A one-dimensional iodine-bridged Pt(II)/Pt(IV) mixed-valence complex, catena-poly[[[bis(ethylenediamine)platinum(II)]-mu-iodo-[bis(ethylenediamine)platinum(IV)]-mu-iodo] hydrogenphosphate dihydrogenphosphate iodide trihydrate].
The title compound, {[PtIIPtIVI2(C2H8N2)4](HPO4)(H2PO4)I.3H2O}n, has a chain structure composed of square-planar [Pt(en)2]2+ and elongated octahedral trans-[PtI2(en)2]2+ cations (en is ethylenediamine) stacked alternately along the c axis and bridged by the I atoms; a three-dimensionally valence-ordered system exists with respect to the Pt sites. The title compound also has a unique cyclic tetramer structure composed of two hydrogenphosphate and two dihydrogenphosphate ions connected by strong hydrogen bonds [O...O = 2.522 (10), 2.567 (10) and 2.569 (11) A]. The Pt and I atoms form a zigzag ...I-PtIV-I...PtII... chain, with PtIV-I bond distances of 2.6997 (7) and 2.6921 (7) A, interatomic PtII...I distances of 3.3239 (8) and 3.2902 (7) A, and PtIV-I...PtII angles of 154.52 (3) and 163.64 (3) degrees . The structural parameters indicating the mixed-valence state of platinum, expressed by delta = (PtIV-I)/(PtII-I), are 0.812 and 0.818 for the two independent I atoms.
Matsushita
Nobuyuki
N
Department of Chemistry, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro, 153-8902 Tokyo, Japan. cnmatsu@mail.ecc.u-tokyo.ac.jp