Encapsulation of a double-helical water-nitrate chain inside unique double helical chiral channels formed from Keggin POM and hexaquo-cobalt(II) units

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• 作者：Rajarshi Chatterjee ; Luna Paul ; Dipak K. Hazra ; Nabanita Pal ; Atish Dipankar Jana ; Monika Mukherjee ; Mahammad Ali
• 关键词：Keggin polyoxometallates ; Chiral ; Hydrothermal synthesis ; Crystal structure ; BVS calculation
• 刊名：Polyhedron
• 出版年：28 January, 2014
• 年：2014
• 卷：68
• 期：Complete
• 页码：265-271
• 全文大小：2129 K

文摘

A new inorganic-organic hybrid chiral molecule [Co(H₂O)₆][C₅H₆N]H₄[CoW₁₂O₄₀]NO₃路3H₂O has been prepared by the hydrothermal method and was characterized by elemental analysis, IR and UV spectra, TG-DTA and single crystal X-ray diffraction techniques. The asymmetric unit consists of [CoW₁₂O₄₀]^{6鈭?/sup> and NO₃鈭?/sup> anions, the charge of which are counterbalanced by one octahedral [Co(H₂O)₆]2+ cation, a pyridinium [C₅H₆N]+ ion and 4H+ ions. The molecular structure of the title complex reveals a 3D supramolecular framework formed through intermolecular hydrogen bonds. This constitutes the first example in which a chiral architecture has been generated from achiral building blocks, where centrosymmetrically related cobalt octahedra and polyoxoanion tetrahedra are entangled through pairs of hydrogen bonds in a double helical way with a channel that houses a 1D water-NO₃鈭?/sup> double helix. This chiral POM shows good efficiency in the oxidation of common olefins in the presence of an environmentally benign oxidant, H₂O₂, under mild conditions.}