Platinum‐Containing Polyoxometalates: syn‐ and anti ‐[Pt II 2 ( α ‐PW 11 O 39 ) 2 ] 10− and Formation of the Metal–Metal‐Bonded di‐Pt III Derivatives

The first examples of dimeric, di‐Pt II ‐containing heteropolytungstates are reported. The two isomeric di‐platinum(II)‐containing 22‐tungsto‐2‐phosphates [ anti ‐Pt II 2 ( α ‐PW 11 O 39 ) 2 ] 10− ( 1 a ) and [ syn ‐Pt II 2 ( α ‐PW 11 O 39 ) 2 ] 10− ( 2 a ) were synthesized in aqueous pH 3.5 medium using one‐pot procedures. Polyanions 1 a and 2 a contain a core comprising two face‐on PtO 4 units, with a Pt⋅⋅⋅Pt distance of 2.9–3 Å. Both polyanions were investigated by single‐crystal XRD, IR, TGA, UV/Vis, 31 P NMR, ESI‐MS, CID‐MS/MS, electrochemistry, and DFT. On the basis of DFT and electrochemistry, we demonstrated that the {Pt 2 II } moiety in 1 a and 2 a can undergo fully reversible two‐electron oxidation to {Pt 2 III }, accompanied by formation of a single Pt−Pt bond. Hence we have discovered the novel subclass of Pt III ‐containing heteropolytungstates.