title: Self-assembly synthesis, structural features, and photophysical properties of dilanthanide complexes derived from a novel amide type ligand: energy transfer from Tb(III) to Eu(III) in a heterodinuclear derivative.
abstract: A novel amide type ligand benzyl-N,N-bis[(2'-furfurylaminoformyl)phenoxyl)ethyl]-amine (L) has been designed and applied for the self-assembly generation of homodinuclear lanthanide coordination compounds [Ln2(μ2-L)2(NO3)6(EtOH)2] [Ln = Eu (1), Tb (2), and Gd (3)] and a heterodinuclear derivative [EuTb(μ2-L)2(NO3)6(EtOH)2] (4). All the complexes have been characterized by the X-ray single-crystal diffraction analyses. They are isostructural, crystallize in a monoclinic space group P21/c, and form [2 + 2] rectangular macrocycle structures. Compound 4 is the first example of a [2 + 2] rectangular macrocycle heterodinuclear EuTb complex assembled from an amide type ligand. In 4, the discrete 0D dimeric [EuTb(μ2-L)2(NO3)6(EtOH)2] units are extended, via the multiple N-H···O hydrogen bonds, into a 2D supramolecular network that has been topologically classified as a uninodal 4-connected underlying net with the sql [Shubnikov tetragonal plane net] topology. The triplet state ((3)ππ*) of L studied by the Gd(III) complex 3 demonstrated that the ligand beautifully populates Tb(III) emission (Φ = 52%), whereas the corresponding Eu(III) derivative 1 shows weak luminescence efficiency (Φ = 0.7%) because the triplet state of L has a poor match with (5)D1 energy level of Eu(III). Furthermore, the photoluminescent properties of heterodinuclear complex 4 have been compared with those of the analogous homodinuclear compounds. The quantum yield and lifetime measurements prove that energy transfer from Tb(III) to Eu(III) is being achieved, namely, that the Tb(III) center is also acting to sensitize the Eu(III) and enhancing Eu(III) emission in 4.
authors.affiliation: Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province, State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University , Lanzhou 730000, P. R. China.
authors.forename: Cunji
authors.initials: C
authors.lastname: Gao
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Kirillov
authors.forename: Wei
authors.initials: W
authors.lastname: Dou
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Tang
authors.forename: Liangliang
authors.initials: L
authors.lastname: Liu
authors.forename: Xuhuan
authors.initials: X
authors.lastname: Yan
authors.forename: Yujie
authors.initials: Y
authors.lastname: Xie
authors.forename: Peixian
authors.initials: P
authors.lastname: Zang
authors.forename: Weisheng
authors.initials: W
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Tang
mesh_terms: D000577:Amides / Q000737:chemistry*; D060326:Chemistry Techniques, Synthetic; D004355:Drug Stability; D004735:Energy Transfer; D005063:Europium / Q000737:chemistry*; D008024:Ligands; D008163:Luminescent Measurements; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013696:Temperature; D013725:Terbium / Q000737:chemistry*
chemical_list: D000577:Amides; D008024:Ligands; D009942:Organometallic Compounds; D013725:Terbium; D005063:Europium