Functionalization of Keggin Fe13-Oxo Clusters

Two Keggin Fe-13-oxo clusters, [Pr12Fe33(NO3)(6)(L-van)(4)(D-van)(5)(TEOA)(12)(mu(3)-OH)(12)(mu(4)-OH)(12)(mu(4)-O)(28)(H2O)(4)]center dot(ClO4)(3)center dot(NO3)center dot 10H(2)O (1) and [Dy12Fe33(NO3)(2)(L-van)(3)(D-van)(3)(TEOA)(12)(mu(3)-OH)(18)(mu(4)-OH)(6)(mu(4)-O)(28)(H2O)(9)]center dot(ClO4)(5)center dot(NO3)(6)center dot 15H(2)O (2), where L-van = L-valine, D-van = D-valine, and TEOA = triethanolamine, were prepared by using Ln(3+) as a stabilizer. Cluster 1 crystallizes in a chiral space group of C2, while cluster 2 crystallizes in a centrosymmetric space group of Pnma. Dynamic magnetic measurements of 2 under a zero direct-current field reveal that 2 exhibits single-molecule-magnet characteristics with an energy barrier of 18.79 K. Significantly, the formation of the chiral cluster 1 is closely related to the larger radius of the Pr3+ ion.