Jump to main content
Jump to site search

Issue 11, 2016
Previous Article Next Article

The nephelauxetic effect of Eu(III)–N-donor compounds probed using fluorescence spectroscopy—further evidence for covalence?

Author affiliations

Abstract

The 7F0 emission bands of Eu(III)–N-donor complexes are investigated using time resolved laser fluorescence spectroscopy (TRLFS) and fluorimetry. The observed bathochromic shifts resulting from the complexation of Eu(III) with N-donor ligands are considerably more pronounced than those observed for hard oxygen donor ligands. The magnitude of these shifts results from a strong nephelauxetic effect caused by the interaction of Eu(III) with N-donor ligands. Since the extent of the nephelauxetic effect is correlated with the degree of covalence in a metal–ligand bond, the results prove a significant share of covalence in the Eu(III)–N-donor bonds in addition to electrostatic interactions. Furthermore, a linear correlation between the shift of the 7F0 emission band of the Eu(III) complexes with BT(B)P/BTPhen ligands relative to the Eu(III) aquo ion and the number of N-donors in the first coordination sphere of Eu(III) is established: CNL = 0.109·Δν + 0.134, [Δν] = cm−1. Taking into account the known denticity of BTP/BTBP/BTPhen ligands the stoichiometry of the investigated complexes is easily determined by using the above equation.

Graphical abstract: The nephelauxetic effect of Eu(iii)–N-donor compounds probed using fluorescence spectroscopy—further evidence for covalence?

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 31 May 2016, accepted on 08 Sep 2016 and first published on 09 Sep 2016


Article type: Paper
DOI: 10.1039/C6NJ01705C
Citation: New J. Chem., 2016,40, 9232-9237
  •   Request permissions

    The nephelauxetic effect of Eu(III)–N-donor compounds probed using fluorescence spectroscopy—further evidence for covalence?

    C. Wagner, C. Ruff, U. Müllich, A. Geist and P. J. Panak, New J. Chem., 2016, 40, 9232
    DOI: 10.1039/C6NJ01705C

Search articles by author