title: Anisotropic lanthanide-based nano-clusters for imaging applications.
abstract: We have developed a new class of lanthanide nano-clusters that self-assemble using flexible Schiff base ligands. Cd-Ln and Ni-Ln clusters, [Ln8Cd24(L1)12(OAc)39Cl7(OH)2] (Ln = Nd, Eu), [Eu8Cd24(L1)12(OAc)44], [Ln8Cd24(L2)12(OAc)44] (Ln = Nd, Yb, Sm) and [Nd2Ni4(L3)2(acac)6(NO3)2(OH)2], were constructed using different types of flexible Schiff base ligands. These molecular nano-clusters exhibit anisotropic architectures that differ considerably depending upon the presence of Cd (nano-drum) or Ni (square-like nano-cluster). Structural characterization of the self-assembled particles has been undertaken using crystallography, transmission electron microscopy and small-angle X-ray scattering. Comparison of the metric dimensions of the nano-drums shows a consistency of size using these techniques, suggesting that these molecules may share similar structural features in both solid and solution states. Photophysical properties were studied by excitation of the ligand-centered absorption bands in the solid state and in solution, and using confocal microscopy of microspheres loaded with the compounds. The emissive properties of these compounds vary depending upon the combination of lanthanide and Cd or Ni present in these clusters. The results provide new insights into the construction of novel high-nuclearity nano-clusters and offer a promising foundation for the development of new functional nanomaterials.
authors.affiliation: College of Chemistry and Materials Engineering, Wenzhou University, Zhejiang Key Laboratory of Carbon Materials, Wenzhou 325035, China. smhuang@wzu.edu.cn.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yang
authors.forename: Shiqing
authors.initials: S
authors.lastname: Wang
authors.forename: Tyler L
authors.initials: TL
authors.lastname: King
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kerr
authors.forename: Clement
authors.initials: C
authors.lastname: Blanchet
authors.forename: Dmitri
authors.initials: D
authors.lastname: Svergun
authors.forename: Robert
authors.initials: R
authors.lastname: Pal
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby
authors.forename: Jamuna
authors.initials: J
authors.lastname: Vadivelu
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Brown
authors.forename: Richard A
authors.initials: RA
authors.lastname: Jones
authors.forename: Lijie
authors.initials: L
authors.lastname: Zhang
authors.forename: Shaoming
authors.initials: S
authors.lastname: Huang
mesh_terms: D028581:Lanthanoid Series Elements; D008024:Ligands; D049329:Nanostructures; D009942:Organometallic Compounds; D012545:Schiff Bases
chemical_list: D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D012545:Schiff Bases