Preparation, crystal structure and vibrational spectra of N-benzylpiperaziniumpentahalodimercury(II) complexes: (NbzpipzH)Hg2X5 (X = Cl, Br)

The preparation of new mercury(II) compounds, (NbzpipzH)Hg2X5 (NbzpipzH = N-benzylpiperazinium monocation; X = Cl, Br) is reported. The determination of the structure of (NbzpipzH)Hg2Cl5 by three-dimensional single-crystal X-ray analysis is described. The structure contains two different mercury atoms. One of them binds covalently two chlorine atoms and two bridged chlorine atoms with long contacts. The coordination around the other mercury is tetrahedrically distorted and involves one terminal and two bridged chlorine atoms and one molecule of N-benzylpiperazinium monocation. Far-infrared and Raman spectra are interpreted on the grounds of the crystal structure of compounds suggesting a relation between the values of a mercuryhalogen stretching frequencies and the related bond distances.