Functionalization of Keggin Fe 13 -Oxo Clusters.

Two Keggin Fe 13 -oxo clusters, [Pr 12 Fe 33 (NO 3 ) 6 (L-van) 4 (D-van) 5 (TEOA) 12 (μ 3 -OH) 12 (μ 4 -OH) 12 (μ 4 -O) 28 (H 2 O) 4 ]·(ClO 4 ) 3 ·(NO 3 )·10H 2 O ( 1 ) and [Dy 12 Fe 33 (NO 3 ) 2 (L-van) 3 (D-van) 3 (TEOA) 12 (μ 3 -OH) 18 (μ 4 -OH) 6 (μ 4 -O) 28 (H 2 O) 9 ]·(ClO 4 ) 5 ·(NO 3 ) 6 ·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 C 2, 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 Pr 3+ ion.