Lanthanide Triangles Supported by Radical Bridging Ligands

The first examples of metallacycles containing rare earth ions bridged by radicals are reported. The molecular triangles [Ln(3)(hfac)(6)(bptz(center dot-))(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(center dot-)) ligands. Magnetic susceptibility measurements and CASS CF calculations performed on [Dy-3(hfac)(6)(bptz(center dot-))(3)] reveal the presence of antiferromagnetic coupling between the Dy-III centers and the bptz(center dot-) ligands, with J = 6.62 cm(-1).