title: Sequential Synthesis of 3d-3d'-4f Heterometallic Heptanuclear Clusters in between Lacunary Polyoxometalates.
abstract: In this work, we have successfully created several unprecedented discrete 3d-3d'-4f heterotrimetallic clusters in between lacunary polyoxometalates (POMs). By the three-step sequential introduction of metal cations into a trivacant lacunary POM TBA4H6[A-α-SiW9O34] (TBA = tetra-n-butylammonium) in organic media, five kinds of sandwich-type POMs with double-diamond-shaped 3d-3d'-4f heptanuclear clusters (IIIFeM4Ln2, TBAnHm[FeM4{Ln(L)2}2O2(A-α-SiW9O34)2], M = Mn(3+), Cu(2+); Ln = Gd(3+), Dy(3+), Lu(3+); L = acac (acetylacetonate), hfac (hexafluoroacetylacetonate)) were successfully synthesized for the first time. By introduction of two [Ln(L)2](+) units on the ends of pentanuclear clusters [FeMn4O18(OH)2](23-) and [FeCu4O18(OH)2](27-), the magnetic interactions between Mn(3+)-Mn(3+) and Cu(2+)-Cu(2+) could be modulated. Among a series of the heterometallic heptanuclear compounds, IIIFeMn4Lu2 exhibited the slow magnetic relaxation characteristic for a single-molecule magnet under the zero applied magnetic fields.
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Rinta
authors.initials: R
authors.lastname: Sato
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Takuo
authors.initials: T
authors.lastname: Minato
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yamaguchi
authors.affiliation: Department of Applied Chemistry, School of Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Noritaka
authors.initials: N
authors.lastname: Mizuno