REACTION-PRODUCTS DISTRIBUTION BETWEEN SQUARE-PLANAR GOLD(III) COMPLEXES AND N,N,N',N'-TETRAMETHYLTHIURAM DISULFIDE - CRYSTAL-STRUCTURE OF BIS(N,N-DIMETHYLDITHIOCARBAMATO)GOLD(III) BROMIDE DIHYDRATE, [AU(ME(2)NCS(2))(2)]BR-CENTER-DOT-2H(2)O

The reactions of N,N,N',N'-tetramethylthiuram disulfide (tmtds) with g old(III) complexes of the [Au(L)X(3)] type [L = N-methylimidazole (N-M eIm), 2-methylbenzoxazole (2-MeBO) and 2,5-dimethylbenzoxazole (2,5-di MeBO), X = Cl, Br or I] are reported, and yielded two main types of pr oduct-[Au(Me(2)dtc)X(2)] (A) and [Au(Me(2)dtc)(2)]X (B) (Me(2)dtc = N, N-dimethyldithiocarbamato anion). The ratio of the product yields (B/A ) depends upon the nature of the ligand (L) and halogen (X). The ratio B/A for the reaction: [Au(L)Cl-3] + tmtds = A + B, increases in the s equence N-MeIm < 2-MeBO < 2,5-diMeBO, which correlates well with the l evel of cytotoxic activity exhibited by the [Au(L)Cl-3] complexes. A a nd B were characterized by their i.r., u.v-vis. and H-1-n.m.r. spectra . The magnetic measurements were also recorded. The data support a squ are-planar geometry for gold(III) complexes with the Me(2)dtc ligand b onded in a bidentate fashion; a conjecture has been verified crystallo graphically for [Au(Me(2)NCS(2))(2)]-Br . 2H(2)O. The X-ray analysis c onfirmed that the complex is composed of ionic units: [Au(Me(2)dtc)(2) ](+) and Br- and H2O molecules. The Au-S distances are markedly simila r, falling in the 2.343(4)-2.350(3) Angstrom range.