Crystal structure of the mixed-valence platinum(II,IV) iodide-bridged chain complex [Pt(en) 2 I](H 2 PO 4 ) 2 (H 3 PO 4 ) 2 within a hydrogen-bonded phosphate framework

The crystal structure of the mixed-valence platinum(II,IV) iodide-bridged chain complex catena -poly[[[bis(ethylenediamine-κ 2 N , N ′)platinum(II,IV)]-μ-iodido] bis(dihydrogen phosphate) bis(phosphoric acid)], {[PtI(C 2 H 8 N 2 ) 2 ](H 2 PO 4 ) 2 ·2H 3 PO 4 } n , is reported. The structure consists of one-dimensional Pt–I chains accommodated within an extended hydrogen-bonded framework formed by dihydrogenphosphate anions and neutral phosphoric acid molecules. The Pt II and Pt IV centers are crystallographically indistinguishable, and the bridging iodide ions are positionally disordered over two sites with equal occupancies. The resulting short and long Pt—I distances are consistent with the local coordination environments expected for alternating Pt II and Pt IV centers. Neutral H 3 PO 4 molecules are located between neighboring MX chains along the a -axis direction and form N—H...O hydrogen bonds with the ethylenediamine ligands. The crystallographically averaged structure may be associated with weak phase correlations between the charge-ordering patterns of neighboring MX chains.