Construction of Metallosupramolecular Coordination Complexes: From Lanthanide Helicates to Octahedral Cages Showing Single-Molecule Magnet Behavior

Abstract

The construction of metallosupramolecular complexes toward interesting topological structures is a critical challenge for chemists. The fluctuation in the synthetic strategy, by keeping the same metal–ligand combination, has proved a very significant approach to construct metallosupramolecular architectures. Herein, by varying the reaction conditions four new DyIII-supramolecular complexes based on a flexible dihydrazone ligand H2L (H2L = bis­(2-hydroxy-3-methoxy­benzylidene)­adipohydrazide) in cooperation with different anions and solvents having formulas [Dy4L4(μ2-N3)2]­(NO3)2·6CH3OH·2H2O (1), [Dy8L8(μ2-CH3OH)4]­Cl8·6CH3OH·14H2O (2), [Dy12L12(μ2-OH)2(OH)6(CH3O)2]­(NO3)2·2CH3OH·14H2O (3), and [Dy12L12(μ2-OH)2(NO3)2(OH)3(CH3O)]­(NO3)4·22H2O (4), have been successfully synthesized and their crystal structures confirmed by single crystal X-ray diffraction studies. The structural study reveals that 1 and 2 have quadruple-stranded helicate and dual triple-stranded helicate supramolecular structures, respectively, while 3 and 4 display “octahedron” cagelike supramolecular structures. The magnetic studies reveal that complexes 1–3 exhibit slow magnetic relaxation behavior, while complex 4 displays a series of typical frequency-dependent relaxation signals at 0 Oe applied dc field which is a rare case in polynuclear 4f single-molecule magnet (SMM) family to date. Interestingly, the distinct magnetic dynamic behavior was noticed for nearly isoskeletal complexes 3 and 4, which can be attributed to the modification of the coordination environment around DyIII ions.

The crystal structure of bis(isothiocyanato-κ1N)-(methanol-κ1O)-[2-morpholine-4-yl-4,6-di(pyrazol-1-yl)-1,3,5-triazine-κ3N,N′,N′′] manganese(II), C16H18MnN10O2S2

“…In the past decades, the crystal materials of supramolecular complexes have attracted great interest due to their potential applications in several fields [6][7][8]. The structure design and synthesis of new manganese complexes are of general interest and beneficial to the research of magnetic materials [9,10].…”

Mesoporous silica nanoparticle-embedded lanthanide organic polyhedra for enhanced stability, luminescence and cell imaging

“…Due to the intrinsic optical and magnetic properties of lanthanide ions stemmed from their shielded 4f electrons, 1,2 lanthanide-containing compounds are quite fascinating due to their potential applications in luminescent displays, [3][4][5][6][7][8][9][10][11] bioimaging, [12][13][14][15][16][17] sensing, [18][19][20][21][22][23][24][25][26] catalysis, [27][28][29][30] single-molecular magnets, [31][32][33][34] MRI contrast agents, [35][36][37][38][39][40] and upconversion materials, [41][42][43][44][45] etc. 46 Particularly, the characteristics of lanthanide-containing compounds, [47][48][49] such as sharp line-like and ligand-independent emission bands, long lifetimes, and large Stokes/anti-Stokes shifts, endow their ...…”

Anion-Dependent Structure and Luminescence Diversity in ZnII-LnIII Heterometallic Architectures Supported by a Salicylamide-Imine Ligand

“…The fast-developing coordination-driven self-assembly strategy has resulted in many examples of metallo-supramolecules for recognizing and responding to negatively charged species. It has also been well documented that the anions usually play an important role in controlling the size and topology of lanthanide coordination species, either as a directing reagent or as templates. − However, how anions act as structural dictators to modulate the luminescent efficiency of heterometallic lanthanide-containing compounds remains an elusive yet intriguing issue. In addition, a deeper understanding of complex self-assembly processes allows greater control of the construction of increasingly complex structures with multiple functions.…”