Studies on polyhalides. 30 - On decamethylferriciniumpolyiodides [(Me5C5)(2)Fe]I-x with x=3, 5, 6.5: Preparation and crystal structures of a triiodide (DMFc)I-3, a pentaiodide (DMFc)I-5 and a hexacosaiodide (DMFc)(4)I-26 [German]

摘要

Decamethylferrocene (DMFc) may be oxidized by iodine analogous to ferrocene (Fc) to the decamethylferrocenium ion (DMFc)(+) and precipitated as the crystalline solids decamethylferrocenium triiodide (DMFc)I-3, decamethylferrocenium pentaiodide (DMFc)I-5 and tetracisdecamethylferrocenium hexacosaiodide (DMFC)(4)I-26. The two compounds with higher iodine content are new. These are characterized by X-ray diffraction methods on single crystals. The structures are built up from complex cations of expected geometry and isolated or remarkably connected polyiodide ions. Decamethylferrocenium triiodide C20H30FeI3 crystallizes monoclinically in C2/m with a=1489.9(4) pm, b=1133.0(2) pm, c=765.9(3) pm, beta=111.76(3)degrees and Z=2. The crystal structure follows the CsCl-type and contains isolated triiodide ions of the linear symmetric form. Decamethylferrocenium pentaiodide C20H30FeI5 crystallizes monoclinically in P2(1)/c with a=1130.0(2) pm. b=1442.6(1) pm, c=1716.6(2) pm, beta=96.62(1)degrees and Z=4. The crystal structure may be deduced from the primitiv quadratic bundle of alternating cationic and anionic rods. It contains exceptionally isolated somewhat opened out pentaiodideions. Tetrakisdecamethylferrocenium hexacosaiodide (C20H30Fe)(4)I-26 crystallises monoclinically in P2(1) with a=1331.3(8) pm, b=1319.4(4) pm, c=3564(2) pm, beta=90.84(5)degrees and Z=2. The crystal structure of this compound with unusual composition may be described as an inclusion compound with channels for the cations. The outstanding anionic grating may be derived from the primitive cubic lattice of iodide ions with iodine bridges on all edges by removing systematically 1/12 of the iodine molecules. [References: 38]