Fluoride Binding and Crystal-Field Analysis of Lanthanide Complexes of Tetrapicolyl-Appended Cyclen

Octavia A Blackburn; Alan M Kenwright; Andrew R Jupp; Jose M Goicoechea; Paul D Beer; Stephen Faulkner

doi:10.1002/chem.201601170

Fluoride Binding and Crystal-Field Analysis of Lanthanide Complexes of Tetrapicolyl-Appended Cyclen

Chemistry. 2016 Jun 20;22(26):8929-36. doi: 10.1002/chem.201601170. Epub 2016 May 11.

Authors

Octavia A Blackburn¹, Alan M Kenwright², Andrew R Jupp¹, Jose M Goicoechea¹, Paul D Beer¹, Stephen Faulkner³

Affiliations

¹ Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK.
² Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE, UK.
³ Chemistry Research Laboratory, Oxford University, 12 Mansfield Road, Oxford, OX1 3TA, UK. stephen.faulkner@keble.ox.ac.uk.

PMID: 27167830
DOI: 10.1002/chem.201601170

Abstract

Lanthanide complexes of tetrapicolyl cyclen displayed remarkably high affinities for fluoride (log K≈5) in water, and were shown to form 1:1 complexes. The behaviour of these systems can be rationalised by changes to the magnitude of the crystal-field parameter, B20 . However, such changes are not invariably accompanied by a change in sign of this parameter: for early lanthanides, the N8 donor set with a coordinated axial water molecule ensures that the magnetic anisotropy has the opposite sense to that observed in the analogous dehydrated lanthanide complexes.

Keywords: NMR spectroscopy; crystal field; fluorides; lanthanides; magnetic anisotropy.