Five new multinuclear rare earth complexes: Magnetism and near-infrared luminescence

Five new tri- and tetra-nuclear rare earth complexes utilizing a Schiff base ligand and co-ligand Hdbm were obtained: [Nd3(dbm)6(H2L)3]center dot 3CH3OH (1), [RE4(dbm)6(L)2(CH3OH)3]center dot 2CH3OH (RE = Dy (2), Ho (3), Er (4), Yb (5)), (H3L = N'-(2-carboxide-imidazole)-[(2-hydroxy-3-methoxyphenyl)methylene]hydrazide, Hdbm = 1,3diphenyl-1,3-propanedione). Complexes 2-5 are centrosymmetric tetranuclear complexes with eightcoordinated REIII ions, while complex 1 is a non-centrosymmetric trinuclear complex with nine-coordinated NdIII ions, which could be caused by lanthanide contraction. The magnetic properties studies show that 2 exhibits representative single-molecule magnets behavior, leading to an energy barrier of 25.3 K as well as preexponential factor of 7.21 x 10- 7 s. Research on near-infrared luminescence reveals that complexes 1, 3, 4 and 5 emit the characteristic emission peaks of the NdIII ions, HoIII ions, ErIII ions and YbIII ions, respectively. The luminescence lifetime and quantum yield of 5 are 1.39 mu s and 0.0695 %, respectively.

Automated summary

Five new multi-nuclear rare earth complexes were synthesized using a Schiff base ligand and co-ligand Hdbm. Among them, Complex 2 exhibits single-molecule magnet behavior, while Complex 1, 3, 4, and 5 emit characteristic emission peaks of NdIII ions, HoIII ions, ErIII ions, and YbIII ions, respectively.