title: Heterobinuclear Zn-Ln (Ln = La, Nd, Eu, Gd, Tb, Er and Yb) complexes based on asymmetric Schiff-base ligand: synthesis, characterization and photophysical properties.
abstract: With a novel asymmetric Schiff-base zinc complex ZnL (H2 L = N-(3-methoxysalicylidene)-N'-(5-bromo-3-methoxysalicylidene)phenylene-1,2-diamine), obtained from phenylene-1,2-diamine, 3-methoxysalicylaldehyde and 5-bromo-3-methoxysalicylaldehyde, as the precursor, a series of heterobinuclear Zn-Ln complexes [ZnLnL(NO3 )3 (CH3 CN)] (Ln = La, 1; Ln = Nd, 2; Ln = Eu, 3; Ln = Gd, 4; Ln = Tb, 5; Ln = Er, 6; Ln = Yb, 7) were synthesized by the further reaction with Ln(NO3 )3 ·6H2 O, and characterized by Fourier transform-infrared, fast atom bombardment mass spectroscopy and elemental analysis. Photophysical studies of these complexes show that the strong and characteristic near-infrared luminescence of Nd(3+) , Yb(3+) and Er(3+) with emissive lifetimes in the microsecond range has been sensitized from the excited state of the asymmetric Schiff-base ligand due to effective intramolecular energy transfer; the other complexes do not show characteristic emission due to the energy gap between the chromophore and lanthanide ions.
authors.affiliation: College of Chemistry and Chemical Engineering, Xi'an University of Science and Technology, Xi'an, 710054, People's Republic of China; Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecular Chemistry, Northwest University, Xi'an, 710069, People's Republic of China.
authors.forename: Shunsheng
authors.initials: S
authors.lastname: Zhao
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Liu
authors.forename: Xingqiang
authors.initials: X
authors.lastname: Lü
authors.forename: Wai-Kwok
authors.initials: WK
authors.lastname: Wong
mesh_terms: D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008024:Ligands; D008163:Luminescent Measurements; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D055668:Photochemical Processes; D012545:Schiff Bases / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D015032:Zinc / Q000737:chemistry*
chemical_list: D028581:Lanthanoid Series Elements; D008024:Ligands; D009942:Organometallic Compounds; D012545:Schiff Bases; D015032:Zinc