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001-es BibID:	BIBFORM103334
035-os BibID:	(WOS)000555801800006 (Scopus)85089285156
Első szerző:	Leone, Loredana
Cím:	Acid-catalyzed proton exchange as a novel approach for relaxivity enhancement in Gd-HPDO3A-like complexes / Loredana Leone, Mariangela Boccalon, Giuseppe Ferrauto, István Fábián, Zsolt Baranyai, Lorenzo Tei
Dátum:	2020
ISSN:	2041-6520 2041-6539
Megjegyzések:	A current challenge in medical diagnostics is how to obtain high MRI relaxation enhancement using Gd-III-based contrast agents (CAs) containing the minimum concentration of Gd(III)ions. We report that in GdHPDO3A-like complexes a primary amide group located in close proximity to the coordinated hydroxyl group can provide a strong relaxivity enhancement at slightly acidic pH. A maximum relaxivity ofr(1)= 9.8 mM(-1)s(-1)(20 MHz, 298 K) at acidic pH was achieved, which is more than double that of clinically approved MRI contrast agents under identical conditions. This effect was found to strongly depend on the number of amide protons,i.e.it decreases with a secondary amide group and almost completely vanishes with a tertiary amide. This relaxivity enhancement is attributed to an acid-catalyzed proton exchange process between the metal-coordinated OH group, the amide protons and second sphere water molecules. The mechanism and kinetics of the corresponding H(+)assisted exchange process are discussed in detail and a novel simultaneous double-site proton exchange mechanism is proposed. Furthermore,H-1 and(17)O NMR relaxometry, Chemical Exchange Saturation Transfer (CEST) on the corresponding Eu(III)complexes, and thermodynamic and kinetic studies are reported. These highlight the optimal physico-chemical properties required to achieve high relaxivity with this series of Gd-III-complexes. Thus, proton exchange provides an important opportunity to enhance the relaxivity of contrast agents, providing that labile protons close to the paramagnetic center can contribute.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Chemical Science. - 11 : 30 (2020), p. 7829-7835. -
További szerzők:	Boccalon, Mariangela Ferrauto, Giuseppe Fábián István (1956-) (vegyész) Baranyai Zsolt Tei, Lorenzo
Pályázati támogatás:	NKFIH-K-124983 Egyéb
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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