Magnetic properties and sensitized visible and NIR luminescence of Dy^III and Eu^III coordination polymers by energy transfer antenna ligands

ABSTRACT

Two coordination polymers, {[Ln(2-stp)(4,4′-bipy)(H₂O)].(H₂O)}, [Ln = Dy (1) and Eu (2), 2-stp = 2-sulfoterephthalate and 4,4′-bipy = 4,4′-bipyridine] have been characterized by solid state UV-vis, FTIR spectra, X-ray single crystal diffraction and solid state photoluminescence. Variable-temperature magnetic susceptibility and isothermal magnetization as function of external magnetic field is also studied for both complexes. After ligand-mediated excitation, both complexes show the characteristic visible and NIR luminescence of the corresponding Ln^III ions (Ln = Dy, Eu) which is due to efficient energy transfer from the ligands to the central Ln^III ions via an antenna effect. The indirect energy transfer in both complexes has been investigated and discussed in detail.

KEYWORDS:

• Lanthanide
• hydrothermal synthesis
• photoluminescence, magnetism

Funding

The authors are grateful to the Research Funds of Balikesir University (BAP-2015/128) and Mugla Sitki Kocman University (BAP-2017/035) for the financial support.

Acknowledgments

The authors thank Dokuz Eylul University for the use of the Agilent Xcalibur Eos diffractometer (purchased under University Research Grant No. 2010.KB.FEN.13) and Balikesir University, Science and Technology Application and Research Center (BUBTAM) for the use of the Photoluminescence Spectrometer. Asma Amjad would like to thank Ente CRF. The authors are also very grateful to Prof. Dr. Andrea Caneschi (Laboratory of Molecular Magnetism, Department of Chemistry, University of Florence) for the use of SQUID magnetometer and helpful suggestions.