Evidence for an unexpected chiral axis in tetraethyldithiooxamide and in its Platinum (II) coordination and organometallic complexes

Tetraethyldithioxamide (Et4-DTO) shows in solution high energy barriers either for chiral torsion around CC axis or for achiral torsion around CN axis. A chiral CC axis was also evidenced by a crystal structure determination on a single crystal, which showed clearly the right absolute configuration in the P43 space group. 1H-NMR signals of the prochiral probe -C2H5 in Et4-DTO provided unequivocal evidence for the persistence of the chiral CC axis also in co-ordination and organometallic complexes of platinum(II) of the chelate ligand Et4-DTO.