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@article{984031,
author = {Lima, Luis M.P. and Delgado, Rita and Hermann, Petr and Ševčík, Radek and Lubal, Přemysl and Carvalho, Henrique F. and Martins, André F. and Tóth, Éva and Geraldes, Carlos F.G.C.},
article_location = {WEINHEIM},
article_number = {15},
doi = {http://dx.doi.org/10.1002/ejic.201101335},
keywords = {macrocyclic ligands; lanthanide complexes; thermodynamics; kinetics; relaxivity},
language = {eng},
issn = {1099-0682},
journal = {Eur. J. Inorg. Chem.},
title = {Tris(phosphonomethyl)cyclen Derivatives: Thermodynamic Stability, Kinetics, Solution Structure, and Relaxivity of Ln(3+) Complexes},
url = {http://onlinelibrary.wiley.com/doi/10.1002/ejic.201101335/abstract},
volume = {2012},
year = {2012}
}
TY - JOUR
ID - 984031
AU - Lima, Luis M.P. - Delgado, Rita - Hermann, Petr - Ševčík, Radek - Lubal, Přemysl - Carvalho, Henrique F. - Martins, André F. - Tóth, Éva - Geraldes, Carlos F.G.C.
PY - 2012
TI - Tris(phosphonomethyl)cyclen Derivatives: Thermodynamic Stability, Kinetics, Solution Structure, and Relaxivity of Ln(3+) Complexes
JF - Eur. J. Inorg. Chem.
VL - 2012
IS - 15
SP - 2548-2559
EP - 2548-2559
PB - Wiley-VCH Verlag GMBH
SN - 10990682
KW - macrocyclic ligands
KW - lanthanide complexes
KW - thermodynamics
KW - kinetics
KW - relaxivity
UR - http://onlinelibrary.wiley.com/doi/10.1002/ejic.201101335/abstract
L2 - http://onlinelibrary.wiley.com/doi/10.1002/ejic.201101335/abstract
N2 - The lanthanide (Ln3+) complexes of three cyclen-based ligands containing three methylphosphonate pendant arms were studied, the ligands being 1,4,7,10-tetraazacyclododecane-1,4,7-triyltris(methylphosphonic acid) (H6do3p), 3-[4,7,10-tris(phosphonomethyl)-1,4,7,10-tetraazacyclododec-1-yl]propanoic acid (H7do3p1pr), and 10-(3-hydroxypropyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyltris(methylphosphonic acid) (H6do3p1ol). The three macrocyclic ligands form complexes of very high thermodynamic stability with all studied Ln3+ ions. Kinetic studies showed that the acid-assisted dissociation of Ce3+ complexes of these ligands is much faster than for the complex of the related ligand H8dotp [1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayltetrakis(methylphosphonic acid)]. The number of water molecules coordinated to the Eu3+ and Gd3+ complexes was estimated to be < 1 for the do3p1ol ligand but ca. 1 for the other two ligands, as obtained by time-resolved luminescence spectroscopy and by 1H and 17O relaxometric measurements. The NMR spectroscopic data indicate the existence of a considerable contribution from second-sphere water molecules to the relaxivity of all the Gd3+ complexes studied. The 1H and 31P NMR spectra of the Eu3+, Yb3+ and Lu3+ complexes showed that the propionate arm in the [Ln(do3p1pr)]4 complexes and the propanol arm in the [Ln(do3p1ol)]3 complexes are not bound to the Ln3+ ion. The [Ln(do3p)]3 and [Ln(do3p1pr)]4 complexes have a clear preference for the TSAP (twisted square antiprismatic) isomer, while both SAP (square antiprismatic) and TSAP isomers are present in solutions of the [Ln(do3p1ol)]3 complexes.
ER -
LIMA, Luis M.P., Rita DELGADO, Petr HERMANN, Radek ŠEVČÍK, Přemysl LUBAL, Henrique F. CARVALHO, André F. MARTINS, Éva TÓTH and Carlos F.G.C. GERALDES. Tris(phosphonomethyl)cyclen Derivatives: Thermodynamic Stability, Kinetics, Solution Structure, and Relaxivity of Ln(3+) Complexes. \textit{Eur. J. Inorg. Chem.}. WEINHEIM: Wiley-VCH Verlag GMBH, 2012, vol.~2012, No~15, p.~2548-2559. ISSN~1099-0682. Available from: https://dx.doi.org/10.1002/ejic.201101335.
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