13762-95-3Relevant articles and documents
Direct detection of aqueous diazene: Its UV spectrum and concerted dismutation
Tang,Stanbury
, p. 1388 - 1391 (2008/10/08)
N2H2 is an intermediate in the acid-assisted hydrolysis of azodiformate, (NCO2)22-. When the hydrolysis is conducted at pH ≈4, the second-order dismutation of diazene occurs on a time scale longer than that of its generation. Due to this property, the intermediate (N2H2) and its decomposition can be observed directly in a stopped-flow instrument. The absorption maximum occurs at 355 nm with ε = 24 ± 3 M-1 cm-1. The region of absorption (300-430 nm) is in fair agreement with that of the gas-phase spectrum reported by other workers. The rate constant for the second-order dismutation of N2H2 is (2.2 ± 0.3) × 104 M-1 s-1 at 25°C and 0.11 M ionic strength, which agrees with the previously reported value (2.0 × 104 M-1 s-1) obtained by indirect methods. The temperature dependence of this process, over the temperature interval from 283 to 313 K, leads to the activation parameters ΔH? = 13.8 ± 0.6 kJ mol-1 and ΔS? = -116 ± 2 J K-1 mol-1. The dismutation displays an overall deuterium kinetic isotope effect of 3.3, as determined by conducting the reaction in a fully deuterated medium.
