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001-es BibID:	BIBFORM120540
035-os BibID:	(Scopus)84897585052 (WoS)000331774600032
Első szerző:	Baranyai Zsolt (vegyész)
Cím:	Comprehensive Evaluation of the Physicochemical Properties of LnIII Complexes of Aminoethyl-DO3A as pH-Responsive T1-MRI Contrast Agents / Zsolt Baranyai, Gabriele A. Rolla, Roberto Negri, Attila Forgács, Giovanni B. Giovenzana, Lorenzo Tei
Dátum:	2014
ISSN:	0947-6539 1521-3765
Megjegyzések:	N-Substituted aminoethyl groups were attached to 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) with the aim to design pH-responsive Ln(III) complexes based on the pH-dependent on/off ligation of the amine nitrogen to the metal ion. The following ligands were synthesized: AE-DO3A (aminoethyl-DO3A), MAE-DO3A (N-methylaminoethyl-DO3A), DMAE-DO3A (N,N-dimethylaminoethyl-DO3A) and MEM-AE-DO3A (N-methoxyethyl-N-methylaminoethyl-DO3A). The physicochemical properties of the Ln(III) complexes were investigated for the evaluation of their potential applicability as magnetic resonance imaging (MRI) contrast agents. In particular, a H-1 and (ONMR)-O-17 relaxometric study was carried out for these Gd-III complexes at two different pH values: at basic pH (pendant amino group coordinated to the metal centre) and at acidic pH (protonated amine, not interacting with the metal ion). Eu-III complexes allow one to estimate the number of inner-sphere water molecules through luminescence lifetime measurements and obtain some structural information through variable-temperature (VT) high-resolution (HNMR)-H-1 studies. Equilibria between differently hydrated species were found for most of the complexes at both acidic and basic pH. The thermodynamic stability of Ca-II, Zn-II, Cu-II and Ln(III) complexes and kinetics of formation and dissociation reactions of Ln(III) complexes of AE-DO3A and DMAE-DO3A were investigated showing stabilities comparable to currently approved Gd-III-based CAs. In detail, higher total basicity (sigma logK(i)(H)) and higher stability constants of Ln(III) complexes were found for AE-DO3A with respect to DMAE-DO3A (i.e., logK(Gd-AE-DO3A)=22.40 and logK(Gd-DMAE-DO3A)=20.56). The transmetallation reactions of Gd-III complexes are very slow (Gd-AE-DO3A: t(1/2)=2.7x10(4)h; Gd-DMAE-DO3A: 1.1x10(5)h at pH7.4 and 298K) and occur through proton-assisted dissociation.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk contrast agents lanthanides macrocyclic ligands NMR spectroscopy thermodynamics
Megjelenés:	Chemistry-A European Journal. - 20 : 10 (2014), p. 2933-2944. -
További szerzők:	Rolla, Gabriele A. Negri, Roberto Forgács Attila (1988-) (vegyész) Giovenzana, Giovanni Battista Tei, Lorenzo
Pályázati támogatás:	TÁMOP 4.2.4. A/2-11-1-2012-0001 Egyéb HU11MO2-TET_10-1-2011-0202 Egyéb
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