Synthesis, structure and magnetic properties of unsymmetrical dodecanuclear Mn–Ln clusters

Reaction of manganese acetate and lanthanide nitrates in the presence of excess of PhCOOH affords highly asymmetric dodecanuclear mixed-metal [Mn10Ln2(OH)(O)8(PhCOOH)(PhCOO)19] (Ln = PrIII (1), NdIII (2)) clusters. The similar reaction, but with only 2 equiv. of PhCOOH resulted in the compounds with higher nuclearity [Mn11Eu4(O)8(OH)8(PhCOO)18(NO3)2(H2O)6]NO3 · 4CH3CN (3). Variable-temperature solid-state magnetic susceptibility of 1 and 2 in the temperature range 1.8–300 K were carried out, and for both complexes antiferromagnetic exchange interactions between the metal centers were observed, giving an estimated S = 17/2 ground state. AC magnetic susceptibility data have revealed out-of-phase signals, which suggest that these complexes exhibit a slow relaxation of magnetization as observed in single-molecule magnets.

Reaction of manganese acetate and lanthanide nitrates in the presence of excess of PhCOOH affords highly asymmetric dodecanuclear mixed-metal [Mn10Ln2(OH)(O)8(PhCOOH)(PhCOO)19] (Ln = PrIII (1), NdIII (2)) clusters. The similar reaction, but with only 2 equiv. of PhCOOH resulted in a compound with the higher nuclearity [Mn11Eu4(O)8(OH)8(PhCOO)18(NO3)2(H2O)6]NO3 · 4CH3CN (3). Variable-temperature solid-state magnetic susceptibility of 1 and 2 in the temperature range 1.8–300 K were carried out, and for both complexes predominantly antiferromagnetic exchange interactions between the metal centers were observed, giving an estimated S = 17/2 ground state. AC magnetic susceptibility data have revealed out-of-phase signals, which suggest that these complexes exhibit a slow relaxation of magnetization as observed in single-molecule magnets.Figure optionsDownload as PowerPoint slide