Incorporation of a high-spin heptanuclear [CuII 6Gd] cluster into carboxyl-functionalized mesoporous silica

We report the immobilization of heptanuclear [Cu6Gd] high-spin magnetic clusters, namely [Cu6Gd(aib)(6)(OAc)(3)(NO3)(3)(OH)(3)] (where, aib = (CH3)(2)C(NH2)COO- and OAc = CH3COO-), inside the channels of -COOH-functionalized mesoporous SBA-15 silica. X-ray diffraction, TEM and N-2 physisorption experiments show that the well-ordered hexagonal structure of the CA/SBA-15 hybrid material is well preserved and that the [Cu6Gd] clusters are located inside the mesopores. The molecular structure of the incorporated [Cu6Gd] was confirmed by elemental X-ray microanalysis, IR and UV-vis-NIR spectroscopy. Magnetic measurements indicate that the polynuclear complexes retain their magnetic properties during the impregnation process. The host-guest nanocomposite displays strong ferromagnetic interactions that result in a high-spin S = 13/2 ground state.