Electronic Structure and Gas‐Phase Thermolysis of 2‐Tetrazenes with Acyclic or Cyclic Amino Groups Studied by Photoelectron Spectroscopy

Abstract

The electronic structures and the gas‐phase thermolyses of the 2‐tetrazenes 2–13 have been studied by He(I) photoelectron spectroscopy. The compounds are characterized by at least three ionization potentials with energies less than 10 eV which are assigned to the molecular orbitals π3 (HOMO), n+, π2, and n‐. In the thermolyses either the formal disproportionation products (amine and imine) of the respective aminyl radical are found, or the latter is stabilized by loss of an alkyl radical affording also an imine. Further products which can be explained by radical reactions are detected in flash vacuum pyrolyses. The tricyclic cis‐2‐tetrazene 13 is cleaved by [2 + 2 + 2] cycloreversion. The methoxymethylsubstituted compound 8 exhibits a more complex cleavage pattern.

First Synthesis and Investigation of Two Hydroxyalkyl-Substituted 2-Tetrazenes

“…Comdirect oxidation. It was, however, impossible to purify the product because it decomposed on distillation in high vac-parison of the δ-15 N values of 2a, its dimethoxy derivative 2c [8] and 1,2-dipyrrolidinodiazene (3) indicates that the subuum or during column chromatography. Better results were obtained when the alcoholic group of the starting com-stituents cause inverse effects on the chemical shifts of the azo and the amino nitrogen atoms.…”

“…Also several attempts starting from trimethylsilyl-protected hydroxyalkylhydrazines failed, while synthesis of a methoxyalkyl-2-tetrazene (2c) by this method was successful without problems. [8] Only in one case (2a) we were finally able to generate the corresponding 2-tetrazene directly from the hydroxyalkyl-groups at 3365 cm Ϫ1 . In CDCl 3 solution three ν OH bands are found with variable intensities depending on concenhydrazine.…”

Pyrolysis of hydrazine derivatives and related compounds with N N single bonds

“…190 and 191) in the 600-1000 o C range was investigated with photoelectron spectroscopic product analysis. Products of formal disproportionation (amine and imine) or loss of an alkyl radical from an aminyl radical were formed (Scheme 54); the methyl radical was detected directly, but the aminyls were not [180]. The tetrazene yields N 2 and the amine (Me 3 Si) 2 NH, presumably due to H-abstraction by the aminyl radical, the triazene yields the azide Me3SiN3 + (Me3Si)2O, and the diazene yields Me3SiOH + N2 [181].…”

The Base-Induced Fragmentation of N,N-Dibenzyl-N′-aryltriazenes

“…10 In addition, the thermolysis of tetrazenes also gives rise to the elimination products. 11 The analogous deprotonation of N-sulfonamides 12 and Nnitrosamines 13 is well known (the overall reaction is similar to an Umpolung reaction 14 however, only the fragmentation of sulfonamides has been reported so far. 12 Overall, this metalation/fragmentation protocol provides a novel route to 1,3-diarylazaanions, which have been used in the synthesis of 2,5-diarylpyrrolidines, 15 blactams 16 and other heterocyclic systems.…”