{Mn-6 (MnDy2)-Mn-III-Dy-IV (III)} Single-Molecule Magnet Based on Cubane Subunits

Ultrasound-assistedsynthesis enables the formation of anew nonanuclear [Mn7Dy2O6(OH)(OMe)(2)(piv)(8)(dea)(2)(MeOH)(2)(H2O)(2)](NO3)& BULL;H2O SMM witha {Mn-6 (MnDy2)-Mn-III-Dy-IV (III)}(28+) core based on vertex-sharing double-cubane unitsunprecedented in Mn-4f chemistry. A new mixed-valence heterometallicnonanuclear cluster [Mn7Dy2(& mu;(4)-O)(2)(& mu;(3)-O)(4)(& mu;(3)-OMe)(2)(& mu;(2)-OH)(piv)(8)(dea)(2)(MeOH)(2)(H2O)(2)](NO3)& BULL;H2O (1) (where Hpiv = pivalic acid)was prepared from the reactionof Mn(piv)(2) with Dy(NO3)(3)& BULL;6H(2)O and diethanolamine (H(2)dea) in a MeOH/CH2Cl2 mixture. The C (2)-symmetriccluster comprises an unprecedented {Mn-6 (MnDy2)-Mn-III-Dy-IV (III)}(28+) core consistingof two distorted {Mn-2 (MnDyO4)-Mn-III-Dy-IV-O-III} cubane moieties sharing a common Mn-IV vertex and decorated with two additional Mn-III atoms.Hirshfeld surface analysis and fingerprint plots are used for decodingthe intermolecular interactions in 1. Magnetic studiesindicate that 1 exhibits a slow relaxation behavior withan effective energy barrier of 15.2 K and & tau;(0) = 1.4x 10(-7) s.