Molecular structure and spectra of bis (1,4-dimethylpyridinium)-tetrachlorocuprate(II)

Reaction of 1,4-dimethylpyridinium chlorosulphite with anhydrous copper(II) chloride in an atmosphere of dry nitrogen yields an ionic complex containing discrete CuCl₄]^2– anions and 1,4-dimethylpyridinium cations. Electronic (solid and in solution), far infrared and¹H NMR spectral data predict a distortedT _d structure which has been confirmed by X-ray crystallography. The crystal structure was solved by the heavy-atom method and refined by full-matrix least squares toR=0.059 for 1685 observed reflections. The CuCl₄]^2– anions exhibit twofold symmetry and there are no unusual interactions with the cations. Bond lengths and angles place it in the select class of complexes with the least flattenedT _d structure.