Übergangsmetallkomplexe mit Schwefelliganden, LXXX. Synthese, Struktur, Oxotransfer- und redoxgekoppelte Kondensationsreaktionen von Molybdän-Oxo-Komplexen mit dem sterisch anspruchsvollen vierzähnigen Thioether-Thiolat-Liganden 'buS4'2- ('buS4'2- = 1,2-Bis(2-mercapto-3,5-di-t-butylphenylthio)ethan(2—))/Transition Metal Complexes with Sulfur Ligands, LXXX. Syntheses, Structures, Oxo Transfer and Redox Coupled Condensation Reactions of Molybdenum Oxo Complexes with the Sterically Demanding Tetradentate Thioether-Thiolato-Ligand 'buS4'2- ('buS4'2- = 1,2-Bis(2-mercapto-3,5-di-/-butylphenylthio)ethane(2—))

In order to obtain soluble molybdenum sulfur oxo complexes, [Mo(O)2('buS4')] (1) ('buS4'2- = 1,2-bis(2-mercapto-3,5-di-t-butylphenylthio)ethane(2-)) was synthesized by reaction of [Mo(O)2(acac)2] (acac- = acetylacetonate(1-) ) with 'buS4'-Li2. Treatment of 1 with PPh3 yielded [μ-O{Mo(O)('buS4')}2] (2) and OPPh3 in an oxo transfer reaction. [Mo(PMe3)2('buS2')2] (3) ('buS2'2- = 3,5-di-t-butyl-1,2 -benzenedithiolate(2-)) was obtained by twofold desoxygenation of 1 with excess PMe3 via a redox coupled addition elimination reaction. 2 reacts with the oxo group donor DMSO to yield 1 and Me2S. The system 1/2 then catalyses the oxo transfer reaction from DMSO to PPh3 and, therefore, shows properties modelling the co-factor in oxotransferases. In contrast to the parent compound [Mo(O)2('S4')] ('S4'2- = 1,2-bis(2-mercaptophenylthio)ethane(2-)), 1 is reactive towards hydrazine and its derivatives. Reactions with hydrazine and alkylhydrazines yield mixtures of products not containing nitrogen. By treatment of 1 with phenylhydrazine, the phenyldiazenido(1-) complex [Mo(NNPh)2('buS4')] (4) was formed in a redox coupled condensation. According to the X-ray structure analyses of 1, 2 and 4, the molybdenum centres in these complexes are coordinated pseudo-octahedrally by the four S-donors of the 'buS4'2- ligands, the oxo- and the N -donors.