Synthesis and NMR studies of new DOTP-like lanthanide(III) complexes containing a hydrophobic substituent on one phosphonate side arm

X. Li, S. Zhang, P. Zhao, Z. Kovacs, A. D. Sherry

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Three derivatives of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylene phosphonic acid) (DOTP) containing a hydrophobic substituent on one side chain were prepared and their lanthanide complexes examined by NMR. The new ligands include 1-(1-octyl-methyl-phosphonic acid)-4,7,10-tris(methylene phosphonic acid)-1,4,7,10-tetraazacyclododecane (C8-DOTP),1-(1 -undecyl-methyl-phosphonic acid)-4,7,10-tris(methylene phosphonic acid)-1,4,7,10-tetraazacyclododecane (C11-DOTP), and 1-(1-4-nitro-phenyl-methyl-phosphonic acid)-4,7,10-tris(methylene phosphonic acid)-1,4,7,10-tetraazacyclododecane (NO2-Ph-DOTP). 1H NMR spectra of the ytterbium(III) complexes were assigned by using a combination of COSY spectroscopy and a fitting procedure that matches experimental NMR hyperfine shifts with those estimated from a MMX-derived structure. The analysis showed that a single isomer is present in solution and that the bulky hydrophobic substituent occupies the less sterically demanding H6 equatorial position in the YbL5- complexes. Although the YbL5- complexes have lower symmetry due to the added substituent, the average 1H hyperfine shifts are 5-10% larger in these complexes compared to YbDOTP5-. This was magnified further in the hyperfine 23Na NMR shifts of ion-paired sodium ions where the extracellular Na+ signal in perfused rat hearts displayed a 28% larger hyperfine shift in the presence of Tm(C11-DOTP)5- than with an equivalent amount of TmDOTP5-.

Original languageEnglish (US)
Pages (from-to)6572-6579
Number of pages8
JournalInorganic Chemistry
Volume40
Issue number26
DOIs
StatePublished - Dec 17 2001

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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