The population of SAP and TSAP isomers in cyclen-based lanthanide(III) chelates is substantially affected by solvent

Inorg Chem. 2010 Oct 4;49(19):8662-4. doi: 10.1021/ic101489t.


The square antiprism/twisted square antiprism ratio in LnDOTA-tetraamide chelates is a critical parameter in governing water-exchange kinetics and ultimately the utility of a chelate as a PARACEST MRI contrast agent. In LnDOTA-tetraamide chelates with tertiary amides, this ratio and the rate of interconversion between these two structural isomers are found to be dramatically dependent upon the solvent and possibly other local environmental factors.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides / chemistry
  • Chelating Agents / chemistry*
  • Contrast Media / chemistry*
  • Cyclams
  • Heterocyclic Compounds / chemistry*
  • Kinetics
  • Lanthanoid Series Elements / chemistry*
  • Magnetic Resonance Imaging
  • Molecular Structure
  • Organometallic Compounds / chemistry*
  • Solvents / chemistry
  • Stereoisomerism
  • Water / chemistry*


  • Amides
  • Chelating Agents
  • Contrast Media
  • Cyclams
  • Heterocyclic Compounds
  • Lanthanoid Series Elements
  • Organometallic Compounds
  • Solvents
  • Water
  • cyclen