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 17 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.