title: Symmetry-related [Ln(III)6Mn(III)12] clusters toward single-molecule magnets and cryogenic magnetic refrigerants.
abstract: A family of high-nuclearity [Ln(III)(6)Mn(III)(12)] (Ln = Gd, Tb) nanomagnets has been synthesized, of which two are in D(2) molecular symmetry and the other two are in C(1) symmetry. X-ray crystallography shows that each of them contains a similar {Mn(III)(8)O(13)} unit, four marginal Mn(III) ions, and two linear {Ln(III)(3)} units with parallel or perpendicular orientation for high- and low-symmetry cores, respectively. For [Gd(III)(6)Mn(III)(12)], the distinct spins of the {Mn(III)(8)O(13)} unit lead to different spin ground states (S(T) = 23 for the high-symmetry one and S(T) = 16 for the low-symmetry one), and significant magnetocaloric effects are observed in a wide temperature range [full width at half-maximum (FWHM) of -ΔS(m) > 18 K] that can maximizes the refrigerant capacity, which may be attributed to the ferromagnetic interactions. By replacement of isotropic Gd(III) with anisotropic Tb(III), they behave as single-molecule magnets, with the high-symmetry one possessing a larger effective barrier (36.6 K) than the low-symmetry one (19.6 K).
authors.affiliation: MOE Key Lab of Bioinorganic and Synthetic Chemistry, School of Chemistry & Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, People's Republic of China.
authors.forename: Jun-Liang
authors.initials: JL
authors.lastname: Liu
authors.forename: Wei-Quan
authors.initials: WQ
authors.lastname: Lin
authors.forename: Yan-Cong
authors.initials: YC
authors.lastname: Chen
authors.forename: Ji-Dong
authors.initials: JD
authors.lastname: Leng
authors.forename: Fu-Sheng
authors.initials: FS
authors.lastname: Guo
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: Tong