Synthesis, relaxometric and photophysical properties of a new pH-responsive MRI contrast agent: The effect of other ligating groups on dissociation of a p-nitrophenolic pendant arm

Mark Woods, Garry E. Kiefer, Simon Bott, Aminta Castillo-Muzquiz, Carrie Eshelbrenner, Lydie Michaudet, Kenneth McMillan, Siva D.K. Mudigunda, Doug Ogrin, Gyula Tircsó, Shanrong Zhang, Piyu Zhao, A. Dean Sherry

Research output: Contribution to journalArticle

110 Scopus citations

Abstract

Two gadolinium(III) chelates, GdNP-DO3A (1-methlyene-(p-NitroPhenol)-1,4,7, 10-tetraazacycloDOdecane-4,7,10-triAcetate) and GdNP-DO3AM (1-methlyene(p- NitroPhenol)-1,4,7,10-tetraazacycloDOdecane-4,7,10-triacetAMide), containing a single nitrophenolic pendant arm plus either three acetate or three amide pendant arms were synthesized and characterized. The properties of the gadolinium, terbium, and dysprosium complexes of these ligands were examined as a function of pH. The extent and mechanism of the changes in water relaxivity with pH of each gadolinium complex was found to differ substantially for the two complexes. The water relaxivity of Gd(NP-DO3A) increases from 4.1 mM -1 s-1 at pH 9 to 7.0 mM-1 s-1 at pH 5 as a result of acid-catalyzed dissociation of the nitrophenol from the lanthanide. The nitrophenol group in Gd(NP-DO3AM) does not dissociate from the metal center even at pH 5; therefore, the very modest increase in relaxivity in this complex must be ascribed to an increase in prototropic exchange rate of the bound water and/or phenolic protons.

Original languageEnglish (US)
Pages (from-to)9248-9256
Number of pages9
JournalJournal of the American Chemical Society
Volume126
Issue number30
DOIs
StatePublished - Aug 4 2004

ASJC Scopus subject areas

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

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    Woods, M., Kiefer, G. E., Bott, S., Castillo-Muzquiz, A., Eshelbrenner, C., Michaudet, L., McMillan, K., Mudigunda, S. D. K., Ogrin, D., Tircsó, G., Zhang, S., Zhao, P., & Sherry, A. D. (2004). Synthesis, relaxometric and photophysical properties of a new pH-responsive MRI contrast agent: The effect of other ligating groups on dissociation of a p-nitrophenolic pendant arm. Journal of the American Chemical Society, 126(30), 9248-9256. https://doi.org/10.1021/ja048299z