STUDIES WITH DITHIZONE .16. WATER-SOLUBLE ARYLMERCURY(2) DITHIZONATES AND SECONDARY ARYLMERCURY(2) DITHIZONATES

Arylmercury(II) cations containing carboxy groups form with dithizone yellow 1:1 complexes of the HOOC⋯R⋯Hg(HDz) which can be extracted quantitatively into carbon tetrachloride over a wide pH range. In alkaline media, water-soluble yellow complexes -OOC ⋯ R ⋯ Hg(HDz) are formed and in strongly alkaline solutions these ionise further to give magneta-coloured anions,-OCR⋯R⋯Hg(Dz)-. Phenylmecury(II) dithizonate, PhHg(HDz), ionises in very alkaline solution to give the magneta anion PhHg(Dz)- and the acid dissociation constant, pK=11.5(in 36-53%v/vethanol-water;μ=0.1MNaClO4) was determined spectrophotometrically. In alkaline solution and in the presence of excess of organomercurial, dithizone yields a series of secondary dithizonates which are less stable and less soluble in organic solvents than the primary complexes; their spectra were recorded. © 1969.