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001-es BibID:	BIBFORM099499
035-os BibID:	(WoS)000747265100001 (Scopus)85123424554
Első szerző:	Csupász Tibor (1991-)
Cím:	A New Oxygen Containing Pyclen-Type Ligand as a Manganese(II) Binder for MRI and 52Mn PET Applications: Equilibrium, Kinetic, Relaxometric, Structural and Radiochemical Studies / Tibor Csupász, Dániel Szücs, Ferenc Krisztián Kálmán, Oldamur Hollóczki, Anikó Fekete, Dezső Szikra, Éva Tóth, Imre Tóth, Gyula Tircsó
Dátum:	2022
ISSN:	1420-3049
Megjegyzések:	A new pyclen-3,9-diacetate derivative ligand (H23,9-OPC2A) is synthesized possessing an etheric O-atom opposite to the pyridine ring, to improve the dissociation kinetics of its Mn(II) complex (pyclen = 3,6,9,15-tetraazabicyclo(9.3.1)pentadeca-1(15),11,13-triene). The new ligand is less basic than the N-containing analogue (H23,9-PC2A) due to the non-protonable O-atom. In spite of its lower basicity, the conditional stability of the (Mn(3,9-OPC2A)) (pMn = ?log(Mn(II)), cL = cMn(II) = 0.01 mM. pH = 7.4) remains unaffected (pMn = 8.69), compared to the (Mn(3,9-PC2A)) (pMn = 8.64). The (Mn(3,9-OPC2A)) possesses one water molecule, having a lower exchange rate with bulk solvents (kex298 = 5.3 ??0.4 ? 107 s?1) than (Mn(3,9-PC2A)) (kex298 = 1.26?108 s?1). These mild dif-ferences are rationalized by the density-functional theory (DFT) calculations. The acid assisted dissociation of (Mn(3,9-OPC2A)) is considerably slower (k1 = 2.81 ??0.07 M?1s?1) than that of the complexes of diacetates or bisamides of various 12-membered macrocycles and the parent H23,9-PC2A. The (Mn(3,9-OPC2A)) is inert in rat/human serum as confirmed by 52Mn labeling (nM range), as well as by relaxometry (mM range). However, a 600-fold excess of EDTA (pH = 7.4) or a mixture of essential metal ions, propagated some transchelation/transmetalation in 7 days. The H23,9-OPC2A is labeled efficiently with 52Mn at elevated temperatures, yet at 37 ?C the parent H23,9-PC2A performs slightly better. Ultimately, the H23,9-OPC2A shows advantageous features for further ligand designs for bifunctional chelators. A new pyclen-3,9-diacetate derivative ligand (H23,9-OPC2A) is synthesized possessing an etheric O-atom opposite to the pyridine ring to improve the dissociation kinetics of its Mn(II) complex (pyclen = 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene). The new ligand is less basic than the N-containing analogue (H23,9-PC2A) due to the non-protonable O-atom. In spite of its lower basicity, the conditional stability of the [Mn(3,9-OPC2A)] (pMn=-log[Mn(II)], cL=cMn(II)=0.01 mM. pH=7.4) remains unaffected (pMn=8.69) compared to the [Mn(3,9-PC2A)] (pMn=8.64). The [Mn(3,9-OPC2A)] possesses one water molecule, having a lower exchange rate with bulk solvent (kex298=5.3?0.4?107 s-1) than [Mn(3,9-PC2A)] (kex298=1.26?108 s-1). These mild differences are ration-alized by density-functional theory (DFT) calculations. The acid assisted dissociation of [Mn(3,9-OPC2A)] is considerably slower (k1=2.81?0.07 M-1s-1) than that of the complexes of diac-etates or bisamides of various 12-membered macrocycles and the parent H23,9-PC2A. The [Mn(3,9-OPC2A)] is inert in rat/human serum as confirmed by 52Mn labeling (nM range) as well as by relaxometry (mM range). However, 600-fold excess of EDTA (pH=7.4) or a mixture of es-sential metal ions propagated some transchelation/transmetalation in 7 days. The H23,9-OPC2A is labeled efficiently with 52Mn at elevated temperatures, yet at 37 oC the parent H23,9-PC2A per-forms slightly better. Altogether the H23,9-OPC2A shows advantageous features for further lig-and design for bifunctional chelators.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Molecules. - 27 (2022), p. 1-27. -
További szerzők:	Szücs Dániel (1994-) (gyógyszerész) Kálmán Ferenc K. (1978-) (vegyész) Hollóczki Oldamur (1983-) (okleveles vegyészmérnök) Fekete Anikó (1973-) (vegyész) Szikra Dezső Péter (1983-) (vegyész) Tóth Éva Tóth Imre (1950-) (vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:	K-120224 OTKA K-128201 OTKA K-134694 OTKA FK-134551 OTKA University of Debrecen Innovation Fund (POC-012) Egyéb the János Bolyai Research Scholarship of the Hungarian Academy of Sciences MTA ÚNKP-21-4 new national excellence program of the Ministry of Human Capacities Egyéb Doctoral School of Chemistry at the University of Debrecen Egyéb
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001-es BibID:	BIBFORM076231
Első szerző:	Molnár Enikő (vegyész)
Cím:	Remarkable differences and similarities between the isomeric Mn(II)-cis- and trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetate complexes / Enikő Molnár, Balázs Váradi, Zoltán Garda, Richárd Botár, Ferenc K. Kálmán, Éva Tóth, Imre Tóth, Ernő Brücher, Gyula Tircsó
Dátum:	2018
ISSN:	0020-1693
Megjegyzések:	Equilibrium, kinetic (solvent exchange and dissociation of the complex) and relaxometric studies (1H and 17O NMR) have been performed with the [M(II)(c-cdta)]2 complexes (c-cdta = cis-1,2-diaminocyclohexane- N,N,N0 ,N0-tetraacetic acid, M(II) = Mn(II), Zn(II), Cu(II),Ca(II), Mg(II)) and the physico-chemical data are compared to the isomeric complexes with trans-1,2-cdta (t-cdta) with the aim of searching appropriate ligands for Mn(II) complexation for safe MRI contrast agents. The total basicity (R log Ki H) of the c-cdta ligand appears to be very similar to that of the trans-derivative under the conditions applied (I = 0.15 M NaCl and 25 C), but the first two protonation constants notably differ. log K1 H is 1.5 log units higher, while the log K2 H is 0.8 log units lower than those determined for the trans-derivative. Similar basicity of the ligands results in similar complex stability (log K[Mn(L)] values are 14.19(2) and 14.32), whereas the conditional stabilities near to physiological pH are different (pMn values are 7.82 and 8.68) for the [Mn (c-cdta)]2 and the [Mn(t-cdta)]2 derivatives, respectively. Dissociation kinetic studies revealed that the [Mn(c-cdta)]2 dissociates 250 times faster than the [Mn(t-cdta)]2 complex. The water exchange rate (kex 298) of [Mn(c-cdta)]2 is ca. 60% higher than that of [Mn(t-cdta)]2 . The differences can likely be attributed to the different distances between the individual donor atoms, and the arrangement of the donor atoms around the metal ions in the cis- and trans- isomers. Interestingly, the relaxivity values of the Mn (II) complexes are very close (r1p = 3.79 mM 1 s 1 and 3.62 mM 1 s 1; 20 MHz, 25 C for the cis- and trans-isomers, respectively). DFT calculations were used to gain insight into the different properties of the [Mn(c-cdta)]2 and the [Mn(t-cdta)]2 complexes. The results gained in our studies confirm that the trans-1,2-cyclohexanediamine ♭♭building block" displays better features for further ligand development.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Inorganica Chimica Acta. - 472 : 1 (2018), p. 254-263. -
További szerzők:	Váradi Balázs (1990-) (vegyész) Garda Zoltán (1989-) (vegyész) Botár Richárd (1992-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Tóth Éva Tóth Imre (1950-) (vegyész) Brücher Ernő (1935-) (vegyész) Tircsó Gyula (1977-) (vegyész, kémia tanár)
Pályázati támogatás:	OTKA K-120224 OTKA GINOP-2.3.2-15-2016-00008 GINOP
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