Title
Synthesis, crystal structures, photoluminescent, magnetic and chiroptical properties of two homochiral ErIII complexes with different nuclearity
Author
Xi-Li Li, Ying-Fan Liu, Xue-Li Zhang, Conghui Cheng, Xianjun Zheng, Cancan Zhu, Liming Zhou
Year
2017
Journal
Journal of Molecular Structure
Abstract
Employing chiral bis-bidentate N-donor ligand, (+)-2,5-bis(4,5-pinene-2-pyridyl) pyrazine (L), as a bridging ligand for Er(dbm)3H2O, and depending on the ratio control of reactants, two mono- and dinuclear homochiral ErIII complexes with the formulae Er(dbm)3L·2H2O (1) (dbm─ = dibenzoylmethanate) and Er2(dbm)6L·6H2O (2) have been synthesized and structurally characterized. Circular dichroic (CD) spectra verify their chiroptical activities. Investigations on the luminescent properties of complexes 1 and 2 demonstrate that they exhibit characteristic near-infrared (NIR) luminescence of the ErIIIion at around 1533 nm and the emission intensity of the mononuclear complex 1 is much larger than that of dinuclear species 2, the reason of which is elucidated in this work. In addition, the measurements of magnetic properties indicate that the direct-current (dc) magnetic behaviors of complexes 1 and 2 mainly result from the thermal depopulation of the excited MJ sublevels of the ErIII ions. Notablely, complex 2 is the first example of chiral polynuclear lanthanide complexes with NIR-luminescence property.
Instrument
J-810
Keywords
Circular dichroism, Solid-state, Coordination chemistry,