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001-es BibID:	BIBFORM076232
035-os BibID:	(WoS)000434245500054 (Scopus)85047071870
Első szerző:	Póta Kristóf
Cím:	Taking the next step toward inert Mn2+ complexes of open-chain ligands: the case of the rigid PhDTA ligand / Kristof Pota, Zoltán Garda, Ferenc Krisztián Kálmán, José Luis Barriada, David Esteban-Gómez, Carlos Platas-Iglesias, Imre Tóth, Ernő Brücher, Gyula Tircsó
Dátum:	2018
ISSN:	1144-0546 1369-9261
Megjegyzések:	In line with our research to find inert Mn(II) complexes as contrast agents for Magnetic Resonance Imaging, we have studied the aromatic?ring rigidified EDTA-analogue o-phenylenediamine-N,N,N',N'-tetraacetic acid (PhDTA). The protonation constants (Ki H) of PhDTA and stability constants of complexes formed between this open-chain ligand and several different biogenic metal ions (Ca2+, Mg2+, Zn2+, Cu2+, Mn2+) have been determined in 0.15 M NaCl at 25 ?C and compared with the values reported in the literature previously. Protonation constants are lower than those of the corresponding cis- and trans-CDTA complexes, which might be attributed to the electron withdrawing effect of the phenylene group. The lower total basicity of the ligand leads to lower stability constants for all the examined metal complexes. On the contrary, we have found that the conditional stability constants of [Mn(PhDTA)]2- and [Mn(trans- CDTA)]2- are approximately the same, as both complexes are 100% formed by pH 5 and their pM values are also comparable. The relaxivity of [Mn(PhDTA)]2- is nearly identical (r1 = 3.72 mM-1s-1) to that determined previously for the [Mn(trans-CDTA)]2- complex (r1 = 3.62 mM-1s-1), and its pH-dependence confirms the equilibrium model used for the fitting of the titration data. The results of kinetic studies of the metal exchange reactions reveal that the [Mn(PhDTA)]2- complex possesses a slightly better dissociation kinetics profile than [Mn(trans-CDTA)]2-, which has been tested in vivo recently (including human injections). The half-life of the dissociation of the complex near to physiological pH at 25 ?C is 19 hours. By using the rate constant calculated for the dissociation (pH=7.4, cCu2+=10 ?M) and the half-life of excretion (1.6 hour), the ratio of the dissociated complex is estimated to represent 8% of the injected dose. DFT studies reveal that the metal coordination environment of [Mn(PhDTA)]2- is very similar to that of [Mn(EDTA)]2-, both containing an inner-sphere water molecule. Cyclic voltammetry studies indicate that [Mn(PhDTA)]2- is slightly more resistant towards oxidation to the Mn3+ complex than the EDTA analogue.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	New Journal Of Chemistry. - 42 : 10 (2018), p. 8001-8011. -
További szerzők:	Garda Zoltán (1989-) (vegyész) Kálmán Ferenc K. (1978-) (vegyész) Barriada, José Luis Esteban-Gómez, David Platas-Iglesias, Carlos 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 GINOP-2.3.3-15-2016-00004 GINOP Bolyai János Kutatási Ösztöndíj Egyéb
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