Divalent Copper Selenate Complex: Two Types of Octahedral Coordination in the Unit Cell and Disordered 1,4-Diazabicyclo[2.2.2]octane

International audienceThe new hybrid compound (C6H14N2)[Cu(H2O)(6)][Cu(SeO4)(2)(H2O)(4)](2) crystallizes in the monoclinic system, space group P2(1)/n, with the unit cell parameters: a = 7.2469(2) angstrom, b = 9.5360(2) angstrom, c = 22.1919(5) angstrom, and beta = 95.789(2)degrees. The structure was solved by conventional direct methods. The R and wR values for 76142 measured reflections were 0.0337 and 0.0625, respectively. Within the structure of this new compound, the transition metal adopts two types of octahedral coordination. Indeed, Cu1 is coordinated by four water molecules and two selenate groups to form the tetraaquadiselenatocuprate(II) anion [Cu(SeO4)(2)(H2O)(4)](2-), whereas Cu2 adopts another octahedral environment formed by six water molecules, but three of them crystallographically independent. The Cu1 and Cu2 atoms display the socalled (4+1+1) and (4+2) type of coordination, respectively, that has often been observed in other compounds containing the same transition metal, which is consistent with a Jahn-Teller distortion. The crystal structure of the title complex consists of isolated metallic polyhedra and disordered dabcodiium cations linked together by two types of hydrogen bond, OW-H center dot center dot center dot O and N-H center dot center dot center dot O, only. The thermogravimetric analysis shows that the dehydration of the compound takes place in four steps. The decomposition leads to the copper oxide in the last stage