Evolution of Luminescent Supramolecular Lanthanide M2nL3n Complexes from Helicates and Tetrahedra to Cubes.
Xiao-Zhen LiLi-Peng ZhouLiang-Liang YanDa-Qiang YuanChen-Sheng LinQing-Fu SunPublished in: Journal of the American Chemical Society (2017)
Lanthanide-containing molecules have many potential applications in material science and biology, that is, luminescent sensing/labling, MRI, magnetic refrigeration, and catalysis among others. Coordination-directed self-assembly has shown great power in the designed construction of well-defined supramolecular systems. However, application of this strategy to the lanthanide edifices is challenging due to the complicated and greatly labile coordination numbers and geometries for lanthanides. Here we demonstrate a sensitive structural switching phenomenon during the stereocontrolled self-assembly of a group of Ln2nL3n (Ln for lanthanides, L for organic ligands, and n = 1, 2, 4) compounds. Systematic variation of the offset distances between the two chelating arms on the bis(tridentate) ligands dictated the final outcomes of the lanthanide assembly, ranging from Ln2L3 helicates and Ln4L6 tetrahedra to Ln8L12 cubes. Remarkably, the borderline case leading to the formation of a mixture of the helicate and the tetrahedron was clearly revealed. Moreover, the concentration-dependent self-assembly of an unprecedented cubic Ln8L12 complex was also confirmed. The luminescent lanthanide cubes can serve as excellent turn-off sensors in explosives detection, featuring high selectivity and sensitivity toward picric acid. All complexes were confirmed by NMR, ESI-TOF-MS, and single crystal X-ray diffraction studies. Our results provide valuable design principles for the coordination self-assembly of multinuclear functional lanthanide architectures.
Keyphrases
- energy transfer
- metal organic framework
- single molecule
- quantum dots
- sensitive detection
- high resolution
- magnetic resonance imaging
- magnetic resonance
- ms ms
- computed tomography
- water soluble
- living cells
- single cell
- metabolic syndrome
- human health
- weight loss
- fluorescent probe
- dual energy
- diffusion weighted imaging
- low cost
- crystal structure