Tridecanuclear [Mn5IIILn8III] Complexes Derived from N-tButyl-diethanolamine: Synthesis, Structures, and Magnetic Properties

The synthesis, structures and magnetic properties of a family of heterometallic [Mn(5)(III)Ln(8)(III)(mu(3)-OH)(12)(L-2)(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-(t)butyldiethanolamine (H2L2) with Mn(OAc)(2)center dot 4H(2)O and Ln(NO3)(3)center dot 6H(2)O in the presence of pivalic acid (pivH) in MeCN under ambient conditions. Compounds 2-6 are isomorphous and crystallize in the monoclinic space group P2(1)/n with four molecules in the unit cell. The complexes have a centrosymmetric tridecanuclear anionic core consisting of two distorted inner heterometallic [Mn(III)Ln(3)(III)(mu(3)-OH)(4)](8+) cubane subunits sharing a common Mn vertex flanked by four edge-sharing heterometallic [Mn(III)Ln(2)(III)(mu(3)-OH)(4)](5+) defect cubane units. Complexes 2-6 are the first high-nuclearity 3d-4f aggregates reported to date using Bu-t-deaH(2) 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 Mn-III and Ln(III) ions resulting from the particular angles at the bridging oxygens.