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001-es BibID:	BIBFORM018843
Első szerző:	Regueiro-Figueroa, Martín
Cím:	Lanthanide dota-like Complexes Containing a Picolinate Pendant: Structural Entry for the Design of LnIII-Based Luminescent Probes / Martín Regueiro-Figueroa, Bachir Bensenane, Erika Ruscsák, David Esteban-Gómez, Loïc J. Charbonnière, Gyula Tircsó, Imre Tóth, Andrès de Blas, Teresa Rodríguez-Blas, Carlos Platas-Iglesias
Dátum:	2011
ISSN:	0020-1669
Megjegyzések:	In this contribution we present two ligands based on a do3a platform containing a picolinate group attached to the fourth nitrogen atom of the cyclen unit, which are designed for stable lanthanide complexation in aqueous solutions. Potentiometric measurements reveal that the thermodynamic stability of the complexes is very high (log K = 21.2?23.5), being comparable to that of the dota analogues. Luminescence lifetime measurements performed on solutions of the EuIII and TbIII complexes indicate that the complexes are nine coordinate with no inner-sphere water molecules. A combination of density functional theory (DFT) calculations and NMR measurements shows that for the complexes of the heaviest lanthanides there is a major isomer in solution consisting of the enantiomeric pair ?(????) and ?(????), which provides square antiprismatic coordination (SAP) around the metal ion. Analysis of the YbIII-induced paramagnetic shifts unambiguously confirms that these complexes have SAP coordination in aqueous solution. For the light lanthanide ions however both the SAP and twisted-square antiprismatic (TSAP) isomers are present in solution. Inversion of the cyclen ring appears to be the rate-determining step for the ?(????) ? ?(????) enantiomerization process observed in the LuIII complexes. The energy barriers obtained from NMR measurements for this dynamic process are in excellent agreement with those predicted by DFT calculations. The energy barriers calculated for the arm-rotation process are considerably lower than those obtained for the ring-inversion path. Kinetic studies show that replacement of an acetate arm of dota by a picolinate pendant results in a 3-fold increase in the formation rate of the corresponding EuIII complexes and a significant increase of the rates of acid-catalyzed dissociation of the complexes. However, these rates are 1?2 orders of magnitude lower than those of do3a analogues, which shows that the complexes reported herein are remarkably inert with respect to metal ion dissociation.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Molekulatudomány
Megjelenés:	Inorganic Chemistry. - 50 : 9 (2011), p. 4125-4141. -
További szerzők:	Bensenane, Bachir Ruscsák Erika (1989-) (vegyész) Esteban-Gómez, David Charbonnière, Loïc J. Tircsó Gyula (1977-) (vegyész, kémia tanár) Tóth Imre (1950-) (vegyész) Blas, Andrès de Rodríguez-Blas, Teresa Platas-Iglesias, Carlos
Pályázati támogatás:	TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP Ritkaföldfém munkacsoport
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001-es BibID:	BIBFORM067433
Első szerző:	Rodríguez-Rodríguez, Aurora
Cím:	Stable Mn2+, Cu2+ and Ln3+ complexes with cyclen-based ligands functionalized with picolinate pendant arms / Aurora Rodríguez-Rodríguez, Zoltán Garda, Erika Ruscsák, David Esteban-Gómez, Andrés de Blas, Teresa Rodríguez-Blas, Luís M. P. Lima, Maryline Beyler, Raphaël Tripier, Gyula Tircsó, Carlos Platas-Iglesias
Dátum:	2015
ISSN:	1477-9226
Megjegyzések:	In this study we present the results of the equilibrium, dissociation kinetics, DFT and X-ray crystallographic studies performed on the complexes of metal ions of biomedical importance (Mn2+, Cu2+ and Gd3+) formed with octadentate ligands based on a cyclen platform incorporating two picolinate pendant arms (dodpa2? and Medodpa2?). The stability constants of the complexes were accessed by multiple methods (pH-potentiometry, direct and competition UV-vis spectrophotometry and 1H-relaxometry). The stability constants of the complexes formed with dodpa2? and Medodpa2? do not differ significantly (e.g. log K[Mn(dodpa)] = 17.40 vs. log K[Mn(Medodpa)] = 17.46, log K[Cu(dodpa)] = 24.34?25.17 vs. log K[Cu(Medodpa)] = 24.74 and log K[Gd(dodpa)]+ = 17.27 vs. log K[Gd(Medodpa)]+ = 17.59), which indicates that the steric hindrance brought by the methyl groups has no significant effect on the stability of the complexes. The stability constants of the Mn2+ complexes formed with the cyclen dipicolinates were found to be ca. 3 log K units higher than those determined for the complex of the cyclen monopicolinate (dompa?), which indicates that the second picolinate moiety attached to the backbone of the macrocycle is very likely coordinated to the Mn2+ ion. However, the stability of the [Cu(dodpa)] and [Cu(Medodpa)] complexes agrees well with the stability constant of [Cu(dompa)]+, in line with the hexadentate coordination around the metal ion observed in the X-ray structure of [Cu(Medodpa)]. The [Gd(dodpa)]+ and [Gd(Medodpa)]+ complexes display a fairly high kinetic inertness, as the rate constants of acid catalysed dissociation (k1 = 2.5(4) ? 10?3 and 8.3(4) ? 10?4 M?1 s?1 for [Gd(dodpa)]+ and [Gd(Medodpa)]+, respectively) are smaller than the value reported for [Gd(do3a)] (k1 = 2.5 ? 10?2 M?1 s?1). The [Mn(dodpa)] complex was found to be more inert than [Mn(Medodpa)]. The results of the diffusion-ordered NMR spectroscopy (DOSY) and DFT calculations of diamagnetic [La(dodpa)]+ and [Lu(dodpa)]+ complexes indicate the formation of a trinuclear entity of the La complex in aqueous solution.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban cyclen-based ligand transition metal lanthanide picolinate pendant thermodynamic stability kinetic inertness
Megjelenés:	Dalton Transactions 44 (2015), p. 5017-5031. -
További szerzők:	Garda Zoltán (1989-) (vegyész) Ruscsák Erika (1989-) (vegyész) Esteban-Gómez, David Blas, Andrès de Rodríguez-Blas, Teresa Lima, Luís M. P. Beyler, Maryline Tripier, Raphaël Tircsó Gyula (1977-) (vegyész, kémia tanár) Platas-Iglesias, Carlos
Pályázati támogatás:	OTKA-84291 OTKA OTKA-109029 OTKA TÁMOP 4.2.2.A-11/1/KONV-2012-0043 TÁMOP János Bolyai Research Scholarship MTA COST TD1004 " Theragnostics Imaging and Therapy: An Action to Develop Novel Nano-sized Systems for Imaging-Guided Drug Delivery " Egyéb CM1006 European F-Element Network (EUFEN) Actions 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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