Vibrational spectra of hydrazinium(1+) and hydrazinium(2+) hexafluorotitanates(IV) and the decomposition of hydrazinium(2+) hexafluorotitanate(IV) difluoride followed by Raman spectroscopy

Abstract

The Raman spectra of [N₂H₅]₂[TiF₆], [N₂H₆][TiF₆], and [N₂H₆]₂[TiF₆]F₂ are reported and analysed together with the already known infrared spectra, for which a corrected assignment is given. Raman spectra of the [TiF₆]^2– ion show a previously unobserved ν₂(455 cm^–1) and a symmetry inactive ν₆ mode (ca. 210–220 cm^–1) in O_h, appearing under the influence of the site group. An inactive torsional vibration of [N₂H₆]²⁺ was observed at 509 cm^–1 in the Raman spectrum of [N₂H₆]₂[TiF₆]F₂. An i.r. type (i) strong hydrogen-bond spectrum was displayed by this compound. [N₂H₆]₂[TiF₆]F₂ is unstable and its decomposition to [N₂H₅]₂[TiF₆] under the heat of a laser beam was followed by means of Raman spectra. Changes in the spectra suggest that the decomposition occurs via a proton transfer from [N₂H₆]²⁺ to a F^– ion, producing [N₂H₅]⁺ and liberating a molecule of HF.