Metal chelates of ligands containing the ONS donor grouping,Part II. Metal chelates of schiff bases derived from β-diketones and α-N-Methyl-S-methyldithiocarbazate

Summary The Schiff bases RC(OH)=CHC(R)=NNMeC(S)SMe (R = Ph,p-MeC₆H₄, R = Me; R = R = Ph) have been prepared by condensation of -diketones with -N-methyl-S-methyldithiocarbazate. By the loss of a proton they act as singly negatively charged tridentate ligands with oxygen, nitrogen and sulphur donor atoms (ONS). Iron forms the high-spin complexes [Fe^III(ONS)₂][Fe^IIICl₄]. Copper(II), palladium(II), and platinum(II) yield the square-planar 1 : 1 complexes, M(ONS)CI (M = Cu, Pd, Pt) and Cu(ONS)NO₃. Cobalt(II) and nickel(II) form high-spin, six-coordinate 1 : 2 complexes, M(ONS)₂. For M = Ni and R = R = Ph, the complex is high-spin and octahedral, but when R = Ph orp-MeC₆ H₄ and R = Me, the complexes are diamagnetic and square-planar with nitrogen and sulphur (NS) coordinatio of the Schiff base, indicating that a change in the Rgroup can bring about a change in spin-state and stereochemistry of nickel.Part I: see ref. 1.