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001-es BibID:	BIBFORM062902
Első szerző:	Kálmán Ferenc K. (vegyész)
Cím:	H4octapa: Highly Stable Complexation of Lanthanide(III) Ions and Copper(II) / Ferenc Krisztián Kálmán, Andrea Végh, Martín Regueiro-Figueroa, Éva Tóth, Carlos Platas-Iglesias, Gyula Tircsó
Dátum:	2015
ISSN:	0020-1669
Megjegyzések:	The acyclic ligand octapa4 (H4octapa = 6,6'-((ethane-1,2-diylbis((carboxymethyl)azanediyl))bis(methylene))dipicolinic acid) forms stable complexes with the Ln3+ ions in aqueous solution. The stability constants determined for the complexes with La3+, Gd3+ and Lu3+ using relaxometric methods are logKLaL = 20.13(7), logKGdL = 20.23(4) and logKLuL = 20.49(5) (I = 0.15 M NaCl). High stability constants were also determined for the complexes formed with divalent metal ions such as Zn2+ and Cu2+ (logKZnL = 18.91(3) and logKCuL = 22.08(2)). A UV-Vis and NMR spectroscopic study and DFT calculations point to hexadentate binding of the ligand to Zn2+ and Cu2+, the donor atoms of the acetate groups of the ligand remaining uncoordinated. The complexes formed with the Ln3+ ions are nine-coordinated thanks to the octadentate binding of the ligand and the presence of a coordinated water molecule. The stability constants of the complexes formed with the Ln3+ ions do not change significantly across the lanthanide series. A DFT investigation shows that this is the result of a subtle balance between the increased binding energies across the 4f period, which contribute to an increasing complex stability, and the parallel increase of the absolute values of the hydration free energies of the Ln3+ ions. In the case of the [Ln(octapa)(H2O)] complexes the interaction between the amine nitrogen atoms of the ligand and the Ln3+ ions is weakened along the lanthanide series, and therefore the increased electrostatic interaction does not overcome the increasing hydration energies. A detailed kinetic study of the dissociation of the [Gd(octapa)(H2O)] complex in the presence of Cu2+ shows that the metal-assisted pathway is the main responsible for complex dissociation at pH 7.4 and physiological [Cu2+] concentration (1 uM).
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Magnetic Resonance Imaging Complexes Equilibrium Kinetics DFT calculation
Megjelenés:	Inorganic Chemistry. - 54 : 5 (2015), p. 2345-2356. -
További szerzők:	Végh Andrea (vegyész) Regueiro-Figueroa, Martín Tóth Éva (1967-) (koordinációs kémia) Platas-Iglesias, Carlos Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:	Centro de Supercomputación de Galicia (CESGA) Egyéb COST Actions CM1006 "European F-Element Network (EuFen)" and TD1004 "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery" Egyéb K-84291 OTKA K-109029 OTKA Hungarian-French bilateral Scientific and Technological Cooperation (project # TÉT_11-2-2012-0010 and PHC Balaton) Egyéb János Bolyai Research Scholarship of the Hungarian Academy of Sciences. MTA TÁMOP 4.2.2.A-11/1/KONV-2012-0043 TÁMOP
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