Reactions of bis(tetrazole)phenylenes. Surprising formation of vinyl compounds from alkyl halides

The reactions of 1,2-bis(tetrazol-5-yl)benzene (1), 1,3-bis(tetrazol-5-yl)benzene (2), 1,4-bis(tetrazol-5-yl)benzene (3), 1,2-(Bu₃SnN₄C)₂C₆H₄ (4), 1,3-(Bu₃SnN₄C)₂C₆H₄ (5) and 1,4-(Bu₃SnN₄C)₂C₆H₄ (6) with 1,2-dibromoethane were carried out by two different methods in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazoles. This lead to the formation of several alkyl halide derivatives, substituted at either N1 or N2 on the tetrazole ring, as well as the surprising formation of several vinyl derivatives. The crystal structures of both 1,2-[(2-vinyl)tetrazol-5-yl)]benzene (1-N,2-N′) (1b) and 1,3-bis[(2-bromoethyl)tetrazol-5-yl]benzene (2-N,2-N′) (5d) are discussed.     

Variable alignment of high resolution data by cluster analysis

High resolution time-of-flight secondary ion mass spectrometry (HR TOF-SIMS) is a powerful surface analytical method. For complex samples, this technique may yield intricate spectra that are difficult to interpret visually. Chemometric methods are useful for data analysis. However, these methods require that spectra are represented in a matrix format. Variances in mass measurements caused by calibration or instrumental effects may present difficulties in properly aligning mass spectral peaks into the correct columns of the data matrix. Cluster analysis of resolution elements is proposed as an alternative approach to construct the data matrix. An automated method for optimizing the data alignment is presented and evaluated for standard steel samples.     

Rate of abstraction of hydrogen atoms from ethane by muonium

Thermal reaction rates for the gas-phase reaction Mu+C₂H₆MuH+C₂H₅ have been measured bySR over the temperature range 510–730 K. The usual Arrhenius expression,k=Aexp(–E _a /RT), fits the data well, giving parametersA=1.0×10^–9 cm³ molecule^–1 s^–1 andE _a =15.35 kcal/mol. The activation energyE _a is 5.5 kcal/mol higher than for the H atom variant of this reaction, indicating a marked difference in reaction dynamics. Preliminary analysis indicates a still greater difference between Mu and H for the corresponding CH₄ reaction.     

Spin relaxation of muonated radicals in the gas phase

We report on recent results obtained for longitudinal field (T ₁) spin relaxation of the muonium-substituted (muonated) free radicals MuCO, MuC₂F₄, MuC₂H₃F, and MuC₄H₈ (t-butyl), comparing with results reported earlier for MuC₂H₄ (and MuC₂D₄). Some comparison with transverse field (T ₂) data is also given. These data are fit to a phenomenological model based on NMR theory of spin relaxation in gases. The parameters of these fits are presented and discussed.     

FK-multiplier spaces

In 1992 Grosse-Erdmann posed the problem of characterizing
those FK-spaces containing the finitely nonzero sequences whose -duals are themselves FK. Here we consider the more general problem of characterizing FK-spaces containing the finitely nonzero sequences with the property that the multipliers into a BK-sum space admit an FK-topology.