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Spectral properties of Tb(III) and Nd(III) complexes with 3,3’-[(phenylmethylene)]bis(4-hydroxy-2H-1-benzopyran- 2-one)



  1. Sofia University, Faculty of Chemistry, Department of Inorganic Chemistry, 1, J. Bourchier Blvd., 1164 Sofia, Bulgaria
  2. Medical University, Faculty of Pharmacy, Department of Organic Chemistry, 1, Dunav Str., 1000 Sofia, Bulgaria


Complexes of the trivalent lanthanoid ions of Nd(III) and Tb(III) with some 3,3’-[(phenylmethylene)]bis(4-hydroxy-2H-1-benzopyran-2-one) derivates such as 3,3’-[(4-chlorоphenyl)methylene)bis-(4-hydroxy-2H-1-benzopyran-2-one) and 3,3’-[(3,5-dimethoxy-4-hydroxyphenyl)methylene]bis-(4-hydroxy-2H-1-benzopyran-2-one) were synthesized, following three synthetic procedures. The complexes formed were investigated with elemental analysis, IR- spectroscopy, and fluorescence spectroscopy. Deconvolution of IR-spectra was applied and used to elucidate the molecular structure and the possibilities for coordination of coumarin ligands to the lanthanoid (III) ions. Based on the vibrational analysis coordination through deprotonated hydroxyl group and oxygen atom of the carbonyl group is suggested. Excitation and emission spectra of the newly synthesized complexes were recorded and interpreted. The water molecules coordinated do not influence the emission in the visible region of the Tb(III) complexes while in the case of Nd(III) complex they perform as a very strong quenching agent. The Nd(III) complexes without any coordinated water molecules but with acetonitrile in the outer sphere show the intensive band at 1050 nm responding to the strongest transition 4F3/2 → 4I11/2..


3,3’-[(phenylmethylene)]bis(4-hydroxy-2H-1-benzopyran-2-one) derivatives, Tb complexes, Nd complexes, Fluorescence.

Submitted at: Aug. 10, 2020
Accepted at: Oct. 7, 2021


V. KIRCHEVA, J. ZAHARIEVA, I. MANOLOV, M. MILANOVA, Spectral properties of Tb(III) and Nd(III) complexes with 3,3’-[(phenylmethylene)]bis(4-hydroxy-2H-1-benzopyran- 2-one), Journal of Optoelectronics and Advanced Materials Vol. 23, Iss. 9-10, pp. 508-517 (2021)