Multifunctional Homochiral Lanthanide Camphorates with Mixed Achiral Terephthalate Ligands

Abstract

Seven homochiral lanthanide camphorates with mixed achiral terephthalate ligands, namely, {Ln(2)(cam)(2)(bdc)(H(2)O)(2)}·DMF [Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6), Er (7); d-H(2)cam = d-(+)-camphoric acid; H(2)bdc = 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 P2(1)2(1)2(1). These structures feature three-dimensional open frameworks based on rodlike [Ln(2)(OCO)(6)(H(2)O)(2)](n) secondary building units, with the guest DMF molecules occupying the void space of the host {Ln(2)(cam)(3)(bdc)(H(2)O)(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 spectroscopy, 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.