Lanthanide Triangles Supported by Radical Bridging Ligands

The first examples of metalla­cycles containing rare earth ions bridged by radicals are reported. The molecular triangles [Ln3­(hfac)6­(bptz•–)3] (Ln = DyIII, YIII; hfac = 1,1,1,5,5,5-hexa­fluoro-2,4-pentane­dionate; bptz = 3,6-bis­(2-pyridyl)-1,2,4,5-tetrazine) consist of lanthanide ions bridged by bptz radical anion (bptz•–) ligands. Magnetic susceptibility measurements and CASSCF calculations performed on [Dy3(hfac)6(bptz•–)3] reveal the presence of anti­ferro­magnetic coupling between the DyIII centers and the bptz•– ligands, with J = −6.62 cm–1.