Terbium complexes of an asymmetric β-diketone: Preparation, photophysical and thermal investigation

Abstract

Chromophoric 1,3-diketone ligand has been utilized to prepare novel ternary complexes of terbium with differently substituted 2,2′-bipyridines as auxiliary ligands. These prepared complexes were thoroughly investigated with the help of numerous spectroscopic techniques. Infrared spectral analysis has suggested the coordination of diketone and ancillary ligand to the Tb(III) ion through oxygen and nitrogen atom respectively. Photoluminescence emission spectra of complexes have displayed only characteristic peaks of Tb3+ ion suggesting the efficient sensitization of metal ion by chromophoric ligands. Emission spectra of all complexes have displayed the ligand sensitized green emission due to the 5D4→7F5 transition situated at around 548 nm. Colorimetric investigation and color purity of complexes reveal the green luminous character of synthesized complexes. Thermogravimetric measurements have revealed the thermal stability of the complexes. Optical and electronic band gaps are found to be in good agreement with each other that shows their importance as semiconductor material. These trivalent complexes of terbium could be utilized as the green component in displays and light emissive materials.