A [Mn₃₂] Double‐Decker Wheel

Abstract

Polynuclear clusters of paramagnetic 3d metal ions continue to attract significant interest because of their intriguing geometrical characteristics (large size, high symmetry, aesthetically pleasing shapes and architectures) and fascinating physical properties. Such complexes often combine large and sometimes abnormally large spin ground states with easyaxis-type magnetic anisotropy, resulting in a significant barrier to magnetization relaxation. [1][2][3] Thus, at sufficiently low temperatures they function as single-domain magnetic particles displaying magnetization hysteresis and quantum tunneling of the magnetization (QTM). [3, 4] Such singlemolecule magnets (SMMs) represent a molecular approach to nanoscale magnetic materials with potential applications in information storage and molecular spintronics.[5] SMMs with nuclearities up to 84 and structural topologies as diverse as (amongst others) dimers, triangles, cubanes, tetrahedra, icosahedra, and wheels are now known. [1][2][3]6] The latter of these have always attracted intense interest, partly because of their inherent structural beauty, but also because they represent model systems for the study of one-dimensional magnetism, spin frustration, and quantum effects and are promising candidates for use as qubits in quantum computation.[7] Homo-and heterometallic molecular wheels are commonly encountered in 3d cluster chemistry, [8][9][10][11][12][13][14][15] and in general they fall into two distinct structural types. By far the most common are single-stranded wheels, which simply describe linked monometallic units. [8, 9] Multiple-stranded wheels are less common and encompass either 1) wheels built from repeating metal clusters, [10] or 2) multiple-layer wheels, that is, complexes that consist of two or more linked parallel wheels. Those of structural type (2) are extremely rare, being restricted to [V 12 (Figure 1 a) (Figure 1 b, (Figure 1 c) [18] charge-balance considerations, and inspection of metric parameters.The metal-oxygen core of the cluster consists of four pairs of edge-sharing {M 4 O} tetrahedra situated at the "corners" of

From antiferromagnetic to ferromagnetic exchange in a family of oxime-based MnIII dimers: a magneto-structural study

“…[28][29][30][31][32][33][34] A highly promising family of ligands for constructing magnetically interesting clusters based on Mn III are the phenolic oximes (R-saoH 2 , Scheme 1). [40][41][42] Our most recent research attempts have therefore focused on deliberately targeting Mn III clusters with the R-saoH 2 family of ligands whose building blocks are not [Mn III 3 O(R-sao) 3 ] + triangles. 37 Nearest neighbour magnetic exchange is dominated by the twisting of the -N-Omoiety of the phenolic oxime and the sign and magnitude of the pairwise exchange can be controlled via chemical substitution at the oximic C-atom.…”

“…36 In basic alcoholic solutions the Mn III /R-saoH 2 reaction mixture generally affords molecules containing the triangular [Mn III 3 O(R-sao) 3 ] + building block. This has already borne some success with the synthesis of a [Mn 32 ] double-decker wheel, 40 homo-and heterometallic dimers, 41 and a family of [Mn III 6 Ln III 2 ] hexagonal prisms. 38 The Mn III /R-sao 2− (Mn-O-N-Mn) moiety therefore represents a potentially interesting building block for functional materials, but while magneto-structural correlations have been investigated for the triangular [Mn III 3 O(R-sao) 3 ] + building block, 39 there is a dearth of examples in the literature of molecules containing alternative topologies.…”

Crystal structure of diazido-dimethanolato-bis(μ2-2-(((3-oxidopropyl)imino)methyl)phenolato-κ4 O:O,O′,N)dimanganese(III), C22H28Mn2N8O6

“…In this field, the manganese Schiff base complex is a fruitful subclass of transition metal compounds, which have been paid much attention on their bioinorganic and physical aspects such as to imitate the oxygen evolution center (OEC) in photosystem (PSII) and single-molecule magnets (SMMs) [5,6]. A number of manganese clusters with extraordinary topologies have been reported [7,8]. However, related research involving azide is rather rare [9].…”

Synthesis, Characterization, Magnetic Properties, and Topological Aspects of Isoskeletal Heterometallic Hexanuclear CoII4LnIII2 Coordination Clusters Possessing 2,3,4M6–1 Topology

“…[21] boat-like and possess a 2,3,4M6-1 topology. The reaction of (E)-2-(5-bromo-2-hydroxy-3-methoxybenzylideneamino)phenol (H 2 L2) with Co(NO 3 ) 2 6H 2 O and DyCl 3 x(H 2 O) afforded [Co II 4 Dy III 2 (μ 3 -OH) 2 (L2) 4 Cl 2 (NO 3 ) 2 (MeOH) 4 ] (5), which is isoskeletal to compounds 1-4. Magnetic studies performed over the temperature range 1.8-300 K show that compound 3 undergoes slow magnetic relaxation.…”