DINUCLEAR AND TRINUCLEAR (ETA-6-ARENE)RUTHENIUM(II) COMPLEXES CONTAINING BRIDGING HETEROCYCLIC THIOAMIDES

Reaction of [(eta6-p-MeC6H4CHMe2)2RuCl2]2 With the heterocyclic thioam ides (L), 2-mercapto-1-methylimidazole (mmimH) or 4,5-diphenyl-2-merca ptoimidazole (dpmimH2) in a 1:1 ratio in the presence of base leads to the formation of the dinuclear complexes [eta6-p-MeC6H4CHMe2)2Ru2(mu- L)(mu-Cl)Cl]CI (3 and 4). The [dpmimH]-ligand in 4 adopts a mu2-(1kapp a1S; 2kappa2N,S) bridging mode, as is also observed for one of the [mt z]- ligands (mtzH=2-mercapto-2-thiazoline) in [(eta6-C6H6)2RU2(mu-mtz) 2Cl]Cl (2). In contrast, the second bridging [mtz]- ligand in 2 exhibi ts the mu2-N,S coordination mode. The pentadentate [dpmimH-1]3- ligand bridges three ruthenium atoms in the trinuclear complex [(eta6-p-MeC6 H4CHMe2)3Ru3(mu3-dpmimH-1)(mu-Cl)Cl2] (6), two of which via the mu2-(1 kappa1S; 2kappa2N,S) coordination mode displayed by 4. A cyclometallat ion leads to the coordination of the third ruthenium atom through the second imidazole N atom and an ortho-C atom of the adjacent phenyl rin g. The structures of [(eta6-p-MeC6H4CHMe2)RuCl2(mtzH)] (1), 2, 4 and 6 were established by X-ray structural analysis.