Mesityl gold(III) complexes. X-ray structure of mononuclear Au(mes)(2)Cl(PPh3) and the dimer Au(mes)(2)Cl (2)

The reaction between PPN[AuCl4] and [Hg(mes)(2)] gives the anionic complex cis-PPN[Au(mes)(2)Cl-2] (1) and [Hg(mes)Cl] as side-product. Complex 1 is a precursor to other compounds both neutral and cationic. Removal of one chloride ligand affords the mononuclear neutral complexes cis-[Au(mes)(2)ClL] (L = PPh3 (2), P{p-tol}(3) (3), AsPh3 (4), SPPh3 (5)) by addition of a neutral ligand or, alternatively if no ligand is added, dimeric cis-[Au(mes)(2)Cl](2) (6). If both chloride groups in 1 are removed, cationic compounds can be obtained by addition of a potentially bidentate ligand affording cis-[Au(mes)(2)(L-L)]X complexes (X = ClO4, L-L = bipy (7), L-L = phen (8), L-L = dppe (9) X = SO3CF3, L-L = dppm (10)). Dithiocarbamate- or acetate salts can be added to solutions of 'Au(mes)(2)X' (obtained by removal of two chloride anions in 1) leading to the neutral compounds cis-[Au(mes),(L-L)] (L-L = S2CNR2 (R = Me (11), Et (12), Bz (13)), O2CCF3 (14)). The structures of cis-[Au(mes)(2)Cl(PPh3)] (2) and cis-[Au(mes)(2)Cl](2) (6) have been established by an X-ray diffraction study