On the Formation of N₃H₃ Isomers in Irradiated Ammonia Bearing Ices: Triazene (H₂NNNH) or Triimide (HNHNNH)

Abstract

The remarkable versatility of triazenes in synthesis, polymer chemistry and pharmacology has led to numerous experimental and theoretical studies. Surprisingly, only very little is known about the most fundamental triazene: the parent molecule with the chemical formula N3 H3 . Here we observe molecular, isolated N3 H3 in the gas phase after it sublimes from energetically processed ammonia and nitrogen films. Combining theoretical studies with our novel detection scheme of photoionization-driven reflectron time-of-flight mass spectroscopy we can obtain information on the isomers of triazene formed in the films. Using isotopically labeled starting material, we can additionally gain insight in the formation pathways of the isomers of N3 H3 under investigation and identify the isomers formed as triazene (H2 NNNH) and possibly triimide (HNHNNH).

Unprecedented Cyclic Isomer of Triazenes: A Computational Identification

“…For example, among the three triimide isomers, II a in trans‐trans (H‐arrangement), II b in trans‐cis , and II c in cis‐cis has the increased relative energy at 18.6, 19.3 and 24.3 kcal/mol, respectively. For the isomers I‐IV , our CBS‐QB3 structural parameters and relative energies are in good agreement with the latest reports …”

“…The CBS‐QB3 pathways of N 3 H 3 are reported in Figure , in which the rate‐determining barriers of the isomers I‐V are marked in red. According to the previous studies, the rate‐determining step of I b is the N‐H rotation into I a with the barrier 38.99 kcal/mol ,. We discovered a new step for I b , i.e., its direct dissociation into P1 (N 2 +NH 3 ) with the barrier 30.09 kcal/mol.…”

A Vacuum Ultraviolet Photoionization Study on the Formation of N-methyl Formamide (HCONHCH3) in Deep Space: A Potential Interstellar Molecule with a Peptide Bond

“…In order to record and monitor the VUV light, a detection system consisting of a Faraday cup and a diode calibrated by the National Institute of Standards and Technology (NIST) is placed behind the detection region. This tunable VUV photon source allows soft-ionization of molecules with ideally no fragmentation (Förstel et al 2015(Förstel et al , 2016a(Förstel et al , 2016dAbplanalp & Kaiser 2017;Góbi et al 2017). In this work we used a mixture of rhodamine610 and rhodamine640 in the first dye laser, pumped by 532nm, to generate 606.948nm, which is frequency-tripled to ω 1 =202.316nm for the twophoton resonance of krypton (Kr).…”

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

“…Triazene, HN=NH-NH2, and possibly the higher-energy isomer azimine (triimide), NH-NH-NH, have also been generated by electron bombardment of ammonia and nitrogen ices [155]. Calculations indicate that cis-and trans-triazene and azimine as well as the higher-energy hydrazinonitrene isomer H 2 N-NH-N: can interconvert via hydrogen shifts, and decompose to N 2 + NH 3 , H 2 + HN 3 , NH 2 + HN2, among other processes.…”