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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
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM100007
035-os BibID:	(WoS)000739628200001 (Scopus)85123758171
Első szerző:	Pérez-Lourido, Paulo
Cím:	Stable and inert macrocyclic cobalt(II) and nickel(II) complexes with paraCEST response / Paulo Pérez-Lourido, Enikő Madarasi, Fanni Antal, David Esteban-Gómez, Gaoji Wang, Goran Angelovski, Carlos Platas-Iglesias, Gyula Tircsó, Laura Valencia
Dátum:	2022
ISSN:	1477-9226
Megjegyzések:	We report the synthesis of the macrocyclic ligands 3,9 PC2AMH (2,2'-(3,6,9-triaza-1(2,6)-pyridinacyclodecaphane-3,9-diyl)diacetamide) and 3,9-PC2AMtBu (2,2'-(3,6,9-triaza-1(2,6)-pyridinacyclodecaphane-3,9-diyl)bis(N-tert-butyl)acetamide) which contain a pyclen platform functionalized with acetamide or tert-butylacetamide pendant arms at positions 3 and 9 of the macrocyclic unit. The corresponding Co(II) and Ni(II) complexes were prepared, isolated and characterised as potential paramagnetic chemical exchange saturation transfer (paraCEST) agents. The X-ray structures of the Ni(II) complexes reveal six-coordination of the ligands to the metal ion. The Co(II) complex with 3,9-PC2AMtBu shows a similar six-coordinate structure in the solid state, while the Co(II) complex with 3,9 PC2AMH contains a seven-coordinate metal ion, seventh coordination being completed by the presence of an inner-sphere water molecule. The structure of the Co(II) complexes was investigated using 1H NMR spectroscopy and computational methods. The complexes present a seven-coordinate structure in solution, as demonstrated by the analysis of the paramagnetic shifts using density functional theory. Ligand protonation constants and stability constants of the complexes with 3,9 PC2AMH were determined using potentiometric titrations (I=0,15 M NaCl). The Co(II) complex was found to be more stable than the Ni(II) analogue (log KCoL = 14.46(5) and log KNiL = 13.15(3)). However, the Ni(II) and Co(II) complexes display similar rate constants characterizing the proton-assisted dissociation mechanism. The presence of highly shifted 1H NMR signals due to the amide protons in slow exchange with bulk water results in sizeable CEST signals, which are observed at +67 and +15 ppm for the Co(II) complex with 3,9 PC2AMH and +42 and +7 ppm for the Ni(II) analogue at 25 oC .
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk paraCEST PC2A-bis(amides) stability inertnes, structure
Megjelenés:	Dalton Transactions. - 51 : 4 (2022), p. 1580-1593. -
További szerzők:	Madarasi Enikő Antal Fanni Esteban-Gómez, David Wang, Gaoji Angelovski, Goran Platas-Iglesias, Carlos Tircsó Gyula (1977-) (vegyész, kémia tanár) Valencia, Laura
Pályázati támogatás:	K-120224 OTKA K-134694 OTKA Doctoral School of Chemistry at the University of Debrecen, Debrecen, Hungary Egyéb COST Action CA15209 "European Network on NMR Relaxometry Egyéb Bilateral Hungarian-Spanish Science and Technology Cooperation Program (2019-2.1.11- TET-2019-00084 supported by NKFIH). Egyéb
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