1,1-DITHIOOXALIC ACID-DERIVATIVES AS LIGANDS IN TRANSITION-METAL COMPLEXES - STRUCTURE OF 1,1-DITHIOOXALATO-BIS(TRIPHENYLPHOSPHINE)COPPER(I) AND SILVER(I)

Despite O-Alkyl-1,1-dithiooxalates are also tetradentate thioligands t heir tendency towards the formation of multi-nuclear bridged chelates as found for the basic 1,1-dithiooxalate does practically not exist be cause of derivatisation. The reaction with triphenylposphinemetal(I)-h alogenides yields defined mono-nuclear mixed ligand complexes: 1,1-dit hiooxalato-bis(triphenylphosphine)copper(I) (2) and silver(I) (1). X-r ay analysis shows that both complexes (1 and 2) are isostructural and crystallize in the monoclinic space group P2(1)/n: (Ph3P)2Ag(S2C2O2Me) (1) with a = 12.794(1), b = 21.314(4), c = 13.560(l) angstrom, beta = 97.983(6)degrees, and (Ph3P)2Cu(S2C2O2Me) (2) with a = 12.622(1), b = 21.196(2), c = 13.426(1) angstrom, beta = 96.533(7)degrees. These com plexes are the first authentic examples of exclusively end-on coordina ted thiooxalate.