Mass spectrometric study of hexamethyldisilazane and some of its N‐substituted derivatives

Abstract

The electron-impact-induced decomposition of the title compounds has been investigated in detail. Deuterium labelling was used to study the mechanisms of fragmentation and the structures of ions generated. Hydrogen, methyl and phenyl group migrations to one of the silicon atoms were observed as significant secondary processes. These processes are usually y-transitions, from which it is inferred that these rearrangements occur via 4-membered cyclic transition complexes. I N T R O D U C T I O NDESPITE the fact that over the past ten years the mass spectra of numerous compounds containing Si-N bonds, mainly those of trimethylsilylated amines (i.e. compounds having one TMS group in each amino group) have been published, very little has been reported on the mass spectrometric behaviour of disilazanes.2-8The interesting fragmentation characteristics of these compounds and their great ability to rearrange could have been deduced from the mass spectra of hexamethyldisilazane (1)2-5 and N-methylhexamethyldisilazane (II)?.' but the mechanisms of the rearrangements and the structure of the product ions could not be defined unambiguously except by isotope labelling or comparative investigations of various derivatives. In the present paper the results of a detailed study of the electronimpact-induced fragmentation of hexamethyldisilazane, its several N-alkyl derivatives (I to IV) and D-labelled analogues, together with other N-substituted derivatives (V to IX), are presented.

Metastable ion study of organosilicon compounds. Part III—trimethoxyphenylsilane

“…(1-d9) (2) Figure 1 shows the mass spectra of 1 and l-d9. Major ions in the mass spectrum of 1 shift to the appropriate mass spectrum of 1-d,, as described above.…”

Atomic layer deposition of LiF using LiN(SiMe3)2 and SF6 plasma

“…26,45 We expect the m/z of 65 amu corresponds with the double ionized species from m/z = 130 (N(SiMe 2 ) 2 + ), and the m/z of 65.5 corresponds with the double ionized species from m/z = 131 (HN(SiMe 2 ) 2 + ). 26,47 Fig. 9b shows the spectra of SF 6 plasma and SF 6 gas, which are essentially identical in terms of detected species.…”

Kristallstruktur und spektroskopische Charakterisierung von Hexamethyl- disilazan-Aluminiumtrichlorid [(H3C)3Si]2NH ∙ AlCl3 / Crystal Structure and Spectroscopic Characterisation of Hexamethyl- disilazane-trichloroalum inum [(H3C)3Si]2NH ∙ AlCl3

“…Setzt m an hingegen die u nverdü nn ten E d u k te oberhalb von 50 °C um, führt dies u n ter A bspaltung von Trim ethylchlorsilan zu [(H 3 C )3S i-N H -A lC l2] 2[2], N ach U m kristallisa tion aus 1,2-D ichlorethan erhält m an die T itelver bindung in Form von großen (bis 20 mm K an ten länge), farblosen, auf dem Lösem ittel schw im m en Im M assenspektrum tritt w eder ein M olekülionenpeak auf, noch ein Fragm ent, das auf A lum inium chlorid schließen ließe. Statt des sen findet m an neben dem M olekülionenpeak für H exam ethyldisilazan (m /z = 146) und den zugehö rigen Fragm ent-Ionen[4] auch ein Fragm ent, das einem C hlorsilan (m /z = 93) zuzuordnen ist. O f fenbar lässt sich das A ddukt unter den B edingun gen d er E lektronenstoßionisation nicht unzersetzt in die G asphase bringen.…”