Family of Nanoclusters, Ln(33) (Ln = Sm/Eu) and Gd-32, Exhibiting Magnetocaloric Effects and Fluorescence Sensing for MnO4-

A family of nanoclusters, [Ln(33)(EDTA)(12)(OAc)(2)(CO3)(4)(mu(3)-OH)(36)(mu(5)-OH)(4)(H2O)(38)]center dot OAc center dot xH(2)O (x approximate to 50, Ln = Sm for 1; x approximate to 70, Ln = Eu for 2) and [Gd-32(EDTA)(12)(OAc)(2)(C2O4)(CO3)(2)(mu(3)-OH)(36)(mu(5)-OH)(4)(H2O)(36)]center dot x(H2O) (x approximate to 70 for 3; H(4)EDTA = ethylene diamine tetraacetic acid), was prepared through the assembly of repeating subunits under the action of an anion template. The analysis of the structures showed that compounds 1 and 2 containing 33 Ln(3+) ions were isostructural, which were constructed by three kinds of subunits in the presence of CO32- as an anion template, while compound 3 had a slightly different structure. Compound 3 containing 32 Gd3+ ions was formed by three types of subunits in the presence of CO32- and C2O42- as a mixed anion template. The CO32- anions came from the slow fixation of CO2 in the air. Meanwhile, one kind of high-nuclearity lanthanide clusters showed high chemical stability. The quantum Monte Carlo (QMC) calculation suggested that weak antiferromagnetic interactions were dominant between Gd3+ ions in 3. Magnetocaloric studies showed that compound 3 had a large entropy change of 43.0 J kg(-1) K-1 at 2 K and 7 T. Surprisingly, compound 2 showed excellent recognition and detection effects for permanganate in aqueous solvents based on the fluorescence quenching phenomenon.