Jump to main content
Jump to site search

Issue 24, 2002
Previous Article Next Article

Structural characterisation, EPR and magnetic properties of f–f and f–d lanthanide(III) phenolic cryptates

Author affiliations

Abstract

The Schiff base axial macrobicyclic ligand L1 forms 4f–4f and 4f–3d cryptates with formula [Gd2(L1 − 3H)(NO3)2](NO3)·1.5H2O (1), [Tb2(L1 − 3H)(NO3)2](NO3)·3EtOH·H2O (2), [GdCu(L1 − 3H)(NO3)](NO3)·H2O (3), [LuCu(L1 − 3H)(NO3)](NO3)·H2O (4) and [GdZn(L1 − 3H)(NO3)](NO3)·H2O (5). The macrobicyclic receptor L1 is an azacryptand N[(CH2)2N[double bond, length as m-dash]CH–R–CH[double bond, length as m-dash]N–(CH2)2]3N (R =1,3-(2-OH-5-Me–C6H2)). The crystal structures of the five compounds have been determined by X-ray crystallography. The ligand is helically wrapped around the two metal ions, leading to pseudo-C3 symmetries around the metals. In the solid state, the conformation of the cation in 1 and 2 is Λ(δδλ)5(δδλ)5 or its enantiomeric form Δ(λλδ)5(λλδ)5, while in 3, 4 and 5 it can be described as Λ(δδλ)5(δ′δ′δ′)5 (or Δ(λλδ)5(λ′λ′λ′)5). In 1, only one enantiomer is found in the crystal lattice, whereas in the other four compounds, both enantiomers are co-crystallised. The magnetic behaviour of the homodinuclear (Gd, Gd) and the heterodinuclear (Gd, Cu) cryptates points to a significant magnetic interaction between the two metal ions. This magnetic interaction is antiferromagnetic in the case of the Gd–Gd cryptate 1 (J = −0.194(6) cm−1), but ferromagnetic for the Gd–Cu one (J = 2.2(1) cm−1). The antiferromagnetic coupling observed for 1 is one of the largest ever reported. Although the ferromagnetic coupling observed for 3 is relatively weak, which is attributed to the strong bending of the bridging network, it is considerably stronger than the one reported for [GdCu(L2 − 3H)(DMF)](ClO4)2·MeCN. In spite of the similar coordination environment of the Gd(III) ion in compounds 1, 3 and 5 their EPR spectra are different, thereby confirming the magnetic interactions between the Gd(III) ion and the Cu(II) ion in 3 and the other Gd(III) ion in 1.

Graphical abstract: Structural characterisation, EPR and magnetic properties of f–f and f–d lanthanide(iii) phenolic cryptates

Back to tab navigation

Supplementary files

Publication details

The article was received on 08 Jul 2002, accepted on 10 Oct 2002 and first published on 08 Nov 2002


Article type: Paper
DOI: 10.1039/B206615G
Citation: J. Chem. Soc., Dalton Trans., 2002,0, 4658-4665
  •   Request permissions

    Structural characterisation, EPR and magnetic properties of f–f and f–d lanthanide(III) phenolic cryptates

    F. Avecilla, C. Platas-Iglesias, R. Rodríguez-Cortiñas, G. Guillemot, J. G. Bünzli, C. D. Brondino, C. F. G. C. Geraldes, A. D. Blas and T. Rodríguez-Blas, J. Chem. Soc., Dalton Trans., 2002, 0, 4658
    DOI: 10.1039/B206615G

Search articles by author

Spotlight

Advertisements