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001-es BibID:BIBFORM067302
035-os BibID:(WoS)000388546800022 (Scopus)84993990174
Első szerző:Garda Zoltán (vegyész)
Cím:Physico-chemical properties of MnII complexes formed with cis- and trans-DO2A : thermodynamic, electrochemical and kinetic studies / Zoltán Garda, Attila Forgács, Quyen N. Do, Ferenc K. Kálmán, Sarolta Timári, Zsolt Baranyai, Lorenzo Tei, Imre Tóth, Zoltán Kovács, Gyula Tircsó
Dátum:2016
ISSN:0162-0134 1873-3344
Megjegyzések:Manganese (MnII) is a promising alternative to gadolinium (GdIII) as a magnetic resonance imaging (MRI) agent. Unlike gadolinium, this biogenic metal might be better tolerated by the body, reducing the risk of toxicity associated with dissociation of the complex. Herein we report detailed equilibrium and kinetic studies performed with MnII complexes of 1,4,7,10-tetraazacyclododecane-1,4-diacetic acid (1,4-DO2A or cis-DO2A) and 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (1,7-DO2A or trans-DO2A). The protonation constants of the ligands as well as stability constants of their MnII complexes have been determined by pH-potentiometry. The stability constants of [Mn(cis-DO2A)] are slightly higher than those of [Mn(trans-DO2A)] (log KMnL = 15.68 and 15.22, respectively). Cyclic voltammetric (CV) experiments performed on [Mn(cis-DO2A)] and [Mn(trans-DO2A)] revealed quasireversible systems with a half-wave potential of + 636 and + 705 mV versus Ag/AgCl, respectively. These values indicate that the MnII ion in these complexes is more stabilized against the oxidation than in [Mn(EDTA)]2 ?. The kinetic inertness of the complexes has been studied in transmetallation reactions with CuII or ZnII ions. Kinetic measurements indicate that both MnII complexes primarily undergo acid catalyzed dissociation and positions of the acetate pendant arms do not influence kinetic inertness. The inertness of these complexes is comparable to that of [Mn(NOTA)]? (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetic acid) and about twenty times lower than that of [Mn(DOTA)]2 ? (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). In conclusion, [Mn(cis-DO2A)] displays some very interesting features (thermodynamic and redox stability as well as kinetic inertness) which makes this complex a promising platform for the development of more efficient MnII complexes as alternatives to Gd-based MRI agents.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Magnetic resonance imaging
Contrast agents (CAs)
Manganese
Thermodynamic stability
Inertness
Electrochemistry
Megjelenés:Journal of Inorganic Biochemistry. - 163 (2016), p. 206-213. -
További szerzők:Forgács Attila (1988-) (vegyész) Do, Quyen N. (1975-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Timári Sarolta (1984-) (vegyész, kémia tanár) Baranyai Zsolt (1977-) (vegyész) Tei, Lorenzo Tóth Imre (1950-) (vegyész) Kovács Zoltán (1963-) (vegyész, angol szakfordító) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:OTKA-84291
OTKA
OTKA-109029
OTKA
TÁMOP 4.2.4. A/2-11-1-2012-0001
TÁMOP
COST TD1004 Action "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery"
Egyéb
Bólyai János Kutatási Ösztöndíj
MTA
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2.

001-es BibID:BIBFORM084939
035-os BibID:(cikkazonosító)1721979
Első szerző:Tircsó Gyula (vegyész, kémia tanár)
Cím:Tuning the physico-chemical properties of the Ln3+complexes formed with some cyclododecane derivatives by careful ligand design / Tircsó Gyula, Kálmán Ferenc Krisztián, Baranyai Zsolt, Forgács Attila, Molnár Enikő, Tóth Imre, Kovacs Zoltán
Dátum:2014
ISSN:0949-8257
Tárgyszavak:Természettudományok Kémiai tudományok idézhető absztrakt
folyóiratcikk
kémia
biokémia és molekuláris biológia
Megjelenés:Journal of Biological Inorganic Chemistry. - 19 : S1 (2014), p. S691. -
További szerzők:Kálmán Ferenc K. (1978-) (vegyész) Baranyai Zsolt (1977-) (vegyész) Forgács Attila (1988-) (vegyész) Molnár Enikő (1991-) (vegyész) Tóth Imre (1950-) (vegyész) Kovács Zoltán
Pályázati támogatás:TÁMOP-4.2.2.A-11/1/KONV-2012-0043
TÁMOP
TÁMOP-4.2.2/B-10/1-2010-0024
TÁMOP
OTKA-84291
OTKA
PD-83253
Egyéb
TÉT_11-2-2012-0010
Egyéb
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3.

001-es BibID:BIBFORM078703
Első szerző:Vágner Adrienn (vegyész, kémikus)
Cím:Equilibrium Thermodynamics, Formation, and Dissociation Kinetics of Trivalent Iron and Gallium Complexes of Triazacyclononane-Triphosphinate (TRAP) Chelators: Unraveling the Foundations of Highly Selective Ga-68 Labeling / Adrienn Vágner, Attila Forgács, Ernő Brücher, Imre Tóth, Alessandro Maiocchi, Alexander Wurzer, Hans-Jürgen Wester, Johannes Notni, Zsolt Baranyai
Dátum:2018
ISSN:2296-2646
Megjegyzések:In order to rationalize the influence of FeIII contamination on labeling with the 68Ga eluted from 68Ge/68Ga-generator, a detailed investigation was carried out on the equilibrium properties, formation and dissociation kinetics of GaIII- and FeIII - complexes of 1,4,7-triazacyclononane-1,4,7-tris(methylene[2-carboxyethylphosphinic acid]) (H6TRAP). The stability and protonation constants of the [Fe(TRAP)]3? complex were determined by pH-potentiometry and spectrophotometry by following the competition reaction between the TRAP ligand and benzhydroxamic acid (0.15 M NaNO3, 25?C). The formation rates of [Fe(TRAP)] and [Ga(TRAP)] complexes were determined by spectrophotometry and 31P-NMR spectroscopy in the pH range 4.5? 6.5 in the presence of 5?40 fold HxTRAP(x?6) excess (x = 1 and 2, 0.15 M NaNO3, 25?C). The kinetic inertness of [Fe(TRAP)]3? and [Ga(TRAP)]3? was examined by the trans-chelation reactions with 10 to 20-fold excess of HxHBED(x?4) ligand by spectrophotometry at 25?C in 0.15 M NaCl (x = 0,1 and 2). The stability constant of [Fe(TRAP)]3? (logKFeL = 26.7) is very similar to that of [Ga(TRAP)]3? (logKGaL = 26.2). The rates of ligand exchange reaction of [Fe(TRAP)]3? and [Ga(TRAP)]3? with HxHBED(x?4) are similar. The reactions take place quite slowly via spontaneous dissociation of [M(TRAP)]3?, [M(TRAP)OH]4? and [M(TRAP)(OH)2] 5? species. Dissociation half-lives (t1/2) of [Fe(TRAP)]3? and [Ga(TRAP)]3? complexes are 1.1 ? 105 and 1.4 ? 105 h at pH = 7.4 and 25?C. The formation reactions of [Fe(TRAP)]3? and [Ga(TRAP)]3? are also slow due to the formation of the unusually stable monoprotonated [?M(HTRAP)]2? intermediates [?logKGa(HL) = 10.4 and ?logKFe(HL) = 9.9], which are much more stable than the [?Ga(HNOTA)]+ intermediate [?logKGa(HL) = 4.2]. Deprotonation and transformation of the monoprotonated [?(HTRAP)]2? intermediates into the final complex occur via OH?-assisted reactions. Rate constants (kOH) characterizing the OH?-driven deprotonation and transformation of [? Ga(HTRAP)]2? and [?Fe(HTRAP)]2? intermediates are 1.4 ? 105 M?1 s-1 and 3.4 ? 104 ?1s?1, respectively. In conclusion, the equilibrium and kinetic properties of [Fe(TRAP)] and [Ga(TRAP)] complexes are remarkably similar due to the close physico-chemical properties of FeIII and GaIII-ions. However, a slightly faster formation of [Ga(TRAP)] over [Fe(TRAP)] provides a rationale for a previously observed, selective complexation of 68GaIII in presence of excess FeIII.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
chelates
gallium
iron
thermodynamics
kinetics
reaction mechanism
positron emission tomography
Megjelenés:Frontiers in Chemistry. - 6 (2018), p. 1-12. -
További szerzők:Forgács Attila (1988-) (vegyész) Brücher Ernő (1935-) (vegyész) Tóth Imre (1950-) (vegyész) Maiocchi, Alessandro (vegyész) Wurzer, Alexander Wester, Hans J. Notni, Johannes Baranyai Zsolt (1977-) (vegyész)
Pályázati támogatás:GINOP-2.3.3-15-2016-00004
GINOP
GINOP-2.3.2-15-2016-00008
GINOP
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DOI
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