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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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2.

001-es BibID:BIBFORM076226
035-os BibID:(WoS)000433013600028 (Scopus)85047315800
Első szerző:Gündüz, Serhat
Cím:Coordination Properties of GdDO3A-Based Model Compounds of Bioresponsive MRI Contrast Agents / Serhat Gündüz, Sandip Vibhute, Richard Botár, Ferenc K. Kálmán, Imre Tóth, Gyula Tircsó, Martín Regueiro-Figueroa, David Esteban-Gómez, Carlos Platas-Iglesias, Goran Angelovski
Dátum:2018
ISSN:0020-1669 1520-510X
Megjegyzések:We report a detailed characterization of the thermodynamic stability and dissociation kinetics of Gd3+ complexes with DO3A derivatives containing a (methylethylcarbamoylmethylamino)acetic acid (L1), (methylpropylcarbamoylmethylamino)acetic acid (L2), 2-dimethylamino-N-ethylacetamide (L3), or 2-dimethylamino-N-propylacetamide (L4) group attached to the fourth nitrogen atom of the macrocyclic unit. These ligands are model systems of Ca2+- and Zn2+-responsive contrast agents (CA) for application in magnetic resonance imaging (MRI). The results of the potentiometric studies (I = 0.15 M NaCl) provide stability constants with log KGdL values in the range 13.9?14.8. The complex speciation in solution was found to be quite complicated due to the formation of protonated species at low pH, hydroxido complexes at high pH, and stable dinuclear complexes in the case of L1,2. At neutral pH significant fractions of the complexes are protonated at the amine group of the amide side chain (log KGdL?H = 7.2?8.1). These ligands form rather weak complexes with Mg2+ and Ca2+ but very stable complexes with Cu2+ (log KCuL = 20.4?22.3) and Zn2+ (log KZnL = 15.5?17.6). Structural studies using a combination of 1H NMR and luminescence spectroscopy show that the amide group of the ligand is coordinated to the metal ion at pH ?8.5, while protonation of the amine group provokes the decoordination of the amide O atom and a concomitant increase in the hydration number and proton relaxivity. The dissociation of the complexes occurs mainly through a rather efficient proton-assisted pathway, which results in kinetic inertness comparable to that of nonmacrocyclic ligands such as DTPA rather than DOTA-like complexes.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganic Chemistry. - 57 : 10 (2018), p. 5973-5986. -
További szerzők:Vibhute, Sandip Botár Richárd (1992-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Tóth Imre (1950-) (vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár) Regueiro-Figueroa, Martín Esteban-Gómez, David Platas-Iglesias, Carlos Angelovski, Goran
Pályázati támogatás:GINOP-2.3.2-15-2016-00008
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
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3.

001-es BibID:BIBFORM047940
Első szerző:Placidi, Matteo P.
Cím:Aryl-Phosphonate Lanthanide Complexes and Their Fluorinated Derivatives : Investigation of Their Unusual Relaxometric Behavior and Potential Application as Dual Frequency 1H/19F MRI Probes / Matteo P. Placidi, Mauro Botta, Ferenc K. Kálmán, Gisela E. Hagberg, Zsolt Baranyai, Andreas Krenzer, Alexandria K. Rogerson, Imre Tóth, Nikos K. Logothetis, Goran Angelovski
Dátum:2013
ISSN:0947-6539
Megjegyzések:A series of low molecular weight lanthanide complexes were developed that have high 1H longitudinal relaxivities (r1) and the potential to be used as dual frequency 1H and 19FMRprobes. Their behavior was investigated in more detail through relaxometry, pH-potentiometry, luminescence, andmultinuclear NMR spectroscopy. Fitting of the 1H NMRD and 17O NMR profiles demonstrated a very short water residence lifetime (<10 ns) and an appreciable second sphere effect. At lower field strengths (20 MHz), two of the complexes displayed a peak in r1 (21.7 and 16.3 mm 1 s 1) caused by anagglomeration, that can be disrupted through the addition of phosphate anions. NMR spectroscopy revealed that at least two species are present in solution interconverting through an intramolecular binding process. Two complexes provided a suitable signal in 19F NMR spectroscopy and through the selection of optimized imaging parameters,phantom images were obtained in a MRI scanner at concentrations as low as 1 mm. The developed probescould be visualized through both 1H and 19F MRI, showing their capability to function as dual frequency MRI contrastagents.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
fluorine
gadolinium
imaging agents
NMR spectroscopy
relaxivity
Megjelenés:Chemistry-A European Journal. - 19 : 35 (2013), p. 11644-11660. -
További szerzők:Botta, Mauro Kálmán Ferenc K. (1978-) (vegyész) Hagberg, Gisela E. Baranyai Zsolt (1977-) (vegyész) Krenzer, Andreas Rogerson, Alexandria K. Tóth Imre (1950-) (vegyész) Logothetis, Nikos K. Angelovski, Goran
Pályázati támogatás:PD-83253
OTKA
K-84291
OTKA
TÁMOP-4.2.2/B-10/1-2010-0024
TÁMOP
TÁMOP-4.2.2A-11/1/KONV-2012-0043
TÁMOP
COST TD1004 "Theranostics Imaging and Therapy: An Action To Develop Novel Nanosized Systems For Imaging-Guided Drug Delivery"
Egyéb
COST CM1006 "EUFEN: European F-Element Network"
Egyéb
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