THE INFRARED-SPECTRA OF COMPLEXES WITH PLANAR DITHIOOXAMIDES .8. THE AU(III) COMPLEXES

In acid media Au(III) forms complexes with dithiooxamide (DTO) of form ula [Au(DTO)(DTO)-H]Cl-2 and with N,N-dimethyldithiooxamide (DMDTO) of formula [Au(DMDTO-H)(1)X(2)] (X is Cl or Br) and [Au(DMDTO)(1)Br-2]Br . In strong alkaline media for the N,N'-disubstituted dithiooxamides a new type of complex could be obtained with formula A[Au(L)(2)] (A is Li, Na or K; LH(2) is DMDTO or N,N'-diethyldithiooxamide (DEDTO)). Inf rared and Raman spectroscopy has been used to study of these complexes and also some thermal analysis is included. A thorough analysis of th e vibrational spectra is carried out to reveal the structure of these complexes. From this it is concluded that all complexes have a square- planar geometry around Au(III) and that in all cases the dithiooxamide s act as bidentate ligands coordinating through both sulphur atoms for ming chelate ring systems. For the complexes formed in acid media spec ial attention is given to the effect of hydrogen bonding on the infrar ed spectra, while for the complexes obtained in alkaline media the inf luence of the alkali counter-ion is investigated. From the TG data it is concluded that the forces in the ionic lattice of the A[Au(L)(2)] c omplexes follow the series Li > Na > K.