Abstract
The structure of the title compound, which represents a mixed-valence platinum(II,IV) complex, {[Pt(II)Pt(IV)I2(C2H8N2)4][CH3(CH2)7SO3]4·2H2O} n , has been redetermined in a different space group. In contrast to the previously reported determination in the space group P21 cn [Matsushita & Taira (1999 ▸). Synth. Met. 102, 1787-1788], the current model was refined in the centrosymmetric space group Pmcn using the original diffraction data. The title compound has a linear chain structure composed of square-planar [Pt(en)2](2+) and elongated octa-hedral trans-[PtI2(en)2](2+) cations (en is ethyl-enedi-amine) stacked alternately, bridged by the I atoms, parallel to the c axis. Inorganic layers aligned parallel to the bc plane, composed of the Pt-complex columns, the -SO3 (-) part of the octane-1-sulfonate anion, and the water mol-ecule of crystallization, are stacked alternately with organic layers composed of the long-chain alkyl groups along the a axis. The Pt and I sites are located on the same mirror plane whereby the I site is equally disordered over two positions. The Pt and I atoms form a slight zigzag ⋯I-Pt(IV)-I⋯Pt(II)⋯ chain, with Pt(IV)-I bond lengths of 2.6888 (17) and 2.7239 (17) Å, Pt(II)⋯I contacts of 3.2065 (17) and 3.1732 (16) Å, and Pt(IV)-I⋯Pt(II) angles of 178.3 (3) and 176.7 (2)°. The mixed-valence state of the Pt site is expressed by the structural parameter δ = (Pt(IV)-I)/(Pt(II)⋯I), with values of 0.839 and 0.858 for the two independent I atoms. In the crystal, N-H⋯O hydrogen bonds involving the cationic chains, the sulfonate groups and water mol-ecules of crystallization, stabilize the columnar structure.
Highlights
The structure of the title compound, which represents a mixed-valence platinum(II,IV) complex, {[PtIIPtIVI2(C2H8N2)4][CH3(CH2)7SO3]42H2O}n, has been redetermined in a different space group
Met. 102, 1787–1788], the current model was refined in the centrosymmetric space group Pmcn using the original diffraction data
The title compound has a linear chain structure composed of square-planar [Pt(en)2]2+ and elongated octahedral trans-[PtI2(en)2]2+ cations stacked alternately, bridged by the I atoms, parallel to the c axis
Summary
The title compound, [Pt(en)2][PtI2(en)2](CH3(CH2)7SO3)42H2O (en is ethylenediamine, C2N2H8), (I), is a member of the family of one-dimensional halogen-bridged mixed-valence metal complexes, formulated as [MII(AA)2][MIVX2(AA)2]Y4. = Cl, Br, I; AA = NH2(CH2)2NH2, etc; Y = ClO4, HSO4, X, etc], hereafter abbreviated as MX-chain compounds, which are typical mixed-valence compounds belonging to class II in the classification of Robin & Day (1967), as described in previous reports (Matsushita et al, 1989, 1995; Matsushita, 1993). The metal–halogen distances in crystals of MX-chain compounds characterize the physical properties based on the mixed-valence state. In a previous article (Matsushita & Taira, 1999), we have briefly reported the crystal data of (I), i.e. lattice parameter, space group, reliability indices, and have presented a view of the crystal packing; atomic coordinates and further structure data were not deposited at that time. E71, 1155–1158 doi:10.1107/S2056989015016801 research communications reported structure was originally refined in the non-centrosymmetric space group P21cn. The structure of (I) was redetermined in the centrosymmetric space group Pmcn and is reported here.
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