1,1-Dithiooxalsäurederivate als Liganden in Übergangsmetallkomplexen: Struktur von O-Methyl-1,1-dithiooxalato-bis(triphenylphosphin)kupfer(I) und -silber(I)

1,1-Dithiooxalic Acid Derivatives as Ligands in Transition Metal Complexes: Structure of O-Methyl-1,1-dithiooxalato-bis(triphenylphosphine)copper(I) and silver(I) Despite O-Alkyl-1,1-dithiooxalates are also tetradentate thioligands their tendency towards the formation of multi-nuclear bridged chelates as found for the basic 1,1-dithiooxalate does practically not exist because of derivatisation. The reaction with triphenylposphinemetal(I)-halogenides yields defined mono-nuclear mixed ligand complexes: O-Methyl-1,1-dithiooxalato-bis(triphenylphosphine)copper(I) ( 2 ) and silver(I) ( 1 ). X-ray analysis shows that both complexes ( 1 and 2 ) are isostructural and crystallize in the monoclinic space group P2₁/n: (Ph₃P)₂Ag(S₂C₂O₂Me) ( 1 ) with a = 12.794(1), b = 21.314(4), c = 13.560(1) Å, β = 97.983(6)°, and (Ph₃P)₂Cu(S₂C₂O₂Me) ( 2 ) with a = 12.622(1), b = 21.196(2), c = 13.426(1) Å, β = 96.533(7)°. These complexes are the first authentic examples of exclusively end-on coordinated thiooxalate.