Schiff base tetranuclear Zn₂Ln₂ single-molecule magnets bridged by hydroxamic acid in association with near-infrared luminescence

Abstract

A series of Zn-Ln heteronuclear SMMs formed by hexadentate compartment Schiff base Zn-precursor and lanthanoid ions were structurally and magnetically characterized, in which the two [Zn-Ln] moieties are bridged by...

Anion-Induced Structural Diversity and Optical Chromism in a Series of Cyano-Bridged Heterometallic 3d-4f Coordination Polymers

“…Coordination polymers and metal–organic frameworks are receiving great attention because of their fascinating architectures and topologies that bestow excellent functionalities in catalysis, sensing, gas storage and chemical separation on these materials, while enhancing the chemical and thermal stability due to the rigidity of the extended (1D to 3D) molecular structure. Moreover, the incorporation of transition metal (3 d ) and lanthanide (4 f ) ions, particularly in heterometallic 3 d -4 f assemblies, can enrich such compounds with additional unique optical and magnetic properties, including tunable colored and white-light generation, near-infrared (NIR) emission, ferromagnetism and slow relaxation of the magnetization [ 1 , 2 , 3 , 4 , 5 , 6 ]. Supramolecular interactions, such as π-stacking and hydrogen bonding, can have a relevant direct impact on the physical properties of the materials, as well as indirect effects, for example, by favoring distance-dependent through-space phenomena, such as Förster’s energy transfer [ 7 , 8 , 9 , 10 , 11 ].…”

Tuning Nuclearity of Biradical-Ln Functional Compounds with Single-Molecule Magnet Behavior and Near-Infrared Luminescence

“…In addition, slow magnetic relaxation of Yb derivant correlates with NIR luminescence emission properties to some extent. − In compound 5 , the existence of quantum tunneling of magnetization and other non-Orbach processes may lead to the energy gap between the first excited state of 2 F 7/2 and the ground state higher than an effective energy barrier of 8.0 K in ac magnetic susceptibility measurement; meanwhile, similar situation can be observed in other Yb-based functional compounds …”

Hierarchical subcomponent self-assembly of covalent triple-stranded complexes with 3d–4f vertices: luminescence and magnetic properties

“…If two different metal ions, such as transition metal ions (3d) and lanthanide ions (4f), are simultaneously introduced into such systems, the intrinsic optical and large single-ion magnetic anisotropy of lanthanides together with remarkable magnetic interactions between 3d and 4f make such 3d-4f based complexes excellent candidates for luminescent materials and single molecular magnets (SMMs). [36][37][38][39][40] As far as we are aware, however, the syntheses of covalent metallo-supramolecular complexes were primarily based on single transition metal ions, 25,26,30,[41][42][43][44][45][46][47][48] very limited to single lanthanide ions. 35 In contrast, 3d-4f heterometallic ions have not been explored, largely because of the challenge of designing a suitable ligand that can bridge the gap between the divergent coordination preferences and abilities of 4f and 3d ions.…”