Transition Metal Complexes with Sulfur Ligands, 123[[ Synthesis and Reactivity of New Complexes Containing the [Ru(“S4”)] Fragment [S42‐ = 1,2‐Bis(2‐mercaptophenylthio)ethane(2‐)]

Abstract

AbstractIn order to synthesize labile and well‐soluble [Ru(L)(L')(“S4”)] complexes, [Ru(CI)2(DMSO)4] was treated With “S4”‐Na2 (S42‐ = 1,2‐bis(2‐mercaptophenylthio)‐ethane(2–1)] yielding [Ru(DMSO)2(“S4”)] (1 which contains two labile DMSO ligands. An X‐ray structural analysis of 1, verifies that both DMSO ligands are coordinated via their S atoms. The reaction of 1 with small ligands such as PR3 (R = Et, nPr, nBu) or tetrahydrothiophene (THT) leads to substitution of both DMSO ligands yielding [Ru(PR3)2(“S4”)] (R = Et 3a, nPr 3b, nBu 3c) and [Ru(THT)2(“S4”] 2, respectively, while bulky phosphane ligands such as PCy3 and PiPr3 substitute one DMSO ligand to yield [Ru(DMSO)(PR3])(“S4”] (R = iPr 4a, Cy 4b). X‐ray structural analyses of [Ru(PnPr3)2(“S4”)] · 0.5 MeOH (3b · 0.5 MeOH), [Ru(PnBu3)2(S4)} (3c), and [Ru(Pme3)2(“S4”)] (3d) confirm the pseudo‐octahedral coordination of the Ru centers by four Sdonors and two cis P‐donors and reveal close similarities bet ween the three complexes. Comparision of the structural parameters of 3b · 0.5 MeOH, 3c and 3d with those of [Ru(PPh3)2(“MeS, 4”)] [MeS4“2” = 1,2‐bis(2‐mercaptophenylthio)propane(2–1)] indicates that the inertness towards substitution of 3b · 0.5 MeOH, 3c and 3d as opposed to the substitution lability of [Ru(PPh3)2(,MeS4“)] is caused by the small cone angles of the alkyl phosphanes. In the DMSO/PCy3 complex 4b both coligands are labile, and which one is substituted depends on the size of the entering ligand. The reactions of 4b with PnR3 yield [Ru(DMSO)(PR3)('S4”)] (R = nPr 4c, nBu 4d) in contrast to the reaction with CO. PMe3, and SMe2 which give [Ru(CO)(Pcy3)(“S4”)] (5b), [Ru(P‐Me3)(PCy3)(“S4”)] (6, and [Ru(SMe2)(PCy3)(“S4”)] (7, respectively. In an analogous manner, the CO complexes [Ru(CO(PR3)(“S4”)] (R = iPr 5a, nBu 5c) have been obtained by treatement of 4a and 4d with CO. The reactions of 4a and 4b with S8 yielded the readily soluble μ‐S2 complexes [μ‐S2[Ru(PR3)(“S4”)]2] (R ‐ iPr 8a, Cy 8b). The spectroscopi9c data of complex 8b and its cyclic voltammogram, which exhibits four quasi‐reversible redox waves, indicate a strong electronic coupling of the two [Ru(PCy3)(“S4”)] fragments via the μ‐S2 bridge.