Systematic Investigation of Reaction‐Time Dependence of Three Series of Copper–Lanthanide/Lanthanide Coordination Polymers: Syntheses, Structures, Photoluminescence, and Magnetism

Abstract

Three series of copper-lanthanide/lanthanide coordination polymers (CPs) Ln(III) Cu(II) Cu(I) (bct)3 (H2 O)2 [Ln=La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Er (10), Yb (11), and Lu (12), H2 bct=2,5-bis(carboxymethylmercapto)-1,3,4-thiadiazole acid], Ln(III) Cu(I) (bct)2 [Ln=Ce (2 a), Pr (3 a), Nd (4 a), Sm (5 a), Eu (6 a), Gd (7 a), Tb (8 a), Dy (9 a), Er (10 a), Yb (11 a), and Lu (12 a)], and Ln(III) 2 (bct)3 (H2 O)5 [Ln=La (1 b), Ce (2 b), Pr (3 b), Nd (4 b), Sm (5 b), Eu (6 b), Gd (7 b), Tb (8 b), and Dy (9 b)] have been successfully constructed under hydrothermal conditions by modulating the reaction time. Structural characterization has revealed that CPs 1-12 possess a unique one-dimensional (1D) strip-shaped structure containing two types of double-helical chains and a double-helical channel. CPs 2 a-12 a show a three-dimensional (3D) framework formed by Cu(I) linking two types of homochiral layers with double-helical channels. CPs 1 b-9 b exhibit a 3D framework with single-helical channels. CPs 6 b and 8 b display visible red and green luminescence of the Eu(III) and Tb(III) ions, respectively, sensitized by the bct ligand, and microsecond-level lifetimes. CP 8 b shows a rare magnetic transition between short-range ferromagnetic ordering at 110 K and long-range ferromagnetic ordering below 10 K. CPs 9 a and 9 b display field-induced single-chain magnet (SCM) and/or single-molecule magnet (SMM) behaviors, with Ueff values of 51.7 and 36.5 K, respectively.

Homochiral Ferromagnetic Coupling Dy2 Single-Molecule Magnets with Strong Magneto-Optical Faraday Effects at Room Temperature

“…Very interestingly, the research on homochiral molecular magnets has been highly valued, mainly because they can exhibit a magnetochiral dichroism (MChD) effect, − which usually requires chirality and a strong magneto-optical Faraday effect corresponding to magnetic circular dichroism (MCD). , These magneto-optical materials themselves may be used in optical current transformer, magneto-optical switches, magneto-optical isolators, and fiber magneto-optical sensors. − In addition, chiral molecular magnets may be attached with ferroelectric properties due to crystallization in a polar space group, becoming multiferroic molecular materials, − or attached with second-order nonlinear optical activity due to crystallization in a noncentral symmetric space group, becoming magnetic-nonlinear optical multifunctional molecular materials. − However, few homochiral SMMs have been reported, and the chirality of most SMMs is derived from N -donor ligands; − ,− unfortunately, most homochiral SMMs require an external dc field to exhibit good magnetic relaxation properties. − Moreover, homochiral SMMs with a strong magneto-optical Faraday effect have not been well developed. Recently, we adopted (−)/(+)-3-trifluoroacetyl camphor ( l -Htfc/ d -Htfc) acting as the chiral ligand to construct enantiomerically pure Dy­(III) dinuclear complexes, [Dy 2 ( l -tfc) 4 (chp) 2 (MeOH) 2 ] ( l - 1 ) (Hchp = 6-chloro-2-hydroxypyridine) and [Dy 2 ( d -tfc) 4 (chp) 2 (MeOH) 2 ] ( d - 1 ), which show ferromagnetic coupling and perform good zero field SMM properties; especially, they display a strong magneto-optical Faraday effect at room temperature.…”

Syntheses, Structures, and Magnetic Properties of Two Series of 3d–4f Heterometallic Coordination Polymers Derived from Pyrazine‐2,3‐dicarboxylic Acid

“…Similar magnetic behaviors are also observed in the previous reports. [9a], For 17 – 19 , the χ m T values decrease slowly in the high‐temperature range, and then drop quickly to 18.89, 8.76, and 1.64 emu mol –1 K at 2 K, respectively, which are ascribed to either antiferromagnetic interactions between paramagnetic ions or thermal depopulation of the Stark sublevels of Dy III /Er III /Yb III .…”

“…Cheng and co‐workers constructed numerous 3d–4f heterometallic CPs by using N‐containing polycarboxylic acids . Recently, we also carried out some work in this field …”

Synthesis, Structure, and Magnetic Properties of a Three‐Dimensional Cobalt Carboxylate Metal‐Organic Framework

“…A large variety of open frameworks solids showing different pore shapes and dimensions with sometimes unique properties have been prepared by strict control of the reaction conditions together with the interacting metal ions and appropriate organic ligands . Following the successes in metal‐oxo compounds bridged by carboxylate ligands bearing benzene ring, carboxylate‐bridged metal compounds containing condensed aromatic rings have been attracting more and more interests . 1,4,5,8‐naphthalenetetracarboxylic acid (H 4 L) has been attracted a lot of attention because of its multiple coordination sites and high symmetry and large π ‐conjugated structure.…”