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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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001-es BibID:	BIBFORM067299
035-os BibID:	(WoS)000371753500032 (Scopus)84960430930
Első szerző:	Rodríguez-Rodríguez, Aurora
Cím:	Complexation of Ln3+ Ions with Cyclam Dipicolinates: A Small Bridge that Makes Huge Differences in Structure, Equilibrium, and Kinetic Properties / Aurora Rodríguez-Rodríguez, Martín Regueiro-Figueroa, David Esteban-Gómez, Raphaël Tripier, Gyula Tircsó, Ferenc Krisztián Kálmán, Attila Csaba Bényei, Imre Tóth, Andrés de Blas, Teresa Rodríguez-Blas, Carlos Platas-Iglesias
Dátum:	2016
ISSN:	0020-1669
Megjegyzések:	The coordination properties toward the lanthanide ions of two macrocyclic ligands based on a cyclam platform containing picolinate pendant arms have been investigated. The synthesis of the ligands was achieved by using the well-known bis-aminal chemistry. One of the cyclam derivatives (cb-tedpa2?) is reinforced with a cross-bridge unit, which results in exceptionally inert [Ln(cb-tedpa)]+ complexes. The X-ray structures of the [La(cb-tedpa)Cl], [Gd(cb-tedpa)]+, and [Lu(Me2tedpa)]+ complexes indicate octadentate binding of the ligands to the metal ions. The analysis of the Yb3+-induced shifts in [Yb(Me2tedpa)]+ indicates that this complex presents a solution structure very similar to that observed in the solid state for the Lu3+ analogue. The X-ray structures of [La(H2Me2tedpa)2]3+ and [Yb(H2Me2tedpa)2]3+ complexes confirm the exocyclic coordination of the metal ions, which gives rise to coordination polymers with the metal coordination environment being fulfilled by oxygen atoms of the picolinate groups and water molecules. The X-ray structure of [Gd(Hcb-tedpa)2]+ also indicates exocyclic coordination that in this case results in a discrete structure with an eight-coordinated metal ion. The nonreinforced complexes [Ln(Me2tedpa)]+ were prepared and isolated as chloride salts in nonaqueous media. However, these complexes were found to undergo dissociation in aqueous solution, except in the case of the complexes with the smallest Ln3+ ions (Ln3+ = Yb3+ and Lu3+). A DFT investigation shows that the increased stability of the [Ln(Me2tedpa)]+ complexes in solution across the lanthanide series is the result of an increased binding energy of the ligand due to the increased charge density of the Ln3+ ion.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk lanthanide complex cross-bridged equilibrium kinetic cyclam
Megjelenés:	Inorganic Chemistry. - 55 : 5 (2016), p. 2227-2239. -
További szerzők:	Regueiro-Figueroa, Martín Esteban-Gómez, David Tripier, Raphaël Tircsó Gyula (1977-) (vegyész, kémia tanár) Kálmán Ferenc K. (1978-) (vegyész) Bényei Attila (1962-) (vegyész) Tóth Imre (1950-) (vegyész) Blas, Andrès de Rodríguez-Blas, Teresa Platas-Iglesias, Carlos
Pályázati támogatás:	OTKA-84291 OTKA OTKA-109029 OTKA COST CM1006 "European F-Element Network (EuFen)" Egyéb COST TD1004 "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging- Guided Drug Delivery" Egyéb Bolyai János Kutatási Ösztöndíj MTA
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001-es BibID:	BIBFORM057620
Első szerző:	Rodríguez-Rodríguez, Aurora
Cím:	Lanthanide(III) Complexes with a Reinforced Cyclam Ligand Show Unprecedented Kinetic Inertness / Aurora Rodríguez-Rodríguez, David Esteban-Gómez, Raphaël Tripier, Gyula Tircsó, Zoltán Garda, Imre Tóth, Andrés de Blas, Teresa Rodríguez-Blas, Carlos Platas-Iglesias
Dátum:	2014
ISSN:	0002-7863
Megjegyzések:	Lanthanide(III) complexes of a cross-bridged cyclam derivative containing two picolinate pendant arms are kinetically inert in very harsh conditions such as 2 M HCl, with no dissociation being observed for at least 5 months. Importantly, the [Ln(dota)] complexes, which are recognized to be extremely inert, dissociate under these conditions with lifetimes in the range ca. 1 minute to 12 hours depending upon the Ln3+ ion. X-ray diffraction studies reveal octadentate binding of the ligand to the metal ion in the [Eu(cb-tedpa)]+ complex, while 1H and 13C NMR experiments in D2O point to the presence of a single diastereoisomer in solution with a very rigid structure. The structure of the complexes in the solid state is retained in solution, as demonstrated by the analysis of the Yb3+-induced paramagnetic shifts.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Lanthanide(III) Complexes Reinforced Cyclam Ligand kinetics inertness picolinates
Megjelenés:	Journal Of The American Chemical Society. - 136 : 52 (2014), p. 17954-17957. -
További szerzők:	Esteban-Gómez, David Tripier, Raphaël Tircsó Gyula (1977-) (vegyész, kémia tanár) Garda Zoltán (1989-) (vegyész) Tóth Imre (1950-) (vegyész) de Blas, Andrés Rodríguez-Blas, Teresa Platas-Iglesias, Carlos
Pályázati támogatás:	Ministerio de Educación y Ciencia (MEC, CTQ2009-10721), Fondo Europeo de Desarrollo Regional (FEDER, CTQ2009-10721) and Xunta de Galicia (CN 2012/011) for generous financial support and Centro de Supercomputación de Galicia (CESGA) Egyéb COST CM1006 "European F-Element Network (EuFen) Egyéb COST TD1004 "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery" Egyéb János Bólyai Research Scholarship of the Hungarian Academy of Sciences MTA K-84291 OTKA K-109029 OTKA TÁMOP-4.2.2.A-11/1/KONV-2012-0043 TÁMOP
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