With a novel asymmetric Schiff-base zinc complex ZnL (H2L = 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(CH3CN)] (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· 6H2O, 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 Nd3+, Yb3+and Er3+ 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.
Scopus Subject Areas
- Chemistry (miscellaneous)
- Asymmetric Schiff-base complexes
- NIR luminescence
- Sensitization and energy transfer