Ammonidsilane mixtures have been studied by ion trap mass spectrometry, and variations of ion abundances with reaction time in 1 5 , 1:1, and 5 : 1 mixtures have been reported. Mechanisms of ion-molecule reactions have been elucidated by single and multiple isolation steps, and exact mass measurements of isobaric ions have been carried out by Fourier transform mass spectrometry. The SiH,+ (n = 0-3) primary ions give self-condensation processes in which Si,H,+ species are formed. These ions react with NH3 and give Si2-NH,+ (n = 3-6) and Si2N2Hn+ (n = 4-7) ions in successive steps with elimination of H2. In parallel processes, the SiH,+ (n = 0-3) primary ions react with NH3 to give ions belonging to the SiNH,+ (n = 2-4) and SiN2H,+ (n = 4-7) families, which do not react with Si& furtherly. A number of precursors give SiNH6+ and N&+ through different pathways, the last ion being the most abundant one also after short reaction times in all the mixtures examined. The rate constants of the gas-phase reactions of the most important ions have been determined by ion trap mass spectrometry, compared with calculated collision rate constants, and the efficiencies have been determined. Formation of Si2N2H,+ (n = 4-7) and SigN2Hn+ (n = 7, 8) ions, even if with rather low efficiencies, suggests that ionic species in addition to radicals can give a contribution to the deposition of solid silicon nitride from ammonidsilane mixtures by radiolytical methods.

The results of gas-phase rate constant measurements by Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry may be influenced by the setting of instrumental parameters. The effects of pressure, ionization duration, ionization energy, selection of the parent ion, mass range, trapping potential, reaction delay and pumping-regulation-valve opening have been investigated and analysed using a two-level Plackett-Burman statistical design which is described in an appendix. This approach was tested on the ion/molecule reaction between acetyl ion and acetone: CH 3 CO + + CH 3 COCH 3 → CH 2 CO + (CH 3 COCH 3 )H + . Although space-charge effects are known to be deleterious to FT-ICR, this is the first study demonstrating, on a statistical basis, the necessity of parent ion selection for obtaining reliable rate constants. Considered independently, the other factors tested do not appear statistically significant, but the possibility of interactions among them is discussed. The mean of the rate constants from experiments with acetyl ion selection, k abs = (2.14 ± 0.18) × 10 -10 cm 3 molecule -1 s -1 , is compared with literature data.

Durch Kondensation des Diazepiniumdiazoniumsalzes mit den entsprechenden Phenolen und Naphtholen werden die Farbstoffe (I) synthetisiert.

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Die Diazoniumsalze (I) ergeben mit Dicarbonylverbindungen (II) die Azo‐ derivate (III), die mit Ethylendiamin zu den 1,4‐Diazepinen (IV) weiterreagieren.