Polyoxometalate cluster [V12B18O60H6] functionalized with the copper(II) bis-ethylenediamine complex

► A transition metal complex can enrich the framework of polyoxometalates. ► The functionalization of [V12B18O60H6] was obtained by the use of [Cu(en)2]2+. ► Vanadyl oxygen atoms of the cluster bind the transition metal centres. ► The stability of [V12B18O60H6] cluster permits to obtain various crystalline lattices.