Preparations, infrared spectra, and structures of some zinc and cadmium arenesulphinates

The complexes, M(O₂SR)₂, 2H₂O (M = Zn or Cd; R = Ph or p-MeC₆H₄), have been prepared by metathesis reactions from the corresponding sodium arenesulphinates or arenesulphinic acids. Zinc benzenesulphinate has also been obtained from the reaction of diphenylzinc with sulphur dioxide and from the reduction of mercuric benzenesulphinate with zinc dust. Anhydrous zinc and cadmium arenesulphinates, M(O₂SR)₂, have been prepared by heating the dihydrates, and each cadmium complex has been obtained in two crystalline forms. From their isomorphism with the corresponding cobalt complexes, the zinc and cadmium arenesulphinate dihydrates have been shown to have octahedral stereochemistry. Both the hydrated and the anhydrous arenesulphinato complexes have sulphur-oxygen stretching frequencies indicative of O-sulphinate coordination, and polymeric structures based on bridging bidentate O-sulphinate groups are likely for all the complexes.