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001-es BibID:	BIBFORM047932
Első szerző:	Baranyai Zsolt (vegyész)
Cím:	Equilibrium, Kinetic and Structural Studies of AAZTA Complexes with Ga3+, In3+ and Cu2+ / Zsolt Baranyai, Fulvio Uggeri, Alessandro Maiocchi, Giovanni B. Giovenzana, Camilla Cavallotti, Anett Takács, Imre Tóth, István Bányai, Attila Bényei, Ernő Brücher, Silvio Aime
Dátum:	2013
Megjegyzések:	A detailed study of the structures, thermodynamic stabilities and kinetics of the dissociation of Ga3+, In3+ and Cu2+ complexes formed with the heptadentate ligand AAZTA is reported. The stability constants (logKML) of the AAZTA complexes of Ga3+, In3+ and Cu2+ are 22.18, 29.58 and 22.27, respectively, which suggests that the seven-membered-ring skeleton is suited to the accommodation of these metal ions. The solid-state structure of Cu(H2AAZTA)]?H2O shows a distorted octahedral coordination. The equatorial coordination sites of Cu2+ are occupied by one of the ring N atoms, a water O atom, one of the carboxylate O atoms and the N atom of the iminodiacetate moiety. The other ring N atom and thecarboxylate O atom of the iminodiacetate moiety coordinate to the Cu2+ in the axial positions. In the pH range 4.5?8.5, Ga3+ is present in the form of the highly stable [Ga(AAZTA)OH]2? (log ?GaLH?1 = 17.69) The exchange reactions of [Ga(AAZTA)OH]2? with Cu2+ and transferrin are very slow and mainly occur through the spontaneous dissociation of the complex close to physiological conditions. The half-life for the dissociation of [Ga(AAZTA)OH]2? is t1/2 = 23 h at pH = 7.5 and 25 ?C in 0.025 M NaHCO3 and 0.15 M NaCl. The high conditional stability, fast formation and sufficiently slow dissociation of [Ga(AAZTA)OH]2? represent promising properties for the complexation and diagnostic applications of radioactive Ga isotopes.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Gallium Indium Copper Complexation Thermodynamics Kinetics Radiopharmaceuticals Imaging agents Molekulatudomány Doktori iskola
Megjelenés:	European Journal Of Inorganic Chemistry. - 2013 : 1 (2013), p. 147-162. -
További szerzők:	Uggeri, Fulvio Maiocchi, Alessandro (vegyész) Giovenzana, Giovanni Battista Cavallotti, Camilla Takács Anett Tóth Imre (1950-) (vegyész) Bányai István (1953-) (vegyész) Bényei Attila (1962-) (vegyész) Brücher Ernő (1935-) (vegyész) Aime, Silvio
Pályázati támogatás:	K-84291 OTKA TÁMOP-4.2.1/B-09/1/KONV-2010-0007 TÁMOP Bimodális kontrasztanyagok tervezése, előállítása és komplexeik fizikai-kémiai tulajdonságaik jellemzése TÁMOP-4.2.2/B-10/1-2010-0024 TÁMOP Kémiai Tudományok Doktori Iskola EU COST (TD1004) "Theragnostics Imaging and Therapy" Action Program. Egyéb HU11MO2-TET_10-1-2011-0202 Egyéb
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001-es BibID:	BIBFORM002545
Első szerző:	Baranyai Zsolt (vegyész)
Cím:	Kinetics of the Formation of [Ln(DOTAM)]3+ Complexes / Zsolt Baranyai, István Bányai, Ernő Brücher, Róbert Király, Enzo Terreno
Dátum:	2007
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Macrocyclic ligands Lanthanides Kinetics Reaction mechanisms
Megjelenés:	European Journal Inorganic Chemistry. - 23 (2007), p. 3639-3645. -
További szerzők:	Brücher Ernő (1935-) (vegyész) Király Róbert (1947-) (vegyész) Terreno, Enzo Bányai István (1953-) (vegyész)
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001-es BibID:	BIBFORM006198
Első szerző:	Kálmán Ferenc K. (vegyész)
Cím:	Synthesis, potentiometric, kinetic, and NMR studies of 1,4,7,10-tetraazacyclododecane-1,7-bis(acetic acid)-4,10-bis(methylenephosphonic acid) (DO2A2P) and its complexes with Ca(II), Cu(II), Zn(II) and lanthanide(III) ions / Kalman, F. K., Baranyai, Z., Toth, I., Banyai, I., Kiraly, R., Brucher, E., Aime, S., Sun, X., Sherry, A. D., Kovacs, Z.
Dátum:	2008
ISSN:	0020-1669
Megjegyzések:	A cyclen-based ligand containing trans-acetate and trans-methylenephosphonate pendant groups, H(6)DO2A2P, was synthesized and its protonation constants (12.6, 11.43, 5.95, 6.15, 2.88, and 2.77) were determined by pH-potentiometry and H-1 NMR spectroscopy. The first two protonations were shown to occur at the two macrocyclic ring N-CH2-PO32- nitrogens while the third and fourth protonations occur at the two phosphonate groups. In parallel with protonation of the two -PO32- groups, the protons from the NH+-CH2-PO32- are transferred to the N-CH2-COO- nitrogens. The stability constants of the Ca2+, Cu2+, and Zn2+ (ML, MHL, MH2L, and M2L) complexes were determined by direct pH-potentiometry. Lanthanide(III) ions (Ln(3+)) form similar species, but the formation of complexes is slow; so, "out-of-cell" pH-potentiometry (La3+, Eu3+, Gd3+, Y3+) and competitive spectrophotometry with Cu(II) ion (Lu3+) were used to determine the stability constants. By comparing the log K-ML values with those of the corresponding DOTA (H(4)DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) and DOTP (H8DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid) complexes, the order DOTA < DO2A2P < DOTP was found for all the metal ion complexes examined here with the exception of the Ca2+ complexes, for which the order is reversed. The relaxivity of Gd(DO2A2P) decreases between pH 2 and 7 but remains constant in the pH range of 7 < pH < 12 (r(1) = 3.6 mM(-1) s(-1)). The linewiths of the O-17 NMR signals of water in the absence and presence of Gd(DO2A2P) (at pH = 3.45 and 8.5) between 274 and 350 K are practically the same, characteristic of a q = 0 complex. Detailed kinetic studies of the Ce3+ and Gd3+ complexes with DO2A2P showed that complex formation is slow and involves a high stability diprotonated intermediate Ln(H(2)DO2A2P). Rearrangement of the diprotonated intermediate into the final complex is an OH- assisted process but, unlike formation of Ln(DOTA) complexes, rearrangement of Ln(H(2)DO2A2P) also takes place spontaneously likely as a result of transfer of one of the protons from a ring nitrogen to a phosphonate group. The order of the OH- assisted formation rates of complexes is DOTA > DO2A2P > DOTP while the order of the proton assisted dissociation rates of the Gd3+ complexes is reversed, DOTP > DO2A2P > DOTA. H-1 and C-13 NMR spectra of Eu(DO2A2P) and Lu(DO2A2P) were assigned using two-dimensional correlation spectroscopy (2D COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear chemical shift correlation (HETCOR), and exchange spectroscopy (EXSY) NMR methods. Two sets of H-1 NMR signals were observed for Eu(DO2A2P) characteristic of the presence of two coordination isomers in solution, a twisted square antiprism (TSAP) and a square antiprism (SAP), in the ratio of 93% and 7%, respectively. Line shape analysis of the H-1 NMR spectra of Lu(DO2A2P) gave lower activation parameters compared to La(DOTP) for interconversion between coordination isomers. This indicates that the Ln(DO2A2P) complexes are less rigid probably due to the different size and spatial requireents of the carboxylate and phosphonate groups.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Inorganic Chemistry. - 47 : 9 (2008), p. 3851-3862. -
További szerzők:	Baranyai Zsolt (1977-) (vegyész) Tóth Imre (1950-) (vegyész) Bányai István (1953-) (vegyész) Király Róbert Brücher Ernő (1935-) (vegyész) Aime, Silvio Sun, Xiankai Sherry, A. Dean Kovács Zoltán
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001-es BibID:	BIBFORM016483
Első szerző:	Purgel Mihály (vegyész)
Cím:	An NMR and DFT Investigation on the Conformational Properties of Lanthanide(III) 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetate Analogues Containing Methylenephosphonate Pendant Arms / Mihály Purgel, Zsolt Baranyai, Andrés de Blas, Teresa Rodríguez-Blas, István Bányai, Carlos Platas-Iglesias, Imre Tóth
Dátum:	2010
ISSN:	0020-1669
Megjegyzések:	The conformational properties of lanthanide(III) complexes with the mono- and biphosphonate analogues of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA) are investigated by means of density functional theory (DFT) calculations and NMR spectroscopy Geometry optimizations performed at the B3LYP/6-31G(d) level and using a 46 + 4f(n) effective core potential for lanthanides provide two energy minima corresponding to the square-antiprismatic (SAP) and twisted square-antiprismatic (TSAP) geometries Our calculations give relative free energies between the SAP and TSAP isomers in fairly good agreement with the experimental values The SAP isomer presents the highest binding energy of the ligand to the metal ion, which further increases with respect to that of the TSAP isomer across the lanthanide senes as the charge density of the metal ion increases The stabilization of the TSAR isomer upon substitution of the acetate arms of DOTA by methylenephosphonate ones is attributed to the higher steric demand of the phosphonate groups and the higher strain of the ligand in the SAP isomer A H-1 NMR band-shape analysis performed on the [Ln(DO(2)A(2)P)](3-) (Ln = La and Lu) complexes provided the activation parameters for enantiomerization of the TSAP form of the complexes. The TSAP isomerization process was also investigated by using DFT calculations on the [Lu(DOTA)](-) and [Ln(DO(2)A(2)P)](3-) (Ln = La and Lu) systems. Our results confirm that enantiomerization requires both rotation of the pendant arms and inversion of the four five-membered chelate rings formed upon coordination of the macrocyclic unit According to our calculations, the arm rotation pathway in [Lu(DOTA)](-) is a one-step process involving the simultaneous rotation of the four acetate arms, while in the DO(2)A(2)P analogue, the arm-rotation process is a multistep path involving the stepwise rotation of each of the four pendant arms The calculated activation free energies are in reasonably good agreement with the experimental data A comparison of the experimental C-13 NMR shifts of [Ln(DO(2)A(2)P)](3-) (Ln=La and Lu) complexes and those calculated by using the GIAO method confirms that the major isomer observed in solution for these complexes corresponds to the TSAP isomer.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban mri contrast agents water exchange-rate macrocyclic polyamino carboxylates density-functional theory x-ray-diffraction aqueous-solution ab-initio coordination sphere gadolinium complexes crystal-structure
Megjelenés:	Journal of Biological Inorganic Chemistry. - 49 : 9 (2010), p. 4370-4382. -
További szerzők:	Baranyai Zsolt (1977-) (vegyész) de Blas, Andrés Rodríguez-Blas, Teresa Bányai István (1953-) (vegyész) Platas-Iglesias, Carlos Tóth Imre (1950-) (vegyész)
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