Triazene, HNNNH2, and Its Conjugate Base

An earlier kinetic investigation was described in [8]. The older literature on the possible formation of N3H3 via radiolysis of N2H4 was briefly discussed in [7, 8]. 

Properties. Ab initio calculations predict that the cis isomer of triazene is energetically less favorable than the trans isomer by 23 to 30 kJ/mol. Activation energies for the cis trans inversion in the range 200 to 380 kJ/mol were calculated for various transition states at the HF/6-31G level [9]. For an earlier theoretical study on this inversion, see [10]. 

The most favorable dimer of frans-triazene was predicted to form by simultaneous approach of the hydrogen of N, to N of the second molecule dissociation of the dimer can lead to the tautomeric triazenes [12]. The tautomerization of triazenes by a [1.3]-H shift probably has a high energy barrier [9]. The thermodynamically favored protonation site of trans-tnazene is N , and Np is the one least favored [12, 14]. Kinetic reasons suggest a protonation at N,, because the resulting cation can be considered a complex of an ammonia molecule and a diazonium ion, products which also result from the protonation of organic triazenes [14]. 

C C6H5NNN(C6H5)H D 2-NH2C(0)C6H4NNN(CH3)2. - The angle NNH is not given. 

The shifts agree qualitatively with earlier results in [21], where the coupling constants J(N Np) = 12.8 Hz and J(NpNy) = 14.0 Hz were additionally given. 

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