Binuclear Lanthanide-Radical Complexes Featuring Two Centers with Different Magnetic and Luminescence Properties

Binuclear complexes with general formula [Ln₂(hfac)₆­(H₂O)₂­(dppnTEMPO)] (Ln^III = Gd, Tb, and Dy) have been obtained using the paramagnetic ligand 1-piperidinyl-4-[(diphenylphosphinyl)­amino]-2,2,6,6-tetramethyl (dppnTEMPO) as a bridge. One of the lanthanide ions is ferromagnetically coupled with the TEMPO moiety. Two of the complexes (Dy and Tb) show slow relaxation of the magnetization, and the non-magneto-equivalence of the two Ln^III ions was clearly observed. The <i>ab initio</i> CASSCF calculations were employed to confirm this behavior, as well as to rationalize the Ln–Rad interaction. The simulations of the magnetic properties were allowed by the insights given by the calculations. The inequivalence of the Tb^III ions was also proved by emission spectroscopy