- Synthesis and reactivity of new complexes containing the [Ru("S4")] fragment ["S4"2- = 1,2-bis(2-mercaptophenylthio)ethane(2-)]
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In order to synthesize labile and well-soluble [Ru(L)(L′)("S4")l complexes, [Ru(Cl)2(DMSO)4] was treated with "S4"-Na2 ["S4"2- = 1,2-bis(2-mercaptophenylthio)ethane(2-)] 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 between the three complexes. Comparison of the structural parameters of 3b · 0.5 MeOH, 3c and 3d with those of [Ru(PPh3)2("MeS4")] ["MeS4"2- = 1,2-bis{2-mercaptophenyl-thio)propane(2-)] 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(PMe3)(PCy3)("S4")] (6), and [Ru(SMe2)(PCy3)("S4")] (7), respectively. In an analogous manner, the CO complexes [Ru(CO)(PR3)("S4")] (R = JPr 5a, nBu 5c) have been obtained by treatment of 4a and 4d with CO. The reactions of 4a and 4b with S8 yielded the readily soluble n-S2 complexes [uS2(Ru(PR3)("S4"))2] (R = iPr 8a, Cy 8b). The spectroscopic 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. VCH Verlagsgesellschaft mbH.
- Sellmann, Dieter,Gottschalk-Gaudig, Torsten,Heinemann, Frank W.,Knoch, Falk
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p. 571 - 579
(2007/10/03)
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