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1.

001-es BibID:BIBFORM112577
035-os BibID:(WoS)000431833500088 (Scopus)85046700183
Első szerző:Aime, Silvio
Cím:Exploiting the Proton Exchange as an Additional Route to Enhance the Relaxivity of Paramagnetic MRI Contrast Agents / Silvio Aime, Simona Baroni, Daniela Delli Castelli, Ernő Brücher, Istvan Fábián, Sonia Colombo Serra, Alberto Fringuello Mingo, Roberta Napolitano, Luciano Lattuada, Fabio Tedoldi, Zsolt Baranyai
Dátum:2018
ISSN:0020-1669 1520-510X
Megjegyzések:The relaxivity of Gd(HP-DO3A) was studied as a function of pH and buffer composition in order to identify the main factors of the observed relaxation enhancement due to the exchange of the coordinated hydroxyl proton. It was established that the paramagnetic relaxation time, T1M, of the coordinated hydroxyl proton is about 50% shorter than that of the protons in the coordinated water molecule. The control of the pK of the coordinated alcoholic ?OH moiety in the ligand is fundamental to utilize the proton exchange enhanced relaxivity under physio/pathologic conditions. A new derivative of Gd(HP-DO3A) was synthesized by replacing the ?CH3 group with a ?CF3 moiety. In this complex, the ?OH group becomes more acidic. Consequently, the maximum contribution of the proton exchange to the relaxivity is shifted to a lower pH region with the fluorinated ligand.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
relaxivity
MRI
proton exchange
Megjelenés:Inorganic Chemistry. - 57 : 9 (2018), p. 5567-5574. -
További szerzők:Baroni, Simona Castelli, Daniela Delli Brücher Ernő (1935-) (vegyész) Fábián István (1956-) (vegyész) Serra, Sonia Colombo Fringuello Mingo, Alberto Napolitano, Roberta Lattuada, Luciano Tedoldi, Fabio Baranyai Zsolt
Pályázati támogatás:124983
OTKA
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2.

001-es BibID:BIBFORM081486
Első szerző:Baranyai Zsolt (vegyész)
Cím:The Role of Equilibrium and Kinetic Properties in the Dissociation of Gd[DTPA-bis(methylamide)] (Omniscan) at near to Physiological Conditions / Zsolt Baranyai, Ernő Brücher, Fulvio Uggeri, Alessandro Maiocchi, Imre Tóth, Melinda Andrási, Attila Gáspár, László Zékány, Silvio Aime
Dátum:2015
ISSN:0947-6539 1521-3765
Megjegyzések:[Gd(DTPA?BMA)] is the principal constituent of Omniscan, a magnetic resonance imaging (MRI) contrast agent. In body fluids, endogenous ions (Zn2+, Cu2+, and Ca2+) may displace the Gd3+. To assess the extent of displacement at equilibrium, the stability constants of DTPA?BMA3? complexes of Gd3+, Ca2+, Zn2+, and Cu2+ have been determined at 37?°C in 0.15?M NaCl. The order of these stability constants is as follows: GdL?CuL>ZnL?CaL. Applying a simplified blood plasma model, the extent of dissociation of Omniscan (0.35?mM [Gd(DTPA?BMA)]) was found to be 17?% by the formation of Gd(PO4), [Zn(DTPA?BMA)]? (2.4?%), [Cu(DTPA?BMA)]? (0.2?%), and [Ca(DTPA?BMA)]? (17.7?%). By capillary electrophoresis, the formation of [Ca(DTPA?BMA)]? has been detected in human serum spiked with [Gd(DTPA?BMA)] (2.0?mM) at pH?7.4. Transmetallation reactions between [Gd(DTPA?BMA)] and Cu2+ at 37?°C in the presence of citrate, phosphate, and bicarbonate ions occur by dissociation of the complex assisted by the endogenous ligands. At physiological concentrations of citrate, phosphate, and bicarbonate ions, the half?life of dissociation of [Gd(DTPA?BMA)] was calculated to be 9.3?h at pH?7.4. Considering the rates of distribution and dissociation of [Gd(DTPA?BMA)] in the extracellular space of the body, an open two?compartment model has been developed, which allows prediction of the extent of dissociation of the GdIII complex in body fluids depending on the rate of elimination of the contrast agent.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
complex stability
gadolinium
kinetics
magnetic
resonance imaging
reaction mechanisms
Megjelenés:Chemistry-A European Journal. - 21 : 12 (2015), p. 4789-4799. -
További szerzők:Brücher Ernő (1935-) (vegyész) Uggeri, Fulvio Maiocchi, Alessandro (vegyész) Tóth Imre (1950-) (vegyész) Andrási Melinda (1979-) (gyógyszerész) Gáspár Attila (1970-) (vegyész, kémikus) Zékány László (1948-) (vegyész) Aime, Silvio
Pályázati támogatás:TÁMOP 4.2.4. A/2-11-1-2012-0001
TÁMOP
A2-MZPD-12-0038
Egyéb
OTKA K109029
OTKA
OTKA K111932
OTKA
OTKA PD83071
OTKA
TÁMOP-4.2.2 A-11/1/KONV-2012-0043
TÁMOP
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3.

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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4.

001-es BibID:BIBFORM008188
Első szerző:Baranyai Zsolt (vegyész)
Cím:Equilibrium and kinetic properties of the lanthanoids(III) and varioous divalent metal complexes of the heptadentate ligand AAZTA / Zsolt Baranyai, Fulvio Uggeri, Giovanni B. Giovenzana, Attila Bényei, Ernő Brücher, Silvio Aime
Dátum:2009
Megjegyzések:The heptadentate ligand 1,4-bis(hydroxycarbonylmethyl)-6-[bis(hy-droxycarbonylmethyl)]amino-6-methyl-perhydro-1,4-diazepine (AAZTA) and its derivatives were recently reported to give stable complexes with Gd3+ with superior efficiency as MRI contrast agents. Nevertheless, only preliminary data are available on the coordination behavior of this interesting ligand. In this work, thermodynamic and kinetic stability data are determined for the formation of complexes with AAZTA and the lanthanoid metal ions, and other divalent metal ions of interest for this application. The AAZTA ligand binds the lanthanoid ions with logKML values of 17.53-21.85 with its affinity steadily increasing from La3+ to Lu3+, suggesting that the seven-membered skeleton is better suited to accommodate smaller metal ions. Even though the denticity is lower, the stability of the heavier lanthanoid complexes is comparable to those of the classical ligand diethylene-triaminepentaacetic acid (DTPA). The transmetalation reactions of [Gd-(AAZTA)] with Cu2+ and Eu3+ predominantly occur through proton-assisted dissociation of the complex. The role of the direct attack of Cu2+ or Eu3+ in the exchange reactions is limited, although the formation of dinuclear complexes decreases the proton-assisted dissociation. Near physiological conditions, [Gd(AAZTA)] is significantly more inert than [Gd(DTPA)]2-, allowing its potentially safe use as contrast agent in magnetic resonance imaging.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
kinetics
lanthanides
Megjelenés:Chemistry-A European Journal. - 15 : 7 (2009), p. 1691-1705. -
További szerzők:Uggeri, Fulvio Giovenzana, Giovanni Battista Bényei Attila (1962-) (vegyész) Brücher Ernő (1935-) (vegyész) Aime, Silvio
Internet cím:DOI
elektronikus változat
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5.

001-es BibID:BIBFORM003002
Első szerző:Baranyai Zsolt (vegyész)
Cím:The effects of intramolecular H-bond formation on the stability constant and water exchange rate of the Gd(III)-diethylenetriamine-N'-(3-amino-1,1-propylenephosphonic)-N,N,N'',N''-tetraacetate complex / Zsolt Baranyai, Eliana Gianolio, Kondareddiar Ramalingam, Rolf Swenson, Ramachandran Ranganathan, E. Brücher, Silvio Aime
Dátum:2007
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Contrast Media & Molecular Imaging. - 2 : 2 (2007), p. 94-102. -
További szerzők:Gianolio, Eliana Ramalingam, Kondareddiar Swenson, Rolf Ranganathan, Ramachandran Brücher Ernő (1935-) (vegyész) Aime, Silvio
Internet cím:elektronikus változat
elektronikus változat
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6.

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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7.

001-es BibID:BIBFORM069142
Első szerző:Takács Anett
Cím:Solution Structures, Stabilities, Kinetics, and Dynamics of DO3A and DO3A-Sulphonamide Complexes / Anett Takács, Roberta Napolitano, Mihály Purgel, Attila Csaba Bényei, László Zékány, Ernő Brücher, Imre Tóth, Zsolt Baranyai, Silvio Aime
Dátum:2014
ISSN:0020-1669
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Inorganic Chemistry. - 53 : 6 (2014), p. 2858-2872. -
További szerzők:Napolitano, Roberta Purgel Mihály (1982-) (vegyész) Bényei Attila (1962-) (vegyész) Zékány László (1948-) (vegyész) Brücher Ernő (1935-) (vegyész) Tóth Imre (1950-) (vegyész) Baranyai Zsolt (1977-) (vegyész) Aime, Silvio
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