Polyoxometalate cluster [V12B18O60H6] functionalized with the copper(II) bis-ethylenediamine complex
Résumé
Three compounds based on the polyoxometalate building block [V12B18O60H6], (Na)(10)[(H2O)V12B18O60H6]center dot 18H(2)O (1), Na-8[Cu(en)(2)](2)[V12B18O60H6](NO3)(2)center dot 14.7H(2)O (2), Na-7[Cu(en)(2)](2)[V12B18O60H6] (NO3)center dot 15.5H(2)O (3), (en = ethylenediamine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction analysis and TGA. Compound 1 consists of polyoxovanadium borate [V12B18O60H6] clusters which are surrounded by sodium countercations in octahedral sites, stabilized by electrostatic interactions with the oxygen atoms of both vanadium and boron centres. However, compounds 2 and 3 correspond to more complicated structures, constructed from the same polyoxometalate clusters, which are interconnected by [Cu(en)(2)](2+) moieties via the terminal oxygen atoms of the polyoxoanions, generating one-dimensional structures. The functionalization of this polyoxovanadium borate cluster has been obtained by the use of [Cu(en)(2)](2+) complex ions, thus demonstrating the capacity of the terminal oxygen atoms of the cluster to bind transition metal centres. The structural stability of the [V12B18O60H6] cluster permits the formation of functionalized polyoxometalate clusters, generating various crystalline lattices.