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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
Internet cím:Szerző által megadott URL
DOI
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2.

001-es BibID:BIBFORM057618
Első szerző:Molnár Enikő (vegyész)
Cím:Picolinate-Containing Macrocyclic Mn(II) Complexes as Potential MRI Contrast Agents / Enikő Molnar, Nathalie Camus, Veronique Patinec, Gabriele A. Rolla, Mauro Botta, Gyula Tircso, Ferenc K. Kalmán, Tamas Fodor, Raphael Tripier, Carlos Platas-Iglesias
Dátum:2014
ISSN:0020-1669
Megjegyzések:We report the synthesis of the ligand Hnompa (6-((1,4,7-triazacyclononan- 1-yl)methyl)picolinic acid) and a detailed characterization of the Mn2+ complexes formed by this ligand and the related ligands Hdompa (6-((1,4,7,10-tetraazacyclododecan-1- yl)methyl)picolinic acid) and Htempa (6-((1,4,8,11-tetraazacyclotetradecan-1-yl)methyl)- picolinic acid). These ligands form thermodynamically stable complexes in aqueous solution with stability constants of logKMnL = 10.28(1) (nompa), 14.48(1) (dompa), and 12.53(1) (tempa). A detailed study of the dissociation kinetics of these Mn2+ complexes indicates that the decomplexation reaction at about neutral pH occurs mainly following a spontaneous dissociation mechanism. The X-ray structure of [Mn2(nompa)2(H2O)2]- (ClO4)2 shows that the Mn2+ ion is seven-coordinate in the solid state, being directly bound to five donor atoms of the ligand, the oxygen atom of a coordinated water molecule and an oxygen atom of a neighboring nompa- ligand acting as a bridging bidentate carboxylate group (1 -carboxylate). Nuclear magnetic relaxation dispersion (1 H NMRD) profiles and 17O NMR chemical shifts and transverse relaxation rates of aqueous solutions of [Mn(nompa)]+ indicate that the Mn2+ ion is six-coordinate in solution by the pentadentate ligand and one innersphere water molecule. The analysis of the 1 H NMRD and 17O NMR data provides a very high water exchange rate of the innersphere water molecule (kex 298 = 2.8 x 109 s -1 ) and an unusually high value of the 17O hyperfine coupling constant of the coordinated water molecule (AO/ = 73.3 ± 0.6 rad s-1 ). DFT calculations performed on the [Mn(nompa)(H2O)]+ ·2H2O system (TPSSh model) provide a AO/ value in excellent agreement with the one obtained experimentally
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
MRI contrast agents
Mn(II) complexes
equilibrium
Kinetics
Structure
Megjelenés:Inorganic Chemistry. - 53 : 10 (2014), p. 5136-5149. -
További szerzők:Camus, Nathalie Patinec, Véronique Rolla, Gabriele A. Botta, Mauro Tircsó Gyula (1977-) (vegyész, kémia tanár) Kálmán Ferenc K. (1978-) (vegyész) Fodor Tamás (1987-) (vegyész) Tripier, Raphaël Platas-Iglesias, Carlos
Pályázati támogatás:Centro de Supercomputacion de Galicia (CESGA)
Egyéb
K-84291
OTKA
K-109029
OTKA
TÁMOP-4.2.2.A-11/ 1/KONV-2012-0043
TÁMOP
János Bolyai Research Scholarship of the Hungarian Academy of Sciences.
Egyéb
COST TD1004 "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery" Action.
Egyéb
Internet cím:Szerző által megadott URL
DOI
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