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001-es BibID:	BIBFORM076222
035-os BibID:	(cikkazonosító)232
Első szerző:	Garda Zoltán (vegyész)
Cím:	Effect of the Nature of Donor Atoms on the Thermodynamic, Kinetic and Relaxation Properties of Mn(II) Complexes Formed With Some Trisubstituted 12-Membered Macrocyclic Ligands / Zoltán Garda, Enikő Molnár, Ferenc K. Kálmán, Richárd Botár, Viktória Nagy, Zsolt Baranyai, Ernő Brücher, Zoltán Kovács, Imre Tóth, Gyula Tircsó
Dátum:	2018
ISSN:	2296-2646
Megjegyzések:	During the past few years increasing attention has been devoted to Mn(II) complexes as possible substitutes for Gd(III) complexes as contrast agents in MRI. Equilibrium (log KMnL or pMn value), kinetic parameters (rates and half-lives of dissociation) and relaxivity of the Mn(II) complexes formed with 12-membered macrocyclic ligands were studied. The ligands were selected in a way to gain information on how the ligand rigidity, the nature of the donor atoms in the macrocycle (pyridine N, amine N, and etheric O atom), the nature of the pendant arms (carboxylates, phosphonates, primary, secondary and tertiary amides) affect the physicochemical parameters of the Mn(II) complexes. As expected, decreasing the denticity of DOTA (to afford DO3A) resulted in a drop in the stability and inertness of [Mn(DO3A)]- compared to [Mn(DOTA)]2-. This decrease can be compensated partially by incorporating the fourth nitrogen atom into a pyridine ring (e.g., PCTA) or by replacement with an etheric oxygen atom (ODO3A). Moreover, the substitution of primary amides for acetates resulted in a noticeable drop in the stability constant (PC3AMH), but it increased as the primary amides (PC3AMH) were replaced by secondary (PC3AMGly) or tertiary amide (PC3AMPip) pendants. The inertness of the Mn(II) complexes behaved alike as the rates of acid catalyzed dissociation increased going from DOTA (k1 = 0.040 M?1s?1) to DO3A (k1 = 0.45 M-1s-1). However, the rates of acid catalyzed dissociation decreased from 0.112 M?1s?1 observed for the anionic Mn(II) complex of PCTA to 0.0107 M?1s?1 and 0.00458 M?1s?1 for the cationic Mn(II) complexes of PC3AMH and PC3AMPip ligands, respectively. In spite of its lower denticity (as compared to DOTA) the sterically more hindered amide complex ([Mn(PC3AMPip)]2+) displays surprisingly high conditional stability (pMn = 8.86 vs. pMn = 9.74 for [Mn(PCTA)]-) and excellent kinetic inertness. The substitution of phosphonates for the acetate pendant arms (DOTP and DO3P), however, resulted in a noticeable drop in the conditional stability as well as dissociation kinetic parameters of the corresponding Mn(II) complexes ([Mn(DOTP)]6? and [Mn(DO3P)]4?) underlining that the phosphonate pedant should not be considered as a suitable building block for further ligand design while the tertiary amide moiety will likely have some implications in this respect in the future.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Frontiers in Chemistry. - 6 (2018), p. 1-14. -
További szerzők:	Molnár Enikő (1991-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Botár Richárd (1992-) (vegyész) Nagy Viktória (1989-) (vegyész és kémia tanár) Baranyai Zsolt (1977-) (vegyész) Brücher Ernő (1935-) (vegyész) Kovács Zoltán (1963-) (vegyész, angol szakfordító) Tóth Imre (1950-) (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 NKFIH K-120224 NKFIH
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001-es BibID:	BIBFORM107388
035-os BibID:	(Wos)000674274600001 (Scopus)85112868977
Első szerző:	Horváth Dávid (vegyész)
Cím:	Towards 213 Bi alpha-therapeutics and beyond: unravelling the foundations of efficient Bi III complexation by DOTP / Dávid Horváth, Fabio Travagin, Nicol Guidolin, Federica Buonsanti, Gyula Tircsó, Imre Tóth, Frank Bruchertseifer, Alfred Morgenstern, Johannes Notni, Giovanni B. Giovenzana, Zsolt Baranyai
Dátum:	2021
ISSN:	2052-1553
Megjegyzések:	Bismuth isotopes are attracting increasing attention for their potential applications in diagnostics and therapy. The emerging use of 213Bi in targeted alpha-therapy (TAT) is a particularly relevant example because it is available from radionuclide generators. A fast formation of stable BiIII-complexes is important for the safe and efficient preparation of labelled (bio)conjugates. Macrocyclic chelating agents are currently the best choice in terms of stability of the corresponding BiIII-complexes. In this work, a thorough study of the thermodynamics and kinetics of formation of BiIII-DOTP including radio-labelling and the comparison with the congener BiIII-DOTA is undertaken. The BiIII-DOTP complex is characterised by a fast formation kinetics (kBi(H2DOTP) = 0.33 s-1), an outstanding thermodynamic stability (log KBiDOTP = 38.67) and an impressive kinetic inertness (t1/2pH=3 = 47 600 h). The results clearly demonstrate that DOTP is a better chelating agent for BiIII both in terms of thermodynamic stability and in terms of kinetics of formation, with clear advantages in the radiolabelling of short-lived bismuth isotopes.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Inorganic Chemistry Frontiers. - 8 : 16 (2021), p. 3893-3904. -
További szerzők:	Travagin, Fabio Guidolin, Nicol Buonsanti, Federica Tircsó Gyula (1977-) (vegyész, kémia tanár) Tóth Imre (1950-) (vegyész) Bruchertseifer, Frank Morgenstern, Alfred Notni, Johannes Giovenzana, Giovanni Battista Baranyai Zsolt (1977-) (vegyész)
Pályázati támogatás:	K-128201 OTKA K-120224 OTKA K-134694 OTKA GINOP-2.3.2-15-2016-00008 GINOP
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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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