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001-es BibID:	BIBFORM103530
035-os BibID:	(WOS)000541873600033 (Scopus)85084399701
Első szerző:	Garda Zoltán (vegyész)
Cím:	Unexpected Trends in the Stability and Dissociation Kinetics of Lanthanide(III) Complexes with Cyclen-Based Ligands across the Lanthanide Series / Zoltán Garda, Viktoria Nagy, Aurora Rodríguez-Rodríguez, Rosa Pujales-Paradela, Véronique Patinec, Goran Angelovski, Éva Tóth, Ferenc K. Kálmán, David Esteban-Gómez, Raphaël Tripier, Carlos Platas-Iglesias, Gyula Tircsó
Dátum:	2020
ISSN:	0020-1669 1520-510X
Megjegyzések:	We report a detailed study of the thermodynamic stability and dissociation kinetics of lanthanide complexes with two ligands containing a cyclen unit, a methyl group, a picolinate arm, and two acetate pendant arms linked to two nitrogen atoms of the macrocycle in either cis (1,4-H(3)DO2APA) or trans (1,7-H(3)DO2APA) positions. The stability constants of the Gd3+ complexes with these two ligands are very similar, with log K-GdL values of 16.98 and 16.33 for the complexes of 1,4-H(3)DO2APA and 1,7-H(3)DO2APA, respectively. The stability constants of complexes with 1,4-H(3)DO2APA follow the usual trend, increasing from log K-LaL = 15.96 to log K-LuL = 19.21. However, the stability of [Ln(1,7-DO2APA)] complexes decreases from log K = 16.33 for Gd3+ to 14.24 for Lu3+. The acid-catalyzed dissociation rates of the Gd3+ complexes differ by a factor of similar to 15, with rate constants (k(1)) of 1.42 and 23.5 M(-1)s(-1) for [Gd(1,4-DO2APA)] and [Gd(1,7DO2APA)], respectively. This difference is magnified across the lanthanide series to reach a 5 orders of magnitude higher k(1) for [Yb(1,7-DO2APA)] (1475 M(-1)s(-1)) than for [Yb(1,4-DO2APA)] (5.79 x 10(-3)M(-1)s(-1)).The acid catalyzed mechanism involves the protonation of a carboxylate group, followed by a cascade of proton-transfer events that result in the protonation of a nitrogen atom of the cyclen unit. Density functional theory calculations suggest a correlation between the strength of the Ln-O-carboxylate bonds and the kinetic inertness of the complex, with stronger bonds providing more inert complexes. The H-1 NMR resonance of the coordinated water molecule in the [Yb(1,7-DO2APA)] complex at 176 ppm provides a sizable chemical exchange saturation transfer effect thanks to a slow water exchange rate of (15.9 +/- 1.6) x 10(3) s(-1).
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry. - 59 : 12 (2020), p. 8184-8195. -
További szerzők:	Nagy Viktória Rodríguez-Rodríguez, Aurora Pujales-Paradela, Rosa Patinec, Véronique Angelovski, Goran Tóth Éva Kálmán Ferenc K. (1978-) (vegyész) Esteban-Gómez, David Tripier, Raphaël Platas-Iglesias, Carlos Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:	GINOP-2.3.2-15-2016-00008 GINOP NKFIH-K-120224 Egyéb NKFIH-K-128201 Egyéb 2019-2.1.11-TÉT-2019-00084 Egyéb
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