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

Three series of copper-lanthanide/lanthanide coordination polymers (CPs) Ln(III)Cu(II)Cu(I)(bct)(3)(H2O)(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), H(2)bct=2,5-bis(carboxymethylmercapto)-1,3,4-thiadiazole acid], Ln(III)Cu(I)(bct)(2) [Ln=Ce (2a), Pr (3a), Nd (4a), Sm (5a), Eu (6a), Gd (7a), Tb (8a), Dy (9a), Er (10a), Yb (11a), and Lu (12a)], and Ln(2)(III)(bct)(3)(H2O)(5) [Ln=La (1b), Ce (2b), Pr (3b), Nd (4b), Sm (5b), Eu (6b), Gd (7b), Tb (8b), and Dy (9b)] 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 2a-12a show a three-dimensional (3D) framework formed by Cu-I linking two types of homochiral layers with double-helical channels. CPs 1b-9b exhibit a 3D framework with single-helical channels. CPs 6b and 8b 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 8b shows a rare magnetic transition between short-range ferromagnetic ordering at 110K and long-range ferromagnetic ordering below 10K. CPs 9a and 9b display field-induced single-chain magnet (SCM) and/or single-molecule magnet (SMM) behaviors, with U-eff values of 51.7 and 36.5K, respectively.