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1.

001-es BibID:BIBFORM099499
035-os BibID:(WoS)000747265100001 (Scopus)85123424554
Első szerző:Csupász Tibor (1991-)
Cím:A New Oxygen Containing Pyclen-Type Ligand as a Manganese(II) Binder for MRI and 52Mn PET Applications: Equilibrium, Kinetic, Relaxometric, Structural and Radiochemical Studies / Tibor Csupász, Dániel Szücs, Ferenc Krisztián Kálmán, Oldamur Hollóczki, Anikó Fekete, Dezső Szikra, Éva Tóth, Imre Tóth, Gyula Tircsó
Dátum:2022
ISSN:1420-3049
Megjegyzések:A new pyclen-3,9-diacetate derivative ligand (H23,9-OPC2A) is synthesized possessing an etheric O-atom opposite to the pyridine ring, to improve the dissociation kinetics of its Mn(II) complex (pyclen = 3,6,9,15-tetraazabicyclo(9.3.1)pentadeca-1(15),11,13-triene). The new ligand is less basic than the N-containing analogue (H23,9-PC2A) due to the non-protonable O-atom. In spite of its lower basicity, the conditional stability of the (Mn(3,9-OPC2A)) (pMn = ?log(Mn(II)), cL = cMn(II) = 0.01 mM. pH = 7.4) remains unaffected (pMn = 8.69), compared to the (Mn(3,9-PC2A)) (pMn = 8.64). The (Mn(3,9-OPC2A)) possesses one water molecule, having a lower exchange rate with bulk solvents (kex298 = 5.3 ??0.4 ? 107 s?1) than (Mn(3,9-PC2A)) (kex298 = 1.26?108 s?1). These mild dif-ferences are rationalized by the density-functional theory (DFT) calculations. The acid assisted dissociation of (Mn(3,9-OPC2A)) is considerably slower (k1 = 2.81 ??0.07 M?1s?1) than that of the complexes of diacetates or bisamides of various 12-membered macrocycles and the parent H23,9-PC2A. The (Mn(3,9-OPC2A)) is inert in rat/human serum as confirmed by 52Mn labeling (nM range), as well as by relaxometry (mM range). However, a 600-fold excess of EDTA (pH = 7.4) or a mixture of essential metal ions, propagated some transchelation/transmetalation in 7 days. The H23,9-OPC2A is labeled efficiently with 52Mn at elevated temperatures, yet at 37 ?C the parent H23,9-PC2A performs slightly better. Ultimately, the H23,9-OPC2A shows advantageous features for further ligand designs for bifunctional chelators.
A new pyclen-3,9-diacetate derivative ligand (H23,9-OPC2A) is synthesized possessing an etheric O-atom opposite to the pyridine ring to improve the dissociation kinetics of its Mn(II) complex (pyclen = 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene). The new ligand is less basic than the N-containing analogue (H23,9-PC2A) due to the non-protonable O-atom. In spite of its lower basicity, the conditional stability of the [Mn(3,9-OPC2A)] (pMn=-log[Mn(II)], cL=cMn(II)=0.01 mM. pH=7.4) remains unaffected (pMn=8.69) compared to the [Mn(3,9-PC2A)] (pMn=8.64). The [Mn(3,9-OPC2A)] possesses one water molecule, having a lower exchange rate with bulk solvent (kex298=5.3?0.4?107 s-1) than [Mn(3,9-PC2A)] (kex298=1.26?108 s-1). These mild differences are ration-alized by density-functional theory (DFT) calculations. The acid assisted dissociation of [Mn(3,9-OPC2A)] is considerably slower (k1=2.81?0.07 M-1s-1) than that of the complexes of diac-etates or bisamides of various 12-membered macrocycles and the parent H23,9-PC2A. The [Mn(3,9-OPC2A)] is inert in rat/human serum as confirmed by 52Mn labeling (nM range) as well as by relaxometry (mM range). However, 600-fold excess of EDTA (pH=7.4) or a mixture of es-sential metal ions propagated some transchelation/transmetalation in 7 days. The H23,9-OPC2A is labeled efficiently with 52Mn at elevated temperatures, yet at 37 oC the parent H23,9-PC2A per-forms slightly better. Altogether the H23,9-OPC2A shows advantageous features for further lig-and design for bifunctional chelators.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Molecules. - 27 (2022), p. 1-27. -
További szerzők:Szücs Dániel (1994-) (gyógyszerész) Kálmán Ferenc K. (1978-) (vegyész) Hollóczki Oldamur (1983-) (okleveles vegyészmérnök) Fekete Anikó (1973-) (vegyész) Szikra Dezső Péter (1983-) (vegyész) Tóth Éva Tóth Imre (1950-) (vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:K-120224
OTKA
K-128201
OTKA
K-134694
OTKA
FK-134551
OTKA
University of Debrecen Innovation Fund (POC-012)
Egyéb
the János Bolyai Research Scholarship of the Hungarian Academy of Sciences
MTA
ÚNKP-21-4 new national excellence program of the Ministry of Human Capacities
Egyéb
Doctoral School of Chemistry at the University of Debrecen
Egyéb
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2.

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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3.

001-es BibID:BIBFORM106987
035-os BibID:(Wos)000645403400001 (Scopus)85103919865 (cikkazonosító)1524
Első szerző:Kálmán Ferenc K. (vegyész)
Cím:Expanding the Ligand Classes Used for Mn(II) Complexation: Oxa-aza Macrocycles Make the Difference / Ferenc K. Kálmán, Viktória Nagy, Rocío Uzal-Varela, Paulo Pérez-Lourido, David Esteban-Gómez,Zoltán Garda, Kristof Pota, Roland Mezei, Agnès Pallier, Éva Tóth, Carlos Platas-Iglesias, Gyula Tircsó
Dátum:2021
ISSN:1420-3049
Megjegyzések:We report two macrocyclic ligands based on a 1,7-diaza-12-crown-4 platform functionalizedwith acetate (tO2DO2A2?) or piperidineacetamide (tO2DO2AMPip) pendant arms and a detailed char-acterization of the corresponding Mn(II) complexes. The X?ray structure of [Mn(tO2DO2A)(H2O)]·2H2Oshows that the metal ion is coordinated by six donor atoms of the macrocyclic ligand and one watermolecule, to result in seven-coordination. The Cu(II) analogue presents a distorted octahedral coor-dination environment. The protonation constants of the ligands and the stability constants of thecomplexes formed with Mn(II) and other biologically relevant metal ions (Mg(II), Ca(II), Cu(II) andZn(II)) were determined using potentiometric titrations (I= 0.15 M NaCl, T = 25?C). The conditionalstabilities of Mn(II) complexes at pH 7.4 are comparable to those reported for the cyclen-basedtDO2A2?ligand. The dissociation of the Mn(II) chelates were investigated by evaluating the rateconstants of metal exchange reactions with Cu(II) under acidic conditions (I= 0.15 M NaCl, T = 25?C).Dissociation of the [Mn(tO2DO2A)(H2O)] complex occurs through both proton?and metal?assistedpathways, while the [Mn(tO2DO2AMPip)(H2O)] analogue dissociates through spontaneous andproton-assisted mechanisms. The Mn(II) complex oftO2DO2A2 is remarkably inert with respectto its dissociation, while the amide analogue is significantly more labile. The presence of a watermolecule coordinated to Mn(II) imparts relatively high relaxivities to the complexes. The parametersdetermining this key property were investigated using17O NMR (Nuclear Magnetic Resonance)transverse relaxation rates and1H nuclear magnetic relaxation dispersion (NMRD) profiles.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
manganese
magnetic resonance imaging
stability
dissociation kinetics
water exchange
contrast agents
macrocycles
Megjelenés:Molecules. - 26 : 6 (2021), p. 1-20. -
További szerzők:Nagy Viktória Uzal-Varela, Rocío Pérez-Lourido, Paulo Esteban-Gómez, David Garda Zoltán (1989-) (vegyész) Póta Kristóf Mezei Roland Pallier, Agnès Tóth Éva Platas-Iglesias, Carlos Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:K-120224
OTKA
K-134694
OTKA
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4.

001-es BibID:BIBFORM076229
035-os BibID:(WoS)000434245500055 (Scopus)85047091952
Első szerző:Laine, Sophie
Cím:Mn complexes of open-chain ligands with a pyridine backbone: less donor atoms lead to higher kinetic inertness / Sophie Laine, Célia S. Bonnet, Ferenc K. Kálmán, Zoltán Garda, Agnès Pallier, Fabien Caillé, Franck Suzenet, Gyula Tircsó, Éva Tóth
Dátum:2018
ISSN:1144-0546 1369-9261
Megjegyzések:The kinetic inertness of Mn2+ complexes is an important parameter for the in vivo safety of potential MRI contrast agents. Rigidifying the ligand structure typically leads to reinforced kinetic inertness. In this context, we studied the Mn2+ complexes of three linear poly(amino carboxylate) ligands containing a pyridine moiety in their skeleton and bearing four (L1, L2) or three carboxylates (L3). The thermodynamic stability constants of the complexes formed with Mn2+, Ca2+, Mg2+, Zn2+ and Cu2+ have been determined using pH-potentiometry, 1H relaxometry and UV/Vis spectrophotometry and are close to those of the EDTA analogues. In contrast, and despite the presence of the pyridine in the ligand backbone, the dissociation rates of the complexes are several orders of magnitude higher than that of [Mn(EDTA)]2?, resulting from a very efficient dissociation pathway catalyzed by the direct attack of Cu2+ or Cu(OH)+. Due to the fewer carboxylate functions, ligand L3 is less favorable for metal-assisted dissociation and provides higher kinetic inertness for its Mn2+ chelate than the L1 and L2 analogues. The water exchange of the monohydrated MnL3 complex has been studied in a variable temperature 17O NMR study. The exchange rate is very high, k298ex = 2.8 ? 109 s?1, which is among the highest values reported for a Mn2+ complex. The NMRD profiles are typical of small molecular weight Mn2+ chelates (r1p = 2.44 mM?1 s?1 at 25 ?C and 20 MHz).
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:New Journal Of Chemistry. - 42 : 10 (2018), p. 8012-8020. -
További szerzők:Bonnet, Célia S. Kálmán Ferenc K. (1978-) (vegyész) Garda Zoltán (1989-) (vegyész) Pallier, Agnès Caillé, Fabien Suzenet, Franck Tircsó Gyula (1977-) (vegyész, kémia tanár) Tóth Éva
Pályázati támogatás:OTKA K-120224
OTKA
Bolyai János Kutatási Ösztöndíj
Egyéb
GINOP-2.3.2-15-2016-00008
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
COST CA15209
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5.

001-es BibID:BIBFORM106968
035-os BibID:(Wos)000779822100036 (Scopus)85126557192
Első szerző:Lucio-Martínez, Fátima
Cím:Rigidified Derivative of the Non-macrocyclic Ligand H4OCTAPA for Stable Lanthanide(III) Complexation / RFátima Lucio-Martínez, Zoltán Garda, Balázs Váradi, Ferenc Krisztián Kálmán, David Esteban-Gómez, Éva Tóth, Gyula Tircsó, Carlos Platas-Iglesias
Dátum:2022
ISSN:0020-1669 1520-510X
Megjegyzések:he stability constants of lanthanide complexes with the potentially octadentate ligand CHXOCTAPA4?, which contains a rigid 1,2-diaminocyclohexane scaffold functionalized with two acetate and two picolinate pendant arms, reveal the formation of stable complexes [log KLaL = 17.82(1) and log KYbL = 19.65(1)]. Luminescence studies on the Eu3+ and Tb3+ analogues evidenced rather high emission quantum yields of 3.4 and 11%, respectively. The emission lifetimes recorded in H2O and D2O solutions indicate the presence of a water molecule coordinated to the metal ion. 1H nuclear magnetic relaxation dispersion profiles and 17O NMR chemical shift and relaxation measurements point to a rather low water exchange rate of the coordinated water molecule (kex298 = 1.58 ? 106 s?1) and relatively high relaxivities of 5.6 and 4.5 mM?1 s?1 at 20 MHz and 25 and 37 ?C, respectively. Density functional theory calculations and analysis of the paramagnetic shifts induced by Yb3+ indicate that the complexes adopt an unprecedented cis geometry with the two picolinate groups situated on the same side of the coordination sphere. Dissociation kinetics experiments were conducted by investigating the exchange reactions of LuL occurring with Cu2+. The results confirmed the beneficial effect of the rigid cyclohexyl group on the inertness of the Lu3+ complex. Complex dissociation occurs following proton- and metal-assisted pathways. The latter is relatively efficient at neutral pH, thanks to the formation of a heterodinuclear hydroxo complex.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganic Chemistry. - 61 : 12 (2022), p. 5157-5171. -
További szerzők:Garda Zoltán (1989-) (vegyész) Váradi Balázs (1990-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Esteban-Gómez, David Tóth Éva Tircsó Gyula (1977-) (vegyész, kémia tanár) Platas-Iglesias, Carlos
Pályázati támogatás:K-134694
OTKA
K-128201
OTKA
FK-134551
OTKA
Bilateral Hungarian-Spanish Science and Technology Cooperation Program (2019-2.1.11-TET-2019-00084 supported by NKFIH).
Egyéb
Gedeon Richter's Talentum Foundation
Egyéb
Cooperative Doctoral Program of the Ministry of Innovation and Technology financed from the National Research, Development and Innovation Fund (NKFIH)
Egyéb
ÚNKP-21-4 new national excellence program of the Ministry of Human Capacities
Egyéb
János Bolyai Research Scholarship of the Hungarian Academy of Sciences
MTA
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6.

001-es BibID:BIBFORM076231
Első szerző:Molnár Enikő (vegyész)
Cím:Remarkable differences and similarities between the isomeric Mn(II)-cis- and trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetate complexes / Enikő Molnár, Balázs Váradi, Zoltán Garda, Richárd Botár, Ferenc K. Kálmán, Éva Tóth, Imre Tóth, Ernő Brücher, Gyula Tircsó
Dátum:2018
ISSN:0020-1693
Megjegyzések:Equilibrium, kinetic (solvent exchange and dissociation of the complex) and relaxometric studies (1H and 17O NMR) have been performed with the [M(II)(c-cdta)]2 complexes (c-cdta = cis-1,2-diaminocyclohexane- N,N,N0 ,N0-tetraacetic acid, M(II) = Mn(II), Zn(II), Cu(II),Ca(II), Mg(II)) and the physico-chemical data are compared to the isomeric complexes with trans-1,2-cdta (t-cdta) with the aim of searching appropriate ligands for Mn(II) complexation for safe MRI contrast agents. The total basicity (R log Ki H) of the c-cdta ligand appears to be very similar to that of the trans-derivative under the conditions applied (I = 0.15 M NaCl and 25 C), but the first two protonation constants notably differ. log K1 H is 1.5 log units higher, while the log K2 H is 0.8 log units lower than those determined for the trans-derivative. Similar basicity of the ligands results in similar complex stability (log K[Mn(L)] values are 14.19(2) and 14.32), whereas the conditional stabilities near to physiological pH are different (pMn values are 7.82 and 8.68) for the [Mn (c-cdta)]2 and the [Mn(t-cdta)]2 derivatives, respectively. Dissociation kinetic studies revealed that the [Mn(c-cdta)]2 dissociates 250 times faster than the [Mn(t-cdta)]2 complex. The water exchange rate (kex 298) of [Mn(c-cdta)]2 is ca. 60% higher than that of [Mn(t-cdta)]2 . The differences can likely be attributed to the different distances between the individual donor atoms, and the arrangement of the donor atoms around the metal ions in the cis- and trans- isomers. Interestingly, the relaxivity values of the Mn (II) complexes are very close (r1p = 3.79 mM 1 s 1 and 3.62 mM 1 s 1; 20 MHz, 25 C for the cis- and trans-isomers, respectively). DFT calculations were used to gain insight into the different properties of the [Mn(c-cdta)]2 and the [Mn(t-cdta)]2 complexes. The results gained in our studies confirm that the trans-1,2-cyclohexanediamine ♭♭building block" displays better features for further ligand development.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganica Chimica Acta. - 472 : 1 (2018), p. 254-263. -
További szerzők:Váradi Balázs (1990-) (vegyész) Garda Zoltán (1989-) (vegyész) Botár Richárd (1992-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Tóth Éva Tóth Imre (1950-) (vegyész) Brücher Ernő (1935-) (vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:OTKA K-120224
OTKA
GINOP-2.3.2-15-2016-00008
GINOP
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