Complex hydrogen bonded cations-IV further symmetric ions

Solutions containing the complex hydrogen bonded cations (NMe imidazole)₂ H⁺; (thiazole)₂H⁺ and (benzothiazole)₂H⁺ have been prepared. The spectra display a pronounced double maximum in the v_s infrared band, which is replaced by a single band in the D-bridged analogues. The activity of the far infrared v_s band, the frequency of the NH bending mode, and the observation of internal modes characteristic of both donor and acceptor all indicate that the hydrogen bonding proton is not located at the mid point of the NβN bridge.Salts of the complex (benzothiazole)₂H⁺ cation have been obtained in the solid state, and have a similar infrared spectrum to the complex in solution.