STRUCTURE OF A ONE-DIMENSIONAL BR-BRIDGED PTII-PTIV MIXED-VALENCE COMPLEX, CATENA-POLY[BIS(ETHYLENEDIAMINE)PLATINUM(II,IV)-MU-BROMO BIS(HYDROGENSULFATE)]

[Pt(II)(C2H8N2)2][PtIVBr2(C2H8N2)2](HSO4)4, M(r) = 1178.65, orthorhombic, Ibam, a = 9.263 (2), b = 14.317 (3), c = 11.036 (5) angstrom, V = 1463.6 (8) angstrom3, Z = 2, D(x) = 2.67 Mg M-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 12.64 mm-1, F(000) = 1116, T = 296K, R = 0.049, wR = 0.079 for 773 observed reflections [\F(o)\ > 3sigma(\F(o)\)]. The crystal contains columns composed of square-planar [Pt(en)2]2+ and elongated octahedral trans-[PtBr2(en)2]2+ units (en = ethylenediamine) stacked alternately along the c axis. The Br ions bridging the adjacent Pt ions are disordered over two sites along the ... Br-Pt(IV)-Br...Pt(II)... linear chain. The Pt(IV)-Br and Pt(II)...Br bonds are 2.474 (3) and 3.044 (4) angstrom, respectively. The structural parameter delta = (Pt(IV)-Br)/(Pt(II)...Br) bears a good correlation with the data of the intervalence charge-transfer (IVCT) absorption edge (delta = 0.813). The hydrogen bonds along the column [N...0 = 3.06 (3) and 3.24 (2) angstrom] and the intercolumn hydrogen bonds [O...0 = 3.13 (3) angstrom] stabilize the structure.