4f-Metal Clusters Exhibiting Slow Relaxation of Magnetization: A {Dy7} Complex with An Hourglass-like Metal Topology

Abstract

The reaction between Dy(NO3)3∙6H2O and the bulky Schiff base ligand, N-naphthalidene-2-amino-5-chlorobenzoic acid (nacbH2), in the presence of the organic base NEt3 has led to crystallization and structural, spectroscopic and magnetic characterization of a new heptanuclear [Dy7(OH)6(OMe)2(NO3)1.5(nacb)2(nacbH)6(MeOH)(H2O)2](NO3)1.5 (1) compound in ~40% yield. Complex 1 has a unique hourglass-like metal topology, among all previously reported {Dy7} clusters, comprising two distorted {Dy4(μ3-OH)3(μ3-OMe)}8+ cubanes that share a common metal vertex (Dy2). Peripheral ligation about the metal core is provided by the carboxylate groups of four η1:η1:η1:μ single-deprotonated nacbH− and two η1:η1:η2:η1:μ3 fully-deprotonated nacb2− ligands. Complex 1 is the first structurally characterized 4f-metal complex bearing the chelating/bridging ligand nacbH2 at any protonation level. Magnetic susceptibility studies revealed that 1 exhibits slow relaxation of magnetization at a zero external dc field, albeit with a small energy barrier of ~5 K for the magnetization reversal, most likely due to the very fast quantum-tunneling process. The combined results are a promising start to further explore the reactivity of nacbH2 upon all lanthanide ions and the systematic use of this chelate ligand as a route to new 4f-metal cluster compounds with beautiful structures and interesting magnetic dynamics.

A family of mono-, di-, and tetranuclear DyIIIcomplexes bearing the ligand 2,6-diacetylpyridine bis(picolinoylhydrazone) and exhibiting slow relaxation of magnetization

“…This is further supported by the fact that the magnetization values at the maximum applied fields (∼5 Nμ B in 1 , ∼11 Nμ B in 2 , ∼10 Nμ B in 3 , and ∼20 Nμ B in 4 ) are significantly lower than the expected values for one (10 Nμ B ), two (20 Nμ B ), and four (40 Nμ B ) isolated Dy III centers. 51…”

New Family of Heptanuclear Lanthanide {Ln7} Clusters: Synthesis, Structure, and Magnetic Studies

“…In the existing literature one can find that heptanuclear lanthanide complexes are a much less explored class in terms of both coordination geometry and magnetism. A handful of heptanuclear lanthanide complexes are documented earlier with varying structural topologies such as metal‐centered hexagon, [19a] ring, [19b,c] metal‐centered octahedron [19d] and trigonal prism, [15,19e] metal vertex‐sharing dicubanes, [19f] tip or vertex sharing double‐butterfly, [19g] edge‐sharing triangles [19h] which are depicted in Figure S3 (Supporting Information). There is no other report of such topology in the literature as of 2 where the two mono capped triangular metal units are connected by a central metal ion.…”

{GdIII7} and {GdIII14} Cluster Formation Based on a Rhodamine 6G Ligand with a Magnetocaloric Effect

“…Among them, rare earth ions play an important role in the assembly of polynuclear clusters [ 1 , 2 , 3 ]. Due to their large ion radius and inherent ability to participate in various coordination environments, rare earth ions can promote the formation of polymetallic clusters [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. Multinuclear rare earth clusters with different structural types, such as {Ln 18 } [ 23 ], {Ln 28 } [ 24 ], {Ln 34 } [ 25 ], {Ln 36 } [ 26 ], {Ln 37 } [ 27 ], {Ln 48 } [ 28 ], {Ln 60 } [ 29 ], {Ln 72 } [ 30 ], {Ln 104 } [ 31 ], {Ln 140 } [ 32 ], etc., were synthesized, and the largest even has a {Nd 288 } structure [ 33 ].…”

“…Multinuclear rare earth clusters with different structural types, such as {Ln 18 } [ 23 ], {Ln 28 } [ 24 ], {Ln 34 } [ 25 ], {Ln 36 } [ 26 ], {Ln 37 } [ 27 ], {Ln 48 } [ 28 ], {Ln 60 } [ 29 ], {Ln 72 } [ 30 ], {Ln 104 } [ 31 ], {Ln 140 } [ 32 ], etc., were synthesized, and the largest even has a {Nd 288 } structure [ 33 ]. These polynuclear clusters usually exhibit fascinating properties, such as single-molecule magnetism [ 8 , 12 , 14 , 15 , 19 , 30 ], luminescence [ 23 , 24 ], magneto-optical properties [ 34 ] and proton-conductive properties [ 35 ].…”