Collect. Czech. Chem. Commun. 2008, 73, 1437-1456

Conformational Analysis of Eu(III)-(Ethylenedinitrilo)tetrakis(methylphosphonates) (EDTMP)

Lidia Smenteka,b,* and B. Andes Hess, Jr.b

a Institute of Physics, N. Copernicus University, 87-100 Toruń, Poland
b Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235 U.S.A.


The optimal geometries obtained from DFT calculations are presented for Eu(III)-EDTMP (the parent system) and cages associated with the water molecules and carbonate and hydroxide ions. The numerical results demonstrate the existence of two conformers of each cage, which might explain the observation of two spectroscopic lines previously assigned to the electric dipole transition 7F05D0 of Eu3+. It is also found that the water molecules are associated with the chelate via hydrogen bonds with the oxygens of the phoshonate arms, while the carbonate and hydroxide ions are chelated with the lanthanide ion due to strong electrostatic interactions between the negatively charged oxygen atoms and positively charged metal ion. The analysis is illustrated by the qualitative comparison of the energies and is concluded with the relative stability of various chelates and energetically favorable, hypothetical reactions.

Keywords: Lanthanides; EDTMP; DFT calculations; Conformers; Europium.

References: 16 live references.