The first cobalt molecule to function as a single-molecule magnet, [Co 4 (hmp) 4 (MeOH) 4 Cl 4 ], where hmpis the anion of hydroxymethylpyridine, is reported.The core of the molecule consists of four Co(II) cations and four hmpoxygen atoms ions at the corners of a cube. Variable-field and variable-temperature magnetization data have been analyzed to establish that the molecule has a S=6 ground state with considerable negative magnetoanisotropy. Single-ion zero-field interactions (DS z 2 ) at each cobalt ion are the origin of the negative magnetoanisotropy. A single-crystal of the compound was studied by means of a micro-SQUID magnetometer in the range of 0.040-1.0K.Hysteresis was found in the magnetization versus magnetic field response of this single crystal. It is concluded that this is the first cobalt molecule to function as a singlemolecule magnet.
Learning from serendipitous assembly, we have prepared a new family of designed 3d-4f Mn6Ln complexes. The dynamics of relaxation of the magnetization via alternating-current magnetic susceptibility for the new Mn6Ln complexes 1 (Ln = La), 2 (Ln = Tb), and 4 (Ln = Dy) have been studied down to 0.2 K.
a b s t r a c tMicrowave assisted synthesis and bench-top reactions are compared for Mn and Mn/Ni reaction systems with substituted salicylic acid (2-hydroxy-6-isopropyl-3-methylbenzoic-acid (SALOH 2 ). When Mn salts are used, the microwave assisted synthesis and the bench-top reaction afford the same product: the new octanuclear Mn(II)/Mn(III) complex [Mn 8 O 2 (OMe) 2 Cl 2 (SALO) 6 (MeOH) 4 (H 2 O) 2 ] (1). However, in a mixed metal Mn/Ni reaction the bench-top reaction results in the new heterometallic distorted cubane complexes [Pr 2 NH 2 ][Mn 2 Ni 2 (OH) 2 (L 1 ) 2 (SALO) 2 (SALOH) 3 ] (where L 1 H = 3-dimethylamino-1-propanol), (2) and [Pr 2 NH 2 ][Mn 2 Ni 2 (OH)(OMe) 2 (L 1 )(MeCN)(SALO) 2 (SALOH) 3 ] (3). The crystal structure and magnetic properties of the prepared complexes are presented.
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