A novel crown-ether stabilized oxonium halogenochalcogenate(IV): [H7O3(bis-dibromo-dibenzo-30-crown-10)][Se2Br9]center dot 1.5CH(2)Cl(2)

摘要

The title compound [H7O3(bis-dibromo-dibenzo-30-crown-10)][Se2Br9].1.5CH(2)Cl(2) (1) was isolated from a solution of SeBr4 and dibenzo-30-crown-10 in CH3CN/CH2Cl2 containing a small amount of hydrobromic acid. During the reaction the crown ether is brominated by HBr. The compound crystallizes in the monoclinic space group P2(1) with a = 17.688(11), b = 14.921(6), c = 20.521(12) A, beta = 97.71(5)degrees, and Z = 4. 1 is a novel example in the series of supramolecular halogenochalcogeno acids prepared in our group in which different oxonium cations are stabilized and encapsulated by crown ethers. Especially in this class of superacids complexation by cyclic polyethers offers covenient and variable possibilities for the controlled synthesis of oxonium cations. In the present case the large dibenzo-30-crown-10 ring systems are able to stabilize trinuclear [H7O3](+) cations within their cavities. Besides the macromolecular cations and some dichloromethane solvent molecules, the crystal structure of 1 contains molecular [Se2Br9](-) ions with approximate D-3h symmetry, each consisting of two face-sharing SeBr6 octahedra.