In:
European Journal of Inorganic Chemistry, Wiley, Vol. 2013, No. 14 ( 2013-05-06), p. 2629-2639
Abstract:
Diethylenetriaminepentaacetic acid (DTPA)–bisamide derivatives functionalized with p ‐toluidine, 6‐aminocoumarin, 1‐naphthalene methylamine and 4‐ethynylaniline were synthesized and fully characterized by mass spectrometry, NMR spectroscopy, FTIR spectroscopy and elemental analysis. Ln III complexes (Ln = Gd, Eu, Tb, Y) of the ligands DTPA–bis‐ p ‐toluidineamide (DTPA–BTolA), DTPA–bis‐6‐coumarinamide (DTPA–BCoumA), DTPA–bis‐1‐naphthylmethylamide (DTPA–BNaphA) and DTPA–bis‐4‐ethynylphenylamide (DTPA–BEthA) were prepared and studied for their bimodal magnetic resonance imaging/optical properties. Eu III and Tb III derivatives in aqueous solutions exhibit characteristic red and green emission, respectively, with quantum yields of 0.73 % for Eu III –DTPA–BNaphA and 2.5 % for Tb III –DTPA–BEthA. Ligand‐centred photophysical properties of the Gd III complexes were investigated to gain insight into energy‐transfer processes that take place in these systems. The Gd III complexes were also analyzed by nuclear magnetic relaxation dispersion (NMRD) techniques. The relaxivity ( r 1 ) at 20 MHz and 310 K equals 4.1 s –1 m M –1 for Gd–DTPA–BTolA, 5.1 s –1 m M –1 for Gd–DTPA–BCoumA, 6.4 s –1 m M –1 for Gd–DTPA–BNaphA and 5.7 s –1 m M –1 for Gd–DTPA–BEthA. These values are higher than the value of 3.8 s –1 m M –1 for Gd–DTPA (Magnevist). The improved relaxivity is due to the increase in the rotational tumbling time τ R with a factor of 1.6 for Gd–DTPA–BTolA, 2.1 for Gd–DTPA–BCoumA, 3.1 for Gd–DTPA–BNaphA and 6.5 for Gd–DTPA–BEthA. In a 4 % human serum albumin solution, the apparent relaxivity at 20 MHz increases to values of 13.9 and 19.1 s –1 m M –1 for Gd–DTPA–BNaphA and Gd–DTPA–BEthA, respectively. All these features assist the search for optimal bimodal optical and magnetic resonance imaging probes.
Type of Medium:
Online Resource
ISSN:
1434-1948
,
1099-0682
DOI:
10.1002/ejic.v2013.14
DOI:
10.1002/ejic.201300196
Language:
English
Publisher:
Wiley
Publication Date:
2013
detail.hit.zdb_id:
1475009-0
