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001-es BibID:BIBFORM116497
035-os BibID:(WoS)001101303500001 (Scopus)85176281648
Első szerző:Bunda Szilvia (vegyész)
Cím:Bipyridil-based chelators for Gd(III) complexation: kinetic, structural and relaxation properties / Szilvia Bunda, Norbert Lihi, Zsófia Szaniszló, David Esteban-Gómez, Carlos Platas-Iglesias, Mónika Kéri, Gábor Papp, Ferenc Krisztián Kálmán
Dátum:2023
ISSN:1477-9226
Megjegyzések:In the last 20 years, research in the field of MRI (magnetic resonance imaging) contrast agents (CAs) has been intensified due to the emergence of a disease called nephrogenic systemic fibrosis (NSF). NSF has been linked to the in vivo dissociation of certain Gd(III)-based compounds applied in MRI as CAs. To prevent the dechelation of the probes after intravenous injection, the improvement of their in vivo stability is highly desired. The inertness of the Gd(III) chelates can be increased through the rigidification of the ligand structure. One of the potential ligands is (2,2 ',2 '',2 '''-(([2,2 '-bipyridine]-6,6 '-diylbis(methylene))bis(azanetriyl))tetraacetic acid) (H(4)DIPTA), which has been successfully used as a fluorescent probe for lanthanides; however, it has never been considered as a potential chelator for Gd(III) ions. In this paper, we report the thermodynamic, kinetic and structural features of the complex formed between Gd(III) and DIPTA. Since the solubility of the [Gd(DIPTA)](-) chelate is very low under acidic conditions, hampering its thermodynamic characterization, we can only assume that its stability is close to that determined for the structural analogue [Gd(FENTA)](-) (H(4)FENTA: (1,10-phenanthroline-2,9-diyl)bis(methyliminodiacetic acid)), which is similar to that determined for the agent [Gd(DTPA)](2-) routinely used in clinical practice. Unfortunately, the inertness of [Gd(DIPTA)](-) is significantly lower (t(1/2) = 1.34 h) than that observed for [Gd(EGTA)](-) and [Gd(DTPA)](2-) as a result of its spontaneous dissociation pathway during dechelation. The relaxivity values of [Gd(DIPTA)](-) are comparable with those of [Gd(FENTA)](-) and somewhat higher than the values characterizing [Gd(DTPA)](2-). Luminescence lifetime measurements indicate the presence of one water molecule (q = 1) in the inner sphere of the complex with a relatively high water exchange rate (k(ex)(298) = 43(5) x 10(6) s(-1)). DFT calculations suggest a rigid distorted tricapped trigonal prismatic polyhedron for the Gd(III) complex. On the basis of these results, we can conclude that the bipyridine backbone is not favourable with respect to the inertness of the chelate.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
koordinációs kémia
Gd(III)-komplex
kinetika
relaxivitás
Megjelenés:Dalton Transactions. - 52 : 45 (2023), p. 17030-17040. -
További szerzők:Lihi Norbert (1990-) (vegyész) Szaniszló Zsófia (1998-) (vegyészmérnök) Esteban-Gómez, David Platas-Iglesias, Carlos Kéri Mónika (1984-) (környezetkutató vegyész) Papp Gábor (1976-) (vegyész, kémikus) Kálmán Ferenc K. (1978-) (vegyész)
Pályázati támogatás:FK-134551
OTKA
2019-2.1.11-TET-2019-00084
Egyéb
ÚNKP-22-5
Egyéb
ÚNKP-23-5
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DOI
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2.

001-es BibID:BIBFORM067454
Első szerző:Tei, Lorenzo
Cím:Solution properties of the Ln(III) complexes of a novel octadentate chelator with rigidified iminodiacetate arms / Lorenzo Tei, Zsolt Baranyai, Claudio Cassino, Marianna Fekete, Ferenc K. Kálmán, Mauro Botta
Dátum:2012
ISSN:1477-9226
Megjegyzések:A novel octadentate ligand derived from the core structure of EGTA (ethyleneglycol-bis(2-aminoethylether)-N,N,N·,N·-tetraacetic acid) with two piperidine-cis-dicarboxylic acid moieties spaced by a triethylenedioxy chain (L1) has been synthesised with the aim to assess the effect of the structural rigidity on the thermodynamic and kinetic stabilities of its LnIII complexes. The stability constants of [Ln(L1)]? complexes show a weaker binding affinity for Ln3+ ions of L1 than EGTA. On the other hand, the selectivity of L1 for Ca2+ over Mg2+ is one of the highest ever reported. The kinetic inertness has been also investigated and faster rates of both acid catalysed and metal assisted decomplexation have been measured for [Gd(L1)]? as compared to [Gd(EGTA)]?. The 1H- and 13C NMR spectra of the diamagnetic La3+, Y3+ and Lu3+ complexes in aqueous media show pronounced stereochemical rigidity and the occurrence of a structural change across the lanthanide series. Finally, a complete 1H and 17O NMR relaxometric study indicates that [Gd(L1)]? possesses a nine-coordinate ground state with one inner coordination sphere water molecule characterized by a fast rate of exchange (298kex = 59 ? 106 s?1).
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
lanthanide
octadentate chelator
rigidified iminodiacetate arms
thermodynamic stability
relaxometry
Megjelenés:Dalton Transactions 41 (2012), p. 12797-12806. -
További szerzők:Baranyai Zsolt (1977-) (vegyész) Cassino, Claudio Fekete Marianna Kálmán Ferenc K. (1978-) (vegyész) Botta, Mauro
Pályázati támogatás:COST Action D38
Egyéb
HU11MO2-TET_10-1-2011-0202
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DOI
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3.

001-es BibID:BIBFORM018852
Első szerző:Tei, Lorenzo
Cím:Mn(ii) complexes of novel hexadentate AAZTA-like chelators : a solution thermodynamics and relaxometric study / Lorenzo Tei, Giuseppe Gugliotta, Marianna Fekete, Ferenc K. Kálmán, Mauro Botta
Dátum:2011
ISSN:1477-9226
Megjegyzések:Three novel chelators based on the 6-amino-6-methylperhydro-1,4-diazepine scaffold and possessing three pendant N-acetic or N-?-methylacetic acid have been synthesised. The ligands contain six donor atoms for complexation of MnII ions and thus potentially leave an additional site for coordination of a water molecule. The protonation constants of the ligands and the stability constants of their complexes formed with MnII ion were determined by pH-potentiometric titrations in 0.15 M NaCl solution at 25 ?C and compared to those of the parent AAZTA ligand (AAZTA = 6-amino-6-methylperhydro-1,4-diazepine tetraacetic acid). In spite of the similar value of the total basicity (?log K), the values of the stability constants of the MnIIAAZTA-like complexes are more than three orders of magnitude lower than that of MnAAZTA (log KMnL = 14.19). A detailed 1H and 17O NMR relaxometric study was carried out on the MnII complexes in aqueous solution as a function of pH, temperature and magnetic field strength. The 1H NMRD profiles of all the complexes show a similar shape, typical of low-molecular weight systems, but amplitudes that markedly differ to indicate a different degree of hydration. A similar behaviour is shown by the 17O NMR transverse relaxation rates and chemical shift data as a function of temperature. The experimental data can be rationalised by considering the presence in solution of a mixture of two isomeric species differing in coordination number (7 and 6) and in the number (1 and 0) of bound water molecules. Whereas this type of coordination equilibrium has been previously reported for lanthanide(III) complexes, it is observed for the first time on MnII chelates.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Dalton Transactions. - 40 : 9 (2011), p. 2025-2032. -
További szerzők:Gugliotta, Giuseppe Fekete Marianna Kálmán Ferenc K. (1978-) (vegyész) Botta, Mauro
Pályázati támogatás:ESF COST Action D38
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Internet cím:DOI
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