Coordination of Palladium(II) and Platinum(II) Complexes to One Vacant Site in an α-Keggin-Type Polyoxotungstate

Abstract

A palladium-platinum bimetal complex containing a mono-lacunary α-Keggin-type polyoxotungstate is demonstrated. The bimetallic complex Cs_2.5{Pd^II(bpy)}_0.25[α-PW₁₁O₃₉{Pd^II(bpy)}{cis-Pt^II(NH₃)₂}]·12H₂O·2CH₃CN (bpy = 2,2'-bipyridine) (PdPt) was synthesized by the reaction of Cs_4.9K_0.1[α-PW₁₁O₃₉{cis-Pt^II(NH₃)₂}]·10H₂O (Pt1) with Pd^II(bpy)Cl₂ in aqueous solution. The compound PdPt was characterized via elemental analysis, thermogravimetric/differential thermal analysis, and Fourier transform infrared, ultraviolet-visible, cold-spray ionization mass, and solution (¹H, ¹³C, and ³¹P) nuclear magnetic resonance spectroscopies. The coordination of {cis-Pt^II(NH₃)₂} and {Pd^II(bpy)} moieties to the mono-vacant site of [PW₁₁O₃₉]^7- resulted in an asymmetric, monomeric compound. A unique exchange reaction between the counter cation [Pd^II(bpy)]²⁺ and {cis-Pt^II(NH₃)₂} moiety in [α-PW₁₁O₃₉{Pd^II(bpy)}{cis-Pt^II(NH₃)₂}]^3- in a dimethylsulfoxide solution was also observed.