Issue 24, 2002
From the journal:

Journal of the Chemical Society, Dalton Transactions

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

Fernando Avecilla,a   Carlos Platas-Iglesias,a   Raquel Rodríguez-Cortiñas,a   Geoffroy Guillemot,b   Jean-Claude G. Bünzli,b   Carlos D. Brondino,c   Carlos F. G. C. Geraldes,d   Andrés de Blas*a  and  Teresa Rodríguez-Blas*a  

* Corresponding authors

a Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira s/n 15071 A Coruña, Spain
E-mail: mayter@mail.udc.es

b Institute of Molecular and Biological Chemistry, Swiss Federal Institute of Technology Lausanne, BCH 1402, CH-1015 Lausanne, Switzerland

c Facultad de Bioquímica y Ciencias Biológicas – U.N.L., Campus Universitario. Pje. El Pozo, CC 242. 3000 Santa Fe, Argentina

d Deparment of Biochemistry, FCT, University of Coimbra, 3001-4001 Coimbra, Portugal

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

About
Cited by
Related
Download options Please wait...

Supplementary files

Article information

DOI
https://doi.org/10.1039/B206615G
Article type
Paper
Submitted
08 Jul 2002
Accepted
10 Oct 2002
First published
08 Nov 2002

J. Chem. Soc., Dalton Trans., 2002, 4658-4665

Permissions

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, 4658 DOI: 10.1039/B206615G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements