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 = Dy^III, Y^III; 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 Dy^III centers and the bptz^•– ligands, with J = −6.62 cm^–1.