Symmetrische 3,3,3′,3′‐Tetraalkyl‐1,1′‐alkandioylbis(thioharnstoffe) als neue Chelatliganden

symmetrical 3,3,3′,3′‐Tetraalkyl‐1,1′‐alkanedioylbis(thioureas) as New Chelate Ligands The synthesis of some new alkyl‐alkanedioylbis(thioureas) ( 3 – 6 ) by reaction of dicarboxylic dichlorides with potassium thiocyanate and secondary amines is described. They act as bisbidentate S,O ligands toward bivalent metal ions which form stable neutral chelates ( 7 – 10 ) extractable with apolar solvents like CHCl 3 or toluene. The chelates of palladium and platinum ( 9 and 10 ) can be separated by chromatography and selectively extracted by solvent extraction.