Unusually sharp dependence of water exchange rate versus lanthanide ionic radii for a series of tetraamide complexes

Shanrong Zhang, Kuangcong Wu, A. Dean Sherry

Research output: Contribution to journalArticle

54 Scopus citations

Abstract

The tetraamide ligand, DOTA-tetra(glycine ethyl ester), forms complexes with the lanthanide(III) cations that exist in solution predominantly as the square antiprism structure with single, slowly exchanging inner-sphere water molecule. Variable-temperature 1H and 17O NMR studies revealed that the bound water lifetimes in these complexes were sharply dependent upon the ionic radius of Ln3+ cation. A novel lanthanide-induced shift technique was used to unmask the bound water 17O resonance of SmL3+ and YL3+ complexes from the bulk water resonance. The bound water lifetime (τM298) was ∼800 μs in the EuL3+ complex but became much shorter (several microseconds) for Ln3+ cations with larger and smaller ionic radii. This demonstrates that water exchange is exquisitely fine-tuned in this macrocyclic tetraamide system and that a variety of Ln3+ complexes meet with the exchange requirement, Δω*τM ≥ 1, necessary for an efficient MT agent.

Original languageEnglish (US)
Pages (from-to)4226-4227
Number of pages2
JournalJournal of the American Chemical Society
Volume124
Issue number16
DOIs
StatePublished - Apr 24 2002

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Unusually sharp dependence of water exchange rate versus lanthanide ionic radii for a series of tetraamide complexes'. Together they form a unique fingerprint.

  • Cite this