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1.

001-es BibID:BIBFORM106980
035-os BibID:(WoS)000643574200067 (Scopus)85100045839
Első szerző:Garda Zoltán (vegyész)
Cím:Complexation of Mn(II) by Rigid Pyclen Diacetates: Equilibrium, Kinetic, Relaxometric, Density Functional Theory, and Superoxide Dismutase Activity Studies / Zoltán Garda, Enikő Molnár, Nadège Hamon, José Luis Barriada, David Esteban-Gómez, Balázs Váradi, Viktória Nagy, Kristof Pota, Ferenc Krisztián Kálmán, Imre Tóth, Norbert Lihi, Carlos Platas-Iglesias, Éva Tóth, Raphaël Tripier, Gyula Tircsó
Dátum:2021
ISSN:0020-1669 1520-510X
Megjegyzések:We report the Mn(II) complexes with two pyclen-based ligands (pyclen = 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene) functionalized with acetate pendant arms at either positions 3,6 (3,6-PC2A) or 3,9 (3,9-PC2A) of the macrocyclic fragment. The 3,6-PC2A ligand was synthesized in five steps from pyclen oxalate by protecting one of the secondary amine groups of pyclen using Alloc protecting chemistry. The complex with 3,9-PC2A is characterized by a higher thermodynamic stability [log K-MnL = 17.09(2)] than the 3,6-PC2A analogue [log K-MnL = 15.53(1); 0.15 M NaCl]. Both complexes contain a water molecule coordinated to the metal ion, which results in relatively high H-1 relaxivities (r(1p) = 2.72 and 2.91 mM(-1) s(-1) for the complexes with 3,6-PC2A and 3,9-PC2A, respectively, at 25 degrees C and 0.49 T). The coordinated water molecule displays fast exchange kinetics with the bulk in both cases; the rates (k(ex)(298)) are 140 x 10(6) and 126 x 10(6) s(-1) for [Mn(3,6-PC2A)(H2O)] and [Mn(3,9-PC2A)(H2O)], respectively. The two complexes were found to be remarkably inert with respect to their dissociation, with half-lives of 63 and 21 h, respectively, at pH = 7.4 in the presence of excess Cu(II). The r(1p) values recorded in blood serum remain constant at least over a period of 120 h. Cyclic voltammetry experiments show irreversible oxidation features shifted to higher potentials with respect to [Mn(EDTA)(H2O)](2-) (H(4)EDTA = ethylenediaminetetraacetic acid) and [Mn(PhDTA)(H2O)](2-) (H(4)PhDTA = phenylenediamine-N,N,N',N'-tetraacetic acid), indicating that the PC2A complexes reported here have a lower tendency to stabilize Mn(III). The superoxide dismutase activity of the Mn(II) complexes was tested using the xanthine/xanthine oxidase/p-nitro blue tetrazolium chloride assay at pH = 7.8. The Mn(II) complexes of 3,6-PC2A and 3,9-PC2A are capable of assisting decomposition of the superoxide anion radical. The kinetic rate constant of the complex of 3,9-PC2A is smaller by 1 order of magnitude than that of 3,6-PC2A.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganic Chemistry. - 60 : 2 (2021), p. 1133-1148. -
További szerzők:Molnár Enikő (1991-) (vegyész) Hamon, Nadège Barriada, José Luis Esteban-Gómez, David Váradi Balázs (1990-) (vegyész) Nagy Viktória Póta Kristóf Kálmán Ferenc K. (1978-) (vegyész) Tóth Imre (1950-) (vegyész) Lihi Norbert (1990-) (vegyész) Platas-Iglesias, Carlos Tóth Éva (1967-) (koordinációs kémia) Tripier, Raphaël Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:K-120224
OTKA
128201
OTKA
134694
OTKA
PD-128326
OTKA
2019-2.1.11- 1179 TET-2019-00084
Egyéb
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2.

001-es BibID:BIBFORM082556
035-os BibID:(WoS)000503330800047 (Scopus)85076051798
Első szerző:Johnston, Hannah M.
Cím:Enhancement of the Antioxidant Activity and Neurotherapeutic Features through Pyridol Addition to Tetraazamacrocyclic Molecules / Hannah M. Johnston, Kristof Pota, Madalyn M. Barnett, Olivia Kinsinger, Paige Braden, Timothy M. Schwartz, Emily Hoffer, Nishanth Sadagopan, Nam Nguyen, Yu Yu, Paulina Gonzalez, Gyula Tircsó, Hongli Wu, Giridhar Akkaraju, Michael J. Chumley, Kayla N. Green
Dátum:2019
ISSN:0020-1669 1520-510X
Megjegyzések:Alzheimer's and other neurodegenerative diseases are chronic conditions affecting millions of individuals worldwide. Oxidative stress is a consistent component described in the development of many neurodegenerative diseases. Therefore, innovative strategies to develop drug candidates that overcome oxidative stress in the brain are needed. To target these challenges, a new, water-soluble 12-membered tetraaza macrocyclic pyridinophane L4 was designed and produced using a building-block approach. Potentiometric data show that the neutral species of L4 provides interesting zwitterionic behavior at physiological pH, akin to amino acids, and a nearly ideal isoelectric point of 7.3. The copper(II) complex of L4 was evaluated by X-ray diffraction and cyclic voltammetry to show the potential modes of antioxidant activity derived, which was also demonstrated by 2,2-diphenyl-1-picrylhydrazyl and coumarin carboxylic acid antioxidant assays. L4 was shown to have dramatically enhanced antioxidant activity and increased biological compatibility compared to parent molecules reported previously. L4 attenuated hydrogen peroxide (H2O2)-induced cell viability loss more efficiently than precursor molecules in the mouse hippocampal HT-22 cell model. L4 also showed potent (fM) level protection against H2O2 cell death in a BV2 microglial cell culture. Western blot studies indicated that L4 enhanced the cellular antioxidant defense capacity via Nrf2 signaling activation as well. Moreover, a low-cost analysis and high metabolic stability in phase I and II models were observed. These encouraging results show how the rational design of lead compounds is a suitable strategy for the development of treatments for neurodegenerative diseases where oxidative stress plays a substantial role.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganic Chemistry. - 58 : 24 (2019), p. 16771-16784. -
További szerzők:Póta Kristóf Barnett, Madalyn M. Kinsinger, Olivia Braden, Paige Schwartz, Timothy M. Hoffer, Emily Sadagopan, Nishanth Nguyen, Nam Yu, Yu Gonzalez, Paulina Tircsó Gyula (1977-) (vegyész, kémia tanár) Wu, Hongli Akkaraju, Giridhar Chumley, Michael J. Green, Kayla N.
Pályázati támogatás:NKFIH K-120224
egyéb
ÚNKP-18-4
egyéb
GINOP-2.3.2-15-2016-00008
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
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Intézményi repozitóriumban (DEA) tárolt változat
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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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Intézményi repozitóriumban (DEA) tárolt változat
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4.

001-es BibID:BIBFORM106875
035-os BibID:(cikkazonosító)112124 (Scopus)85146456835
Első szerző:Póta Kristóf
Cím:Synthesis and characterization of two piperazine containing macrocycles and their transition metal complexes / Kristof Pota, Hannah M. Johnston, Enikő Madarasi, Gyula Tircsó, Kayla N. Green
Dátum:2023
ISSN:0162-0134 1873-3344
Megjegyzések:Rigidification of the ligand scaffolds has been a particular mechanism of interest employed to achieve properties suitable for MRI contrast, catalysis, or other applications of metal complexes. Towards the goal of targeting a 15-anePyN5Pip type ligand, a serendipitous isolation of a 30-anePy2N10Pip2 aza-macrocycle was achieved, instead. X-ray diffraction and determination of pKa events were carried out and compared to 17-anePyN5Pip. Furthermore, the X-ray diffraction of the Cu(II) and Zn(II) complexes of 17-anePyN5Pip was achieved and compared to previous reports of other first-row transition metal derivatives of this ligand. Determination of the log beta with both 30-anePy2N10Pip2 and 17-anePyN5Pip with the divalent Mnsingle bondZn metal-ion series was used to demonstrate the impact that the piperazine ring plays compared to other, less rigid macrocycles reported to date.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Piperazine
Macrocycle
Manganese
Log B
Pyridinophane
Megjelenés:Journal of Inorganic Biochemistry. - 241 (2023), p. 112124-. -
További szerzők:Johnston, Hannah M. Madarasi Enikő Tircsó Gyula (1977-) (vegyész, kémia tanár) Green, Kayla N.
Pályázati támogatás:K-134694
OTKA
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Intézményi repozitóriumban (DEA) tárolt változat
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5.

001-es BibID:BIBFORM103532
035-os BibID:(WOS)000562989200022 (Scopus)85089180629
Első szerző:Póta Kristóf
Cím:Manganese complex of a rigidified 15-membered macrocycle: A comprehensive study / Kristof Pota, Enikő Molnár, Ferenc Krisztián Kálmán, David M. Freire, Gyula Tircsó, Kayla N. Green
Dátum:2020
ISSN:0020-1669 1520-510X
Megjegyzések:Owing to the increasing importance of manganese(II) complexes in the field of magnetic resonance imaging (MRI), large efforts have been devoted to find an appropriate ligand for Mn(II) ion encapsulation by providing balance between the seemingly contradictory requirements (i.e., thermodynamic stability and kinetic inertness vs low ligand denticity enabling water molecule(s) to be coordinated in its metal center). Among these ligands, a large number of pyridine or pyridol based open-chain and macrocyclic chelators have been investigated so far. As a next step in the development of these chelators, 15-pyN(3)O(2)Ph and its transition metal complexes were synthesized and characterized using established methods. The 15-pyN(3)O(2) Ph ligand incorporates both pyridine and ortho-phenylene units to decrease ligand flexibility. The thermody-namic properties, protonation and stability constants, were determined using pH-potentiometry; the solid-state structures of two protonation states of the free ligand and its manganese complex were obtained by single crystal X-ray diffractometry. The results show a seven-coordinate metal center with two water molecules in the first coordination sphere. The longitudinal relaxivity of [Mn(15-pyN(3)O(2)Ph)](2+) was found to be 5.16 mM(-1) s(-1) at 0.49 T (298 K). Furthermore, the r(2p) value of 11.72 mM(-1) s(-1) (0.49 T), which is doubled at 1.41 T field, suggests that design of this Mn(II) complex does achieve some characteristics required for contrast imaging. In addition, 17 0 NMR measurements were performed in order to access the microscopic parameters governing this key feature (e.g., water exchange rate). Finally, manganese complexes of ligands with analogous polyaza macrocyclic scaffold have been investigated as low molecular weight Mn(CAT) mimics. Here, we report the H2O2 disproportionation study of [Mn(15pyN(3)O(2)Ph)](2+) to demonstrate the versatility of this ligand scaffold as well.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Inorganic Chemistry. - 59 : 16 (2020), p. 11366-11376. -
További szerzők:Molnár Enikő (1991-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Freire, David M. Tircsó Gyula (1977-) (vegyész, kémia tanár) Green, Kayla N.
Pályázati támogatás:NKFIH-K-120224
Egyéb
GINOP-2.3.2-15-2016-00008
GINOP
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Intézményi repozitóriumban (DEA) tárolt változat
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6.

001-es BibID:BIBFORM076232
035-os BibID:(WoS)000434245500054 (Scopus)85047071870
Első szerző:Póta Kristóf
Cím:Taking the next step toward inert Mn2+ complexes of open-chain ligands: the case of the rigid PhDTA ligand / Kristof Pota, Zoltán Garda, Ferenc Krisztián Kálmán, José Luis Barriada, David Esteban-Gómez, Carlos Platas-Iglesias, Imre Tóth, Ernő Brücher, Gyula Tircsó
Dátum:2018
ISSN:1144-0546 1369-9261
Megjegyzések:In line with our research to find inert Mn(II) complexes as contrast agents for Magnetic Resonance Imaging, we have studied the aromatic?ring rigidified EDTA-analogue o-phenylenediamine-N,N,N',N'-tetraacetic acid (PhDTA). The protonation constants (Ki H) of PhDTA and stability constants of complexes formed between this open-chain ligand and several different biogenic metal ions (Ca2+, Mg2+, Zn2+, Cu2+, Mn2+) have been determined in 0.15 M NaCl at 25 ?C and compared with the values reported in the literature previously. Protonation constants are lower than those of the corresponding cis- and trans-CDTA complexes, which might be attributed to the electron withdrawing effect of the phenylene group. The lower total basicity of the ligand leads to lower stability constants for all the examined metal complexes. On the contrary, we have found that the conditional stability constants of [Mn(PhDTA)]2- and [Mn(trans- CDTA)]2- are approximately the same, as both complexes are 100% formed by pH 5 and their pM values are also comparable. The relaxivity of [Mn(PhDTA)]2- is nearly identical (r1 = 3.72 mM-1s-1) to that determined previously for the [Mn(trans-CDTA)]2- complex (r1 = 3.62 mM-1s-1), and its pH-dependence confirms the equilibrium model used for the fitting of the titration data. The results of kinetic studies of the metal exchange reactions reveal that the [Mn(PhDTA)]2- complex possesses a slightly better dissociation kinetics profile than [Mn(trans-CDTA)]2-, which has been tested in vivo recently (including human injections). The half-life of the dissociation of the complex near to physiological pH at 25 ?C is 19 hours. By using the rate constant calculated for the dissociation (pH=7.4, cCu2+=10 ?M) and the half-life of excretion (1.6 hour), the ratio of the dissociated complex is estimated to represent 8% of the injected dose. DFT studies reveal that the metal coordination environment of [Mn(PhDTA)]2- is very similar to that of [Mn(EDTA)]2-, both containing an inner-sphere water molecule. Cyclic voltammetry studies indicate that [Mn(PhDTA)]2- is slightly more resistant towards oxidation to the Mn3+ complex than the EDTA analogue.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:New Journal Of Chemistry. - 42 : 10 (2018), p. 8001-8011. -
További szerzők:Garda Zoltán (1989-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Barriada, José Luis Esteban-Gómez, David Platas-Iglesias, Carlos 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
GINOP-2.3.3-15-2016-00004
GINOP
Bolyai János Kutatási Ösztöndíj
Egyéb
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Intézményi repozitóriumban (DEA) tárolt változat
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7.

001-es BibID:BIBFORM103038
035-os BibID:(wos)000481917100005 (scopus)85071026081
Első szerző:Tircsó Gyula (vegyész, kémia tanár)
Cím:Dialing in on pharmacological features for a therapeutic antioxidant small molecule / Green Kayla N., Pota Kristof, Tircsó Gyula, Gogolák Réka Anna, Kinsinger Olivia, Davda Collin, Blain Kimberly, Brewer Samantha M. Gonzalez Paulina, Johnston Hannah M., Akkaraju Giridhar
Dátum:2019
ISSN:1477-9226
Megjegyzések:The pyridinophane molecule L2 (3,6,9,15-tetraazabicyclo[9.3.1]penta-deca-1(15),11,13-trien-13- ol) has shown promise as a therapuetic for neurodegenerative diseases involving oxidative stress and metal ion misregulation. Protonation and metal binding stability constants with Mg2+, Ca2+, Cu2+, and Zn2+ ions were determined to further explore the therapeutic and pharmacological potential of this water soluble small molecule. These studies show that incorporation of an ?OH group in position 4 of the pyridine ring decreases the pI values compared to cyclen and L1 (3,6,9,15-tetraazabicyclo[9.3.1]penta-deca-1(15),11,13-triene). Furthermore, this approach tunes the basicity of the tetra-aza macrocyclic ligand through the enhanced resonance stabilization of the ?OH in position 4 and rigidity of the pyridine ring such that L2 has increased basicity compared to previously reported tetra-aza macrocycles. A metal binding preference for Cu2+, a redox cycling agent known to produce oxidative stress, indicates that this would be the in vivo metal target of L2. However, the binding constant of L2 with Cu2+ is moderated compared to cyclen due to the rigidity of the ligand and shows how ligand design can be used to tune metal selectivity. An IC50=298.0 ?M in HT-22 neuronal cells was observed. Low metabolic liability was determined in both Phase I and II in vitro models. Throughout these studies other metal binding systems were used for comparison and as appropriate controls. The reactivity reported to date and pharmacological features described herein warrant further studies in vivo and the pursuit of L2 congeners using the knowledge that pyridine substitution in a pyridinophane can be used to tune the structure of the ligand and retain the positive therapeutic outcomes.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Ligand
Pyridinophane
tetra-aza macrocycle
binding
transition metal-ion
Megjelenés:Dalton Transactions. - 48 : 33 (2019), p. 12430-12439. -
További szerzők:Green, Kayla N. Póta Kristóf Gogolák Réka Anna (kémia tanár) Olivia Kinsinger Collin Davda Kimberly Blaina Samantha M. Brewer Paulina Gonzalez Hannah M. Johnston Giridhar Akkarajuc
Pályázati támogatás:(NKFIH K-120224)
MTA
ÚNKP-18?4 N
Egyéb
GINOP-2.3.2-15-2016-00008
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
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Intézményi repozitóriumban (DEA) tárolt változat
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