Ditopic Extractants to Separate Palladium(II) and Platinum(IV) Chloridometalates <i>via</i> Inner or Outer Sphere Binding

New thioetheramide ligands (L, PhS(CH2)nCONRR’) co-extract Pd(II) and Pt(IV) from acidic chloride solutions. The Pd is transferred to a water-immiscible phase as [Pd(L)2Cl2] complex with thioether groups in the inner sphere whilst Pt extracted an outer-sphere assembly, [(LH)2·PtCl6], containing protonated reagent molecules LH+ that charge-balance chloridoplatinate dianion, [PtCl6]2-. much higher kinetic thermodynamic stability of makes it possible strip into weakly aqueous before recovering by back-extraction ammonia form [Pd(NH3)4]Cl2, thereby separating two elements. An alkyl spacer group methylene units between (S) amide (C) atoms stronger extractant for both metals than those one or three units. extractants reject trianionic chloridometalates hydration energies such [IrCl6]3-. X-ray structures complexes PhSCH2CONH-n-C4H9 PhS(CH2)2CONH-n-C4H9) have planar coordination transarrangement geometries very similar predicted DFT calculations. These calculations show addition proton proligands L generates pseudochelate added H+ located S atom carbonyl O atom. In contrast related ether- amino-amide extractants, this ring broken [(LH)2.PtCl6] assemblies formed thioetheramides OH+ NH make close contacts PtCl62- ion.