Proposed Proton-Transfer Mechanism for the Initial Decomposition Steps of BTATz.

The first steps in the gas-phase decomposition mechanism of N3,N6-bis (1 H-tetrazol-5-yl)-1,2,4,5-tetrazine-3,6-diamine, BTATz, anions and the kinetic isotope effects in these processes were studied using combined multistage mass spectrometry (MS/MS) and computational techniques. Two major fragmentation processes, the exergonic loss of nitrogen molecules and the endergonic loss of hydrazoic acid, were identified. The observation of a primary isotope effect supported by calculations suggests that the loss of a nitrogen molecule from the tetrazole ring involves proton migration, either to or within the terazole ring, as a rate-determining step. The fragmentation of a hydrazoic acid occurs through an asymmetrical retro-pericyclic reaction. Calculations show the relevance of these mechanisms to neutral BTATz. Our findings may contribute to the understanding of decomposition routes in these nitrogen-rich energetic materials and allow tailoring their reactivity and decomposition pathways for better control of performance.

Versatile ruthenium complexes based on 2,2'-bipyridine modified peptoids.

Helical peptoids bearing 2,2'-bipyridine form ruthenium complexes via intermolecular binding to linear peptoid strands or intramolecular binding to a cyclic scaffold. Ru(ii) binding promoted changes in the conformational order of the peptoids, and chiral induction from the peptoids to their metal center was observed.

Homolytic reactive mass spectrometry of fullerenes: peculiarities of the reactions of C60 with aromatic compounds in the ionization chambers of mass spectrometers and in solution.

C60 reacted with PhH, PhCl, BnH, BnNH2, and o-C2H2B10H10 in the electron impact (EI) ion source of a mass spectrometer at 300 °C forming phenyl, benzyl, and o-carboranyl adducts, respectively, stabilized by hydrogen addition and loss. Besides, the additions to C60 of methyl and phenyl radicals for toluene, and a phenyl radical for benzylamine were observed. A homolytic reaction mechanism was suggested involving the reaction of the radicals formed from the aromatics under EI with C60 at the ionization chamber walls. While the ion/molecule reaction of C60 with benzene performed by Sun et al. under chemical ionization conditions at 200 °C afforded the complex C60•PhH(+•), quite a different isomer, HC60Ph(+•), was detected in the present study as a sequence of the different reaction mechanisms. C60 also reacted with benzyl bromide in the laser desorption/ionization (LDI) source of a mass spectrometer to give C60CPh(+). Phenyl and benzyl derivatives of C60 were found, respectively, when the reactions of the fullerene with PhCl, BnH, and BnBr were performed in solution under ultra violet irradiation. For the reaction with toluene, the strong chemically induced dynamic electron polarization of the intermediate benzylfullerenyl radical with the reverse phase effect was found. The coincidence of the results of the mass spectrometry and solution reactions of C60 with aromatics, even though incomplete, additionally supports the hypothesis, formulated earlier, that the former results can predict the latter ones to a significant extent and shows that this conclusion is valid for both EI and LDI initiated reactions in mass spectrometers.