Tridecanuclear [MnIII 5 LnIII 8 ] Complexes Derived from N-tButyl-diethanolamine: Synthesis, Structures, and Magnetic Properties

The synthesis, structures and magnetic properties of a family of heterometallic [MnIII 5 LnIII 8 (μ3-OH)12(L2)4(piv)12- (NO3)4(OAc)4]- (Ln = Pr, 2; Nd, 3; Sm, 4; Gd, 5; Tb, 6) aggregates are reported. The complexes were obtained from the direct reaction of N-tbutyldiethanolamine (H2L2) with Mn(OAc)2 3 4H2O and Ln(NO3)3 3 6H2O in the presence of pivalic acid (pivH) in MeCN under ambient conditions. Compounds 2-6 are isomorphous and crystallize in the monoclinic space group P21/n with four molecules in the unit cell. The complexes have a centrosymmetric tridecanuclear anionic core consisting of two distorted inner heterometallic [MnIIILnIII 3 (μ3-OH)4]8+ cubane subunits sharing a common Mn vertex flanked by four edge-sharing heterometallic [MnIIILnIII 2 (μ3-OH)4]5+ defect cubane units. Complexes 2-6 are the first high-nuclearity 3d-4f aggregates reported to date using tBu-deaH2 as ligand. These compounds show no evidence of slow relaxation behavior above 1.8 K, which appears to be the consequence of the very weak or non-existent magnetic interactions between the MnIII and LnIII ions resulting from the particular angles at the bridging oxygens