Übergangsmetallkomplexe mit Schwefelliganden, XCl+ Fell-Komplexe des fünfzähnigen Thioether-Thiolat-Aminliganden ′buNHS4′-H2: Synthese, Charakterisierung, Reaktivität und Stereochemie (′buNHS4′-H2 = 2,2′-Bis(2-mercapto-3,5-di-tertiärbutyl-phenylthio)diethylamin) / Transition Metal Complexes with Sulfur Ligands, XCI+ Fell Complexes of the Pentadentate Thioether-Thiolate-Amine Ligand ′buNHS4′-H2: Synthesis, Characterization, Reactivity and Stereochemistry (′buNHS4′-H2 = 2,2′-Bis(2-mercapto-3,5-di-tertiarybutyl-phenylthio)diethylamine)

Abstract

In search of model compounds for the active centers of nitrogenases, [Fe(L)(′buNHS4')] complexes of the pentadentate thioether-thiolate-amine ligand ′buNHS4'2- (′buNHS4'-H2 = 2,2′-bis(2-mercapto-3,5-di-tertiarybutyl-phenylthio)diethylamine) were obtained. Alkylation of′buS2'-H2 with (BrC2H4)2NH yielded the new ligand ′buNHS4'-H2 as a mixture of positional isomers. Isolation of single isomers was achieved by reacting the mixture with FecL2•4H2O and CO in order to give the corresponding [Fe(CO)] complexes which were separated and hydrolyzed to yield the free ligands. Reaction of'buNHS4'-H2 with FeCl2•4H2O led to the high-spin complex [Fe(′buNHS4')] which is extremely air-sensitive in solution. It rapidly reacts with L = CO, NO, PMe3, and N2H4, and is the most suitable starting material for syntheses of [Fe(L)(′buNHS4')] complexes which were characterized for L = CO, NO+, NO, PMe3 and N2H4. All complexes are considerably better soluble in organic solvents than the corresponding parent compounds [Fe(L)(′NHS4')], (′NHS4'-H2 = 2,2′-bis(2-mercaptophenylthio)diethylamine), but have similar properties in most other respects. In the oxidation of [Fe(N2H4)(′buNHS4')] at low temperatures, there is evidence for the formation of the diazene complex [μ-N2H2{Fe(′buNHS4')}2].