Synthesis and characterization of terbium(III) complexes with the biscoumarin derivative 3,3′-[(4-hydroxyphenyl)methyl]bis-(4-hydroxy-2H-chromen-2-one)

Complexes of Tb(III) with the biscoumarin derivative 3,3'-[(4-hydroxyphenyl)methyl]bis-(4-hydroxy-2H-chromen-2-one) are synthesized by using a solution of tetraethylammonium hydroxide, [(C2H5)(4)N]OH, in water as deprotonating base. Elemental analysis, IR- and fluorescence spectroscopy are used to characterize the samples obtained. The complexes have good fluorescent properties and show the characteristic emission bands of the Tb(III) ion. The triplet state of the mono-deprotonated ligand H2L- was determined. The optimised geometries of the ligand and the complexes were obtained by means of molecular modelling with first principles (DFT) methods. (C) 2015 Published by Elsevier B.V.