Unprecedented pentanuclear mixed-valence Pt(II)-Pt(IV) complex anion in Q2[Pt5Cl20] salts (Q = TBA, PPN)

Red crystals of [TBA](2)[Pt5Cl20] were obtained by reacting [TBA](2)[PtCl6] with an excess of AlCl3 at room temperature in CH2Cl2. The salt [PPN](2)[Pt5Cl20] containing the same anion was prepared by reaction of platinum tetrachloride with a small excess of [PPN]Cl in 1,2-dichloroethane at room temperature. Single crystal X-Ray diffraction studies confirmed that both species contained the mixed-valence [Pt5Cl20](2-) anion with two dinuclear platinum((IV)) Pt2Cl10 fragments organized around a central square planar platinum((II)) in a chair arrangement.