Mn₄ Single-Molecule-Magnet-Based Polymers of a One-Dimensional Helical Chain and a Three-Dimensional Network: Syntheses, Crystal Structures, and Magnetic Properties

Abstract

Two Mn 4 single-molecule-magnet (SMM)based coordination polymers, {[Mn 4 O(salox) systems with dpp and NaN 3 in DMF/MeOH, respectively. Both compounds comprise a mixed-valence tetranuclear manganese core, [Mn II Mn III 3 O] 9+ , which serves as a building unit for subsequent assembly via oximate and azido ligands. The flexible dpp ligand links with a Mn 4 unit, leading to the formation of a one-dimensional helical structure in 1•0.5MeOH and a three-dimensional pcu network in 2•1.5Et 2 O. The magnetic data analysis shows that antiferromagnetic interactions within the Mn 4 units resulted in S = 3 / 2 and 7 / 2 ground states for 1•0.5MeOH and 2•1.5Et 2 O, respectively. Both compounds show SMM behavior, as evidenced by frequency-dependent out-of-phase signals in alternating-current magnetic susceptibility and magnetic hysteresis loop studies with an energy barrier of U eff = 37 K for 2•1.5Et 2 O.

A Series of Lanthanide Coordination Polymers Based on Designed Bifunctional 1,4-Bis(imidazol-1-yl)terephthalic Acid Ligand: Structural Diversities, Luminescence, and Magnetic Properties

“…The design and selection of organic linkers proved to be an efficiently routine in the assembly of functional LnCPs. − Notably, the polycarboxylates and nitrogen heterocyclic compounds are two most selective candidates in building high-dimensional architectures for their strong coordination abilities and versatile bridging fashion. − However, bifunctional organic ligands, which contain both polycarboxylate and imidazole ring, were rarely reported, comparatively. − …”

Various Structural Types of Cyanide-Bridged FeIII–MnIII Bimetallic Coordination Polymers (CPs) and Polynuclear Clusters Based-on A New mer-Tricyanoiron(III)Building Block: Synthesis, Crystal Structures, and Magnetic Properties

“…Among which, since their magnetic coupling nature between neighboring paramagnetic metal centers through the cyanogroup and the molecular topological structures can be relatively easily predicted and controlled, the cyanide-bridged magnetic systems have been widely and intensely studied. Recently, with the aim not only of further disclosing the magneto-structure correlation but also more importantly for the great potential in many high-tech fields, a large numberof molecular magnetic materials containing a cyanide linkagewith different structural types have been synthesized and magnetically studied.Many of the reported cyanide-bridged magnetic assemblies showed very interesting magnetic properties [5,6,7,8,9,10,11,12,13,14] including single-molecule magnet (SMM) and single-chain magnet (SCM), which behave as nanosized magnets under the blocking temperature because of the energy barrierscoming from the large ground spin state (ST) and the strong easy axial anisotropy (D) [15,16,17].…”

Syntheses, Crystal Structures, and Magnetic Properties of Four New Cyano-Bridged Bimetallic Complexes Based on the mer-[FeIII(qcq)(CN)3]− Building Block

“…Low-dimensional magnets have been the hot topic in the last two decades due to their potential applications in molecular devices, high-density information storage, and quantum computers, etc . The single molecule magnet (SMM) behaves as a nanomagnet under a certain temperature because of the energy barrier for reversing the magnetization derived from a large ground state spin ( S T ) and strong easy-axis anisotropy ( D ) . Similar to a SMM, a single chain magnet (SCM) also exhibits slow magnetic relaxation at low temperatures because of large uniaxial anisotropy and strong intrachain exchange interactions without spin compensation between the high-spin magnetic units. , The ultimate goal of this research field is obviously to design new low-dimensional magnets, and enhance their blocking temperature ( T B ) as high as possible.…”