor chromophores display independent phosphorescent and fluorescent lifetime responses onto variations in oxygen concentration and pH, respectively. Colocalization studies on Chinese hamster ovary cells demonstrate the preferential localization in endosomes and lysosomes. The fluorescent lifetime imaging microscopy‐phosphorescent lifetime imaging microscopy (FLIM‐PLIM) experiments show that the phosphorescent O2 sensor provides unambiguous information onto hypoxia versus normoxia cell status as well as semi‐quantitative data on the oxygen concentration in cells in between these two states. However, the results of FLIM measurements indicate that dynamic lifetime interval of the sensor (≈0.5 ns between pH values 5.0 and 8.0) is insufficient even for qualitative estimation of pH in living cells because half‐width of lifetime distribution in the studied samples is higher than the sensor dynamic interval. Nevertheless, the variations in rhodamine emission intensity are much higher and allow rough discrimination of acidic and neutral cell conditions. Thus, the results of this study indicate that the suggested approach to the design of dual pH‐O2 sensors makes possible to prepare the biocompatible and water‐soluble conjugate with fast cellular uptake.