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001-es BibID:BIBFORM067302
035-os BibID:(WoS)000388546800022 (Scopus)84993990174
Első szerző:Garda Zoltán (vegyész)
Cím:Physico-chemical properties of MnII complexes formed with cis- and trans-DO2A : thermodynamic, electrochemical and kinetic studies / Zoltán Garda, Attila Forgács, Quyen N. Do, Ferenc K. Kálmán, Sarolta Timári, Zsolt Baranyai, Lorenzo Tei, Imre Tóth, Zoltán Kovács, Gyula Tircsó
Dátum:2016
ISSN:0162-0134 1873-3344
Megjegyzések:Manganese (MnII) is a promising alternative to gadolinium (GdIII) as a magnetic resonance imaging (MRI) agent. Unlike gadolinium, this biogenic metal might be better tolerated by the body, reducing the risk of toxicity associated with dissociation of the complex. Herein we report detailed equilibrium and kinetic studies performed with MnII complexes of 1,4,7,10-tetraazacyclododecane-1,4-diacetic acid (1,4-DO2A or cis-DO2A) and 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (1,7-DO2A or trans-DO2A). The protonation constants of the ligands as well as stability constants of their MnII complexes have been determined by pH-potentiometry. The stability constants of [Mn(cis-DO2A)] are slightly higher than those of [Mn(trans-DO2A)] (log KMnL = 15.68 and 15.22, respectively). Cyclic voltammetric (CV) experiments performed on [Mn(cis-DO2A)] and [Mn(trans-DO2A)] revealed quasireversible systems with a half-wave potential of + 636 and + 705 mV versus Ag/AgCl, respectively. These values indicate that the MnII ion in these complexes is more stabilized against the oxidation than in [Mn(EDTA)]2 ?. The kinetic inertness of the complexes has been studied in transmetallation reactions with CuII or ZnII ions. Kinetic measurements indicate that both MnII complexes primarily undergo acid catalyzed dissociation and positions of the acetate pendant arms do not influence kinetic inertness. The inertness of these complexes is comparable to that of [Mn(NOTA)]? (NOTA = 1,4,7-triazacyclononane-1,4,7-triacetic acid) and about twenty times lower than that of [Mn(DOTA)]2 ? (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid). In conclusion, [Mn(cis-DO2A)] displays some very interesting features (thermodynamic and redox stability as well as kinetic inertness) which makes this complex a promising platform for the development of more efficient MnII complexes as alternatives to Gd-based MRI agents.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Magnetic resonance imaging
Contrast agents (CAs)
Manganese
Thermodynamic stability
Inertness
Electrochemistry
Megjelenés:Journal of Inorganic Biochemistry. - 163 (2016), p. 206-213. -
További szerzők:Forgács Attila (1988-) (vegyész) Do, Quyen N. (1975-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Timári Sarolta (1984-) (vegyész, kémia tanár) Baranyai Zsolt (1977-) (vegyész) Tei, Lorenzo Tóth Imre (1950-) (vegyész) Kovács Zoltán (1963-) (vegyész, angol szakfordító) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:OTKA-84291
OTKA
OTKA-109029
OTKA
TÁMOP 4.2.4. A/2-11-1-2012-0001
TÁMOP
COST TD1004 Action "Theragnostics Imaging and Therapy: An Action to Develop Novel Nanosized Systems for Imaging-Guided Drug Delivery"
Egyéb
Bólyai János Kutatási Ösztöndíj
MTA
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DOI
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2.

001-es BibID:BIBFORM103942
035-os BibID:(WOS)000528630900017 (Scopus)85080905990
Első szerző:Tircsó Gyula (vegyész, kémia tanár)
Cím:Comparison of the equilibrium, kinetic and water exchange properties of some metal ion-DOTA and DOTA-bis(amide) complexes / Gyula Tircsó, Enikő Tircsóné Benyó, Zoltán Garda, Jaspal Singh, Robert Trokowski, Ernő Brücher, A. Dean Sherry, Éva Tóth, Zoltán Kovács
Dátum:2020
ISSN:0162-0134 1873-3344
Megjegyzések:The 1,7-diacetate-4,10-diacetamide substituted 1,4,7,10-tetraazacyclododecane structural unit is common to several responsive Magnetic Resonance Imaging (MRI) contrast agents (CAs). While some of these complexes (agents capable of sensing fluctuations in Zn2+, Ca2+ etc. ions) have already been tested in vivo, the detailed physico-chemical characterization of such ligands have not been fully studied. To fill this gap, we synthesized a representative member of this ligand family possessing two acetate and two n-butylacetamide pendant side-arms (DO2A2M(nBu) = 1,4,7,10-tetraazacyclodoecane-1,7-di(acetic acid)-4,10-di(N-butylacetamide)), and studied its complexation properties with some essential metal and a few lanthanide(III) (Ln(III)) ions. Our studies revealed that the ligand basicity, the stability of metal ion complexes, the trend of stability constants along the Ln(III) series, the formation rates of the Ln(III) complexes and the exchange rate of the bound water molecule in the Gd (III) complex fell between those of Ln(DOTA) - and Ln(DOTA-tetra(amide))(3+) complexes (DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, DOTAM = 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane). The only exception is the stability of Cu(DO2A2M(nBu)) which was found to be only slightly lower than that of Cu(DOTA)(2-) (log K-CuL = 19.85 vs. 21.98). This is likely reflects exclusive coordination of the negatively charged acetate donor atoms to the Cu2+ ion forming an octahedral complex with the amides remaining uncoordinated. The only anomaly observed during the study was the rates of acid assisted dissociation of the Ln(III) complexes, which occur at a rate similar to those observed for the Ln(DOTA)(-) complexes. These data indicate that even though the Ln(DO2A2M(nBu))(+) complexes have lower thermodynamic stabilities, their kinetic inertness should be sufficient for in vivo use.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény hazai lapban
folyóiratcikk
Coordination chemistry
Complexes
Physico-chemical parameters
Synthesis
Stability
Inertness
Water exchange rate
Megjelenés:Journal of Inorganic Biochemistry. - 206 (2020), p. 1-12. -
További szerzők:Tircsóné Benyó Enikő (1977-) (vegyész, kémia tanár) Garda Zoltán (1989-) (vegyész) Singh, Jaspal Trokowski, Robert Brücher Ernő (1935-) (vegyész) Sherry, A. Dean Tóth Éva Kovács Zoltán
Pályázati támogatás:NKFIH-K-120224
Egyéb
NKFIH-128201
Egyéb
GINOP-2.3.2-15-2016-00008
GINOP
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DOI
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3.

001-es BibID:BIBFORM047601
035-os BibID:PMID:23850669
Első szerző:Tircsó Gyula (vegyész, kémia tanár)
Cím:Lanthanide(III) complexes of some natural siderophores : a thermodynamic, kinetic and relaxometric study / Gyula Tircsó, Zoltán Garda, Ferenc K. Kálmán, Zsolt Baranyai, István Pócsi, György Balla, Imre Tóth
Dátum:2013
ISSN:0162-0134
Megjegyzések:Stability constants of the complexes formed between the natural trihydroxamic acids desferrioxamine B (DFB) and desferricoprogen (DFC) with NdIII, GdIII and YbIII ions were determined using pH-potentiometry. The equilibrium in these systems can be described by models containing mononuclear protonated (Ln(HL), Ln(H2L) and Ln(H3L)), deprotonated (LnL) and ternary hydroxo Ln(H-1L) complexes, but for both ligands dinuclear complexes of low stability were also detected. The stability constants for the Ln(HDFB)+ complexes are 11.95 (NdIII), 13.16 (GdIII) and 14.67 (YbIII), while these values of the Ln(DFC) complexes are considerably higher (14.42 (NdIII), 15.14 (GdIII) and 16.49 (YbIII)). The stability constants of the complexes of DFB and DFC are much lower than those of the Ln(L)3 complexes formed with some aromatic hydroxamic acids indicating that the relatively long spacer between the hydroxamic acid moieties in DFB and DFC is unfavorable for LnIII complexation. The relaxometric study conducted for the Gd(HDFB)+ species revealed an interesting pH dependence of the relaxivity associated with a large hydration number (bishydrated complex) and fast water exchange (kex=(29.9±0.4)x106s-1), which would be favorable for CA use. However the dissociation of Gd(HDFB)+ is fairly fast (<2ms) under all conditions employed in the present work thus the kinetically labile Gd(HDFB)+ is not suitable for in vivo CA applications. Some low stability ternary complexes were also detected with K(Gd(HDFB)(HCO3))=17.5±1.9 and K(Gd(HDFB)(Lactate))=8.4±3.2 but in the presence of citrate and phosphate ions the Gd(HDFB)+ complex was found to dissociate.
Tárgyszavak:Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Equilibrium
Kinetic inertness
Ln(III) complexes
Natural siderophores
Relaxivity
Water exchange rate
Megjelenés:Journal of Inorganic Biochemistry. - 127 (2013), p. 53-61. -
További szerzők:Garda Zoltán (1989-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Baranyai Zsolt (1977-) (vegyész) Pócsi István (1961-) (vegyész) Balla György (1953-) (csecsemő és gyermekgyógyász, neonatológus) Tóth Imre (1950-) (vegyész)
Pályázati támogatás:TÁMOP-4.2.2.A-11/1/KONV-2012-0045
TÁMOP
Gyermekgyógyászat Kutatócsoport
OTKA-K75883
OTKA
MTA-DE
MTA-DE Vascularis Biológia, Thrombosis- Haemostasis Kutatócsoport 11003
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