Katherine M. Broadus

Conjugate base of a cyclic hydrazine: formation and energetics of N-diaziridyl anion

N-Diaziridyl anion (1), the conjugate base of a simple hydrazine, has been generated in a Fourier transform mass spectrometer (FTMS) by reduction of the nitrogen‐nitrogen double bond in diazirine. The acidity of its conjugate acid (390 6 3 kcal mol 21 ) and the electron affinity of its corresponding radical (0.50 6 0.10 eV) were measured. These data are combined in a thermodynamic cycle to afford the N‐H bond strength in trans-diaziridine (2 ,8 86 4 kcal mol 21 ). This value represents one of the few such bond energies reported for a hydrazine. High-level ab initio complete basis set-quadratic configuration interaction/atomic pair natural orbital (CBS-QCI/APNO) calculations on 1 and the parent hydrazyl anion (NH2NH 2 ) are presented. These results provide strong confirming evidence for Berkowitz’s recent determination of the N‐H bond strength in hydrazine. (Int J Mass Spectrom 185/186/187 (1999) 179 ‐187)