Multifunctional Homochiral Lanthanide Camphorates with Mixed Achiral Terephthalate Ligands

Seven homochiral lanthanide camphorates with mixed achiral terephthalate ligands, namely, {Ln₂(cam)₂(bdc)(H₂O)₂}·DMF [Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7); d-H₂cam = d-(+)-camphoric acid; H₂bdc = 1,4-benzenedicarboxylic acid; DMF = N,N′-dimethylformamide], have been solvothermally synthesized. Single-crystal X-ray diffraction analyses reveal that compounds 1−7 are isostructural and crystallize in orthorhombic, chiral space group P2₁2₁2₁. These structures feature three-dimensional open frameworks based on rodlike [Ln₂(OCO)₆(H₂O)₂]_n secondary building units, with the guest DMF molecules occupying the void space of the host {Ln₂(cam)₃(bdc)(H₂O)₂} framework. The photophysical and magnetic properties of some of these complexes have been investigated. Notably, the terbium compound 4 is highly emissive with a quantum yield of 63.68%. Additionally, thermogravimetric analyses, variable-temperature IR spectrscopy, and powder X-ray diffraction of 2 as a representative were performed to determine its thermal stability, which indicates that the framework still remains intact until 300 °C.